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Implementation of Open and Closed Kinetic Chain Quadriceps Strengthening Exercises after Anterior Cruciate Ligament Reconstruction.
ERIC Educational Resources Information Center
Reviews the effects of open kinetic chain (OKC) and closed kinetic chain (CKC) exercise on anterior cruciate ligament (ACL) strain and patellofemoral joint stress, suggesting a combination of the two for quadriceps strengthening after ACL reconstruction. Both OKC and CKC exercises may be modified and implemented for quadriceps strengthening after…
Ross, Michael D.; Denegar, Craig R.; Winzenried, Jay A.
Electromyographic normalization procedures for determining exercise intensity of closed chain exercises for strengthening the quadriceps femoris muscles.
The purpose of this study was to compare the electromyographic (EMG) amplitudes of the quadriceps femoris (QF) muscles during a maximum voluntary isometric contraction (MVIC) to submaximal and maximal dynamic concentric contractions during active exercises. A secondary purpose was to provide information about the type of contraction that may be most appropriate for normalization of EMG data if one wants to determine if a lower extremity closed chain exercise is of sufficient intensity to produce a strengthening response for the QF muscles. Sixty-eight young healthy volunteers (39 female, 29 male) with no lower extremity pain or injury participated in the study. Surface electrodes recorded EMG amplitudes from the vastus medialis obliquus (VMO), rectus femoris (RF), and vastus lateralis (VL) muscles during 5 different isometric and dynamic concentric exercises. The last 27 subjects performed an additional 4 exercises from which a second data set could be analyzed. Maximum isokinetic knee extension and moderate to maximum closed chain exercises activated the QF significantly more than a MVIC. A 40-cm. lateral step-up exercise produced EMG amplitudes of the QF muscles of similar magnitude as the maximum isokinetic knee extension exercises and would be an exercise that could be considered for strengthening the QF muscles. Most published EMG studies of exercises for the QF have been performed by comparing EMG amplitudes during dynamic exercises to a MVIC. This procedure can lead one to overestimate the value of a dynamic exercise for strengthening the QF muscles. We suggest that when studying the efficacy of a dynamic closed chain exercise for strengthening the QF muscles, the exercise be normalized to a dynamic maximum muscle contraction such as that obtained with knee extension during isokinetic testing. PMID:22310511
Ekstrom, Richard A; Osborn, Roy W; Goehner, Heather M; Moen, Adam C; Ommen, Brian M; Mefferd, Michael J; Bergman, Thomas R; Molencamp, Timothy B; Kelsey, Steven A
The Effect of Quadriceps Femoris Muscle Strengthening Exercises on Spasticity in Children With Cerebral Palsy
Background and Purpose. The Bobath neurodevelopmental treatment approach advised against the use of resistive exercise, as proponents felt that increased effort would increase spasticity. The purpose of this study was to test the premise that the performance of exercises with maximum efforts will increase spasticity in people with cerebral palsy (CP). Spasticity, in the present study, was defined as a
Eileen G Fowler; Teresa W Ho; Azuka I Nwigwe; Fredrick J Dorey
Effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain: randomised controlled trial
Objective To determine whether dietary intervention or knee strengthening exercise, or both, can reduce knee pain and improve knee function in overweight and obese adults in the community. Design Pragmatic factorial randomised controlled trial. Setting Five general practices in Nottingham. Participants 389 men and women aged 45 and over with a body mass index (BMI) of ?28.0 and self reported knee pain. Interventions Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; advice leaflet only (control group). Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 2.5 MJ (600 kcal) a day. Interventions were delivered at home visits over a two year period. Main outcome measures The primary outcome was severity of knee pain scored with the Western Ontario McMaster (WOMAC) osteoarthritis index at 6, 12, and 24 months. Secondary outcomes (all at 24 months) included WOMAC knee physical function and stiffness scores and selected domains on the SF-36 and the hospital anxiety and depression index. Results 289 (74%) participants completed the trial. There was a significant reduction in knee pain in the knee exercise groups compared with those in the non-exercise groups at 24 months (percentage risk difference 11.61, 95% confidence interval 1.81% to 21.41%). The absolute effect size (0.25) was moderate. The number needed to treat to benefit from a ?30% improvement in knee pain at 24 months was 9 (5 to 55). In those randomised to knee exercise improvement in function was evident at 24 months (mean difference ?3.64, ?6.01 to ?1.27). The mean difference in weight loss at 24 months in the dietary intervention group compared with no dietary intervention was 2.95 kg (1.44 to 4.46); for exercise versus no exercise the difference was 0.43 kg (?0.82 to 1.68). This difference in weight loss was not associated with improvement in knee pain or function but was associated with a reduction in depression (absolute effect size 0.19). Conclusions A home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain. A moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression but is without apparent influence on pain or function. Trial registration Current Controlled Trials ISRCTN 93206785.
Comparative Study of Hamstring and Quadriceps Strengthening Treatments in the Management of Knee Osteoarthritis
[Purpose] Osteoarthritis (OA) of the knee is the most common form of joint disease. It is one of the major causes of impaired function that reduces quality of life (QOL) worldwide. The purpose of this study was to compare exercise treatments for hamstring and quadriceps strength in the management of knee osteoarthritis. [Subjects and Methods] Forty patients with OA knee, aged 50–65 years were divided into 2 groups. The first group (57.65±4.78 years) received hot packs and performed strengthening exercises for the quadriceps and hamstring, and stretching exercises for the hamstring. The second group (58.15±5.11 years) received hot packs and performed strengthening exercises for only the quadriceps, and stretching exercise for the hamstring. Outcome measures were the WOMAC (Western Ontario and McMaster Universities OA index questionnaire), Visual Analogue Scale (VAS) assessment of pain, the Fifty-Foot Walk Test (FWS), and Handheld dynamometry. [Results] There was a significant difference between the groups. The first group showed a more significant result than the second group. [Conclusion] Strengthening of the hamstrings in addition to strengthening of the quadriceps was shown to be beneficial for improving subjective knee pain, range of motion and decreasing the limitation of functional performance of patients with knee osteoarthritis.
Al-Johani, Ahmed H; Kachanathu, Shaji John; Ramadan Hafez, Ashraf; Al-Ahaideb, Abdulaziz; Algarni, Abdulrahman D; Meshari Alroumi, Abdulmohsen; Alanezi, Aqeel M.
Safe and effective quadriceps femoris muscle exercise of resisted front bridge with a leg support in patients with anterior cruciate ligament insufficiency
BackgroundMuscle strengthen exercise of quadriceps femoris is important but risky to the anterior cruciate ligament (ACL) graft, because quadriceps muscle exercise near the knee extension may causes anterior tibial translation. We developed a new exercise method, 'resisted front bridge exercise with a leg support at proximal tibia' (RFBP) in a prone position to avoid a risk. Our hypothesis is that
N Nakae; M Koyanagi; M Sato; T Sakai; Y Kimura; K Hidaka; K Nakata
Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises.
Study Design Single-group, repeated-measures design. Objective To compare patellofemoral joint (PFJ) stress among weight-bearing and non-weight-bearing quadriceps exercises. Background An important consideration when prescribing exercises to strengthen the quadriceps in persons with patellofemoral pain is to minimize PFJ loading. Currently, there is disagreement in the literature as to which exercises and ranges of motion best accomplish this goal. Methods Ten healthy subjects participated. Lower extremity kinematics, kinetics, and electromyography of the knee musculature were obtained during a weight-bearing squatting exercise and 2 non-weight-bearing knee extension exercises: (1) knee extension with variable resistance, and (2) knee extension with constant resistance. A previously described biomechanical model was used to estimate PFJ stress at 0°, 15°, 30°, 45°, 60°, 75°, and 90° of knee flexion. PFJ stress was compared among the 3 exercises using a 2-way analysis of variance with repeated measures. Results Compared to the 2 non-weight-bearing exercises, the squat exercise produced significantly higher PFJ stress at 90°, 75°, and 60° of knee flexion. Conversely, the 2 non-weight-bearing exercises produced significantly higher PFJ stress at 30°, 15°, and 0° of knee flexion when compared to the squat exercise. The knee-extension-with-variable-resistance exercise produced significantly lower PFJ stress than the knee-extension-with-constant-resistance exercise at 90°, 75°, and 60° of knee flexion. Conclusion To minimize PFJ stress while performing quadriceps exercises, our data suggest that the squat exercise should be performed from 45° to 0° of knee flexion and the knee-extension-with-variable-resistance exercise should be performed from 90° to 45° of knee flexion. J Orthop Sports Phys Ther 2014;44(5):320-327. Epub 27 March 2014. doi:10.2519/jospt.2014.4936. PMID:24673446
Powers, Christopher M; Ho, Kai-Yu; Chen, Yu-Jen; Souza, Richard B; Farrokhi, Shawn
Quadriceps and Hamstrings Coactivation During Common Therapeutic Exercises
Context Anterior tibial shear force and knee valgus moment increase anterior cruciate ligament (ACL) loading. Muscle coactivation of the quadriceps and hamstrings influences anterior tibial shear force and knee valgus moment, thus potentially influencing ACL loading and injury risk. Therefore, identifying exercises that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in ACL injury rehabilitation and prevention. Objective To quantify and compare quadriceps with hamstrings coactivation electromyographic (EMG) ratios during commonly used closed kinetic chain exercises. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants Twenty-seven healthy, physically active volunteers (12 men, 15 women; age = 22.1 ± 3.1 years, height = 171.4 ± 10 cm, mass = 72.4 ± 16.7 kg). Intervention(s) Participants completed 9 separate closed chain therapeutic exercises in a randomized order. Main Outcome Measure(s) Surface electromyography quantified the activity level of the vastus medialis (VM), vastus lateralis (VL), medial hamstrings (MH), and biceps femoris (BF) muscles. The quadriceps-to-hamstrings (Q:H) coactivation ratio was computed as the sum of average quadriceps (VM, VL) EMG amplitude divided by the sum of average hamstrings (MH, BF) EMG amplitude for each trial. We used repeated-measures analyses of variance to compare Q:H ratios and individual muscle contributions across exercises (? = .05), then used post hoc Tukey analyses. Results We observed a main effect for exercise (F3,79 = 22.6, P < .001). The post hoc Tukey analyses revealed smaller Q:H ratios during the single-limb dead lift (2.87 ± 1.77) than the single-limb squat (5.52 ± 2.89) exercise. The largest Q:H ratios were observed during the transverse-lunge (7.78 ± 5.51, P < .001), lateral-lunge (9.30 ± 5.53, P < .001), and forward-lunge (9.70 ± 5.90, P < .001) exercises. Conclusions The most balanced (smallest) coactivation ratios were observed during the single-limb dead-lift, lateral-hop, transverse-hop, and lateral band-walk exercises. These exercises potentially could facilitate balanced activation in ACL rehabilitation and injury-prevention programs. They also could be used in postinjury rehabilitation programs in a safe and progressive manner.
Begalle, Rebecca L.; DiStefano, Lindsay J.; Blackburn, Troy; Padua, Darin A.
Cross-exercise on quadriceps deficit after ACL reconstruction.
A few studies concerning the improvement of quadriceps muscle strength deficit (QD) at an early stage following anterior cruciate ligament (ACL) reconstruction have been conducted whereas, ACL rehabilitation protocols based on contralateral quadriceps strength (QS) do not exist. Given these, the goals of our study were (1) to evaluate the effects of cross-eccentric exercise (CEE) on QD on ACL reconstructed knees, and (2) to explore any changes in QD following CEE provided at the frequencies of 3 or 5 times per week. For this study, 42 ACL-reconstructed patients were randomly assigned into 3 groups, two experimental and one control and followed an 8-week rehabilitation program. Additionally, the experimental groups received CEE for 3 and 5 days per week for 8 weeks in their uninjured knees. QS was evaluated with an isokinetic/isometric test, at 60 degrees of knee flexion of both limbs before and after completion of CEE. Two-factor ANOVA showed a significant improvement of QD between groups (F = 5.16, p = 0.01) after CEE completion on ACL reconstructed knees. Statistically significant results arose from the 3 days per week (D = 18.60, p = 0.01) and 5 days per week (D = 15.12, p = 0.04) experimental groups, whereas the control group did not yield any statistically significant differences. CEE used as an adjunct to the ACL traditional rehabilitation program at the weekly frequencies of 3 and 5 times at the early stage of reconstruction significantly improved QD. PMID:23288773
Papandreou, Maria; Billis, Evdokia; Papathanasiou, George; Spyropoulos, Panagiotis; Papaioannou, Nikos
Vassilis, P, Vassilios, B, Vassilis, M, Athanasios, JZ, Vassilis, T, Christina, K, and Yiannis, K. Isokinetic eccentric exercise of quadriceps femoris does not affect running economy. JS trength Cond Res 22: 1222-1227, 2008—The purpose of this study was to investigate whether running economy is affected by isokinetic eccentric exercise designed to cause muscle damage. Twenty- four young healthy men performed
Damage to the human quadriceps muscle from eccentric exercise and the training effect.
Nine participants performed two bouts of a step exercise, during which the quadriceps muscle of one leg acted eccentrically. Before and after the exercise, isokinetic torque was measured over a range of knee angles to determine the optimum angle for torque. Immediately after the first bout of exercise, the quadriceps showed a significant (P < 0.05) shift of 15.6 +/- 1.4 degrees (mean +/-sx) of its optimum angle in the direction of longer lengths, suggesting the presence of damage. A drop in peak torque, together with delayed soreness and swelling, confirmed that damage to muscle fibres had occurred. After the second bout of exercise, 8 days later, the shift in optimum angle was 10.4 +/- 1.0 degrees, which was significantly less than after the first bout (P < 0.05). Other indicators of damage were also reduced. In addition, the muscle exhibited a sustained shift in optimum angle (3.4 +/- 0.9 degrees), suggesting that some adaptation had taken place after the first bout of exercise. We conclude that muscles like the quadriceps can show evidence of damage after a specific programme of eccentric exercise, followed by an adaptation response. This is despite the fact that the quadriceps routinely undergoes eccentric contractions in everyday activities. PMID:15801494
Bowers, E J; Morgan, D L; Proske, U
Acute effects of dietary ginger on quadriceps muscle pain during moderate-intensity cycling exercise.
Ginger has known hypoalgesic and anti-inflammatory properties. The effects of an oral dose of ginger on quadriceps muscle pain, rating of perceived exertion (RPE), and recovery of oxygen consumption were examined during and after moderate-intensity cycling exercise. Twenty-five college-age participants ingested a 2-g dose of ginger or placebo in a double-blind, crossover design and 30 min later completed 30 min of cycling at 60% of VO2peak. Quadriceps muscle pain, RPE, work rate, heart rate (HR), and oxygen uptake (VO2) were recorded every 5 min during exercise, and HR and VO2 were recorded for 20 min after exercise. Compared with placebo, ginger had no clinically meaningful or statistically significant effect on perceptions of muscle pain, RPE, work rate, HR, or VO2 during exercise. Recovery of VO2 and HR after the 30-min exercise bout followed a similar time course in the ginger and placebo conditions. The results were consistent with related findings showing that ingesting a large dose of aspirin does not acutely alter quadriceps muscle pain during cycling, and this suggests that prostaglandins do not play a large role in this type of exercise-induced skeletal-muscle pain. Ginger consumption has also been shown to improve VO2 recovery in an equine exercise model, but these results show that this is not the case in humans. PMID:19164834
Black, Christopher D; Oconnor, Patrick J
Effect of Isometric Quadriceps Exercise on Muscle Strength, Pain, and Function in Patients with Knee Osteoarthritis: A Randomized Controlled Study
[Purpose] The aim of present study was to investigate the effects of isometric quadriceps exercise on muscle strength, pain, and function in knee osteoarthritis. [Subjects and Methods] Outpatients (N=42, 21 per group; age range 40–65 years; 13 men and 29 women) with osteoarthritis of the knee participated in the study. The experimental group performed isometric exercises including isometric quadriceps, straight leg raising, and isometric hip adduction exercise 5 days a week for 5 weeks, whereas the control group did not performed any exercise program. The outcome measures or dependent variables selected for this study were pain intensity, isometric quadriceps strength, and knee function. These variables were measured using the Numerical Rating Scale (NRS), strength gauge device, and reduced WOMAC index, respectively. All the measurements were taken at baseline (week 0) and at the end of the trial at week 5. [Results] In between-group comparisons, the maximum isometric quadriceps strength, reduction in pain intensity, and improvement in function in the isometric exercise group at the end of the 5th week were significantly greater than those of the control group (p<0.05). [Conclusion] The 5-week isometric quadriceps exercise program showed beneficial effects on quadriceps muscle strength, pain, and functional disability in patients with osteoarthritis of the knee.
Anwer, Shahnawaz; Alghadir, Ahmad
Differential Glucose Uptake in Quadriceps and Other Leg Muscles During One-Legged Dynamic Submaximal Knee-Extension Exercise
One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron emission tomography (PET) determined uptake of [18F]-fluoro-deoxy-glucose (GU) during DKE. Five healthy male subjects performed DKE at 25?W for 35?min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest in the vastus intermedius (VI) and lowest in the vastus lateralis (VL; VI vs VL, p?0.05), whereas the coefficient of variation was highest in VL (VL vs VI, p?0.05). Coefficient of variation between the mean values of the four quadriceps femoris (QF) muscles in the exercising leg was 35?±?9%. Compared to mean GU in QF (=100%), GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between individuals vary greatly during DKE, and suggests that muscle activity is not equal between quadriceps muscles in this exercise model. Furthermore, posterior thigh muscles and lower leg muscles are more active than hitherto thought even during this moderate exercise intensity.
Kalliokoski, Kari K.; Boushel, Robert; Langberg, Henning; Scheede-Bergdahl, Celena; Ryberg, Ann Kathrine; D?ssing, Simon; Kjaer, Andreas; Kjaer, Michael
Beta 2-adrenergic stimulation does not prevent potassium loss from exercising quadriceps muscle.
During exercise K+ is released from contracting muscle and plasma K+ concentration rises. Because beta 2-adrenergic agonists stimulate K+ uptake by skeletal muscle in vitro, we tested whether terbutaline, a selective beta 2-agonist, would reduce the loss of K+ from working muscle. Dynamic quadriceps muscle exercise was performed by 12 healthy male volunteers for 50 or 80 min at an average workload of 38 W. A steady K+ loss estimated at 0.16 +/- 0.02 mmol.min-1.kg working muscle-1 and a 0.30 +/- 0.05 mM elevation of arterial plasma K+ concentration were observed. The addition of terbutaline during exercise caused leg blood flow to increase 13% from 5.10 +/- 0.16 to 5.75 +/- 0.13 l/min and arterial K+ concentration to fall monoexponentially by 0.90 +/- 0.05 mM with a rate constant of 0.26 min-1. Terbutaline increased, rather than decreased, the washout of K+ from working quadriceps by 40% to an average value of 0.23 +/- 0.02 mmol.min-1.kg muscle-1. In an additional subject who exercised to exhaustion, terbutaline failed to diminish muscle K+ loss. We conclude that terbutaline does not augment Na(+)-K+ pump activity to a degree sufficient to prevent K+ loss from exercising muscle in humans. On the other hand, the rapid reduction in plasma K+ concentration observed with beta 2-adrenergic stimulation is compatible with an uptake of K+ by nonexercising tissue at an estimated maximal rate of 0.5 micromol.g-1.min-1. PMID:1970926
Rolett, E L; Strange, S; Sjřgaard, G; Kiens, B; Saltin, B
Assessment of the quadriceps femoris muscle in women after injury induced by maximal eccentric isokinetic exercise with low angular speed
The objectives of this study were to propose a model for exer- cise-induced muscle injury by way of a maximal eccentric isokinetic exercise at low angular speed, and assess the time course of functional recovery of the injured quadriceps femoris muscle from the maximal voluntary contraction (MVC) torque and electrical activity (root mean square - RMS and median frequency -
Fábio Viadanna Serrăo; Paula Regina Mendes da Silva Serrăo; Bernd Foerster; Alberto Tannús; Vanessa Monteiro Pedro; Tania F. Salvini
Assessment of the Quadriceps Femoris Muscle in Women after Injury Induced by Maximal Eccentric Isokinetic Exercise with Low Angular Speed
The objectives of this study were to propose a model for exercise- induced muscle injury by way of a maximal eccentric isokinetic exercise at low angular speed, and assess the time course of functional recovery of the injured quadriceps femoris muscle from the maximal voluntary contraction (MVC) torque and electrical activity (root mean square - RMS and median frequency - MDF). The effectiveness of the proposed eccentric exercise in inducing injury was assessed from the activity of creatine kinase (CK). In addition, the presence of edema of the quadriceps femoris muscle was assessed by a visual inspection of the intensity of the magnetic resonance imaging (MRI) signal. These measurements were carried out before and after the exercise. Ten healthy women (21.9 ± 1.5) took part in this study. The injury was induced by 4 series of 15 maximal eccentric isokinetic contractions at 5°/s. The MVC torque reduced up to the 4th day after the exercise (p < 0.05). The RMS of the vastus medialis oblique (VMO) and the rectus femoris (RF) muscles decreased on the 2nd (VMO and RF; p < 0.05) and 3rd (RF; p < 0.05) days after. The MDF of the VMO increased immediately after (p < 0.05), whilst the MDF of the RF and VL decreased immediately after (RF; p < 0.05), on the 1st (RF and VL; p < 0.05) and on the 2nd (VL; p < 0.05) days after. The CK activity increased on the 2nd day after (p < 0.05). An increase in the intensity of the MRI signal was observed on the 2nd and 7th days after. In conclusion: 1- the eccentric exercise with low angular speed was effective in inducing injury, 2- the quadriceps femoris already started its functional recovery, as shown by the MVC torque and electrical activity, in the first week after the exercise, despite the presence of an increase in the intensity of the MRI signal. Key pointsThe low angular speed eccentric exercise was effec-tive in inducing injury of the quadriceps femoris muscle, and could be used as a muscle injury induc-ing model in future studies;The quadriceps femoris muscle injured by eccentric exercise started its functional recovery in the first week after low angular speed eccentric exercise.
Serrao, Fabio Viadanna; Serrao, Paula Regina Mendes da Silva; Foerster, Bernd; Tannus, Alberto; Monteiro Pedro, Vanessa; Salvini, Tania F.
Effects of muscle strengthening versus aerobic exercise program in fibromyalgia
The purpose of this study was to compare the effects of aerobic training with a muscle-strengthening program in patients with\\u000a fibromyalgia. Thirty women with fibromyalgia were randomized to either an aerobic exercise (AE) program or a strengthening\\u000a exercise (SE) program for 8 weeks. Outcome measures included the intensity of fibromyalgia-related symptoms, tender point\\u000a count, fitness (6-min walk distance), hospital anxiety and
Çi?dem Bircan; Seide Alev Karasel; Berrin Akgün; Özlem El; Serap Alper
Importance of Attenuating Quadriceps Activation Deficits after Total Knee Arthroplasty
Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Since quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Further, surgical approaches such as minimally invasive TKA may minimize post-operative quadriceps dysfunction.
Thomas, Abbey C.; Stevens-Lapsley, Jennifer E.
Neuropsychological and neurophysiological effects of strengthening exercise for early dementia: A pilot study
Research demonstrates a positive effect of aerobic exercise on cognitive functioning in older adults. Unfortunately, aerobic exercise is often contraindicated for older adults due to cardiovascular and functional limitations. Low-intensity strengthening exercise may offer a practical alternative, but the neuropsychological benefits and potential neurophysiological mechanisms are less well understood. The current study evaluated the effects of a 10-week strengthening exercise
Vadim Yerokhin; Cay Anderson-Hanley; Michael J. Hogan; Mina Dunnam; Daniel Huber; Sandra Osborne; Mollie Shulan
Neuropsychological and neurophysiological effects of strengthening exercise for early dementia: A pilot study
Research demonstrates a positive effect of aerobic exercise on cognitive functioning in older adults. Unfortunately, aerobic exercise is often contraindicated for older adults due to cardiovascular and functional limitations. Low-intensity strengthening exercise may offer a practical alternative, but the neuropsychological benefits and potential neurophysiological mechanisms are less well understood. The current study evaluated the effects of a 10-week strengthening exercise
Vadim Yerokhin; Cay Anderson-Hanley; Michael J. Hogan; Mina Dunnam; Daniel Huber; Sandra Osborne; Mollie Shulan
Which Treatment is More Effective for Functional Ankle Instability: Strengthening or Combined Muscle Strengthening and Proprioceptive Exercises?
[Purpose] The purpose of this study was to implement combined muscle strengthening and proprioceptive exercises to examine the effects of combined exercises on functional ankle instability. [Subjects and Methods] Experiments were conducted with 30 adult males and females. The study subjects were randomly assigned to either a control group (Group A), a muscle strengthening exercise group (Group B), or a combined muscle strengthening and proprioceptive exercise group (Group C) consisting of 10 subjects each. In Group A, measurements were only conducted before and after the experiment without any intervention, whereas the exercise programs for Group B and Group C were implemented three days per week for four weeks. [Results] Muscle strength showed significant increases in Groups B and C compared with the control group during plantar flexion, dorsiflexion, inversion, and eversion. The Cumberland ankle instability tool showed significant increases in Group B and Group C compared with Group A and significant increases in Group C compared with Group B. [Conclusion] Applying combined muscle strengthening and proprioceptive exercises to those who have functional ankle instability is more effective than applying only muscle strengthening exercises. PMID:24707089
Kim, Ki-Jong; Kim, Young-Eok; Jun, Hyun-Ju; Lee, Jin-Su; Ji, Sung-Ha; Ji, Sang-Goo; Seo, Tae-Hwa; Kim, Young-Ok
Which Treatment is More Effective for Functional Ankle Instability: Strengthening or Combined Muscle Strengthening and Proprioceptive Exercises?
[Purpose] The purpose of this study was to implement combined muscle strengthening and proprioceptive exercises to examine the effects of combined exercises on functional ankle instability. [Subjects and Methods] Experiments were conducted with 30 adult males and females. The study subjects were randomly assigned to either a control group (Group A), a muscle strengthening exercise group (Group B), or a combined muscle strengthening and proprioceptive exercise group (Group C) consisting of 10 subjects each. In Group A, measurements were only conducted before and after the experiment without any intervention, whereas the exercise programs for Group B and Group C were implemented three days per week for four weeks. [Results] Muscle strength showed significant increases in Groups B and C compared with the control group during plantar flexion, dorsiflexion, inversion, and eversion. The Cumberland ankle instability tool showed significant increases in Group B and Group C compared with Group A and significant increases in Group C compared with Group B. [Conclusion] Applying combined muscle strengthening and proprioceptive exercises to those who have functional ankle instability is more effective than applying only muscle strengthening exercises.
Kim, Ki-Jong; Kim, Young-Eok; Jun, Hyun-Ju; Lee, Jin-Su; Ji, Sung-Ha; Ji, Sang-Goo; Seo, Tae-Hwa; Kim, Young-Ok
Treatment of Knee Osteoarthritis in Relation to Hamstring and Quadriceps Strength
[Purpose] To assess the effect of hamstring and quadriceps strengthening exercises on pain intensity, gait velocity, maximum isometric strength, and activities of daily living of patients with knee osteoarthritis (OA). [Subjects and Methods] A total of 20 patients with knee OA, 50 to 65?years of age (57.65 ± 4.78?years), received hot packs, strengthening exercises for the quadriceps and the hamstring muscles and stretching exercises for hamstring muscles. Outcome measures included: the Western Ontario and McMaster Universities OA index questionnaire (WOMAC) scores for assessing health status and health outcomes of knee OA; self-reported pain intensity scores, measured using a visual analogue scale; the 50 ft walk test (a measure of gait velocity and function); and handheld dynamometry (a tool used to measure maximum isometric strength of knee extension and flexion). [Results] There was a significant difference between pre- and post-intervention measures of pain intensity, 50 ft walk times, hamstring strength, and quadriceps strength. Significant differences in WOMAC measures were also observed in the subscales of pain, stiffness and physical function, as well as WOMAC total scores. [Conclusion] Strengthening the hamstring muscles in addition to strengthening the quadriceps muscles proved to be beneficial for perceived knee pain, range of motion, and decreasing the limitation of functional performance of patients with knee OA.
Hafez, Ashraf Ramadan; Al-Johani, Ahmed H.; Zakaria, Abdul Rahim; Al-Ahaideb, Abdulaziz; Buragadda, Syamala; Melam, Ganeswara Rao; Kachanathu, SJ
Cognitive health benefits of strengthening exercise for community-dwelling older adults
While aerobic exercise has been linked to improved performance on cognitive tasks of executive functioning among older adults, not all older adults can avail themselves of such exercise due to physical limitations. In this study, community-dwelling older adults were evaluated on tasks of executive functioning before and after a month-long strengthening, nonaerobic exercise program. A total of 16 participants who
Cay Anderson-Hanley; Joseph P. Nimon; Sarah C. Westen
... quadriceps contusion can lead to other difficulties, like myositis ossificans , a serious condition that occurs when bone starts ... swelling and may be a contributing cause to myositis ossificans. Make careful use of massage. Having a sports ...
Nonuniform changes in MRI measurements of the thigh muscles after two hamstring strengthening exercises.
Although many different hamstring strengthening exercises exist, the effect on site specific activation of these exercises on different muscles of the leg is unclear. This study investigated the effects of the eccentric leg curl (LC) and lunge (L) exercises on the biceps femoris long head (BFl), biceps femoris short head (BFs), semitendinosus (ST), semimembranosus (SM), and adductor magnus (AM). Each leg of 11 male professional soccer players was randomly assigned to an LC or L exercise protocol (3 sets of 6 repetitions). Functional magnetic resonance imaging (fMRI) of the subjects' thighs were performed before and 48 hours after the intervention. Fifteen axial scans of the thigh interspaced by a distance of 1/15 right femur length (Lf) were obtained. The fMRI data were analyzed for signal intensity changes. No significant changes were observed in absolute short tau inversion recovery values for the SM and BFs. Significant changes for the ST (?21-45%) from sections 4 to 10, AM (?2-13%) at section 4, and BFl (? -3 vs. 8%) at section 7 were noted. LC exercises load all the regions of the ST muscle. The L exercises load the proximal regions of the BFl and AM. These findings may have relevance when designing protocols for prevention and rehabilitation of hamstring injuries. PMID:23443215
Mendiguchia, Jurdan; Garrues, Mirian A; Cronin, John B; Contreras, Bret; Los Arcos, Asier; Malliaropoulos, Nikos; Maffulli, Nicola; Idoate, Fernando
Objective: Decreased hip muscle strength is frequently reported in patients with hip injury or pathology. Furthermore, soccer players suffering from groin injury show decreased strength of hip muscles. Estimating 10?repetition maximum can be time?consuming and difficult, thus, using the Borg category rating 10 scale (Borg CR10 scale) can be a useful tool for estimating the intensity of exercise. The aims of this study were 1) to investigate the feasibility of the use of the Borg CR10 scale for rating strength training intensity of the hip abductor and hip adductor muscles, and 2) to compare hip muscle activity during hip abduction and hip adduction exercises using elastic resistance and isotonic machines, using electromyography (EMG). Methods: EMG activity was recorded from 11 muscles at the hip, thigh and trunk during hip adduction and hip abduction exercises in 16 untrained women, using elastic resistance and isotonic exercise machines. These recordings were normalized to maximal voluntary contraction (MVC) EMG (nEMG). The exercises were performed at four levels of perceived loading reported using the Borg CR10: light (Borg ?2), moderate (Borg >2–<5), heavy (Borg ?5–<7) and near maximum (Borg ?7). Results: Moderate to strong associations were observed between perceived loading and nEMG obtained during the adduction exercise with elastic resistance (r=0.8±0.3) as well as in machine (r=0.69±0.55) and the abduction exercise with elastic resistance (r=0.66±0.29) as well as in machine (r =0.62±0.54). The abduction exercise performed with elastic resistance displayed significantly higher gluteus medius nEMG recruitment than the in machine exercise. Conclusions: The results of this study show that the Borg CR10 scale can be a useful tool for estimating intensity levels during resistance training of the hip adductor and hip abductor muscles. Although elastic resistance and exercise machine seem equally effective for recruiting muscle activity of the hip adductors, the elastic resistance condition was able to demonstrate greater muscle recruitment than the exercise machine during hip abduction.
Jakobsen, Markus Due; Thorborg, Kristian; Sundstrup, Emil; Jay, Kenneth; Andersen, Lars L.
Effectiveness of home exercise on pain and disability from osteoarthritis of the knee: a randomised controlled trial
OBJECTIVETo assess the effect of a home based exercise programme, designed to improve quadriceps strength, on knee pain and disability.Methods—191 men and women with knee pain aged 40–80 were recruited from the community and randomised to exercise (n=113) or no intervention (n=78). The exercise group performed strengthening exercises daily for six months. The primary outcome measure was change in knee
Sheila C O'Reilly; Ken R Muir; Michael Doherty
Home-Based Leg Strengthening Exercise Improves Function One Year After Hip Fracture: A Randomized Controlled Study
Objectives Examine the effectiveness of a short term leg strengthening exercise program compared to attentional control on improving strength, walking abilities, and function one year after hip fracture. Design Randomized controlled pilot study. Setting Interventions occurred in patients' homes. Participants Community-dwelling older adults (n=26) six months post hip fracture at baseline. Intervention Exercise and control participants received interventions by physical therapists twice weekly for 10 weeks. The exercise group received high intensity leg strengthening exercises. The control group received transcutaneous electrical nerve stimulation and mental imagery. Measurements Isometric force production of lower extremity muscles; usual and fast gait speed, six minute walk (6-MW) distance, modified physical performance test (mPPT), and SF-36 physical function. Results The primary endpoint was at one year post fracture. Isometric force production (p<.01), usual and fast gait speed (p=.02 & .03, respectively), 6-MW (p<.01), and mPPT (p<.01) improved at one year post fracture with exercise. Effect sizes were 0.79 for strength, 0.81 for mPPT scores, 0.56 for gait speed, 0.49 for 6-MW, and 0.30 for SF-36 scores. More patients in the exercise group made meaningful changes in gait speed and 6-MW distance than control patients (?2: p=.004). Conclusion A 10-week home-based progressive resistance exercise program was sufficient to achieve moderate to large effects on physical performance and quality of life and may offer an alternative intervention mode for hip fracture patients who are unable to leave home at 6 months after the fracture. The effects were maintained at 3 months after completion of the training program.
Mangione, Kathleen K.; Craik, Rebecca L.; Palombaro, Kerstin M.; Tomlinson, Susan S.; Hofmann, Mary T.
Shoulder-strengthening exercise with an orthosis for multidirectional shoulder instability: quantitative evaluation of rotational shoulder strength before and after the exercise program.
We evaluated the results of shoulder-strengthening exercises with our novel shoulder orthosis to stabilize the scapula in 46 patients with multidirectional shoulder instability. We quantified the changes in muscle strength produced by our rehabilitation program. Our study included 34 female patients and 12 male patients (mean age, 20 years) with 73 affected shoulders. All patients performed the prescribed exercise program for 8 weeks. Their mean total scores on the modified Rowe grading system significantly increased from 51.9 to 74.9 points (P <.001). The mean peak torque of internal and external rotation, measured with an isokinetic dynamometer, significantly increased (P <.05); the mean external/internal peak torque ratios significantly decreased (P <.05) and were normalized upon completion of the rehabilitation program. Because of failure of conservative treatment, 3 patients underwent surgery at a mean follow-up duration of 7 years. We conclude that the prescribed shoulder-strengthening exercise represents a useful treatment option for patients with multidirectional shoulder instability. PMID:12934027
Ide, Junji; Maeda, Satoshi; Yamaga, Makio; Morisawa, Keizo; Takagi, Katsumasa
The Effect of NeuroMuscular Electrical Stimulation on Quadriceps Strength and Knee Function in Professional Soccer Players: Return to Sport after ACL Reconstruction
The aim of this study was to assess the clinical efficacy and safety of NMES program applied in male soccer players (after ACL reconstruction) on the quadriceps muscle. The 80 participants (NMES = 40, control = 40) received an exercise program, including three sessions weekly. The individuals in NMES group additionally received neuromuscular electrical stimulation procedures on both right and left quadriceps (biphasic symmetric rectangular pulses, frequency of impulses: 2500?Hz, and train of pulses frequency: 50?Hz) three times daily (3 hours of break between treatments), 3 days a week, for one month. The tensometry, muscle circumference, and goniometry pendulum test (follow-up after 1 and 3 months) were applied. The results of this study show that NMES (in presented parameters in experiment) is useful for strengthening the quadriceps muscle in soccer athletes. There is an evidence of the benefit of the NMES in restoring quadriceps muscle mass and strength of soccer players. In our study the neuromuscular electrical stimulation appeared to be safe for biomechanics of knee joint. The pathological changes in knee function were not observed. This trial is registered with Australian and New Zealand Clinical Trials Registry ACTRN12613001168741.
Taradaj, J.; Halski, T.; Kucharzewski, M.; Walewicz, K.; Smykla, A.; Ozon, M.; Slupska, L.; Dymarek, R.; Ptaszkowski, K.; Rajfur, J.; Pasternok, M.
The Effect of Warm-Up and Cool-Down Exercise on Delayed Onset Muscle Soreness in the Quadriceps Muscle: a Randomized Controlled Trial
The aim of the present study was to investigate the effect of warm-up and cool-down exercise on delayed onset of muscle soreness at the distal and central parts of rectus femoris following leg resistance exercise. Thirty-six volunteers (21 women, 15 men) were randomly assigned to the warm-up (20 min ergometer cycling prior to the resistance exercise), cool-down (20 min cycling after the resistance exercise), or control group performing resistance exercise only. The resistance exercise consisted of front lunges (10×5 repetitions/sets) with external loading of 40% (women) and 50% (men) of body mass. Primary outcomes were pressure pain threshold along rectus femoris and maximal isometric knee extension force. Data were recorded before the resistance exercise and on the two consecutive days. Pressure pain threshold at the central muscle belly was significantly reduced for the control group on both day 2 and 3 (p?0.003) but not for the warm-up group (p?0.21). For the cool-down group, pressure pain threshold at the central muscle belly was significantly reduced on day 2 (p?0.005) and was also lower compared to the warm-up group (p=0.025). Force was significantly reduced on day 2 and 3 for all groups (p<0.001). This study indicates that aerobic warm-up exercise performed prior to resistance exercise may prevent muscle soreness at the central but not distal muscle regions, but it does not prevent loss of muscle force.
Olsen, Olav; Sj?haug, Mona; van Beekvelt, Mireille; Mork, Paul Jarle
The use of ambulatory EMG monitoring to measure compliance with lumbar strengthening exercise.
This study validates the use of ambulatory EMG monitoring as a measure of exercise compliance. The model rehabilitative exercise used was the Prone Back Extension. Thirty-two undergraduate volunteers were videorecorded as they performed the exercise alone in a closed room. The correlation between a direct observation count of the number of repetitions and an independent EMG-based count was .95. EMG amplitude was examined by repetition and gender with regression and ANOVA. There were significant gender differences in the amplitude of EMG across repetitions. There were no significant differences by gender in the declining slope of amplitude across repetitions. This slope may represent a typical "fatigue" curve. Thus, not only the occurrence but also the intensity of exercise can be quantified. PMID:8448239
Cassisi, J E; Sexton-Radek, K; Castrogiovanni, M; Chastain, D; Robinson, M E
Hamstring\\/quadriceps ratios in college football players: A high velocity evaluation
Hamstring\\/quadriceps ratios were assessed on 60 in tercollegiate football players at functional speeds of 90, 180, and 300 deg\\/sec on the Cybex II. The ratio rose as velocity of exercise increased and the quadriceps was stronger than the hamstrings at all speeds. The flexor\\/extensor ratio differed bilaterally at all speeds with ratio lower for the dominant knee.The study helped establish
Maureen G. Stafford; William A. Grana
Effect of motor control and strengthening exercises on shoulder function in persons with impingement syndrome: A single-subject study design
The aim of the study was to evaluate the effect of an intervention including shoulder control and strengthening exercises on function in persons with shoulder impingement. Eight subjects with shoulder impingement were evaluated weekly during the nine weeks of this single-subject design study. The study was divided into three phases (A1–B–A2) and involved repeated measures of shoulder pain and function
Jean-Sébastien Roy; Hélčne Moffet; Luc J. Hébert; Richard Lirette
Strengthening and stretching for rheumatoid arthritis of the hand (SARAH): design of a randomised controlled trial of a hand and upper limb exercise intervention - ISRCTN89936343
Background Rheumatoid Arthritis (RA) commonly affects the hands and wrists with inflammation, deformity, pain, weakness and restricted mobility leading to reduced function. The effectiveness of exercise for RA hands is uncertain, although evidence from small scale studies is promising. The Strengthening And Stretching for Rheumatoid Arthritis of the Hand (SARAH) trial is a pragmatic, multi-centre randomised controlled trial evaluating the clinical and cost effectiveness of adding an optimised exercise programme for hands and upper limbs to best practice usual care for patients with RA. Methods/design 480 participants with problematic RA hands will be recruited through 17 NHS trusts. Treatments will be provided by physiotherapists and occupational therapists. Participants will be individually randomised to receive either best practice usual care (joint protection advice, general exercise advice, functional splinting and assistive devices) or best practice usual care supplemented with an individualised exercise programme of strengthening and stretching exercises. The study assessors will be blinded to treatment allocation and will follow participants up at four and 12 months. The primary outcome measure is the Hand function subscale of the Michigan Hand Outcome Questionnaire, and secondary outcomes include hand and wrist impairment measures, quality of life, and resource use. Economic and qualitative studies will also be carried out in parallel. Discussion This paper describes the design and development of a trial protocol of a complex intervention study based in therapy out-patient departments. The findings will provide evidence to support or refute the use of an optimised exercise programme for RA of the hand in addition to best practice usual care. Trial registration Current Controlled Trials ISRCTN89936343
Pathways associated with reduced quadriceps oxidative fibres and endurance in COPD.
Reduced quadriceps endurance in chronic obstructive pulmonary disease (COPD) is associated with a predominance of type II glycolytic fibres over type I oxidative fibres (fibre shift) and reduced muscle energy stores. The molecular mechanisms responsible for this remain unknown. We hypothesised that expression of known regulators of type I fibres and energy production in quadriceps muscle would differ in COPD patients with and without fibre shift. We measured lung function, physical activity, exercise performance, quadriceps strength and endurance (nonvolitionally) in 38 Global Initiative for Chronic Obstructive Lung Disease stage I-IV COPD patients and 23 healthy age-matched controls. Participants underwent a quadriceps biopsy: type I and II fibre proportions were determined using immunohistochemistry and fibre shift defined using published reference ranges. Calcineurin A, phosphorylated AMP kinase (phospho-AMPK)-?, protein kinase A-? catalytic subunits, modulators of calcineurin activity and calmodulin, 14-3-3 proteins were measured by Western blotting, and myocyte-enriched calcineurin-interacting protein-1 mRNA measured by quantitative PCR. Downstream, nuclear myocyte enhancer factor-2 capable of DNA binding was quantified by transcription factor ELISA. Unexpectedly, calcineurin expression was higher, while phospho-AMPK was lower, in COPD patients with fibre shift compared to COPD patients without fibre shift. Phospho-AMPK levels correlated with quadriceps endurance in patients. Reduced phospho-AMPK may contribute to reduced quadriceps oxidative capacity and endurance in COPD. PMID:23258787
Natanek, Samantha A; Gosker, Harry R; Slot, Ilse G M; Marsh, Gemma S; Hopkinson, Nicholas S; Moxham, John; Kemp, Paul R; Schols, Annemie M W J; Polkey, Michael I
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Concentric and Eccentric Time-Under-Tension during Strengthening Exercises: Validity and Reliability of Stretch-Sensor Recordings from an Elastic Exercise-Band
Background Total, single repetition and contraction-phase specific (concentric and eccentric) time-under-tension (TUT) are important exercise-descriptors, as they are linked to the physiological and clinical response in exercise and rehabilitation. Objective To investigate the validity and reliability of total, single repetition, and contraction-phase specific TUT during shoulder abduction exercises, based on data from a stretch-sensor attached to an elastic exercise band. Methods A concurrent validity and interrater reliability study with two raters was conducted. Twelve participants performed five sets of 10 repetitions of shoulder abduction exercises with an elastic exercise band. Exercises were video-recorded to assess concurrent validity between TUT from stretch-sensor data and from video recordings (gold standard). Agreement between methods was calculated using Limits of Agreement (LoA), and the association was assessed by Pearson correlation coefficients. Interrater reliability was calculated using intraclass correlation coefficients (ICC 2.1). Results Total, single repetition, and contraction-phase specific TUT – determined from video and stretch-sensor data – were highly correlated (r>0.99). Agreement between methods was high, as LoA ranged from 0.0 to 3.1 seconds for total TUT (2.6% of mean TUT), from -0.26 to 0.56 seconds for single repetition TUT (6.9%), and from -0.29 to 0.56 seconds for contraction-phase specific TUT (13.2-21.1%). Interrater reliability for total, single repetition and contraction-phase specific TUT was high (ICC>0.99). Interrater agreement was high, as LoA ranged from -2.11 to 2.56 seconds for total TUT (4.7%), from -0.46 to 0.50 seconds for single repetition TUT (9.7%) and from -0.41 to 0.44 seconds for contraction-phase specific TUT (5.2-14.5%). Conclusion Data from a stretch-sensor attached to an elastic exercise band is a valid measure of total and single repetition time-under-tension, and the procedure is highly reliable. This method will enable clinicians and researchers to objectively quantify if home-based exercises are performed as prescribed, with respect to time-under-tension.
Skovdal Rathleff, Michael; Thorborg, Kristian; Bandholm, Thomas
Phototherapy during treadmill training improves quadriceps performance in postmenopausal women.
Abstract Objective To evaluate the effects of infrared-light-emitting diode (LED) during treadmill training on functional performance. Methods Thirty postmenopausal women aged 50-60 years were randomly assigned to one of three groups and successfully completed the full study. The three groups were: (1) the LED group, which performed treadmill training associated with phototherapy (n = 10); (2) the exercise group, which carried out treadmill training only (n = 10); and (3) the sedentary group, which neither performed physical training nor underwent phototherapy (n = 10). Training was performed over a period of 6 months, twice a week for 45 min per session at 85-90% of maximal heart rate, which was obtained during progressive exercise testing. The irradiation parameters were 100 mW, 39 mW/cm(2) and 108 J/cm(2) for 45 min. Quadriceps performance was measured during isokinetic exercise testing at 60°/s and 300°/s. Results Peak torque did not differ amongst the groups. However, the results showed significantly higher values of power and total work for the LED group (? = 21 ± 6 W and ? = 634 ± 156 J, p < 0.05) when compared to both the exercise group (? = 13 ± 10 W and = 410 ± 270 J) and the sedentary group (? = 10 ± 9 W and ? = 357 ± 327 J). Fatigue was also significantly lower in the LED group (? = -7 ± 4%, p < 0.05) compared to both the exercise group (? = 3 ± 8%) and the sedentary group (? = -2 ± 6%). Conclusions Infrared-LED during treadmill training may improve quadriceps power and reduce peripheral fatigue in postmenopausal women. PMID:23895414
Paolillo, F R; Corazza, A V; Paolillo, A R; Borghi-Silva, A; Arena, R; Kurachi, C; Bagnato, V S
Intervention program in college instrumental musicians, with kinematics analysis of cello and flute playing: a combined program of yogic breathing and muscle strengthening-flexibility exercises.
College musicians encounter health risks not dissimilar to those of professional musicians. Fifteen collegiate instrumental musicians participated in the intervention program of yogic-breathing and muscle-strengthening and flexibility exercises for 8 weeks. Pre- and post-intervention data from the Health-Pain-Injury Inventory (HPI) and the Physical & Musical-Performance Efficacy Assessment Survey (PME) were analyzed for the effects of the program on the musicians' physical and musical-performance efficacy. HPI results showed that the majority of our sample had healthy lifestyles and minimal pain and injuries but irregular eating and exercise habits. The pre-intervention PME data showed a high level of musical efficacy (i.e., awareness of music technique, tone, and flow) but a low-level of physical efficacy (i.e., awareness of posture, tension, and movement flexibility). Post-intervention data showed that the program improved physical efficacy by increased awareness of posture and tension. In 2 volunteer musicians, kinematics motion analysis was conducted for exploratory purposes. Our cellist played the scale using a larger range of motion (ROM) in right shoulder flexion and abduction and slightly increased rotation while keeping decreased right elbow ROM after the intervention program. The flutist shifted the body weight from one foot to the other more in the second playing post-intervention. These changes can be attributed to the increased physical efficacy that allowed freedom to express musicality. Findings from these case scenarios provide empirically based hypotheses for further study. We share our experience so that others may use our model and instruments to develop studies with larger samples. PMID:22739821
Lee, Sang-Hie; Carey, Stephanie; Dubey, Rajiv; Matz, Rachel
Neuromuscular Control of the Knee During a Resisted Single-Limb Squat Exercise
Background Closed kinetic chain exercises such as single-limb squats are preferred for knee rehabilitation. A complete understanding of the neuromuscular control of the knee during the single-limb squat is essential to increase the efficiency of rehabilitation programs. Hypothesis Performing a controlled single-limb squat with resistance to knee flexion and extension will increase the coactivation of the hamstring muscle group, thus reducing the quadriceps/hamstrings ratio. Study Design Descriptive laboratory study. Methods A total of 15 healthy human subjects (7 women, 8 men) performed controlled single-limb squats in a custom mechanical device that provided resistance to both flexion and extension. Subjects performed the task at 3 levels of resistance, set as a percentage of body weight. Surface electromyographic recordings from 7 muscles (gluteus medius, rectus femoris, vastus medialis oblique, vastus lateralis, biceps femoris, semitendinosus, and medial gastrocnemius) were collected during the task. Results Biceps femoris activity during knee flexion increased from approximately 12% maximum voluntary isometric contractions during low resistance (0% body weight) to approximately 27% maximum voluntary isometric contractions during high resistance (8% body weight). Although the quadriceps had greater activity than the hamstrings at all levels of resistance, the quadriceps/hamstrings ratio declined significantly with resistance (F2,27 = 29.05; P = .012) from 3.0 at low resistance to 2.32 at the highest resistance. Conclusions Performing controlled resisted single-limb squats may help to simultaneously strengthen the quadriceps and facilitate coactivation of the hamstrings, thus reducing anterior tibial shear forces. The coactivation may also increase the dynamic control of the knee joint. Clinical Relevance The typical single-limb squat exercise performed in the clinic does not usually control for bidirectional resistance and knee joint excursion. As seen in this study, controlled single-limb squats at increased levels of resistance help to increase the coactivation of the hamstring muscles, which is essential to optimize neuromuscular control of the knee.
Shields, Richard K.; Madhavan, Sangeetha; Gregg, Emy; Leitch, Jennifer; Petersen, Ben; Salata, Sara; Wallerich, Stacey
Intra- and intermuscular variation in human quadriceps femoris architecture assessed in vivo
Despite the functional importance of the human quadriceps femoris in movements such as running, jumping, lifting and climbing, and the known effects of muscle architecture on muscle function, no research has fully described the complex architecture of this muscle group. We used ultrasound imaging techniques to measure muscle thickness, fascicle angle and fascicle length at multiple regions of the four quadriceps muscles in vivo in 31 recreationally active, but non-strength-trained adult men and women. Our analyses revealed a reasonable similarity in the superficial quadriceps muscles, which is suggestive of functional similarity (at least during the uni-joint knee extension task) given that they act via a common tendon. The deep vastus intermedius (VI) is architecturally dissimilar and therefore probably serves a different function(s). Architecture varies significantly along the length of the superficial muscles, which has implications for the accuracy of models that assume a constant intramuscular architecture. It might also have consequences for the efficiency of intra- and intermuscular force transmission. Our results provide some evidence that subjects with a given architecture of one superficial muscle, relative to the rest of the subject sample, also have a similar architecture in other superficial muscles. However, this is not necessarily true for vastus lateralis (VL), and was not the case for VI. Therefore, the relative architecture of one muscle cannot confidently be used to estimate the relative architecture of another. To confirm this, we calculated a value of whole quadriceps architecture by four different methods. Regardless of the method used, we found that the absolute or relative architecture of one muscle could not be used as an indicator of whole quadriceps architecture, although vastus medialis, possibly in concert with VL and the anterior portion of VI, could be used to provide a useful snapshot. Importantly, our estimates of whole quadriceps architecture show a gender difference in whole quadriceps muscle thickness, and that muscle thickness is positively correlated with fascicle angle whereas fascicle length is negatively, although weakly, correlated with fascicle angle. These results are supportive of the validity of estimates of whole quadriceps architecture. These data are interpreted with respect to their implications for neural control strategies, region-specific adaptations in muscle size in response to training, and gender-dependent differences in the response to exercise training.
Blazevich, Anthony J; Gill, Nicholas D; Zhou, Shi
Exercise - National Multiple Sclerosis Society Skip to navigation Skip to content Menu Navigation National Multiple Sclerosis Society Search v Make a Donation ... now Download now Publication Stretching for People with MS Illustrated manual showing range of motion, stretching, and ...
Dynamic strength of the quadriceps muscle and sports activity
The study objectives were to examine the dynamic strength of the quadriceps muscle in athletes, and investigate its association with participation in sport. The study comprised 168 active competitive non-pregnant athletes, aged 14-24 years. The dynamic strength of their quadriceps muscle was measured, and they answered a questionnaire about sports activity and occupation. The dynamic strength of the quadriceps muscle
T. Hahn; A. Foldspang; T. Ingemann-Hansen
Simultaneous bilateral rupture of the quadriceps tendon.
The simultaneous, complete rupture of both quadriceps tendons is a rare event. Only 30 previous cases have been reported and the majority have had well-documented predisposing factors, such as chronic renal failure, gout, hyperparathyroidism, diabetes and obesity. We report a case which presented without any predisposing cause, and review the literature to date. PMID:2692688
Ribbans, W J; Angus, P D
Quadriceps and respiratory muscle fatigue following high-intensity cycling in COPD patients.
Exercise intolerance in COPD seems to combine abnormal ventilatory mechanics, impaired O2 transport and skeletal muscle dysfunction. However their relative contribution and their influence on symptoms reported by patients remain to be clarified. In order to clarify the complex interaction between ventilatory and neuromuscular exercise limiting factors and symptoms, we evaluated respiratory muscles and quadriceps contractile fatigue, dynamic hyperinflation and symptoms induced by exhaustive high-intensity cycling in COPD patients. Fifteen gold II-III COPD patients (age = 67 ± 6 yr; BMI = 26.6 ± 4.2 kg.m(-2)) performed constant-load cycling test at 80% of their peak workload until exhaustion (9.3 ± 2.4 min). Before exercise and at exhaustion, potentiated twitch quadriceps strength (Q(tw)), transdiaphragmatic (P(di,tw)) and gastric (P(ga,tw)) pressures were evoked by femoral nerve, cervical and thoracic magnetic stimulation, respectively. Changes in operational lung volumes during exercise were assessed via repetitive inspiratory capacity (IC) measurements. Dyspnoea and leg discomfort were measured on visual analog scale. At exhaustion, Q(tw) (-33 ± 15%, >15% reduction observed in all patients but two) and Pdi,tw (-20 ± 15%, >15% reduction in 6 patients) were significantly reduced (P<0.05) but not Pga,tw (-6 ± 10%, >15% reduction in 3 patients). Percentage reduction in Q(tw) correlated with the percentage reduction in P(di,tw) (r = 0.66; P<0.05). Percentage reductions in P(di,tw) and P(ga,tw) negatively correlated with the reduction in IC at exhaustion (r = -0.56 and r = -0.62, respectively; P<0.05). Neither dyspnea nor leg discomfort correlated with the amount of muscle fatigue. In conclusion, high-intensity exercise induces quadriceps, diaphragm and less frequently abdominal contractile fatigue in this group of COPD patients. In addition, the rise in end-expiratory lung volume and diaphragm flattening associated with dynamic hyperinflation in COPD might limit the development of abdominal and diaphragm muscle fatigue. This study underlines that both respiratory and quadriceps fatigue should be considered to understand the complex interplay of factors leading to exercise intolerance in COPD patients. PMID:24324843
Bachasson, Damien; Wuyam, Bernard; Pepin, Jean-Louis; Tamisier, Renaud; Levy, Patrick; Verges, Samuel
Quadriceps Tendon Rupture due to Postepileptic Convulsion
We present a case of quadriceps tendon (QT) rupture. QT ruptures can occur in all ages. The cause is mostly traumatic in origin. Spontaneous ruptures that are thought to result from predisposing conditions are rare. Post-convulsion QT ruptures lacking traumas in their history can be overlooked in clinical examinations. This should be born in mind by the attending physician, as early diagnosis and treatment of the condition can lead to satisfactory outcomes.
Erkut, Adem; Guvercin, Yilmaz; Sahin, Rifat; Keskin, Davut
Partial rupture of the quadriceps muscle in a child
BACKGROUND: The quadriceps femoris muscle ruptures usually occur in the middle-aged population. We present a 4-year-old patient with partial rupture of the quadriceps femoris muscle. To our knowledge, this is the youngest patient reported with a quadriceps femoris muscle rupture. CASE PRESENTATION: A 4-year-old girl admitted to our clinic with left knee pain and limitation in knee movements. Her father
Gokhan Aydemir; Selami Cakmak; Secil Aydinoz
Stimulated and voluntary fatiguing contractions of quadriceps femoris similarly disturb postural control in the bipedal stance.
The aim of this work was to compare the effects of fatigue of the quadriceps femoris after fatiguing voluntary contractions (VOL) and fatiguing neuromuscular electrical stimulation (ES) on bipedal postural control. Nineteen active male subjects (22.2 ± 1.7 years) completed these two fatiguing exercises. Isometric maximal voluntary contraction (MVC) and postural control were recorded using an ergometer and a force platform that registered the center of foot pressure (COP). We analyzed the COP surface, the mean COP velocity and the spectral power density given by the wavelet transform. Recordings were performed before (PRE condition) and after the completion of each fatiguing task (immediately POST condition, after a 5 min recovery POST 5 condition). In POST condition, the ES exercise affected MVC more than the VOL exercise. However, bipedal postural control was similarly deteriorated for both exercises. In POST 5 condition, for both fatiguing exercises, muscle strength and postural control did not recover their initial level. These results suggest that the postural control disturbance could not be distinguished for the two fatiguing exercises in the bipedal stance. In addition, the recovery speeds of postural control and muscle strength abilities did not differ for the ES exercise and the VOL exercise. PMID:21922258
Chaubet, Vincent; Maitre, Julien; Cormery, Bruno; Paillard, Thierry
Effectiveness of exercise training in patients with COPD: the role of muscle fatigue.
The improvement in exercise performance in response to exercise training varies greatly from one patient with chronic obstructive pulmonary disease to another. It is possible that in a portion of patients the muscle stimulus applied during exercise training is insufficient to elicit training effects. We investigated whether patients presenting quadriceps contractile fatigue after training have more favourable effects of a rehabilitation programme. 46 patients followed a 3-month high-intensity exercise training programme. Exercise capacity, quadriceps force and quality of life were measured before and after the programme. Exercise training-induced quadriceps contractile fatigue was assessed after 1 month of rehabilitation with magnetic stimulation. A fall in quadriceps force of ?15%, 15 min after training was considered as significant fatigue. 29 (63%) out of 46 patients developed significant fatigue. Patients with fatigue had a higher increase in 6-min walk distance (median (interquartile range) 57 (47-103) m versus 17 (-7-46) m; p=0.0023) and Chronic Respiratory Disease Questionnaire score (mean±sd 22±12 points versus 14±12 points; p=0.028) after the training programme compared with patients without fatigue. Improvements in quadriceps force and maximal exercise capacity were similar in both subgroups. Patients who develop quadriceps contractile fatigue during exercise training show greater training effects in terms of functional exercise capacity and health-related quality of life. PMID:22135284
Burtin, Chris; Saey, Didier; Saglam, Melda; Langer, Daniel; Gosselink, Rik; Janssens, Wim; Decramer, Marc; Maltais, François; Troosters, Thierry
Comparison of electrical and magnetic stimulations to assess quadriceps muscle function.
This study aimed to 1) compare electrical and magnetic stimulations for quadriceps muscle function assessment, and 2) ascertain whether the ratios of the second twitch elicited by supramaximal electrical and magnetic femoral nerve stimulation at 10 and 100 Hz (T2(10:100)) and the total twitch force elicited by the same types of stimulations (Fpaired(10:100)) are equivalent to the standard low- to high-frequency force ratio associated with submaximal electrical tetanic stimulations (Ftet(10:100)). Quadriceps force and vastus lateralis EMG were recorded at rest (n = 21 subjects), immediately after, and 30 min after a 30-min downhill run (n = 10) when 1) supramaximal electrical nerve stimulation (ENS), 2) magnetic nerve stimulation (MNS) and 3) submaximal electrical muscle stimulation (EMS) were delivered in random order at 1 (single stimulation), 10, and 100 Hz (paired stimulations). Ten- and 100-Hz 500-ms tetani were also evoked with EMS to determine Ftet(10:100). Before exercise, contractile properties with single and paired stimulations were similar for ENS and MNS (all intraclass correlation coefficients k > 0.90), but smaller for EMS (P < 0.001). M-wave characteristics were also similar for ENS and MNS (all k > 0.90). After exercise, changes in all parameters did not differ between methods. With fatigue, the changes in Ftet(10:100) were inconsistently correlated with the changes in T2(10:100) (r(2) = 0.24-0.73, P = 0.002-0.15) but better correlated with the changes in Fpaired(10:100) (immediately after exercise: r(2) = 0.80-0.83, P < 0.001; 30 min after exercise: r(2) = 0.46-0.82, P = 0.001-0.03). We conclude that ENS and MNS provide similar quadriceps muscle function assessment, while Fpaired(10:100) is a better index than T2(10:100) of low- to high-frequency fatigue of the quadriceps in vivo. PMID:18756009
Verges, Samuel; Maffiuletti, Nicola A; Kerherve, Hugo; Decorte, Nicolas; Wuyam, Bernard; Millet, Guillaume Y
A pilot randomised controlled trial of a home-based exercise programme aimed at improving endurance and function in adults with neuromuscular disorders
Aim To investigate the feasibility and effect of a home?based exercise programme on walking endurance, muscle strength, fatigue and function in people with neuromuscular disorders (NMDs). Methods 20 adults with NMDs recruited to a control (n?=?11) or exercise (n?=?9) group were assessed by blinded assessors at baseline and at week 8. Walking and strengthening exercises were given to the exercise group in an 8?week home exercise programme. A 2?min walk distance was the main outcome measurement; isometric muscle strength, fatigue and function were secondary measurements. Results 2?min walk distances were not found to change in either group (p>0.05; control: mean 14.50 (SD 22.06)?m; exercise: mean 2.88 (SD 20.08)?m), and no difference was observed in the change scores between groups (p>0.05). Leg muscle strength increased in the exercise group (p<0.05) but not in the control group (p>0.05). Significance was reached between the groups with respect to the difference in change in muscle strength scores in the right quadriceps (p<0.05; control: mean ?2.82 (SD 4.87) kg; exercise: mean ?7.08 (SD 2.82) kg). No change was observed in fatigue or function scores (p<0.05). Conclusions A home?based approach aimed at improving endurance in adults with NMDs is feasible and further investigation on a larger sample is warranted.
Dawes, H; Korpershoek, N; Freebody, J; Elsworth, C; van Tintelen, N; Wade, D T; Izadi, H; Jones, D H
Development and delivery of an exercise intervention for rheumatoid arthritis: strengthening and stretching for rheumatoid arthritis of the hand (SARAH) trial.
This paper describes the development and implementation of a hand exercise intervention for rheumatoid arthritis (RA) as part of a large multi-centred randomised controlled trial in a U.K. National Health Service (NHS) setting. Participants are eligible if diagnosed with RA according to American College of Rheumatology criteria, have a history of disease activity, functional deficit or impairment in the hand and/or wrist, and have been on a stable medication regime for at least 3 months. The intervention development was informed by the current evidence base, published guidelines, clinician and expert opinion, and a pilot study. The exercise programme targets known, potentially modifiable physical impairments of the hand with 5 exercise sessions and a home exercise component over a 12 week period. The intervention will be provided to 240 participants along with usual care. A further 240 will receive usual care only as part of the control arm. Specific details of the treatments delivered are described. [ISRCTN no: 89936343]. PMID:22507362
Heine, P J; Williams, M A; Williamson, E; Bridle, C; Adams, J; O'Brien, A; Evans, D; Lamb, S E
Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease
Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls. Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables. Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI –17.9 to –4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H2O v 204.8 cm H2O; 95% CI –5.4 to 50.6; p = 0.11). Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes.
Man, W; Hopkinson, N; Harraf, F; Nikoletou, D; Polkey, M; Moxham, J
Type II neurofibromatosis presenting as quadriceps atrophy.
A young woman aged 26 years presented with atrophy of the left quadriceps progressing over one year. Magnetic resonance imaging (MRI) showed a large lesion of the lumbar plexus compatible with neurinoma. Cerebral MRI revealed a lesion in the right eighth cranial nerve also compatible with neurinoma. On further questioning of the patient, it was learned that her mother had undergone surgery twice for acoustic neurinoma. Type II neurofibromatosis was diagnosed from the basis of clinical picture, neuroimaging findings and family history. This case is unusual for the lack of central nervous system (CNS) symptoms. Expansive radicular lesions compatible with neurinoma should prompt cerebral MRI. Regular examination of family members at risk and early diagnosis can decrease the high mortality associated with this condition. PMID:10935844
Grazzi, L; Chiapparini, L; Parati, E A; Giombini, S; D'Amico, D; Leone, M; Bussone, G
A new concept for isokinetic hamstring: quadriceps muscle strength ratio.
Conventionally, the hamstring:quadriceps strength ratio is calculated by dividing the maximal knee flexor (hamstring) moment by the maximal knee extensor (quadriceps) moment measured at identical angular velocity and contraction mode. The agonist-antagonist strength relationship for knee extension and flexion may, however, be better described by the more functional ratios of eccentric hamstring to concentric quadriceps moments (extension), and concentric hamstring to eccentric quadriceps moments (flexion). We compared functional and conventional isokinetic hamstring: quadriceps strength ratios and examined their relation to knee joint angle and joint angular velocity. Peak and angle-specific (50 degrees, 40 degrees, and 30 degrees of knee flexion) moments were determined during maximal concentric and eccentric muscle contractions (10 degrees to 90 degrees of motion; 30 and 240 deg/sec). Across movement speeds and contraction modes the functional ratios for different moments varied between 0.3 and 1.0 (peak and 50 degrees), 0.4 and 1.1 (40 degrees), and 0.4 and 1.4 (30 degrees). In contrast, conventional hamstring:quadriceps ratios were 0.5 to 0.6 based on peak and 50 degrees moments, 0.6 to 0.7 based on 40 degrees moment, and 0.6 to 0.8 based on 30 degrees moment. The functional hamstring:quadriceps ratio for fast knee extension yielded a 1:1 relationship, which increased with extended knee joint position, indicating a significant capacity of the hamstring muscles to provide dynamic knee joint stability in these conditions. The evaluation of knee joint function by use of isokinetic dynamometry should comprise data on functional and conventional hamstring:quadriceps ratios as well as data on absolute muscle strength. PMID:9548116
Aagaard, P; Simonsen, E B; Magnusson, S P; Larsson, B; Dyhre-Poulsen, P
Exercise increases utrophin protein expression in the mdx mouse model of Duchenne muscular dystrophy.
Introduction: Duchenne muscular dystrophy (DMD) is a lethal genetic disease caused by mutations in the dystrophin gene resulting in chronic muscle damage, muscle wasting, and premature death. Utrophin is a dystrophin protein homologue that increases dystrophic muscle function and reduces pathology. Currently, no treatments that increase utrophin protein expression exist. However, exercise increases utrophin mRNA expression in healthy humans. Therefore, the purpose was to determine whether exercise increases utrophin protein expression in dystrophic muscle. Methods: Utrophin protein was measured in the quadriceps and soleus muscles of mdx mice after 12 weeks of voluntary wheel running exercise or sedentary controls. Muscle pathology was measured in the quadriceps. Results: Exercise increased utrophin protein expression 334?±?63% in the quadriceps relative to sedentary controls. Exercise increased central nuclei 4?±?1% but not other measures of pathology. Conclusions: Exercise may be an intervention that increases utrophin expression in patients with DMD. Muscle Nerve 49: 915-918, 2014. PMID:24375286
Gordon, Bradley S; Lowe, Dawn A; Kostek, Matthew C
Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking.
The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. -1.45%, p < 0.001), RF (37.5% vs. -8.33%, p < 0.001), VM (12% vs. -12%, p < 0.018), and VL EMG activity (20% vs. -6.67%, p < 0.001) after dynamic stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching. PMID:24511339
Amiri-Khorasani, Mohammadtaghi; Kellis, Eleftherios
Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking
The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. ?1.45%, p < 0.001), RF (37.5% vs. ?8.33%, p < 0.001), VM (12% vs. ?12%, p < 0.018), and VL EMG activity (20% vs. ?6.67%, p < 0.001) after dynamic stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching.
Amiri-Khorasani, Mohammadtaghi; Kellis, Eleftherios
Quadriceps atrophy after knee traumatisms and immobilization: electrophysiological assessment.
Automatic analysis of EMG (T/A analysis) and invasive muscle fiber conduction velocity in situ (MFCV) were performed in 15 patients after traumatic lesions of the knee and immobilization with quadriceps atrophy. T/A analysis showed transient reduced number of turns, consistent with inhibition of quadriceps motoneurons, that recovered within the first 2 weeks after the plaster cast had been removed. MFCV was significantly slowed and showed a gradual improvement, reaching normal values after 6 weeks. These results suggest that decrement in activated motor units may be the cause of the disproportionate weakness of the quadriceps muscle on the first days after immobilization by the plaster cast. The recovery of MFCV was related with functional improvement of strength after the first weeks. PMID:10686470
Cruz-Martínez, A; Ramírez, A; Arpa, J
Non-invasive quantitative assessment of oxidative metabolism in quadriceps muscles by near infrared spectroscopy
Background—Near infrared spectroscopy can be used in non-invasive monitoring of changes in skeletal muscle oxygenation in exercising subjects. Objective—To evaluate whether this method can be used to assess metabolic capacity of muscles. Two distinctive variables abstracted from a curve of changes in muscle oxygenation were assessed. Methods—Exercise on a cycle ergometer was performed by 18 elite male athletes and eight healthy young men. A measuring probe was placed on the skin of the quadriceps muscle to measure reflected light at two wavelengths (760 and 850 nm), so that the relative index of muscle oxygenation could be calculated. Exercise intensity was increased from 50 W in 50 W increments until the subject was exhausted. During exercise, changes in muscle oxygenation and blood lactate concentration were recorded. The following two variables for assessment of muscle oxygenation were then abstracted and analysed by plotting curves of changes in muscle oxygenation: the rate of recovery of muscle oxygen saturation (RR) and the relative value of the effective decrease in muscle oxygenation (Deff). Results—Data analysis showed a correlation between muscle oxygenation and blood lactate concentration at the various exercise intensities and verified the feasibility of the experiment. Data for the athletes were compared with those for the controls using the Aspin-Welch test of significance; t = 2.3 and 2.86 for RR and Deff respectively. There were significant differences (p = 0.05) between the athletes and the control group with respect to these two variables. Conclusion—RR and Deff may be distinctive variables that can be used to characterise muscle oxidative metabolism during human body movement. Key Words: recovery; muscle; oxygen saturation; exercise; elite athletes
Ding, H; Wang, G; Lei, W; Wang, R; Huang, L; Xia, Q; Wu, J
Quantification Method Affects Estimates of Voluntary Quadriceps Activation
Introduction: The aim of this study was to investigate the effect of quantification method on estimates of voluntary quadriceps muscle activation. Methods: Twenty-two people with no history of serious lower extremity injuries underwent voluntary quadriceps activation testing at 60° of knee flexion. Estimates of quadriceps activation were derived with: 1) a formula based on the interpolated twitch technique, 2) the central activation ratio, and 3) a modified central activation ratio. Predictive equations were developed that describe the relationships between the three methods. Results: Significant differences (P < 0.001) were observed between the estimates of voluntary quadriceps muscle activation obtained using the three methods (ITT percent activation = 93.0 ± 6.4%, CAR = 95.9 ± 3.8%, modified CAR = 98.5 ± 4.1%). Excellent correlation (r = 0.995) was observed between ITT based percent activation and the CAR method. The associations between these methods and the modified CAR approach were weaker. Discussion: Quantification method affects activation estimates. The equations developed will assist scientists in accurately comparing results of studies that use different methods of quantifying activation.
Krishnan, Chandramouli; Williams, Glenn N.
Quadriceps EMG muscle activation during accurate soccer instep kicking
Six competitive soccer players were recruited to examine EMG activation in three quadriceps muscles during a kicking accuracy task. Participants performed three maximum instep place kicks of a stationary ball, 11 m perpendicular from the centre of the goal line towards targets (0.75 m) in the four corners of the goal. Surface EMG of the vastus lateralis, vastus medialis, and rectus
Joanna C. Scurr; Victoria Abbott; Nick Ball
Quantification method affects estimates of voluntary quadriceps activation.
The aim of this study was to investigate the effect of quantification method on estimates of voluntary quadriceps muscle activation. Twenty-two people with no history of serious lower extremity injuries underwent voluntary quadriceps activation testing at 60 degrees of knee flexion. Estimates of quadriceps activation were derived with: (1) a formula based on the interpolated twitch technique (ITT); (2) the central activation ratio (CAR); and (3) a modified central activation ratio. Predictive equations were developed that describe the relationships between the three methods. Significant differences (P < 0.001) were observed between the estimates of voluntary quadriceps muscle activation obtained using the three methods (ITT percent activation = 93.0 +/- 6.4%, CAR = 95.9 +/- 3.8%, modified CAR = 98.5 +/- 4.1%). Excellent correlation (r = 0.995) was observed between ITT-based percent activation and the CAR method. The associations between these methods and the modified CAR approach were weaker. Quantification method affects activation estimates. The equations developed will assist scientists in accurately comparing the results of studies that use different methods of quantifying activation. PMID:20229578
Krishnan, Chandramouli; Williams, Glenn N
The effects of exercise and neuromuscular electrical stimulation in subjects with knee osteoarthritis: a 3-month follow-up study
Background Strengthening exercises of the quadriceps femoris muscle (QFM) are beneficial for patients with knee osteoarthritis (OA). Studies reporting short-term effects of neuromuscular electrical stimulation (NMES) of the QFM in this population support the use of this modality as an adjunct treatment. The objectives of this follow-up study are to compare the effects of an exercise program with and without NMES of the QFM on pain, functional performance, and muscle strength immediately posttreatment and 12 weeks after completion of the intervention. Methods Sixty-three participants with knee OA were randomly assigned into two groups receiving 12 biweekly treatments: An exercise-only program or an exercise program combined with NMES. Results A significantly greater reduction in knee pain was observed immediately after treatment in the NMES group, which was maintained 12 weeks postintervention in both groups. Although at this stage NMES had no additive effect, both groups demonstrated an immediate increase in muscle strength and in functional abilities, with no differences between groups. Although the improvements in gait velocity and in self-report functional ability were maintained at the follow-up session, the noted improvements in muscle strength, time to up and go, and stair negotiation were not maintained. Conclusion Supplementing an exercise program with NMES to the QFM increased pain modulation immediately after treatment in patients with knee OA. Maintenance of the positive posttreatment effects during a 12-week period was observed only for pain, self-reported functional ability, and walk velocity, with no difference between groups. Clinical rehabilitation effect The effects of a comprehensive group exercise program with or without NMES are partially maintained 12 weeks after completion of the intervention. The addition of NMES is recommended primarily for its immediate effect on pain. Further studies are necessary to determine the effects of repeated bouts of exercise with and without NMES in this population.
Laufer, Yocheved; Shtraker, Haim; Elboim Gabyzon, Michal
Relationship between functional hamstring: quadriceps ratios and running economy in highly trained and recreational female runners.
Sundby, ŘH and Gorelick, MLS. Relationship between functional hamstring:quadriceps ratios and running economy in highly trained and recreational female runners. J Strength Cond Res 28(8): 2214-2227, 2014-The purpose of this study was to investigate the relationship between running economy (RE), functional hamstring:quadriceps peak torque ratios (f-H:Q), and flexibility among female runners. Seven highly trained (HT) female runners (age: 25.7 ± 4.7 years, V[Combining Dot Above]O2peak of 62.0 ± 4.8 ml·kg·min) and 11 recreational female runners (age of 28.8 ± 5.6 years, V[Combining Dot Above]O2peak of 49.2 ± 4.6 ml·kg·min) were measured for maximal aerobic power (V[Combining Dot Above]O2peak), RE, heart rate, respiratory exchange ratio, f-H:Q (Hecc:Qcon and Hcon:Qecc), and sit-and-reach hamstring/trunk flexibility. On 2 separate days, RE was measured on a treadmill at 1% grade at 2 velocities (160.9 and 201.2 m·min) for 6 minutes each, and isokinetic knee strength was measured at 3 angular velocities (60, 120, and 180°·s) for both concentric and eccentric muscle actions. The unpaired t-tests showed a consistent trend toward higher f-H:Q ratios at all angular velocities among the HT runners. Highly trained runners had significantly higher Hecc:Qcon at 120°·s (p ? 0.05) and 180°·s (p ? 0.05). Whole group correlations demonstrated a significant correlation between Hcon:Qecc at 180°·s and RE (ml·kg·km) at 201.2 m·min (R = -0.48, p ? 0.05). No significant relationships were found between flexibility, or hamstring and quadriceps peak torque (N·m) and RE (p > 0.05). This cross-sectional analysis suggests that higher f-H:Q torque ratios, and not muscle strength per se, are associated with a lower metabolic cost of running. Therefore, runners should consider implementing hamstring exercises to improve their f-H:Q ratios. PMID:24476769
Sundby, Oyvind H; Gorelick, Mark L S
Diminished sub-maximal quadriceps force control in anterior cruciate ligament reconstructed patients is related to quadriceps and hamstring muscle dyskinesia.
The aim of this study was to determine the effects of anterior cruciate ligament reconstruction (ACLR) on sub-maximal quadriceps force control with respect to quadriceps and hamstring muscle activity. Thirty ACLR individuals together with 30 healthy individuals participated. With real-time visual feedback of muscle force output and electromyographic electrodes attached to the quadriceps and hamstring muscles, subjects performed an isometric knee extension task where they increased and decreased their muscle force output at 0.128Hz within a range of 5-30% maximum voluntary capacity. The ACLR group completed the task with more error and increased medial hamstring and vastus medialis activation (p<0.05). Moderate negative correlations (p<0.05) were observed between quadriceps force control and medial (Spearman's rho=-0.448, p=0.022) and lateral (Spearman's rho=-0.401, p=0.034) hamstring activation in the ACLR group. Diminished quadriceps sub-maximal force control in ACLR subjects was reflective of medial quadriceps and hamstring dyskinesia (i.e., altered muscle activity patterns and coordination deficits). Within the ACLR group however, augmented hamstring co-activation was associated with better quadriceps force control. Future studies should explore the convergent validity of quadriceps force control in ACLR patients. PMID:24875460
Telianidis, Stacey; Perraton, Luke; Clark, Ross A; Pua, Yong-Hao; Fortin, Karine; Bryant, Adam L
Quadriceps femoris electromyogram during concentric, isometric and eccentric phases of fatiguing dynamic knee extensions.
The objective of this study was to examine the superficial quadriceps femoris (QF) muscle electromyogram (EMG) during fatiguing knee extensions. Thirty young adults were evaluated for their one-repetition maximum (1RM) during a seated, right-leg, inertial knee extension. All subjects then completed a single set of repeated knee extensions at 50% 1RM, to failure. Subjects performed a knee extension (concentric phase), held the weight with the knee extended for 2s (isometric phase), and lowered the weight in a controlled manner (eccentric phase). Raw EMG of the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) muscles were full-wave rectified, integrated and normalized to the 1RM EMG, for each respective phase and repetition. The EMG median frequency (f(med)) was computed during the isometric phase. An increase in QF muscle EMG was observed during the concentric phase across the exercise duration. VL EMG was greater than the VM and RF muscles during the isometric phase, in which no significant changes occurred in any of the muscles across the exercise duration. A significant decrease in EMG across the exercise duration was observed during the eccentric phase, with the VL EMG greater than the VM and RF muscles. A greater decrease in VL and RF muscle f(med) during the isometric phase, than the VM muscle, was observed with no gender differences. The findings demonstrated differential recruitment of the superficial QF muscle, depending on the contraction mode during dynamic knee extension exercise, where VL muscle dominance appears to manifest across the concentric-isometric-eccentric transition. PMID:16321626
Pincivero, Danny M; Gandhi, Varsha; Timmons, Mark K; Coelho, Alan J
Neuromuscular Electrical Stimulation of the Quadriceps in Patients with Non-Small Cell Lung Cancer Receiving Palliative Chemotherapy: A Randomized Phase II Study
Background A reduced exercise capacity is associated with increased morbidity and mortality in patients with advanced non-small cell lung cancer (NSCLC). Therapeutic exercise can be beneficial and neuromuscular electrical stimulation (NMES) of the quadriceps muscles may represent a practical approach. The primary aim of this study was to determine the acceptability of NMES of the quadriceps to patients with NSCLC used alongside palliative chemotherapy. Secondary aims explored aspects of safety and efficacy of NMES in this setting. Methods Patients with advanced NSCLC due to receive first-line palliative chemotherapy were randomized to usual care with or without NMES. They were asked to undertake 30 minute sessions of NMES, ideally daily, but as a minimum, three times weekly. For NMES to be considered acceptable, it was predetermined that ?80% of patients should achieve this minimum level of adherence. Qualitative interviews were held with a subset of patients to explore factors influencing adherence. Safety was assessed according to the Common Terminology Criteria for Adverse Events. Quadriceps muscle strength, thigh lean mass, and physical activity level were assessed at baseline and after three cycles of chemotherapy. Results 49 patients (28 male, median (IQR) age 69 (64?75) years) participated. Of 30 randomized to NMES, 18 were eligible for the primary endpoint, of whom 9 (50% [90% CI, 29 to 71]) met the minimum level of adherence. Adherence was enhanced by incorporating sessions into a daily routine and hindered by undesirable effects of chemotherapy. There were no serious adverse events related to NMES, nor significant differences in quadriceps muscle strength, thigh lean mass or physical activity level between groups. Conclusions NMES is not acceptable in this setting, nor was there a suggestion of benefit. The need remains to explore NMES in patients with cancer in other settings. Trial Registration Current Controlled Trials ISRCTN 42944026 www.controlled-trials.com/ISRCTN42944026
Maddocks, Matthew; Halliday, Vanessa; Chauhan, Alpna; Taylor, Victoria; Nelson, Annmarie; Sampson, Cathy; Byrne, Anthony
Influence of knee alignment on quadriceps cross-sectional area.
Previous studies of methods for stimulating the individual muscles composing the quadriceps femoris have not considered the structural features of a subject's knee joint. In this study, we compared the ratios of the individual muscles composing the quadriceps between subjects with different knee alignments using magnetic resonance (MR) imaging. A total of 18 healthy males were examined: 6 normal knees (age, 23.0+/-0.6 yr; femorotibial angle (FTA), 176.8+/-0.4 degrees), 6 genu varum (age, 21.8+/-2.9 yr; FTA, 181.7+/-2.6 degrees) and 6 genu valgum (age, 21.0+/-1.6 yr; FTA, 172.3+/-1.5 degrees). The cross-sectional areas (CSAs) of quadriceps muscles were obtained by MR imaging of the entire left thigh. The CSAs of the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM) and vastus intermedius (VI) muscles were obtained by MR imaging of the entire left thigh in a supine position. The VM/VL ratio was also obtained by dividing the CSA of the VM by that of the VL and compared among the three groups of subjects with different knee alignments. The genu varum group showed a significantly higher %CSA of VM in the CSA of the quadriceps (VM/Quad) (49.0+/-2.6%) than values for the other two groups. The genu valgum group showed significantly higher values of RF/Quad (15.2+/-2.1%) and VL/Quad (40.6+/-4.0%) than the other groups. The VM/VL ratio was significantly higher in the genu varum than in values for the other two groups. This difference in CSA, in respect to knee alignment, may be considered when devising muscle training programs. PMID:19698946
Sogabe, Akitoshi; Mukai, Naoki; Miyakawa, Shunpei; Mesaki, Noboru; Maeda, Kazuaki; Yamamoto, Tadashi; Gallagher, Philip M; Schrager, Matt; Fry, Andrew C
Strengthening of silicon Monel
In silicon Monel (S-Monel) the (Ni, Fe)3Si strengthening phase is formed. This phase is precipitated at a high rate from the solid solution during cooling in air from 1000–700°C and the alloy is considerably strengthened as the result. The alloy is additionally strengthened during aging at 600–650°C.
N. F. Lashko; K. P. Sorokina; A. N. Gorbunov
Effect of Knee Position on Quadriceps Muscle Force Steadiness and Activation Strategies
Introduction This study investigated the effect of knee position on quadriceps force steadiness and activation strategies. Methods Quadriceps force steadiness was evaluated in twenty-two volunteers at two knee positions by testing their ability to regulate submaximal force. Muscle activation strategies were studied in both time and frequency domains using surface electromyography. Results Quadriceps force fluctuations and the associated agonist and antagonist activity were significantly higher at 90° than at 30° of flexion (P < 0.05). The quadriceps median frequency recorded at 30° was significantly higher than at 90° of flexion (P < 0.05). Regression analyses revealed that force steadiness was related to quadriceps activation and median frequency (P < 0.001), but not to hamstring coactivation (P > 0.05). Discussion The results indicate that knee position significantly affects quadriceps force steadiness and activation strategies. This finding may have important implications for designing a force control testing protocol and interpreting test results.
Krishnan, Chandramouli; Allen, Eric J.; Williams, Glenn N.
Effects of Kinesiology Taping on Repositioning Error of the Knee Joint after Quadriceps Muscle Fatigue
[Purpose] The purpose of this study was to identify the effects of kinesiology taping on repositioning error of the knee joint after quadriceps muscle fatigue. [Subjects] Thirty healthy adults with no orthopaedic or neurological problems participated in this study. [Methods] The repositioning error of the knee joint was measured using a digital goniometer when the subjects extended their dominant-side knee to a random target angle (30°, 45°, or 60°) with their eyes closed, before and after a quadriceps muscle fatigue protocol, and after application of kinesiology tape. [Results] We found that repositioning errors of the dominant-side knee joint increased after quadriceps fatigue compared with no-fatigue conditions. However, kinesiology taping of the quadriceps muscle and patella after quadriceps fatigue significantly decreased repositioning errors of the knee joint. [Conclusion] These results suggest that quadriceps fatigue increases the repositioning error of the knee joint, whereas application of kinesiology tape decreases fatigue-induced joint repositioning error.
Han, Jin Tae; Lee, Jung-hoon
Quadriceps strength and weight acceptance strategies continue to improve two years after anterior cruciate ligament reconstruction
The anterior cruciate ligament (ACL) is the most commonly-injured knee ligament during sporting activities. After injury, most individuals experience episodes of the knee giving way during daily activities (non-copers). Non-copers demonstrate asymmetrical quadriceps strength and movement patterns which could have long-term deleterious effects on the integrity of the knee joint. The purpose of this study was to determine if non-copers resolve their strength and movement asymmetries within two years after surgery. 26 non-copers were recruited to undergo pre-operative quadriceps strength testing and 3-dimensional gait analysis. Subjects underwent surgery to reconstruct the ligament followed by physical therapy focused on restoring normal range of motion, quadriceps strength, and function. Subjects returned for quadriceps strength testing and gait analysis six months and two years after surgery. Acutely after injury, quadriceps strength was asymmetric between limbs, but resolved six months after surgery. Asymmetric knee angles, knee moments, and knee and hip power profiles were also observed acutely after injury and persisted six months after surgery despite subjects achieving symmetrical quadriceps strength. Two years after surgery, quadriceps strength in the involved limb continued to improve and most kinematic and kinetic asymmetries resolved. These findings suggest that adequate quadriceps strength does not immediately resolve gait asymmetries in non-copers. They also suggest that non-copers have the capacity to improve their quadriceps strength and gait symmetry long after ACL reconstruction.
Roewer, Ben D.; Di Stasi, Stephanie L.; Snyder-Mackler, Lynn
Quadriceps muscle function characteristics in severely obese and nonobese adolescents.
The purpose of this cross-sectional study was to compare quadriceps muscle strength and fatigue between severely obese (body mass index 34 kg/m2) and nonobese adolescents. Maximal isokinetic torque and angle of peak torque as well as isometric torque at short (40 degrees of knee flexion) and long (80 degrees of knee flexion) muscle length were measured using an isokinetic dynamometer. Muscle fatigue was quantified as the percent torque loss during an isokinetic voluntary protocol and an electrical stimulation isometric protocol. Obese adolescents produced greater absolute isokinetic (+16%; P < 0.05) and isometric torque at short (+25%; P < 0.01) but not at long muscle length (P > 0.05) compared to their lean counterparts. The angle of peak torque was significantly lower in obese than in nonobese subjects (-11%; P < 0.05), i.e., obese produced their maximal strength at shorter muscle length. Isokinetic and isometric torque normalized to the fat-free mass were not significantly different between the two groups. No significant difference in voluntary and stimulated torque loss was observed between groups. Muscle strength per unit of fat-free mass and muscle fatigue were similar in the obese and nonobese adolescents tested in this study, therefore suggesting that obesity has little or no effect on quadriceps muscle function characteristics. On the other hand, it remains to be confirmed whether the observed quadriceps muscle length specificity contributes to the reduced functional capacity of obese adolescents during complex motor tasks involving deep knee flexion (squatting, kneeling). PMID:18389275
Maffiuletti, Nicola A; Jubeau, Marc; Agosti, Fiorenza; De Col, Alessandra; Sartorio, Alessandro
Primary Tuberculous Pyomyositis of Quadriceps Femoris in an Immunocompetent Individual
Primary tuberculous pyomyositis is a rare manifestation of musculoskeletal tuberculosis especially in immunocompetent individuals without a focus of tuberculosis in the body and the underlying bone disease. It can cause a diagnostic dilemma for a physician and surgeon because of its similar presentation to soft tissue sarcomas, hematomas, and myopathies. We present a case of a 45-year-old immunocompetant gentleman with a thigh swelling with sepsis due to pyomyositis of the quadriceps requiring a multimodal management of drainage of abscess, debridement of devitalized muscle, antitubercular drugs, and physiotherapy. In a tubercular endemic country, a high index of suspicion is required to diagnose this disease which can be cured completely.
Modi, M. A.; Mate, A. D.; Nasta, A. M.; Gvalani, A. K.
Electrode Type and Placement Configuration for Quadriceps Activation Evaluation
Context: The ability to accurately estimate quadriceps voluntary activation is an important tool for assessing neuromuscular function after a variety of knee injuries. Different techniques have been used to assess quadriceps volitional activation, including various stimulating electrode types and electrode configurations, yet the optimal electrode types and configurations for depolarizing motor units in the attempt to assess muscle activation are unknown. Objective: To determine whether stimulating electrode type and configuration affect quadriceps central activation ratio (CAR) and percentage-of-activation measurements in healthy participants. Design: Crossover study. Setting: Research laboratory. Patients and Other Participants: Twenty participants (13 men, 7 women; age = 26 ± 5.3 years, height = 173.85 ± 7.3 cm, mass = 77.37 ± 16 kg) volunteered. Intervention(s): All participants performed 4 counter-balanced muscle activation tests incorporating 2 different electrode types (self-adhesive, carbon-impregnated) and 2 electrode configurations (vastus, rectus). Main Outcome Measure(s): Quadriceps activation was calculated with the CAR and percentage-of-activation equations, which were derived from superimposed burst and resting torque measurements. Results: No differences were found between conditions for CAR and percentage-of-activation measurements, whereas resting twitch torque was higher in the rectus configuration for both self-adhesive (216 ± 66.98 Nm) and carbon-impregnated (209.1 ± 68.22 Nm) electrodes than in the vastus configuration (209.5 ± 65.5 Nm and 204 ± 62.7 Nm, respectively) for these electrode types (F1,19 = 4.87, P = .04). In addition, resting twitch torque was greater for both electrode configurations with self-adhesive electrodes than with carbon-impregnated electrodes (F1,19 = 9.33, P = .007). Bland-Altman plots revealed acceptable mean differences for agreement between electrode type and configuration for CAR and percentage of activation, but limits of agreement were wide. Conclusions: Although these electrode configurations and types might not necessarily be able to be used interchangeably, differences in electrode type and configuration did not seem to affect CAR and percentage-of-activation outcome measures.
Pietrosimone, Brian G.; Selkow, Noelle M.; Ingersoll, Christopher D.; Hart, Joseph M.; Saliba, Susan A.
Anterior-posterior and rotational displacement of the tibia elicited by quadriceps contraction
The anterior-posterior displacement and rotation of the tibia elicited by isolated loading of the quadriceps mus cle was determined as a function of joint angle and muscle load using a computerized radiographic tech nique. Data collected from 12 fresh-frozen cadaveric knees demonstrated that quadriceps contraction can result in significant (<7 mm) anterior displacement of the tibia in the range of
Shunji Hirokawa; Moshe Solomonow; Yun Lu; Zong-Ping Lou; Robert DAmbrosia
Study of the fatigue curve in quadriceps and hamstrings of soccer players during isokinetic endurance testing.
Many studies have presented regression models of quadriceps (Q) muscle strength loss with fatigue development. Paradoxically, the hamstrings (H), which are the principal site of muscle injury in soccer players, have received little attention, and no regression model has been established. This study investigated strength loss in the Q and H to establish a regression model using the lowest number of flexions-extensions during isokinetic endurance testing. Twenty-four semiprofessional soccer players performed 50 flexion-extension movements at 180 degrees x s(-1) on an isokinetic dynamometer. The theoretical equations were calculated from the first 10, first 15, first 20, and first 25 contractions for each muscle group by several regression models (linear, quadratic, cubic). The linear model was the best fit to this exercise protocol to describe the strength loss in both muscle groups. The quadratic model was the best fit to predict the changes in the H/Q ratio. This study showed that a regression model can be established for both muscle groups. A minimum of 20 extensions and 15 flexions was needed to establish a linear model that represented strength loss in, respectively, Q and H. A minimum of 25 flexions-extensions was needed with the quadratic model to accurately determine the decrease in the H/Q ratio. Isokinetic endurance testing can be carried out with only 25 flexions-extensions. This reduction should facilitate the implementation of this protocol. Regular evaluation would contribute to the efforts to prevent muscle injury during competitive sports activity. PMID:18714243
Sangnier, Sébastien; Tourny-Chollet, Claire
FRP : Strengthened RC Structures
NASA Astrophysics Data System (ADS)
The strengthening of reinforced concrete (RC) structures using advanced fibre-reinforced polymer (FRP) composites, and in particular the behaviour of FRP-strengthened RC structures is a topic which has become very popular in recent years. This popularity has arisen due to the need to maintain and upgrade essential infrastructure in all parts of the world, combined with the well-known advantages of FRP composites, such as good corrosion resistance and ease for site handling due to their light weight. The continuous reduction in the material cost of FRP composites has also contributed to their popularity. While a great amount of research now exists in the published literature on this topic, it is scattered in various journals and conference proceedings. This book therefore provides the first ever comprehensive, state-of-the-art summary of the existing research on FRP strengthening of RC structures, with the emphasis being on structural behaviour and strength models. The main topics covered include: Bond behaviour Flexural and shear strengthening of beams Column strengthening Flexural strengthening of slabs. For each area, the methods of strengthening are discussed, followed by a description of behaviour and failure modes and then the presentation of rational design recommendations, for direct use in practical design of FRP strengthening measures. Researchers, practicing engineers, code writers and postgraduate students in structural engineering and construction materials, as well as consulting firms, government departments, professional bodies, contracting firms and FRP material suppliers will find this an invaluable resource.
Teng, J. G.; Chen, J. F.; Smith, S. T.; Lam, L.
Post-exercise alcohol ingestion exacerbates eccentric-exercise induced losses in performance.
The effect of acute alcohol intake on muscular performance in both the exercising and non-exercising legs in the days following strenuous eccentric exercise was investigated to ascertain whether an interaction between post-exercise alcohol use and muscle damage causes an increase in damage-related weakness. Ten healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed either a beverage containing 1 g of ethanol per kg bodyweight ethanol (as vodka and orange juice; ALC) or a non-alcoholic beverage (OJ). At least 2 weeks later they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed the other beverage. Measurement of peak and average peak isokinetic (concentric and eccentric) and isometric torque produced by the quadriceps of both exercising and non-exercising legs was made before and 36 and 60 h post-exercise. Greatest decreases in exercising leg performance were observed at 36 h with losses of 28.7, 31.9 and 25.9% occurring for OJ average peak isometric, concentric, and eccentric torques, respectively. However, average peak torque loss was significantly greater in ALC with the same performance measures decreasing by 40.9, 42.8 and 44.8% (all p < 0.05). Performance of the non-exercising leg did not change significantly under either treatment. Therefore, consumption of moderate amounts of alcohol after damaging exercise magnifies the loss of force associated with strenuous eccentric exercise. This weakness appears to be due to an interaction between muscle damage and alcohol rather than the systemic effects of acute alcohol consumption. PMID:20012446
Barnes, Matthew J; Mündel, Toby; Stannard, Stephen R
Quadriceps EMG muscle activation during accurate soccer instep kicking.
Six competitive soccer players were recruited to examine EMG activation in three quadriceps muscles during a kicking accuracy task. Participants performed three maximum instep place kicks of a stationary ball, 11 m perpendicular from the centre of the goal line towards targets (0.75 m(2)) in the four corners of the goal. Surface EMG of the vastus lateralis, vastus medialis, and rectus femoris of the kicking leg was normalized and averaged across all participants to compare between muscles, targets, and the phase of the kick. Although no significant difference were observed between muscles or kick phases, kicks to the right targets produced significantly greater muscle activity than those towards the left targets (P < 0.01). In addition, kicks towards the top right target demonstrated significantly greater muscle activity than towards the top and bottom left (P < 0.01). Under accurate soccer shooting conditions, kicks aimed to the top right corner of the goal demonstrated a higher level of quadriceps muscle activation than those towards the other corners. PMID:21170796
Scurr, Joanna C; Abbott, Victoria; Ball, Nick
MedlinePLUS Videos and Cool Tools
... strengthening that you did when you didn't move the joint, that you just held the joint in one position and tightened the muscles around it, was the best and the safest thing. However, now we know that isometric exercise can ...
Novel treatment of a failed quadriceps tendon repair in a diabetic patient using a patella-quadriceps tendon allograft.
Recurrent quadriceps tendon rupture is a debilitating condition that may be challenging to treat, especially in the presence of systemic disease such as diabetes mellitus (Bedi et al., J Shoulder Elbow Surg 19:978-988, 2010; Chbnou and Frenette, Am J Physiol Regul Integr Comp Physiol 5:R952-R957, 2004; Chen et al., J Shoulder Elbow Surg 5:416-421, 2003). Many surgical treatment protocols have been proposed (Azar, in Canale and Beatty, eds., Campbell's Operative Orthopedics, Mosby/Elsevier, Philadelphia, PA, 2008; Ilan et al., J Am Acad Orthop Surg 3:192-200, 2003; Rodeo and Izawa, in Garrett et al., eds., Principles and Practice of Orthopedic Sports Medicine, Lippincott Williams & Wilkins, Philadelphia, PA, 2000). We report the case of a diabetic male with multiple treatment failures. He ultimately sustained a good outcome following treatment with a novel surgical technique that utilized a patella quadriceps tendon allograft. Tendon allograft-to-native bone healing had previously failed in this patient, so we used a bone-tendon construct allograft to provide an allograft bone-to-native bone healing site. Now, 13 months postoperative, the patient has increased strength, minimal pain, 20 ° of extensor lag and 130 ° of flexion. PMID:24426867
Druskin, Sasha C; Rodeo, Scott A
... and Knee Replacement Rehabilitation News News Multimedia Resources Knee Exercises | If my knee hurts, why exercise? | How do I start exercising? | ... Exercises Print Article Text Size: + | - Next If my knee hurts, why exercise? Having strong, flexible muscles is ...
[Reconstruction of quadriceps femoris muscle function with muscle transfer].
Femoral nerve palsy, mostly of iatrogen cause, leads to paresis of quadriceps muscle with complete loss of knee extension. Therapeutical options include neurolysis, nerve reconstruction or functional muscle transplantations. Another concept is the transfer of hamstring muscles as described in post polio surgery. We describe our experience of biceps femoris and semitendinosus muscle transfer for reconstruction of knee extension. From 2003 to 2007 seven patients (mean age 43) with complete loss of knee extension after femoral nerve lesion were treated. Nerve palsy was caused by direct lesion, traction, hematoma after collapse, lesion of lumbosacral plexus and an unclear muscle dystrophy. Indication for muscle transfer was due to long standing muscle paresis. All patients received a transfer of biceps femoris and semitendinosus muscle/tendon into the quadriceps tendon. Patients were immobilised in a cast for 6 weeks in extended knee position. Weight bearing started after 8 weeks. Operations went uneventfully. All patients were able to extend the knee postoperatively against gravity and were able to climb stairs without help. 4 Patients had complete knee extension, 2 had a lack of 20 degrees , one of 30 degrees. Daily routine was possible in all cases. No instability of knee joints occurred postoperatively. In a nerve lesion close to the muscle a nerve reconstruction should be aimed. If not performed or with unsuccessful outcome, muscle transfer is a good option to restore function. All recent studies describe good to excellent results with stable knees, allowing the patient to manage daily routine without assistance and to climb stairs up and down. Long term complications such as dislocation of patella or genu recurvatum were not observed in our patients. The latter results as typical complication in polio from weakening knee flexion through biceps femoris transfer, if the gastrocnemius muscle is not forceful enough. However in an isolated femoral nerve lesion this will rarely occur. PMID:20235008
Fansa, H; Meric, C
EMG-based measures of fatigue during a repetitive squat exercise
We have demonstrated a technique to calculate the EMG instantaneous median frequency to assess muscle fatigue during a dynamic exercise commonly prescribed in patients with ACL deficiency. We used Cohen-Posch time-frequency representations to improve upon the variability of the instantaneous median frequency estimates derived using Cohen Class transformations. The technique was applied to surface EMG data recorded from the quadriceps
P. Bonato; M. S. S. Heng; J. Gonzalez-Cueto; A. Leardini; J. O'Connor; S. H. Roy
Spontaneous, bilateral, quadriceps tendon rupture caused by local exposure to methidathion
Spontaneous, bilateral, quadriceps tendon rupture is a rare injury. Many predisposing conditions have been reported that contribute to quadriceps tendon degeneration. We report a case of a 42-year-old farmer with spontaneous, bilateral, quadriceps tendon rupture and clear medical history. Clinical and laboratory investigations revealed no risk factors for tendon degeneration but the patient reported that he was exposed locally to methidathion 1 week before the rupture. Methidathion is an organophosphate insecticide commonly used in agriculture that is highly toxic via the dermal route. Methidathion induces lipid pre-oxidation and consequently alters quadriceps tendon blood supply and ultrastructure. The injury was treated with early surgical repair and final outcome was excellent 44 months postoperatively.
Papastergiou, Stergios G; Koukoulias, Nikolaos E; Ziogas, Evangelos; Dimitriadis, Theofilos; Koumis, Panagiotis
Spontaneous, bilateral, quadriceps tendon rupture caused by local exposure to methidathion.
Spontaneous, bilateral, quadriceps tendon rupture is a rare injury. Many predisposing conditions have been reported that contribute to quadriceps tendon degeneration. We report a case of a 42-year-old farmer with spontaneous, bilateral, quadriceps tendon rupture and clear medical history. Clinical and laboratory investigations revealed no risk factors for tendon degeneration but the patient reported that he was exposed locally to methidathion 1 week before the rupture. Methidathion is an organophosphate insecticide commonly used in agriculture that is highly toxic via the dermal route. Methidathion induces lipid pre-oxidation and consequently alters quadriceps tendon blood supply and ultrastructure. The injury was treated with early surgical repair and final outcome was excellent 44 months postoperatively. PMID:22114623
Papastergiou, Stergios G; Koukoulias, Nikolaos E; Ziogas, Evangelos; Dimitriadis, Theofilos; Koumis, Panagiotis
Strength and physiological response to exercise in patients with chronic fatigue syndrome
OBJECTIVE—To measure strength, aerobic exercise capacity and efficiency, and functional incapacity in patients with chronic fatigue syndrome (CFS) who do not have a current psychiatric disorder.?METHODS—Sixty six patients with CFS without a current psychiatric disorder, 30 healthy but sedentary controls, and 15 patients with a current major depressive disorder were recruited into the study. Exercise capacity and efficiency were assessed by monitoring peak and submaximal oxygen uptake, heart rate, blood lactate, duration of exercise, and perceived exertion during a treadmill walking test. Strength was measured using twitch interpolated voluntary isometric quadriceps contractions. Symptomatic measures included physical and mental fatigue, mood, sleep, somatic amplification, and functional incapacity.?RESULTS—Compared with sedentary controls, patients with CFS were physically weaker, had a significantly reduced exercise capacity, and perceived greater effort during exercise, but were equally unfit. Compared with depressed controls, patients with CFS had significantly higher submaximal oxygen uptakes during exercise, were weaker, and perceived greater physical fatigue and incapacity. Multiple regression models suggested that exercise incapacity in CFS was related to quadriceps muscle weakness, increased cardiovascular response to exercise, and body mass index. The best model of the increased exercise capacity found after graded exercise therapy consisted of a reduction in submaximal heart rate response to exercise.?CONCLUSIONS—Patients with CFS were weaker than sedentary and depressed controls and as unfit as sedentary controls. Low exercise capacity in patients with CFS was related to quadriceps muscle weakness, low physical fitness, and a high body mass ratio. Improved physical fitness after treatment was associated with increased exercise capacity. These data imply that physical deconditioning helps to maintain physical disability in CFS and that a treatment designed to reverse deconditioning helps to improve physical function.??
Fulcher, K.; White, P.
"Central" Quadriceps Tendon Harvest With Patellar Bone Plug: Surgical Technique Revisited
The objective of this article is to review the surgical technique for quadriceps tendon graft harvest while highlighting an additional technical note that has not been previously emphasized. The quadriceps tendon typically inserts eccentrically on the superior pole of the patella. By shifting the soft-tissue harvest to a location just off the medial edge of the tendon, the adjoining patellar bone plug will be centered on the superior pole of the patella, reducing the risk of an iatrogenic patellar fracture.
Scully, William F.; Wilson, David J.; Arrington, Edward D.
Bilateral simultaneous complete quadriceps rupture following chronic symptomatic tendinopathy: a case report
Introduction Quadriceps rupture is a disabling injury mostly seen in men over 40 years of age. Bilateral quadriceps rupture is a rare injury that is often secondary to predisposing medical conditions. Ultrasound is a cheap and reliable tool for diagnosis but is operator dependent. Thus, magnetic resonance imaging is the preferred method of investigation despite its cost and availability. Prompt diagnosis and early surgical repair are needed for an optimal end result. Case presentation We report the case of a healthy 54-year-old Caucasian male farmer who presented with bilateral simultaneous complete quadriceps rupture, which was managed surgically and he was followed up for three years. He was previously under our care for enthesopathy of the quadriceps on both sides. We believe that chronic enthesopathy of the superior pole of patella made his quadriceps susceptible to complete rupture on eccentric loading. Conclusion Only a few cases of bilateral simultaneous complete quadriceps rupture in patients with symptomatic enthesopathy have been previously reported. We stress the importance of warning patients of the risk of developing complete tendon rupture when they present with an enthesopathy around the knee.
Ventilatory requirements of quadriceps resistance training in people with COPD and healthy controls
Background It is proposed that resistance training (RT) does not activate the cardiopulmonary system to the same extent as whole-body exercise. This is important for patients with chronic obstructive pulmonary disease (COPD) who are ventilatory limited. Objective The aim was to assess the ventilatory response to an isokinetic quadriceps RT program in people with COPD and healthy controls. Design Observational. Registration number ISRCTN22764439. Setting Outpatient, university teaching hospital. Participants and outcome measures People with COPD (n=14) and healthy controls (n=11) underwent breath-by-breath analysis of their ventilation during an RT session (five sets of 30 maximal knee extensions at 180°/sec). Subjects performed a maximal cycle ergometry test (CET) at baseline. Peak ventilation (VE; L/min) and oxygen consumption (VO2; mL/kg/min) were collected. The same system measured VO2 and VE during the RT session. Parameters are presented as a percentage of the maximal CET. Isokinetic workload, symptom scores, heart rate (HR), and oxygen saturation were documented post-training. Results People with COPD worked at higher percentages of their maximal capacity than controls (mean range between sets 1–5 for VO2 =49.1%–60.1% [COPD], 45.7%–51.43% [controls] and for VE =57.6%–72.2% [COPD], 49.8%–63.6% [controls]), although this was not statistically significant (P>0.1 in all cases). In absolute terms, the difference between groups was only significant for actual VO2 on set 2 (P<0.05). Controls performed more isokinetic work than patients with COPD (P<0.05). Median Borg symptom scores after RT were the same in both groups (3 breathlessness, 13 exertion), no de-saturation occurred, and both groups were training at ?65% of their maximum HR. Conclusion No statistically significant differences were found between people with COPD and healthy controls for VO2 and VE achieved during training. The symptoms associated with training were within acceptable limits.
Houchen-Wolloff, Linzy; Sandland, Carolyn J; Harrison, Samantha L; Menon, Manoj K; Morgan, Mike D; Steiner, Michael C; Singh, Sally J
Corticospinal and intracortical excitability of the quadriceps in active older and younger healthy adults.
Age-related declines in neuromuscular function are well-documented, though the mechanisms underlying these deficits are unclear. Specific changes in corticospinal and intracortical neurophysiology may contribute, but have not been well studied, especially in lower extremity muscles. Furthermore, variations in physical activity levels may potentially confound the interpretation of neurophysiologic findings. Therefore, the purpose of this study was to quantify differences in transcranial magnetic stimulation (TMS) measures of corticospinal and intracortical excitability of the quadriceps between healthy, active older and younger adults. Twenty younger (age: 25.2 ± 2.4 years; body mass index [BMI]: 22.1 ± 3.0 kg/m(2); 11 males and 9 females) and twenty older (age: 67.7 ± 5.5 years; BMI: 26.8 ± 3.8 kg/m(2); 11 males and 9 females) subjects who exercised regularly (at least 30 min, 3 times/week) completed testing. Motor evoked potentials (MEPs) were measured by superficial electromyographic recordings of the vastus lateralis (VL). Measures of corticospinal excitability using a double cone TMS coil included resting motor thresholds (RMT), resting recruitment curves (RRCs) and silent periods (SP). Intracortical excitability was measured using paired pulse paradigms for short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). No statistically significant differences between older and younger adults were found for RMT, RRC slopes, SP, SICI or ICF measures (p>0.05). The physically active nature of the older adults included in this study may have contributed to the lack of differences in corticospinal and intracortical excitability since physical activity in older adults attenuates age-related declines in neuromuscular function. PMID:22951029
Stevens-Lapsley, Jennifer E; Thomas, Abbey C; Hedgecock, James B; Kluger, Benzi M
Corticospinal and Intracortical Excitability of the Quadriceps in Active Older and Younger Healthy Adults
Age-related declines in neuromuscular function are well-documented, though the mechanisms underlying these deficits are unclear. Specific changes in corticospinal and intracortical neurophysiology may contribute, but have not been well studied, especially in lower extremity muscles. Furthermore, variations in physical activity levels may potentially confound the interpretation of neurophysiologic findings. Therefore, the purpose of this study was to quantify differences in transcranial magnetic stimulation (TMS) measures of corticospinal and intracortical excitability of the quadriceps between healthy, active older and younger adults. Twenty younger (age: 25 ± 2.4 years; body mass index [BMI]: 22.1 ± 2.96 kg/m2; 11 males and 9 females) and twenty older (age: 68 ± 5.5 years; BMI: 26.8 ± 3.78 kg/m2; 11 males and 9 females) subjects who exercised regularly (at least 30 minutes, 3 times/week) completed testing. Motor evoked potentials (MEPs) were measured by superficial electromyographic recordings of the vastus lateralis (VL). Measures of corticospinal excitability using a double cone TMS coil included resting motor thresholds (RMT), resting recruitment curves (RRC) and silent periods (SP). Intracortical excitability was measured using paired pulse paradigms for short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). No statistically significant differences between older and younger adults were found for RMT, RRC slopes, SP, SICI or ICF measures (p>0.05). The physically active nature of the older adults included in this study may have contributed to the lack of differences in corticospinal and intracortical excitability since physical activity in older adults attenuates age-related declines in neuromuscular function.
Stevens-Lapsley, Jennifer E.; Thomas, Abbey C.; Hedgecock, James B.; Kluger, Benzi M.
Effect of eccentric isokinetic strengthening in the rehabilitation of patients with knee osteoarthritis: Isogo, a randomized trial
Background Femorotibial knee osteoarthritis is associated with muscle weakness in the lower limbs, particularly in the quadriceps, which results in disease progression. The interest of having muscular strengthening as part of the therapeutic arsenal for the medical treatment of knee osteoarthritis is now well established. The functional disability induced by knee osteoarthritis manifests itself principally when walking, notably downhill, during which the muscles are called upon to contract eccentrically. We can therefore think that eccentric muscular strengthening could bring a functional benefit that is superior to concentric muscular strengthening. Methods/Design This is a prospective, randomized, bicenter, parallel-group, international study. Eighty patients aged from 40 to 75 years old, suffering from medical-stage knee osteoarthritis, will undertake 6 weeks of isokinetic muscular strengthening. Randomization determines the mode of muscular strengthening: either exclusively eccentric or exclusively concentric. The principal objective is to demonstrate the superiority of the improvement in the quadriceps isokinetic torque after isokinetic muscular strengthening by the eccentric mode compared to the concentric mode. The following parameters are also evaluated: the variations in the level of pain, the parameters of walking (maximum speed over 10 and 200 meters, analysis on a computerized Gaitrite™ treadmill), static equilibrium (on a FUSYO™ force platform), and the functional status of the patient using the Western Ontario and MacMaster Universities osteoarthritis index (WOMAC) questionnaire after the strengthening period and at 6 months. Discussion A better knowledge of the most effective mode of muscular strengthening is needed to optimize the functional benefits to the patients. In case of superiority in terms of efficacy of the eccentric mode, the latter could be given priority in the rehabilitation treatment of knee osteoarthritis patients. Trial registration Clinical trials.gov number: NCT01586130.
The effect of beta-blockade on plasma potassium concentrations and muscle excitability following static exercise
The effects of ?-blockade on plasma [K+], muscle excitability and force during fatiguing exercise were examined. Nine healthy males (mean age 22.3±1.7 yr) performed\\u000a a 3-min fatigue protocol that consisted of a sustained submaximal contraction (30% of the maximal voluntary contraction, MVC)\\u000a of the right quadriceps muscle. Subjects performed the exercise after treatment with either placebo, ?1-selective (metoprolol, 100 mg) or an
Karen Unsworth; A. Hicks; Robert McKelvie
Strengthening America's Families.
ERIC Educational Resources Information Center
Improving parenting practices and the family environment is the most effective, enduring strategy for combating juvenile delinquency. Describes the Office of Juvenile Justice and Delinquency Prevention's Strengthening America's Families Initiative. Highlights several family-focused prevention programs identified as exemplary, explaining how they…
Alvarado, Rose; Kumpfer, Karol
Dispersion strengthened copper
A composition of matter is described which is comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide. A method for making this composition of matter is also described. This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals.
Sheinberg, H.; Meek, T.T.; Blake, R.D.
Isometric and isokinetic measurement of hamstring and quadriceps strength.
This study evaluates quadriceps strength at varying movement velocities in a group of healthy subjects. Specific objectives included (1) investigating the effect of angular velocity on peak torque (PT) (2) investigating the effect of angular velocity on joint angle at peak torque (JAPT) and (3) evaluating whether the use of a relatively new isokinetic testing device yields new insights to previously accepted relationships between angular velocity and PT or JAPT. Twenty healthy subjects were tested for isometric and isokinetic knee extension and flexion strength on a LIDO Active Isokinetic Rehabilitation System at velocities of 0 degrees, 60 degrees, 120 degrees, and 180 degrees/sec. Isometric PT (0 degrees/sec) was found to be highly correlated with isokinetic PT for both extensors and flexors at all velocities (r = .88-.93, p less than .01). PT declined significantly as angular velocity increased for both extension (p less than .01) and flexion (p less than .05). A relationship between isometric and isokinetic JAPT was significant for extension only at 60 degrees and 180 degrees/sec (r = .48-.52, p less than .05). These results indicate that knee isometric and isokinetic PT as measured on the LIDO Active system are highly related for both extension and flexion. PT declined as isokinetic angular velocity increased. Isometric and isokinetic JAPT are significantly related only for extension. PMID:1554304
Lord, J P; Aitkens, S G; McCrory, M A; Bernauer, E M
Maximal voluntary quadriceps strength patterns in Olympic overtrained athletes.
Peak torques were studied in 10 elite male overtrained athletes and 10 controls matched for sex, age, sport, and performance level. Isokinetic concentric (CON) and eccentric (ECC) maximal voluntary contractions (MVC) of quadriceps muscle were assessed at the angular velocities of 60 degrees, 120 degrees, and 180 degrees.s-1. Sustained isometric MVCs were also measured at knee angles of 10 degrees, 45 degrees, and 80 degrees of flexion. Six seconds after the beginning of each isometric MVC, a 40-Hz electrical stimulation was superimposed on the MVC for a further 6 s. The overtrained subjects developed significantly smaller CON peak torques at 180 degrees.s-1 (P < 0.001), although ECC torques were similar at all three velocities. ECC/CON ratios were higher in the overtrained subjects at 120 degrees.s-1 (P < 0.01) and 180 degrees.s-1 (P < 0.001) compared with the controls. Isometric MVCs at 10 degrees and 45 degrees knee flexion were lower in the overtrained at P < 0.01 and P < 0.05, respectively. Also in the overtrained subjects, at knee angle of 10 degrees, the addition of the electrical stimulation to the isometric MVC produced an increase (P < 0.05) in torque levels. It is suggested that impaired central drive may account for the present findings. PMID:7791588
Koutedakis, Y; Frischknecht, R; Vrbová, G; Sharp, N C; Budgett, R
Altered mitochondrial regulation in quadriceps muscles of patients with COPD.
Evidence exists for locomotor muscle impairment in patients with chronic obstructive pulmonary disease (COPD), including fiber type alterations and reduced mitochondrial oxidative capacity. In this study high-resolution respirometry was used to quantify oxygen flux in permeabilized fibres from biopsies of the vastus lateralis muscle in patients with COPD and compared to healthy control subjects. The main findings of this study were that (i) routine state 2 respiration was higher in COPD; (ii) state 3 respiration in the presence of ADP was similar in both groups with substrate supply of electrons to complex I (COPD 38·28 ± 3·58 versus control 42·85 ± 3·10 pmol s(-1) mg tissue(-1) ), but O(2) flux with addition of succinate was lower in COPD patients (COPD 63·72 ± 6·33 versus control 95·73 ± 6·53 pmol s(-1) mg tissue(-1) ); (iii) excess capacity of cytochrome c oxidase in COPD patients was only ~50% that of control subjects. These results indicate that quadriceps muscle mitochondrial function is altered in patients with COPD. The regulatory mechanisms underlying these functional abnormalities remain to be uncovered. PMID:21091605
Naimi, Ashley I; Bourbeau, Jean; Perrault, Helene; Baril, Jacinthe; Wright-Paradis, Cynthia; Rossi, Amanda; Taivassalo, Tanja; Sheel, A William; Rabřl, Rasmus; Dela, Flemming; Boushel, Robert
Whole body oxygen uptake and evoked knee torque in response to low frequency electrical stimulation of the quadriceps muscles: V•O2 frequency response to NMES
Background There is emerging evidence that isometric Neuromuscular Electrical Stimulation (NMES) may offer a way to elicit therapeutically significant increases in whole-body oxygen uptake in order to deliver aerobic exercise to patients unable to exercise volitionally, with consequent gains in cardiovascular health. The optimal stimulation frequency to elicit a significant and sustained pulmonary oxygen uptake has not been determined. The aim of this study was to examine the frequency response of the oxygen uptake and evoked torque due to NMES of the quadriceps muscles across a range of low frequencies spanning the twitch to tetanus transition. Methods Ten healthy male subjects underwent bilateral NMES of the quadriceps muscles comprising eight 4 minute bouts of intermittent stimulation at selected frequencies in the range 1 to 12 Hz, interspersed with 4 minutes rest periods. Respiratory gases and knee extensor torque were simultaneously monitored throughout. Multiple linear regression was used to fit the resulting data to an energetic model which expressed the energy rate in terms of the pulse frequency, the torque time integral and a factor representing the accumulated force developed per unit time. Results Additional oxygen uptake increased over the frequency range to a maximum of 564 (SD 114) ml min-1 at 12 Hz, and the respiratory exchange ratio was close to unity from 4 to 12 Hz. While the highest induced torque occurred at 12 Hz, the peak of the force development factor occurred at 6 Hz. The regression model accounted for 88% of the variability in the observed energetic response. Conclusions Taking into account the requirement to avoid prolonged tetanic contractions and to minimize evoked torque, the results suggest that the ideal frequency for sustainable aerobic exercise is 4 to 5 Hz, which coincided in this study with the frequency above which significant twitch force summation occurred.
Adaptive force regulation of muscle strengthening rehabilitation device with magnetorheological fluids
In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based
Shufang Dong; Ke-Qian Lu; Jian Qiao Sun; Katherine Rudolph
The effect of workplace based strengthening on low back injury rates: A case study in the strip mining industry
The purpose of this study was to demonstrate the effect of a once a week exercise program focused specially at lumbar extensor strengthening. This is a comparative study where workers volunteered to exercise were compared to workers who did not exercise. Low back claims for one year were noted to document efficacy of the training program. Change in strength was
Vert Mooney; Marvin Kron; Patrick Rummerfield; Bryon Holmes
Effects of Directional Exercise on Lingual Strength
ERIC Educational Resources Information Center
Purpose: To examine the application of known muscle training principles to tongue strengthening exercises and to answer the following research questions: (a) Did lingual strength increase following 9 weeks of training? (b) Did training conducted using an exercise moving the tongue in one direction result in strength changes for tongue movements in…
Clark, Heather M.; O'Brien, Katy; Calleja, Aimee; Corrie, Sarah Newcomb
Quadriceps activation normative values and the affect of subcutaneous tissue thickness.
Calculation of the central activation ratio (CAR) using the superimposed burst technique (SIB) is widely used. 0.95 is considered a normal value of the CAR in healthy subjects, but it has not been objectively examined. Since an electrical stimulation penetrates the subcutaneous tissue, the intensity of electrical stimulation may vary depending on the subcutaneous tissue thickness. Subjects performed a maximal voluntary isometric contraction (MVIC) of the quadriceps with the knee at 90°. Once the MVIC reached a plateau, an electrical stimulation was manually delivered to the quadriceps. Quadriceps CAR was quantified using the equation: CAR=MVIC/MVIC+SIB torque. Quadriceps subcutaneous thickness was measured using ultrasound imaging and skinfolder pinch calipers. CAR values were estimated at 0.95 ± 0.04 for dominant and 0.93 ± 0.05 for non-dominant limbs. Pearson's correlation coefficient revealed that there were negative correlations for quadriceps torque output (Nm/kg) and subcutaneous tissue thickness measured by ultrasound imaging (dominant: r=-0.54, p<0.001; non-dominant: r=-0.53, p<0.001). We found no relationship between CAR and subcutaneous tissue thickness. A CAR of 0.95 may be considered full activation in healthy young adults, and CAR in healthy adults generated by the SIB technique may not be dependent on subcutaneous thickness. PMID:20947373
Park, Jihong; Hopkins, J Ty
OPTOTRAK Measurement of the Quadriceps Angle Using Standardized Foot Positions
Objective: While there is evidence to suggest that the magnitude of the quadriceps (Q) angle changes with alterations in foot position, a detailed quantitative description of this relationship has not been reported. Our purpose was to determine the effect of varying foot placement on the magnitude of the Q angle. Design and Setting: A mixed between-within, repeated-measures design was used to compare Q angles derived under static weight-bearing conditions with the feet positioned in self-selected versus standardized stance positions. Subjects: Twenty healthy young-adult men and women with no history of acute injury to or chronic dysfunction of the lower limbs. Measurements: We placed light-emitting diodes bilaterally on the left and right anterior superior iliac spines, the tibial tuberosities, and the midpoints of the patellae to bilaterally define the Q angles. An OPTOTRAK motion-measurement system was used to capture x,y coordinate data at a sampling rate of 60 Hz. These data were subsequently filtered and used to calculate the magnitude of the left and right Q angles. Results: A repeated-measures analysis of variance revealed that when measured statically, Q angles differed significantly between stance positions (P < .001) and limbs (P < .05). Depending on the stance adopted, mean Q angles varied from 7.2° to 12.7° and 11.0° to 16.1° in the left and right lower limbs, respectively. Q-angle measurements taken in conjunction with the Romberg foot position most closely resembled those gathered with the feet in a self-selected stance (Pearson r = 0.86 to 0.92). Conclusions: Q-angle magnitude varies with changes in foot position, increasing or decreasing as the foot rotates internally or externally, respectively. These data demonstrate the need for a standardized foot position for Q-angle measurements.
Livingston, Lori A.; Spaulding, Sandi J.
In vivo specific tension of the human quadriceps femoris muscle.
It is not known to what extent the inter-individual variation in human muscle strength is explicable by differences in specific tension. To investigate this, a comprehensive approach was used to determine in vivo specific tension of the quadriceps femoris (QF) muscle (Method 1). Since this is a protracted technique, a simpler procedure was also developed to accurately estimate QF specific tension (Method 2). Method 1 comprised calculating patellar tendon force (F (t)) in 27 young, untrained males, by correcting maximum voluntary contraction (MVC) for antagonist co-activation, voluntary activation and moment arm length. For each component muscle, the physiological cross-sectional area (PCSA) was calculated as volume divided by fascicle length during MVC. Dividing F (t) by the sum of the four PCSAs (each multiplied by the cosine of its pennation angle during MVC) provided QF specific tension. Method 2 was a simplification of Method 1, where QF specific tension was estimated from a single anatomical CSA and vastus lateralis muscle geometry. Using Method 1, the variability in MVC (18%) and specific tension (16%) was similar. Specific tension from Method 1 (30 +/- 5 N cm(-2)) was similar to and correlated with that of Method 2 (29 +/- 5 N cm(-2); R (2) = 0.67; P < 0.05). In conclusion, most of the inter-individual variability in MVC torque remains largely unexplained. Furthermore, a simple method of estimating QF specific tension provided similar values to the comprehensive approach, thereby enabling accurate estimations of QF specific tension where time and resources are limited. PMID:19468746
Erskine, Robert M; Jones, David A; Maganaris, Constantinos N; Degens, Hans
Multi-modal exercise programs for older adults
Background: various modalities of exercise have been demonstrated to improve physical function and quality of life in older adults. Current guidelines stress the importance of multi-modal exercise for this cohort, including strengthening exercises, cardiovascular, flexibility and balance training. There is a lack of evidence, however, that simultaneously prescribed doses and intensities of strength, aerobic, and balance training in older adults
An examination of possible quadriceps force at the time of anterior cruciate ligament injury during landing: A simulation study.
Anterior cruciate ligament (ACL) rupture is a common and traumatic injury. Although, identifying the mechanism of ACL injury has received considerable research attention, there are still many unanswered questions. One proposed mechanism asserts that the ACL is injured due to an aggressive quadriceps muscle contraction. However, recently it has been questioned if the magnitude of quadriceps force needed to tear the ACL is physiologically realistic under the conditions where injury occurs during landing (e.g. near full knee extension and within 50ms after impact). To answer this question, a simple simulation model was developed to examine the upper bounds of quadriceps force that can be developed under these conditions. The model included force-length, and force-velocity properties as well as activation dynamics. Model parameters were chosen to provide a high estimate for possible quadriceps force in a young healthy man. The effects of varying quadriceps pre-activation levels were also examined. When using realistic pre-activation levels, the simulated quadriceps force was less than half of what has been shown to cause ACL injury. Even when using maximum pre-activation, the quadriceps force still did not reach close to the level shown to cause injury. Therefore, we conclude that quadriceps force alone seems to be an unlikely mechanism for ACL injury. PMID:21457987
Domire, Zachary J; Boros, Rhonda L; Hashemi, Javad
[Bilateral quadriceps rupture in a patient with osteogenesis imperfecta. A case report].
We present the case of a 24-year-old patient with bilateral quadriceps rupture and history of type I congenital osteogenesis imperfecta diagnosed clinically and with ultrasound. Bilateral quadriceps tenoplasty was performed with an anterior approach and without any complications. The patient was discharged with bilateral neoprene knee-guards. The sutures were removed at the 21-day follow-up visit, rehabilitation was started at six weeks and the patient was doing well at the 2- and 3-month follow-up visits. Timely management and early rehabilitation contribute to decrease the risk of sequelae despite the poor functional prognosis. PMID:20377006
Salcedo-Dueńas, Jesús Alejandro; Torres Castro, Carlos; Estrada Gómez, José Andrés; Algarín Reyes, José Antonio; Bello González, Alejandro
Simultaneous bilateral quadriceps tendon rupture in a patient with chronic renal failure.
Bilateral quadriceps tendon rupture is an unusual injury, but may be encountered in patients with various chronic diseases after minor trauma. This article presents a case of bilateral quadriceps tendon rupture of a 38-year-old woman with chronic renal failure. Surgical repair was performed using a bone tunnel technique with a nonabsorbable suture and a suture anchor. Postoperative magnetic resonance imaging confirmed complete healing of the repair site, and clinically active extension with 120 degrees of range of motion was achieved. PMID:22570854
Kim, Byung Soo; Kim, Yong Wook; Song, Eun Kyoo; Seon, Jong Keun; Kang, Kyung Do; Kim, Hyung Nam
Effects of different duration isometric contractions on tendon elasticity in human quadriceps muscles
The present study aimed to investigate the influence of isometric training protocols with long- and short-duration contractions on the elasticity of human tendon structures in vivo. The elasticity was assessed through in vivo determination of the elongation (L) of the tendons and aponeuroses using ultrasonography, while the subjects performed ramp isometric exercise up to maximum voluntary contraction (MVC).Eight young males completed 12 weeks (4 days per week) of a unilateral isometric training programme on knee extensors, which consisted of two different combinations of contraction and relaxation times at 70 % MVC: one leg was trained using a short-duration protocol (3 sets of 50 repetitions of contraction for 1 s and relaxation for 2 s), and the other leg was trained using a long-duration protocol (4 sets of a combination of contraction for 20 s and relaxation for 1 min). The training volume per session, expressed as the integrated torque, was the same for the two protocols.Both protocols resulted in a significant increase in MVC: 31.8 ± 17.2 % for the short-duration protocol and 33.9 ± 14.4 % for the long-duration protocol. Moreover, the training produced significant increases in the muscle volume of the constituents of the quadriceps femoris, with similar relative gains for the two protocols: 7.4 ± 3.9 % for the short-duration protocol and 7.6 ± 4.3 % for the long-duration protocol.The short-duration protocol produced no significant change in L values at any of the force production levels. For the long-duration protocol, however, the L values above 550 N were significantly shorter after training. Analysis revealed that the group × test time interaction effect on tendon stiffness was significant. Stiffness increased significantly for the long-duration protocol, but not for the short-duration protocol.The present study demonstrates a greater increase in stiffness of human tendon structures following isometric training using longer duration contractions compared to shorter contractions. This suggests that the changes in the elasticity of the tendon structures after resistance training may be affected by the duration of muscle contraction.
Kubo, Keitaro; Kanehisa, Hiroaki; Fukunaga, Tetsuo
The role of muscle mass in exercise-induced hyperemia.
Exercise-induced hyperemia is often normalized for muscle mass, and this value is sometimes evaluated at relative exercise intensities to take muscle recruitment into account. Therefore, this study sought to better understand the impact of muscle mass on leg blood flow (LBF) during exercise. LBF was assessed by Doppler ultrasound in 27 young healthy male subjects performing knee-extensor (KE) exercise at three absolute (5, 15, and 25 W) and three relative [20, 40, and 60% of maximum KE (KEmax)] workloads. Thigh muscle mass (5.2-8.1 kg) and LBF were significantly correlated at rest (r = 0.54; P = 0.004). Exercise-induced hyperemia was linearly related to absolute workload, but revealed substantial between-subject variability, documented by the coefficient of variation (5 W: 17%; 15 W: 16%; 25 W: 16%). Quadriceps muscle mass (1.5-2.7 kg) and LBF were not correlated at 5, 15, or 25 W (r = 0.09-0.01; P = 0.7-0.9). Normalizing blood flow for quadriceps muscle mass did not improve the coefficient of variation at each absolute workload (5 W: 21%; 15 W: 21%; 25 W: 22%), while the additional evaluation at relative exercise intensities resulted in even greater variance (20% KEmax: 29%; 40% KEmax: 29%; 60% KEmax: 27%). Similar findings were documented when subjects were parsed into high and low aerobic capacity. Thus, in contrast to rest, blood flow during exercise is unrelated to muscle mass, and simply normalizing for muscle mass or comparing normalized blood flow at a given relative exercise intensity has no effect on the inherent blood flow variability. Therefore, during exercise, muscle mass does not appear to be a determinant of the hyperemic response. PMID:24674856
Garten, Ryan S; Groot, H Jonathan; Rossman, Matthew J; Gifford, Jayson R; Richardson, Russell S
Strengthening regional safeguards
Nuclear cooperation between Argentina and Brazil has been growing since the early 1980`s and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States.
Palhares, L.; Almeida, G.; Mafra, O. [Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials, Rio de Janeiro (Brazil)] [and others
Hip and knee muscle function following aerobic exercise in individuals with patellofemoral pain syndrome.
Patellofemoral pain syndrome (PFPS) is a commonly experienced knee disorder that can result in altered muscle activation of the surrounding musculature. There is little evidence on effects of aerobic exercise on quadriceps torque and EMG activation of the vastus medialis obliquus (VMO), vastus lateralis (VL), and gluteus medius (GM). In this study 20 healthy individuals and 20 patients with PFPS had measures of torque and muscle activation taken following aerobic exercise. A modified Balke-Ware protocol was used for the exercise intervention. Baseline and post-aerobic measurements of knee extension torque and VMO, VL, and GM activation during a single leg anterior reaching task. These measurements were only taken on the injured limb. Following exercise, knee extension torque was lower in PFPS patients when compared to controls (p=0.03). Patients reporting no pain after exercise experienced decreases (p=0.021) in GM activation following exercise. There was a decrease in VMO (p=0.010) and VL (p=0.021) activation in PFPS patients with elevated knee pain. Recreationally active individuals with PFPS may experience different responses in the quadriceps and GM after exercise. Responses may be confounded by whether or not pain is exacerbated by exercise. PMID:21689607
Ott, Brittany; Cosby, Nicole L; Grindstaff, Terry L; Hart, Joseph M
The Relationship between Quadriceps Thickness, Radiological Staging, and Clinical Parameters in Knee Osteoarthritis.
[Purpose] The aim of this study was to investigate the relationship between clinical parameters, radiological staging and evaluated ultrasound results of quadriceps muscle thickness in knee osteoarthritis. [Subjects] The current study comprised 75 patients (51 female, 24 male) with a mean age of 57.9±5.2?years (range 40-65 years) and a diagnosis of osteoarthritis in both knees. [Methods] Knee radiographs were evaluated according to the Kellgren-Lawrence grading system. Clinical evaluation performed with the visual analog scale (VAS), Western Ontario and McMaster Osteoarthritis Index (WOMAC), the 50-meter walking test, and the 10-step stair test. The thickness of the muscle layer of the quadriceps femoris (M. vastus intermedius and M. rectus femoris) was measured with high-resolution real-time ultrasonography. [Results] The results of this study showed a significant negative correlation between quadriceps thickness and age, duration of disease, stage of knee OA, and VAS, WOMAC, 50-m walking test, and 10-step stair test scores. [Conclusion] The evaluation of quadriceps muscle thickness with ultrasound can be considered a practical and economical method in the diagnosis and follow-up of knee osteoarthritis. PMID:25013299
Koca, Irfan; Boyaci, Ahmet; Tutoglu, Ahmet; Boyaci, Nurefsan; Ozkur, Ayhan
Quadriceps and hamstrings prelanding myoelectric activity during landing from different heights among male and female athletes.
ACL tear is a major concern among athletes, coaches and sports scientists. More than taking the athlete away from training and competition, ACL tear is a risk factor for early-onset of knee osteoarthritis, and, therefore addressing strategies to avoid such injury is pertinent not only for competitive athletes, but for all physically active subjects. Imbalances in the prelanding myoelectric activity of the hamstrings and quadriceps muscles have been linked to ACL injuries. We investigated the effect of landing from different heights on prelanding myoelectric activity of the hamstrings and quadriceps muscles in recreational athletes. Thirty recreational athletes (15 male and 15 female) performed three bilateral drop jumps from two different heights; 20cm and 40cm while myoelectric activity of the vastus medialis, rectus femoris, biceps femoris and medial hamstrings were collected. When increasing the height of drop landing tasks prelanding normalized myoelectric activity of the quadriceps was increased by 15-20% but no significant changes were found for the hamstrings. Female athletes exhibited higher activity of the medial hamstrings compared to their male counterparts. We concluded that increasing the height of drop landing tasks is associated with increased myoelectric activity of the quadriceps but not the hamstrings in recreational athletes. These differences in muscle activity may be related to increased risk for ACL injury when the height is increased. Female athletes demonstrated higher recruitment of the medial hamstrings. PMID:24837628
de Britto, Morgana Alves; Carpes, Felipe P; Koutras, Georgios; Pappas, Evangelos
Quadriceps function, proprioceptive acuity and functional performance in healthy young, middle-aged and elderly subjects
Background: muscle functions to generate force-producing movement and also has a role in proprioception. If ageing compromises these sensorimotor functions of muscle, the ability of older subjects to detect and correct postural sway may be impeded, resulting in impairment of functional performance. Method: to see if age-related changes occurred and, if so, what their effects might be. Quadriceps strength, proprioception,
Comprehensive isokinetic knee measurements and quadriceps tendon evaluations in footballers for assessing functional performance
Objectives: To ascertain whether detailed isokinetic knee muscle testing reflects the results of other functional measurements in footballers and to look for any correlations between quadriceps tendon thickness and knee strength. Methods: Ultrasonographic evaluation of the quadriceps tendon (Hitachi EUB-405), isokinetic knee testing (Biodex System 3), and sprint measurements using telemetric photoelectric cells (Chronometre Prosport ESC TX02) were carried out on 29 elite footballers. Jumping capacity was evaluated using Bosco's jumping mat (Ergojump). Anaerobic fitness was assessed by auricular capillary blood lactate measurements (YSI Model 1500 Sport Lactate Analyzer). Results: Quadriceps tendon thickness correlated positively with jumping and sprint measurements and negatively with extensor and flexor strength. However, these correlations did not reach statistical significance. There were significant correlations between knee extensor strength at 60 °/s and jumping or sprint measurements and between the extension acceleration values of both knees during isokinetic tests at 240 °/s and the sprint measurements. No significant correlation was found between the fatigue ratio values of both knees at 240 °/s and the calculated fatigue ratios from the sprint measurements. Conclusions: Apart from a few variables which correlated with the performance tests, the isokinetic studies did not fully predict the various functional measurements. Neither was there any relation between the quadriceps tendon measurements and the knee strength values nor with the functional performance.
Ozcakar, L; Kunduracyoolu, B; Cetin, A; Ulkar, B; Guner, R; Hascelik, Z
The Relationship between Quadriceps Thickness, Radiological Staging, and Clinical Parameters in Knee Osteoarthritis
[Purpose] The aim of this study was to investigate the relationship between clinical parameters, radiological staging and evaluated ultrasound results of quadriceps muscle thickness in knee osteoarthritis. [Subjects] The current study comprised 75 patients (51 female, 24 male) with a mean age of 57.9±5.2?years (range 40–65 years) and a diagnosis of osteoarthritis in both knees. [Methods] Knee radiographs were evaluated according to the Kellgren-Lawrence grading system. Clinical evaluation performed with the visual analog scale (VAS), Western Ontario and McMaster Osteoarthritis Index (WOMAC), the 50-meter walking test, and the 10-step stair test. The thickness of the muscle layer of the quadriceps femoris (M. vastus intermedius and M. rectus femoris) was measured with high-resolution real-time ultrasonography. [Results] The results of this study showed a significant negative correlation between quadriceps thickness and age, duration of disease, stage of knee OA, and VAS, WOMAC, 50-m walking test, and 10-step stair test scores. [Conclusion] The evaluation of quadriceps muscle thickness with ultrasound can be considered a practical and economical method in the diagnosis and follow-up of knee osteoarthritis.
Koca, Irfan; Boyaci, Ahmet; Tutoglu, Ahmet; Boyaci, Nurefsan; Ozkur, Ayhan
Effective Family Strengthening Interventions. Juvenile Justice Bulletin. Family Strengthening Series.
ERIC Educational Resources Information Center
This bulletin summarizes the results of a training and technology transfer program focussing on strengthening families for the prevention of delinquency. A national search was conducted for representative family strengthening programs, and through a process that involved national conferences, regional training sessions, and technical assistance,…
Alvarado, Rose; Kumpfer, Karol L.
Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion
To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30–60% of normal (CON) and approximately 5–10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake.
Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark
The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise.
Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass. PMID:24740653
Rossman, Matthew J; Garten, Ryan S; Venturelli, Massimo; Amann, Markus; Richardson, Russell S
Iron supplementation improves progressive fatigue resistance during dynamic knee extensor exercise in iron-depleted
Background: Tissue iron depletion may negatively affect endurance performance and muscle fatigability. Objective: We investigated tissue-level iron depletion and pro- gressive fatigue of the quadriceps during dynamic knee-extension exercise in young women. Design: Twenty iron-depleted (serum ferritin < 20 ? g\\/L), nonane- mic (hemoglobin > 110 g\\/L) women (x - ± SEM age: 29.1 ± 1.2 y) received iron (iron
Tom D Brutsaert; Sonia Hernandez-Cordero; Juan Rivera; Tracey Viola; Gail Hughes; Jere D Haas
Neuromuscular Control of the Knee During a Resisted Single-Limb Squat Exercise
Background:Closed kinetic chain exercises such as single-limb squats are preferred for knee rehabilitation. A complete understanding of the neuromuscular control of the knee during the single-limb squat is essential to increase the efficiency of rehabilitation programs.Hypothesis:Performing a controlled single-limb squat with resistance to knee flexion and extension will increase the coactivation of the hamstring muscle group, thus reducing the quadriceps\\/hamstrings
Richard K. Shields; Sangeetha Madhavan; Emy Gregg; Jennifer Leitch; Ben Petersen; Sara Salata; Stacey Wallerich
ACL deficient potential copers and non-copers reveal different isokinetic quadriceps strength profiles in the early stage after injury
Background Isokinetic muscle strength tests using the peak torque value is the most frequently included quadriceps muscle strength measurement for anterior cruciate ligament (ACL) injured subjects. Aims The purpose of this study was to investigate quadriceps muscle performance during the whole isokinetic curve in ACL deficient subjects classified as potential copers or non-copers, and investigate whether these curve profiles were associated with single-leg hop performance. We hypothesized that quadriceps muscle torque at other knee flexion angles than peak torque would give more information about quadriceps muscle strength deficits. Furthermore, we hypothesized that there would be significant torque differences between potential copers and non-copers, and a significant relationship between angle specific torque values and single-leg hop performance. Study Design Cross-sectional study; Level of evidence, 2 Methods Seventy-six individuals with a complete unilateral ACL rupture within the last 3 months were included. The subjects were classified into potential copers and non-copers according to the criteria from Fitzgerald et al12. Isokinetic quadriceps muscle tests were performed at 60°/sec (Biodex 6000). Mean torque values were calculated for peak torque as well as for specific knee flexion angles. The one-leg hop and the 6 meter timed hop tests were included and symmetry indices were used. Results The peak torque value did not identify the largest quadriceps muscle strength deficit. Rather, these were established at knee flexion angles of less than 40°. There were significant differences in angle specific torque values between potential copers and non-copers (p<0.05). Moderate to strong associations were disclosed between angle specific torque values and single-leg hop performance, but only for non-copers (r?0.32– 0.58). Conclusions Angle specific quadriceps muscle torque values of less than 40° of knee flexion provide more information on the quadriceps strength deficits after ACL injury compared to the commonly used peak torque values.
Eitzen, I; Eitzen, TJ; Holm, I; Snyder-Mackler, L; Risberg, MA
Effect of a high intensity quadriceps fatigue protocol on knee joint mechanics and muscle activation during gait in young adults
The purpose of this study was to determine the effect of impaired quadriceps function on knee joint biomechanics and neuromuscular\\u000a function during gait. Surface electromyograms, three-dimensional motion and ground reaction forces were collected during gait\\u000a before and after 20 healthy adults completed a high intensity quadriceps fatigue protocol. Pattern recognition techniques\\u000a were utilized to examine changes in amplitude and temporal
Gillian Hatfield Murdock; Cheryl L. Hubley-Kozey
Efficacy of kinesio taping on isokinetic quadriceps torque in knee osteoarthritis: a double blinded randomized controlled study.
Abstract Study design: Double blind pre-test post-test control group design. Objectives: To compare the isokinetic quadriceps torque, standardized stair-climbing task (SSCT) and pain during SSCT between subjects diagnosed with knee osteoarthritis pre and post kinesio tape (KT) application with and without tension. Background: Strength of the quadriceps and torque producing capability is frequently found to be compromised in knee osteoarthritis. The efficacy of KT in improving isokinetic quadriceps torque in knee osteoarthritis is unknown, forming the basis for this study. Methods and measures: Forty subjects were randomly allocated to either the experimental (therapeutic KT with tension) or control group (sham KT without tension) with the allocation being concealed. Pre and post test measurements of isokinetic quadriceps torque, SSCT and pain during SSCT were carried out by a blinded assessor. Results: A large effect size with significant improvements in the peak quadriceps torque (concentric and eccentric at angular velocities of 90° per second and 120° per second), SSCT and pain were obtained in the experimental group when compared to the control group. Conclusion: Application of therapeutic KT is effective in improving isokinetic quadriceps torque, SSCT and reducing pain in knee osteoarthritis. PMID:24617598
Anandkumar, Sudarshan; Sudarshan, Shobhalakshmi; Nagpal, Pratima
Cardiovascular benefits of exercise.
Regular physical activity during leisure time has been shown to be associated with better health outcomes. The American Heart Association, the Centers for Disease Control and Prevention and the American College of Sports Medicine all recommend regular physical activity of moderate intensity for the prevention and complementary treatment of several diseases. The therapeutic role of exercise in maintaining good health and treating diseases is not new. The benefits of physical activity date back to Susruta, a 600 BC physician in India, who prescribed exercise to patients. Hippocrates (460-377 BC) wrote "in order to remain healthy, the entire day should be devoted exclusively to ways and means of increasing one's strength and staying healthy, and the best way to do so is through physical exercise." Plato (427-347 BC) referred to medicine as a sister art to physical exercise while the noted ancient Greek physician Galen (129-217 AD) penned several essays on aerobic fitness and strengthening muscles. This article briefly reviews the beneficial effects of physical activity on cardiovascular diseases. PMID:22807642
Agarwal, Shashi K
Strengthening University-Industry Interactions.
National Technical Information Service (NTIS)
Three broad approaches to strengthening university-industry interactions to promote industrial innovation are direct corporate funding of university research, cooperative (cost shared) research, and measures to enhance knowledge transfer and the exchange ...
W. S. Baer
[Isokinetic torque of quadriceps in patients with untreated anterior cruciate ligament injury of the knee joint].
In order to study the role of muscle strength in patients with untreated anterior cruciate ligament (ACL) injury of the knee joint, the torque of the quadriceps was isokinetically measured during concentric contraction (CC) and passive eccentric contraction (PEC). The results were compared with those in normal individuals and sports players. Ninety patients with untreated ACL injury were subjected for the study. There were 50 men and 40 women. The normal group consisted of 20 students and the sports player group consisted of 20 soccer players. The peak torque and the torque at 30 degrees flexion of the quadriceps were isokinetically measured during CC and PEC by using a BIODEX machine. Results: In patients with ACL injury, the peak torque was smaller in the injured side as compared with the uninjured side. At the same angle velocity, decrease of PEC in the injured side was larger than that of CC. These results were compared with the normal group and the sports player group. There was significant difference in the peak torque per body weight among each groups. But, the torque per body weight at 30 degrees flexion was almost consistent in these three groups. Discussion: A considerable quadriceps atrophy occurs following ACL injury. In our experience, patients with functional absence of ACL are much more difficult to return to vigorous sports which require explosive eccentric contraction than to return to endurance sports which require repetitive concentric contractile efforts of the quadriceps. In the present study, decrease of the passive eccentric contraction in the injured side was more pronounced than that of the concentric contraction. From these results, the significantly decreased passive eccentric torque in the patients with untreated ACL injury can be a factor to cause instability of the knee joint in active daily life as well as in sports activities. PMID:8409643
Ikeda, H
A dynamic warm-up model increases quadriceps strength and hamstring flexibility.
Research suggests that static stretching can negatively influence muscle strength and power and may result in decreased functional performance. The dynamic warm-up (DWU) is a common alternative to static stretching before physical activity, but there is limited research investigating the effects of a DWU. The purpose of this study was to compare the acute effects of a DWU and static stretching warm-up (SWU) on muscle flexibility, strength, and vertical jump using a randomized controlled trial design. Forty-five volunteers were randomly assigned into a control (CON), SWU, or DWU group. All participants rode a stationary bicycle for 5 minutes and completed a 10-minute warm-up protocol. During this protocol, the DWU group performed dynamic stretching and running, the SWU group performed static stretching, and the CON group rested. Dependent variables were measured immediately before and after the warm-up protocol. A digital inclinometer measured flexibility (degrees) for the hamstrings, quadriceps, and hip flexor muscles. An isokinetic dynamometer measured concentric and eccentric peak torque (N·m/kg) for the hamstrings and quadriceps. A force plate was used to measure vertical jump height (meters) and power (watts). In the DWU group, there was a significant increase in hamstring flexibility (pretest: 26.4 ± 13.5°, posttest: 16.9 ± 9.4°; p < .0001) and eccentric quadriceps peak torque (pretest: 2.49 ± 0.83 N·m/kg, posttest: 2.78 ± 0.69 N·m/kg; p = 0.04). The CON and SWU did not significantly affect any flexibility, strength, or vertical jump measures (p > 0.05). The DWU significantly improved eccentric quadriceps strength and hamstrings flexibility, whereas the SWU did not facilitate any positive or negative changes in muscle flexibility, strength, power, or vertical jump. Therefore, the DWU may be a better preactivity warm-up choice than an SWU. PMID:22446678
Aguilar, Alain J; DiStefano, Lindsay J; Brown, Cathleen N; Herman, Daniel C; Guskiewicz, Kevin M; Padua, Darin A
Evaluation of Electromyographic Biofeedback for the Quadriceps Femoris: A Systematic Review
Objective: To critically review evidence for the effectiveness of electromyographic biofeedback (EMGB) of the quadriceps femoris muscle in treating various knee conditions. Data Sources: Databases used to locate randomized controlled trials included PubMed (1980–2010), Cumulative Index of Nursing and Allied Health Literature (CINAHL, 1995–2007), Web of Science (1986–2010), SPORTDiscus (1990–2007), and Physiotherapy Evidence Database (PEDro). Key words were knee and biofeedback. Study Selection: The criteria for selection were clinical randomized controlled trials in which EMGB of the quadriceps femoris was used for various knee conditions of musculoskeletal origin. Trials were excluded because of research designs other than randomized controlled trials, articles published in a non-English language, inclusion of healthy research participants, inability to identify EMGB as the source of clinical improvement, and lack of pain, functional outcome, or quadriceps torque as outcome measures. Data Extraction: Twenty specific data points were abstracted from each clinical trial under the broad categories of attributes of the patient and injury, treatment variables for the EMGB group, treatment variables for the control group, and attributes of the research design. Data Synthesis: Eight trials yielded a total of 319 participants with patellofemoral pain syndrome (n = 86), anterior cruciate ligament reconstruction (n = 52), arthroscopic surgery (n = 91), or osteoarthritis (n = 90). The average methodologic score of the included studies was 4.6/10 based on PEDro criteria. Pooled analyses demonstrated heterogeneity of the included studies, rendering the interpretation of the pooled data inappropriate. The EMGB appeared to benefit short-term postsurgical pain or quadriceps strength in 3 of 4 postsurgical investigations but was ineffective for chronic knee conditions such as patellofemoral pain and osteoarthritis in all 4 studies. Because the findings are based on limited data, caution is warranted until more randomized controlled trials are conducted to support or refute the general trends observed in this report.
Wasielewski, Noah J.; Parker, Tonya M.; Kotsko, Kevin M.
Diagnosis of acute rupture of the quadriceps tendon by magnetic resonance imaging. A case report.
Quadriceps tendon rupture occurred in a 56-year-old man receiving anticoagulant therapy. The diagnosis was inconclusive until magnetic resonance imaging (MRI) was used to delineate the rupture site clearly. MRI is a useful adjunct to diagnosis of soft-tissue injuries in cases in which swelling or other soft-tissue abnormalities obscure examination or preclude the use of more routine diagnostic modalities. PMID:1984922
Kuivila, T E; Brems, J J
Size and strength of the respiratory and quadriceps muscles in patients with chronic asthma
Size and strength of the respiratory and quadriceps muscles in patients with chronic asthma. P.F. de Bruin, J. Ueki, A. Watson, N.B. Pride. ©ERS Journals 1997. ABSTRACT: There have been few studies of respiratory and limb muscle size and function in middle-aged patients with asthma and persistent airways obstruction. We have compared the forces generated by the respiratory and thigh
P. F. de Bruin; J. Ueki; A. Watson; N. B. Pride
Quadriceps femoris electromyogram during concentric, isometric and eccentric phases of fatiguing dynamic knee extensions
The objective of this study was to examine the superficial quadriceps femoris (QF) muscle electromyogram (EMG) during fatiguing knee extensions. Thirty young adults were evaluated for their one-repetition maximum (1RM) during a seated, right-leg, inertial knee extension. All subjects then completed a single set of repeated knee extensions at 50% 1RM, to failure. Subjects performed a knee extension (concentric phase),
Danny M. Pincivero; Varsha Gandhi; Mark K. Timmons; Alan J. Coelho
Knee extensor torque and quadriceps femoris EMG during perceptually-guided isometric contractions
The aim of this study was to examine superficial quadriceps femoris (QF) EMG and torque at perceived voluntary contraction efforts. Thirty subjects (15 males, 15 females) performed 9, 5 s, sub-maximal contractions at prescribed levels of perceived voluntary effort at points 1–9 on an 11-point scale (0–10), in a random order. Surface electromyograms (EMG) of the vastus medialis (VM), vastus
D. M. Pincivero; A. J. Coelho; R. M. Campy; Y. Salfetnikov; E. Suter
Bilateral eccentric and concentric torque of quadriceps and hamstring muscles in females and males
Summary This study assessed maximum eccentric (ECC) and concentric (CON) torque of quadriceps (QUAD) and hamstring (HAM) muscle groups\\u000a in healthy females (n=13) and males (n=27). Peak torques (PT) of bilateral muscle actions were recorded at constant angular velocities of 0.52, 1.57 and 2.61 rad·s?1. The QUADcon and HAMcon PT decreased (pecc and HAMecc PT increased (pecc PT decreased (pecc PT
Erland B. Colliander; Per A. Tesch
Anterior Cruciate Ligament Revision ReconstructionResults Using a Quadriceps Tendon–Patellar Bone Autograft
Background: The quadriceps tendon is a viable graft source for revision anterior cruciate ligament reconstruction.Purpose: To determine the functional results and graft failure rates in knees in which the patellar tendon had been previously harvested or was unavailable, expanded tunnels precluded the use of a semitendinosus-gracilis graft, or patients requested autogenous tissues instead of allografts for revision reconstruction.Study Design: Case
Frank R. Noyes; Sue D. Barber-Westin
An Acute Bout of Quadriceps Muscle Stretching has no Influence on Knee Joint Proprioception
The main objective of this study was to determine if an acute bout of static stretching of the quadriceps muscle affects the sense of joint position, the threshold to detect passive movement, and the sense of force. Thirty young, healthy men (age : 22.1 ± 2.7 years) were randomly divided into two groups. The Stretching Group (n=15) underwent stretching of the dominant quadriceps muscle, which comprised ten passive stretches lasting 30 seconds each, while the Control Group (n=15) remained seated for the same length of time. A repeated-measures analysis of variance was used to establish intragroup differences over time, and an independent sample t-test was used to compare the dependent variables between groups at each moment. None of the measurements revealed any significant change between both groups in each assessment moment or between moments within groups (p>0.05). This study demonstrated that static quadriceps muscle stretching has no effect on the sense of knee joint position, threshold to detect passive movement, and force sense, suggesting that stretching does not have appreciable effect on the spindle firing characteristics and tendon organs activation.
Torres, Rui; Duarte, Jose Alberto; Cabri, Jan MH
Asymptomatic Achilles, patellar, and quadriceps tendinopathy: a longitudinal clinical and ultrasonographic study in elite fencers.
Lower limb tendon changes detected at imaging are common among asymptomatic athletes. We aimed to prospectively assess the clinical status, tendon structure, and vascularity of lower limb tendons of elite fencers, and predict the risk of developing symptoms over time. Clinical examination, changes at ultrasonography (US), and Power Doppler (PD) flow of both the Achilles, patellar, and quadriceps tendon were assessed in 37 elite fencers in January 2007 and 3 years after. Two hundred and twenty-two tendons were examined. At the last appointment, patellar tendons diagnosed as abnormal at baseline were more likely to develop symptoms than those normal at baseline (P?0.05, Fisher's exact test), while US and PD abnormalities on Achilles and quadriceps tendons were no predictive for development of symptoms over years. A very low percentage of tendons diagnosed as normal at baseline (1.45%) showed US abnormalities at 3-year follow-up. In asymptomatic elite fencers, structural changes are relatively common at US and PD assessment of Achilles, quadriceps, and patellar tendons. It seems unlikely that additional PD investigations provide further information or change prognosis in patients with US diagnosis of tendinopathy. PMID:22092963
Giombini, A; Dragoni, S; Di Cesare, A; Di Cesare, M; Del Buono, A; Maffulli, N
Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome.
Patients with the chronic fatigue syndrome (CFS) complain consistently of delay in recovery of peripheral muscle function after exercise. The purpose of this study was to try to confirm this observation. A fatiguing exercise test was carried out on the quadriceps muscle group of ten patients and ten control subjects. The test consisted of 18 maximum voluntary contractions (MVCs) with a 50% duty cycle (10 s contraction, 10 s rest), and the force generated by each contraction was recorded using a KinCom dynamometer. This was followed by a recovery phase lasting 200 min in which quadriceps strength was evaluated at increasing intervals, and a follow-up session at 24 h post-exercise involving three 10 s MVCs. Throughout the exercise period, the MVCs obtained from the control group were significantly higher than those of the patient group (P = 0.006), but both groups showed a parallel decline in force over the 18 contractions, in keeping with a similar endurance capacity. Recovery was prolonged in the patient group, however, with a significant difference compared to initial MVCs being evident during the recovery phase after exercise (P = 0.001) and also at 24 h (P < 0.001). In contrast, the control group achieved MVCs which were not significantly different from initial values during the recovery phase, and maintained these at 24 h. These findings support the clinical complaint of delayed recovery after exercise in patients with CFS. PMID:10209352
Paul, L; Wood, L; Behan, W M; Maclaren, W M
Effect of unaccustomed eccentric exercise on proprioception of the knee in weight and non-weight bearing tasks.
The study investigates the effects of eccentric exercise of the quadriceps on proprioception of the knee in weight and non-weight bearing tasks. Proprioception of the exercised leg was assessed at 120° and 150° of knee extension in 15 healthy adults (age 25.0 ± 3.6 yrs) before, immediately after, and 24h following eccentric exercise of the quadriceps. Three tests of proprioception were performed: 1. matching the position of the exercised leg (right leg) to the reference leg (left leg) in sitting (non-weight bearing matching task); 2. repositioning the exercised leg after active movement in sitting (non-weight bearing repositioning task); 3. repositioning the exercised leg after active movement in standing (weight bearing task). Maximum knee extension force was reduced by 77.0 ± 12.3 % immediately after the exercise, and by 82.7 ± 16.2% 24h post exercise, with respect to baseline (P<0.001). The absolute error in the non-weight bearing matching task at 120° of knee extension was greater immediately following eccentric exercise (12.3 ± 5.6, P<0.001) and 24h after exercise (8.1 ± 4.5, P<0.05) compared to baseline (5.8 ± 2.7). Similarly, the absolute error in the non-weight bearing repositioning task at 120° was greater both immediately (5.9 ± 3.1°, P<0.01) and 24h post exercise (5.2 ± 3.0°, P<0.05) compared to baseline (4.5 ± 2.6°). Therefore, in both non-weight bearing tasks, the subjects matched the position of their leg after eccentric exercise by adopting a more extended knee position of the exercised limb. Furthermore, the subjects showed higher variability in their performance immediately post exercise (P<0.05, compared to baseline) but not 24h after. In contrast, eccentric exercise did not affect the repositioning errors in the weight bearing task. In conclusion, eccentric exercise of the quadriceps impairs proprioception of the knee both immediately after and 24h post exercise, but only in non-weight bearing tasks. PMID:21044850
Vila-Chă, Carolina; Riis, Simone; Lund, Ditte; Mřller, Anders; Farina, Dario; Falla, Deborah
... Health Information > Healthy Lifestyle > Exercise > Exercise at Home Exercise at Home Exercise and staying active are an ... plans to begin exercising with your doctor. Posture Exercises Better posture means better breathing and movement. Axial ...
The effects of high-fat diet, branched-chain amino acids and exercise on female C57BL/6 mouse Achilles tendon biomechanical properties
Objectives The goals of this study were: 1) to determine if high-fat diet (HFD) feeding in female mice would negatively impact biomechanical and histologic consequences on the Achilles tendon and quadriceps muscle; and 2) to investigate whether exercise and branched-chain amino acid (BCAA) supplementation would affect these parameters or attenuate any negative consequences resulting from HFD consumption. Methods We examined the effects of 16 weeks of 60% HFD feeding, voluntary exercise (free choice wheel running) and BCAA administration in female C57BL/6 mice. The Achilles tendons and quadriceps muscles were removed at the end of the experiment and assessed histologically and biomechanically. Results HFD feeding significantly decreased the Achilles tendon modulus without histological alterations. BCAA administration significantly decreased the stiffness of Achilles tendons in the exercised normal diet mice. Exercise partially ameliorated both the weight gain and glucose levels in the HFD-fed mice, led to a significant decrease in the maximum load of the Achilles tendon, and an increase in the average fibril diameter of the quadriceps femoris muscle. There were significant correlations between body weight and several biomechanical properties, demonstrating the importance of controlling obesity for maintaining healthy tendon properties. Conclusions In summary, this study showed a significant impact of obesity and body weight on tendon biomechanical properties with limited effects of exercise and BCAAs. Cite this article: Bone Joint Res 2013;2:186–92.
Boivin, G. P.; Platt, K. M.; Corbett, J.; Reeves, J.; Hardy, A. L.; Elenes, E. Y.; Charnigo, R. J.; Hunter, S. A.; Pearson, K. J.
The Feasibility of performing resistance exercise with acutely ill hospitalized older adults
BACKGROUND: For older adults, hospitalization frequently results in deterioration of mobility and function. Nevertheless, there are little data about how older adults exercise in the hospital and definitive studies are not yet available to determine what type of physical activity will prevent hospital related decline. Strengthening exercise may prevent deconditioning and Pilates exercise, which focuses on proper body mechanics and
Laurie H Mallery; Elizabeth A MacDonald; Cheryl L Hubley-Kozey; Marie E Earl; Kenneth Rockwood; Chris MacKnight
Effect of carbohydrate-protein supplement timing on acute exercise-induced muscle damage
Purpose To determine if timing of a supplement would have an effect on muscle damage, function and soreness. Methods Twenty-seven untrained men (21 ± 3 yrs) were given a supplement before or after exercise. Subjects were randomly assigned to a pre exercise (n = 9), received carbohydrate/protein drink before exercise and placebo after, a post exercise (n = 9), received placebo before exercise and carbohydrate/protein drink after, or a control group (n = 9), received placebo before and after exercise. Subjects performed 50 eccentric quadriceps contractions on an isokinetic dynamometer. Tests for creatine kinase (CK), maximal voluntary contraction (MVC) and muscle soreness were recorded before exercise and at six, 24, 48, 72, and 96 h post exercise. Repeated measures ANOVA were used to analyze data. Results There were no group by time interactions however, CK significantly increased for all groups when compared to pre exercise (101 ± 43 U/L) reaching a peak at 48 h (661 ± 1178 U/L). MVC was significantly reduced at 24 h by 31.4 ± 14.0%. Muscle soreness was also significantly increased from pre exercise peaking at 48 h. Conclusion Eccentric exercise caused significant muscle damage, loss of strength, and soreness; however timing of ingestion of carbohydrate/protein supplement had no effect.
White, James P; Wilson, Jacob M; Austin, Krista G; Greer, Beau K; St John, Noah; Panton, Lynn B
Regional variations in human patellar trabecular architecture and the structure of the quadriceps enthesis: a cadaveric study
We investigated whether there were regional differences in the quadriceps enthesis and the patella bone structure that could suggest unequal force transmission to the patella. Quadriceps tendon enthesis was removed by cutting the patellae transversally in the middle and the quadriceps tendon approximately 1 cm from the bone. Tissues were post-fixed, decalcified, dehydrated through and embedded in paraffin wax. Serial longitudinal sections were cut, mounted on glass slides at 1-mm intervals and slides were stained. Trabecular architecture was analysed from digital images taken from the histological slides, and regional differences at the enthesis in the thickness of the uncalcified fibrocartilage and the cortical zone of calcified tissue (calcified cartilage and lamellar bone) were evaluated. At the quadriceps enthesis, the thickness of the cortical zone of calcified tissue was significantly greater in the central part of the enthesis than medially and laterally. The trabeculae were thicker in the central and lateral parts compared with the medial region. Similarly, the zone of uncalcified fibrocartilage was thicker laterally and centrally than medially. Bone structure and the thickness of uncalcified fibrocartilage presented a similarity between the centre and the lateral parts; however, the medial side was different. We suggest that the mechanical stress at the proximal quadriceps tendon enthesis is higher laterally and centrally compared with medially. This could induce a lateral patellar translation, which is potentially a risk factor for knee osteoarthritis.
Toumi, Hechmi; Larguech, Gaith; Filaire, Edith; Pinti, Antonio; Lespessailles, Eric
Neuromuscular fatigue after maximal exercise in patients with cystic fibrosis.
The aim of this study was to determine whether patients with cystic fibrosis (CF), despite their ventilatory limitation, would develop neuromuscular fatigue of quadriceps muscles following a maximal cycling exercise. Eleven adults with CF (age=26.8±6.9years; forced expiratory volume in 1s=54.1±12.8% predicted) and 11 age-matched healthy subjects performed a maximal incremental cycle test with respiratory gas exchange measurements. Maximal voluntary contraction (MVC) and electromyographic (EMG) activity of the vastus medialis muscle were recorded before and after exercise. Neural and contractile properties of the quadriceps were also investigated using femoral nerve electrical stimulation. Patients had lower exercise capacity, peak oxygen uptake and MVC than controls. MVC fell significantly postexercise in both groups (CF: -20±10%, controls: -19±6%; p<0.01). EMG root mean square values, M-wave amplitude and duration were unchanged in both groups. Peak twitch (-46.9±13.8%), maximal rate of twitch torque development (-50.3±13.8%) and relaxation (-35.2±19.5%) were all reduced after exercise in CF patients. The control group followed the same pattern (-38.4±14.4%, -42.1±14.7% and -15±20.4%) but the statistical significance was not reached for the maximal rate of twitch torque relaxation. In conclusion, CF patients demonstrated lower limb fatigue following symptom-limited cycle exercise, which was comparable to that exhibited by healthy controls. This fatigue may be due to contractile impairments and not to transmission failure. Further studies should be conducted in a larger sample to confirm these preliminary results. PMID:21078561
Vallier, J M; Gruet, M; Mely, L; Pensini, M; Brisswalter, J
Doublet stimulation protocol to minimize musculoskeletal stress during paralyzed quadriceps muscle testing
With long-term electrical stimulation training, paralyzed muscle can serve as an effective load delivery agent for the skeletal system. Muscle adaptations to training, however, will almost certainly outstrip bone adaptations, exposing participants in training protocols to an elevated risk for fracture. Assessing the physiological properties of the chronically paralyzed quadriceps may transmit unacceptably high shear forces to the osteoporotic distal femur. We devised a two-pulse doublet strategy to measure quadriceps physiological properties while minimizing the peak muscle force. The purposes of the study were 1) to determine the repeatability of the doublet stimulation protocol, and 2) to compare this protocol among individuals with and without spinal cord injury (SCI). Eight individuals with SCI and four individuals without SCI underwent testing. The doublet force-frequency relationship shifted to the left after SCI, likely reflecting enhancements in the twitch-to-tetanus ratio known to exist in paralyzed muscle. Posttetanic potentiation occurred to a greater degree in subjects with SCI (20%) than in non-SCI subjects (7%). Potentiation of contractile rate occurred in both subject groups (14% and 23% for SCI and non-SCI, respectively). Normalized contractile speed (rate of force rise, rate of force fall) reflected well-known adaptations of paralyzed muscle toward a fast fatigable muscle. The doublet stimulation strategy provided repeatable and sensitive measurements of muscle force and speed properties that revealed meaningful differences between subjects with and without SCI. Doublet stimulation may offer a unique way to test muscle physiological parameters of the quadriceps in subjects with uncertain musculoskeletal integrity.
Dudley-Javoroski, Shauna; Littmann, Andrew E.; Iguchi, Masaki; Shields, Richard K.
Interstitial pH, K(+), lactate, and phosphate determined with MSNA during exercise in humans
NASA Technical Reports Server (NTRS)
The purpose of the present study was to use the microdialysis technique to simultaneously measure the interstitial concentrations of several putative stimulators of the exercise pressor reflex during 5 min of intermittent static quadriceps exercise in humans (n = 7). Exercise resulted in approximately a threefold (P < 0.05) increase in muscle sympathetic nerve activity (MSNA) and 13 +/- 3 beats/min (P < 0.05) and 20 +/- 2 mmHg (P < 0.05) increases in heart rate and blood pressure, respectively. During recovery, all reflex responses quickly returned to baseline. Interstitial lactate levels were increased (P < 0.05) from rest (1.1 +/- 0.1 mM) to exercise (1. 6 +/- 0.2 mM) and were further increased (P < 0.05) during recovery (2.0 +/- 0.2 mM). Dialysate phosphate concentrations were 0.55 +/- 0. 04, 0.71 +/- 0.05, and 0.48 +/- 0.03 mM during rest, exercise, and recovery, respectively, and were significantly elevated during exercise. At the onset of exercise, dialysate K(+) levels rose rapidly above resting values (4.2 +/- 0.1 meq/l) and continued to increase during the exercise bout. After 5 min of contractions, dialysate K(+) levels had peaked with an increase (P < 0.05) of 0.6 +/- 0.1 meq/l and subsequently decreased during recovery, not being different from rest after 3 min. In contrast, H(+) concentrations rapidly decreased (P < 0.05) from resting levels (69.4 +/- 3.7 nM) during quadriceps exercise and continued to decrease with a mean decline (P < 0.05) of 16.7 +/- 3.8 nM being achieved after 5 min. During recovery, H(+) concentrations rapidly increased and were not significantly different from baseline after 1 min. This study represents the first time that skeletal muscle interstitial pH, K(+), lactate, and phosphate have been measured in conjunction with MSNA, heart rate, and blood pressure during intermittent static quadriceps exercise in humans. These data suggest that interstitial K(+) and phosphate, but not lactate and H(+), may contribute to the stimulation of the exercise pressor reflex.
MacLean, D. A.; Imadojemu, V. A.; Sinoway, L. I.
NSDL National Science Digital Library
This homework exercise, which builds on knowledge gained in previous homework exercises located at the same site, asks students in an undergraduate class at Tulane University to answer some basic questions about volcanoes, and to determine the volcanic hazards associated with Mt. Rainier, Washington; Montserrat, West Indies; and Long Valley Caldera, California by searching the World Wide Web.
Nelson, Stephen
[Pyomyositis of the M. quadriceps femoris in an 8-month-old boy following pneumococcal meningitis].
An 8-month-old boy developed pyomyositis of the M. quadriceps femoris following meningitis caused by Streptococcus pneumoniae. The child had no underlying immune defect. Conservative treatment with antibiotics led to complete clinical and radiological resolution of the infection. In Europe, pyomyositis is rarely seen in children. Pyomyositis should be considered in the differential diagnosis in children with fever and complaints of joint pain or myalgia. Ultrasound and MRI are helpful techniques for establishing the diagnosis and for differentiating pyomyositis from other pathological conditions. Treatment consists of adequate antibiotics and in some cases drainage. PMID:16235801
Berg, R P; Smets, A M J B; Bosman, D K; Besselaar, P P
Functional results following surgical repair of simultaneous bilateral quadriceps tendon ruptures.
Background: Unilateral quadriceps tendon ruptures are common conditions treated by orthopedic surgeons. There is a paucity of information concerning functional outcomes in bilateral tendon ruptures. The aim of this study is to assess a series of 5 cases with simultaneous quadriceps tendon ruptures that underwent acute surgical repair with the purpose of identifying the functional outcomes as compared with unilateral injuries. We hypothesize that patients with bilateral quadriceps tendon ruptures have worse functional outcomes than patients with unilateral ruptures. Methods: Five cases of bilateral quadriceps tendon ruptures were identified. All patients underwent acute surgical extensor tendon repair employing a 3-patellar hole and a locked, running, nonabsorbable suture technique followed by a 6-week period of immobilization and bracing for 10 to 12 weeks. Mechanism of injury, medical history, social history, operative report, and postoperative exam were recorded with a minimum 1-year follow-up. In addition, each patient completed a subjective International Knee Documentation Committee (IKDC) score at 18 months. Five patients with unilateral injuries and with similar medical history were included as age-matched controls. Results: The mean age for the bilateral group was 54.8 years (range, 44-68 years). Mean postoperative knee flexion was 129 degrees and all patients had active, resisted knee extension. Only 1 patient had a medical comorbidity (diabetes mellitus). The mean IKDC score (mean follow-up, 25.4 months; range, 22-29 months) was 71.9 (range, 34.4 to 91.6), whereas the age-matched control group had a mean IKDC score of 88.3 (P = 0.23). There was no statistical significance between the 2 groups with regard to range of motion (P = 0.24), IKDC score, and return to activity (P = 0.29). Conclusion: Patients with early surgical repair of bilateral, simultaneous extensor mechanism ruptures exhibit adequate recovery and return to a high level of function. Our patients were younger than those reported in the literature and had minimal comorbidities. The IKDC scores reflected good outcomes in the bilateral rupture group, albeit lower than in the unilateral group. PMID:24875978
Chang, Edward S; Dodson, Christopher C; Tjoumakaris, Fotios; Cohen, Steven B; Chang, Edward S; Dodson, Christopher C; Tjoumakaris, Fotios; Cohen, Steven B
Effects of Motorized vs Non-Motorized Treadmill Training on Hamstring/Quadriceps Strength Ratios
Previous literature suggests that muscular involvement and biomechanical changes elicit different responses between overground and treadmill training. The objective of this study was to examine the effects of training on two different treadmill designs on the conventional (CR; concentric only) and functional (FR; eccentric to concentric) hamstring and quadriceps strength ratios. Fifteen men and sixteen women were randomly divided into three groups: motorized (MT), non-motorized (NMT) or control (C). Subjects completed pre and post-test isokinetic concentric and eccentric quadriceps and hamstring testing of both legs. Subjects completed 4 weeks of training on their respective treadmills with mileage increasing ˝ mile each week, beginning with 2 miles. The C group did not participate in any training. The CR revealed a significant two way interaction of group x time with MT increasing (pre: 0.80 ± 0.09 to post: 0.84 ± 0.09), NMT decreasing (pre: 0.76 ± 0.13 to post: 0.74 ± 0.10), and C showing no change (pre: 0.79 ± 0.10 to post: 0.79 ± 0.09. The FR revealed a significant two way interaction of speed x sex with the FR increasing as speeds increased for men (60 degrees.s-1: 1.04 ± 0.11; 180 degrees.s-1: 1.66 ± 0.27; 300 degrees.s-1: 2.36 ± 0.45) and women (60 degrees.s-1: 1.05 ± 0.16; 180 degrees.s-1: 1.90 ± 0.26; 300 degrees.s-1: 2.75 ± 0.47) but women increased greater relative to men. Training mode elicited a specific change in concentric hamstring and quadriceps strength resulting in specific changes to the CR; however, neither training mode had an effect on eccentric hamstrings nor the FR. Special attention should be given to the mode of endurance training when the goal is to alter the hamstring/quadriceps CR. Key points Specificity of treadmill training had different effects on concentric strength. Specificity of treadmill training had little or no effect on eccentric strength. Conventional and functional strength ratios may give different results based on training mode. Four weeks is long enough for strength results to be apparent in untrained people.
Franks, Kelly A.; Brown, Lee E.; Coburn, Jared W.; Kersey, Robert D.; Bottaro, Martim
Measurements of the quadriceps femoris function after meniscus refixation at the stable athlete's knee
Introduction The purpose of this study was to monitor the muscular changes regarding the isokinetic strength and torque pattern of the\\u000a quadriceps femoris at the stable athlete's knee after meniscus tear refixation.\\u000a \\u000a \\u000a \\u000a Materials and methods Therefore 15 athletes (10 male, 5 female) performing recreational or competitional sports at least five times a week before\\u000a injury were retrospectively examined in the average 2.5 years
T. Stein; A. P. Mehling; K. Jost; T. C. Auhuber; A. Jäger
Meta-analysis of the effect of strengthening interventions in individuals with cerebral palsy.
This study aimed to investigate the evidence that strengthening interventions can improve muscle strength and activity in individuals with cerebral palsy. The search focused on studies that employed strength training for children with cerebral palsy for which six electronic databases were used to extract literature published from 2001 to 2012. The key terms used in these searches were combined strength training, strengthening, weight training, weight lifting, resistance, and cerebral palsy. The quality of each study was assessed using the PEDro (Physiotherapy Evidence Database) scale. Thirteen randomized controlled trial studies were selected and divided into categories according to program type, mode, and outcome measures. The overall effect sizes of each study and types of strengthening were large. Strengthening exercise improved muscle strength to a greater degree, when practiced 3 times per week in 40-50 min sessions than in other categories of session length, and greater improvement was observed in younger children than in older. The effect size of the activities and variables related to gait, except for gait endurance, were medium to large. The effect size of individual muscles was large, but the effect sizes for ankle plantar flexor, hip abductor/adductor, and extensor were insignificant. Strengthening interventions are useful for increasing muscle strength in individuals with cerebral palsy, specifically in youth and children, and optimal exercise consisted of 40- to 50-min sessions performed 3 times per week. Although strengthening interventions may improve activities, including gait, more studies that are rigorous are needed to determine the contributions to gross motor function. PMID:24291625
Park, Eun-Young; Kim, Won-Ho
Early Neuromuscular Electrical Stimulation to Improve Quadriceps Muscle Strength After Total Knee Arthroplasty: A Randomized Controlled Trial
Background The recovery of quadriceps muscle force and function after total knee arthroplasty (TKA) is suboptimal, which predisposes patients to disability with increasing age. Objective The purpose of this investigation was to evaluate the efficacy of quadriceps muscle neuromuscular electrical stimulation (NMES), initiated 48 hours after TKA, as an adjunct to standard rehabilitation. Design This was a prospective, longitudinal randomized controlled trial. Methods Sixty-six patients, aged 50 to 85 years and planning a primary unilateral TKA, were randomly assigned to receive either standard rehabilitation (control) or standard rehabilitation plus NMES applied to the quadriceps muscle (initiated 48 hours after surgery). The NMES was applied twice per day at the maximum tolerable intensity for 15 contractions. Data for muscle strength, functional performance, and self-report measures were obtained before surgery and 3.5, 6.5, 13, 26, and 52 weeks after TKA. Results At 3.5 weeks after TKA, significant improvements with NMES were found for quadriceps and hamstring muscle strength, functional performance, and knee extension active range of motion. At 52 weeks, the differences between groups were attenuated, but improvements with NMES were still significant for quadriceps and hamstring muscle strength, functional performance, and some self-report measures. Limitations Treatment volume was not matched for both study arms; NMES was added to the standard of care treatment. Furthermore, testers were not blinded during testing, but used standardized scripts to avoid bias. Finally, some patients reached the maximum stimulator output during at least one treatment session and may have tolerated more stimulation. Conclusions The early addition of NMES effectively attenuated loss of quadriceps muscle strength and improved functional performance following TKA. The effects were most pronounced and clinically meaningful within the first month after surgery, but persisted through 1 year after surgery.
Balter, Jaclyn E.; Wolfe, Pamela; Eckhoff, Donald G.; Kohrt, Wendy M.
Age and exercise ... It's never too late to start exercising. Exercise has benefits at any age. Don't worry if you've never exercised, or if you stopped exercising for some reason. Being physically ...
Treadmill Training Increases SIRT-1 and PGC-1? Protein Levels and AMPK Phosphorylation in Quadriceps of Middle-Aged Rats in an Intensity-Dependent Manner
The present study investigated the effects of running at 0.8 or 1.2?km/h on inflammatory proteins (i.e., protein levels of TNF-?, IL-1?, and NF-?B) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1?, and AMPK phosphorylation) in quadriceps of rats. Male Wistar rats at 3 (young) and 18 months (middle-aged rats) of age were divided into nonexercised (NE) and exercised at 0.8 or 1.2?km/h. The rats were trained on treadmill, 50?min per day, 5 days per week, during 8 weeks. Forty-eight hours after the last training session, muscles were removed, homogenized, and analyzed using biochemical and western blot techniques. Our results showed that: (a) running at 0.8?km/h decreased the inflammatory proteins and increased the metabolic proteins compared with NE rats; (b) these responses were lower for the inflammatory proteins and higher for the metabolic proteins in young rats compared with middle-aged rats; (c) running at 1.2?km/h decreased the inflammatory proteins and increased the metabolic proteins compared with 0.8?km/h; (d) these responses were similar between young and middle-aged rats when trained at 1.2?km. In summary, the age-related increases in inflammatory proteins, and the age-related declines in metabolic proteins can be reversed and largely improved by treadmill training.
Oliveira, Nara R. C.; Marques, Scherolin O.; Luciano, Thais F.; Pauli, Jose R.; Moura, Leandro P.; Caperuto, Erico; Pieri, Bruno L. S.; Engelmann, Julia; Scaini, Gisele; Streck, Emilio L.; Lira, Fabio S.; Pinho, Ricardo A.; Ropelle, Eduardo R.; Silva, Adelino S. R.; De Souza, Claudio T.
Alpha-sarcoglycan deficiency featuring exercise intolerance and myoglobinuria.
An 8-year-old boy was referred for recent onset of easy fatigue. He showed hyperCKemia and mild scapular winging. Muscle biopsy on the quadriceps muscle demonstrated slight fibre size variability. Dystrophin was normally distributed, carnitine palmitoyl transferase and glycolytic enzymes had normal activities. In the following years the patient developed exercise intolerance and myoglobinuria. Immunohistochemistry showed marked reduction of alpha-sarcoglycan, confirmed by Western blotting. Molecular analysis revealed compound heterozygosity with Arg284Cys and Glu137Lys substitutions, corresponding to nucleotide changes C850 T and G409 A in the gene. At present the patient, 20 years old, shows mild proximal weakness with prominent involvement of the paraspinal muscles, dorsal kyphosis and lumbar hyperlordosis. Exercise intolerance and myoglobinuria, already described in Becker muscular dystrophy, should be also considered among the possible presentations of sarcoglycan deficiencies. PMID:12075495
Mongini, T; Doriguzzi, C; Bosone, I; Chiadň-Piat, L; Hoffman, E P; Palmucci, L
Sleep On It: How Snoozing Strengthens Memories
... disclaimer . Subscribe Sleep On It How Snoozing Strengthens Memories When you learn something new, the best way ... sleep on it. That's because sleeping helps strengthen memories you've formed throughout the day. It also ...
Measurement of the quadriceps femoris muscle using magnetic resonance and ultrasound imaging.
OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare the results of measurements obtained by the MRI method with those obtained by the conventional method of static B-mode ultrasound in order to evaluate whether MRI is a reliable alternative to ultrasound. METHODS: A preliminary MRI study was undertaken on a single female volunteer in order to optimise the scanning technique and sampling design for estimating the muscle volume using the Cavalieri method. Ten healthy volunteers participated in the method comparison study. Each volunteer underwent static B-mode ultrasonography, immediately followed by MRI. The cross sectional area of the quadriceps femoris was estimated at the junction of the proximal one third and distal two thirds of the thigh, and seven systematic sections of the thigh were obtained in order to estimate muscle volume by both modalities. RESULTS: Seven sections through the muscle are required to achieve a coefficient of error of 4-5%. There was no significant difference in the cross sectional area estimates or volume estimates when ultrasound and MRI were compared. CONCLUSION: Muscle cross sectional area and volume can be measured without bias by MRI in conjunction with stereological methods and the method is a reliable alternative to static B-mode ultrasound for this purpose. Images Figure 1 Figure 4 Figure 5
Walton, J M; Roberts, N; Whitehouse, G H
Effective therapy of transected quadriceps muscle in rat: Gastric pentadecapeptide BPC 157.
We report complete transection of major muscle and the systemic peptide treatment that induces healing of quadriceps muscle promptly and then maintains the healing with functional restoration. Initially, stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, M.W. 1419, PL-10, PLD-116, PL 14736 Pliva, Croatia; in trials for inflammatory bowel disease; wound treatment; no toxicity reported; effective alone without carrier) also superiorly accelerates the healing of transected Achilles tendon. Regularly, quadriceps muscle completely transected transversely 1.0 cm proximal to patella presents a definitive defect that cannot be compensated in rat. BPC 157 (10 microg, 10 ng, 10 pg/kg) is given intraperitoneally, once daily; the first application 30 min posttransection, the final 24 h before sacrifice. It consistently improves muscle healing throughout the whole 72-day period. Improved are: (i) biomechanic (load of failure increased); (ii) function (walking recovery and extensor postural thrust/motor function index returned toward normal healthy values); (iii) microscopy/immunochemistry [i.e., mostly muscle fibers connect muscle segments; absent gap; significant desmin positivity for ongoing regeneration of muscle; larger myofibril diameters on both sides, distal and proximal (normal healthy rat-values reached)]; (iv) macroscopic presentation (stumps connected; subsequently, atrophy markedly attenuated; finally, presentation close to normal noninjured muscle, no postsurgery leg contracture). Thus, posttransection healing-consistently improved-may suggest this peptide therapeutic application in muscle disorders. PMID:16609979
Staresinic, Mario; Petrovic, Igor; Novinscak, Tomislav; Jukic, Ivana; Pevec, Damira; Suknaic, Slaven; Kokic, Neven; Batelja, Lovorka; Brcic, Luka; Boban-Blagaic, Alenka; Zoric, Zdenka; Ivanovic, Domagoj; Ajduk, Marko; Sebecic, Bozidar; Patrlj, Leonardo; Sosa, Tomislav; Buljat, Gojko; Anic, Tomislav; Seiwerth, Sven; Sikiric, Predrag
Heat production and chemical changes during isometric contractions of the human quadriceps muscle.
1. Development of a new thermal probe and use in conjunction with chemical analysis of needle biopsy samples, has made possible a thermodynamic study of the energetics of muscular contraction in the human quadriceps. 2. The observed rate of muscle temperature rise was proportional to the force of the contraction. During maximal contractions the rate of heat production was 54 +/-8-5 W/kg wet muscle (mean +/- s.d.). 3. The observed rates of muscle temperature rise agreed well with the rates calculated from the measured metabolite changes when standard values for the enthalpy changes of the reactions involved were used. 4. During prolonged stimulation of the quadriceps at 15/sec via the femoral nerve, the rate of heat production per unit force fell to nearly half the initial value. It is estimated that this represented a two- to fourfold increased in economy of ATP turn-over required to maintain a given force. 5. Relaxation becomes progressively slower during prolonged contractions and it is suggested that the slowing of relaxation and the increased economy of force maintenance may both be due to an increased cross-bridge cycle time in the fatigued muscle.
Edwards, R H; Hill, D K; Jones, D A
Augmentation of Deglutitive Thyrohyoid Muscle Shortening by the Shaker Exercise
Earlier studies of the effect of 6 weeks of the Shaker Exercise have shown significant increase in UES opening and anterior excursion of larynx and hyoid during swallowing in patients with upper esophageal sphincter (UES) dysfunction, resulting in elimination of aspiration and resumption of oral intake. This effect is attributed to strengthening of the suprahyoid muscles, as evidenced by comparison of electromyographic changes in muscle fatigue before and after completion of the exercise regime. The effect of this exercise on thyrohyoid muscle shortening is unknown. Therefore the aim of this study was to determine the effect of the exercise on thyrohyoid muscle shortening. We studied 11 dysphagic patients with UES dysfunction. Six were randomized to traditional swallowing therapy and five to the Shaker Exercise. Videofluoroscopy was used to measure deglutitive thyrohyoid shortening before and after completion of assigned therapy regimen. Maximum thyrohyoid muscle shortening occurred at close temporal proximity to the time of maximal thyroid cartilage excursion. The percent change in thyrohyoid distance from initiation of deglutition to maximal anterior/superior hyoid excursion showed no statistically significant difference between the two groups prior to either therapy (p = 0.54). In contrast, after completion of therapy, the percent change in thyrohyoid distance in the Shaker Exercise group was significantly greater compared to the traditional therapy (p = 0.034). The Shaker Exercise augments the thyrohyoid muscle shortening in addition to strengthening the suprahyoid muscles. The combination of increased thyrohyoid shortening and suprahyoid strengthening contributes to the Shaker Exercise outcome of deglutitive UES opening augmentation.
Mepani, Rachel; Antonik, Stephen; Massey, Benson; Kern, Mark; Logemann, Jerilyn; Pauloski, Barbara; Rademaker, Alfred; Easterling, Caryn
The effect of rowing ergometry and resistive exercise on skeletal muscle structure and function during bed rest.
Exposure to microgravity causes functional and structural impairment of skeletal muscle. Current exercise regimens are time-consuming and insufficiently effective; an integrated countermeasure is needed that addresses musculoskeletal along with cardiovascular health. High-intensity, short-duration rowing ergometry and supplemental resistive strength exercise may achieve these goals. Twenty-seven healthy volunteers completed 5 wk of head-down-tilt bed rest (HDBR): 18 were randomized to exercise, 9 remained sedentary. Exercise consisted of rowing ergometry 6 days/wk, including interval training, and supplemental strength training 2 days/wk. Measurements before and after HDBR and following reambulation included assessment of strength, skeletal muscle volume (MRI), and muscle metabolism (magnetic resonance spectroscopy); quadriceps muscle biopsies were obtained to assess muscle fiber types, capillarization, and oxidative capacity. Sedentary bed rest (BR) led to decreased muscle volume (quadriceps: -9 ± 4%, P < 0.001; plantar flexors: -19 ± 6%, P < 0.001). Exercise (ExBR) reduced atrophy in the quadriceps (-5 ± 4%, interaction P = 0.018) and calf muscle, although to a lesser degree (-14 ± 6%, interaction P = 0.076). Knee extensor and plantar flexor strength was impaired by BR (-14 ± 15%, P = 0.014 and -22 ± 7%, P = 0.001) but preserved by ExBR (-4 ± 13%, P = 0.238 and +13 ± 28%, P = 0.011). Metabolic capacity, as assessed by maximal O2 consumption, (31)P-MRS, and oxidative chain enzyme activity, was impaired in BR but stable or improved in ExBR. Reambulation reversed the negative impact of BR. High-intensity, short-duration rowing and supplemental strength training effectively preserved skeletal muscle function and structure while partially preventing atrophy in key antigravity muscles. Due to its integrated cardiovascular benefits, rowing ergometry could be a primary component of exercise prescriptions for astronauts or patients suffering from severe deconditioning. PMID:24790012
Krainski, Felix; Hastings, Jeffrey L; Heinicke, Katja; Romain, Nadine; Pacini, Eric L; Snell, Peter G; Wyrick, Phil; Palmer, M Dean; Haller, Ronald G; Levine, Benjamin D
Strengthening Community with Individual Development.
ERIC Educational Resources Information Center
Explores how the middle school concept is designed to make two seemingly contradictory goals compatible, those of providing a common core curriculum while meeting individual needs. Suggests that, similar to team sports or musical groups, it is possible to allow students to exercise personalized choices of how to meet the common objectives of the…
Erb, Tom
ERIC Educational Resources Information Center
Practical guidelines for physical education teachers concerning the right amount of exercise to develop and maintain health-related fitness among students are outlined, along with some techniques for developing student motivation. (JMF)
Pollock, Michael L.; Blair, Steven N.
... distance faster now? Are you at your target heart rate? Think about joining a health club or community ... thing when you're done exercising until your heart rate returns to normal. Pay attention to your body. ...
NSDL National Science Digital Library
This homework exercise, which was designed for an undergraduate level geology class at Tulane University, asks the student to make evaluations about the Loma Prieta Earthquake and other earthquakes using seismograms, time travel curves, maps and other information.
Nelson, Stephen
NSDL National Science Digital Library
These exercises help students understand how the code of the Insertion Sort and the Selection Sort work. It also compares how efficient several different algorithms are. Advanced Exercise 1 - Understanding the Insertion Sort code Remember that the Insertion Sort sort works by making sure everything to the left of the pointer is sorted. The variable j of the for loop represents this pointer, and therefore it starts at 1 and continues to the end of the ...
Watts, Mrs.
NASA Technical Reports Server (NTRS)
The bicycle ergometer and a graded stress protocol were used to conduct exercise stress tests for the Apollo project. The graded exercise tests permitted a progressive evaluation of physiological control system response and provided a better understanding of safe stress limits; heart rate was used for determining stress levels. During each test, workload, heart rate, blood pressure, and respiratory gas exchange (oxygen consumption, carbon dioxide production, and minute volume) measurements were made. The results are presented and discussed.
Rummel, J. A.; Sawin, C. F.; Michel, E. L.
Exercise performance is regulated during repeated sprints to limit the development of peripheral fatigue beyond a critical threshold.
We hypothesized that exercise performance is adjusted during repeated sprints in order not to surpass a critical threshold of peripheral fatigue. Twelve men randomly performed three experimental sessions on different days, i.e. one single 10 s all-out sprint and two trials of 10 × 10 s all-out sprints with 30 s of passive recovery in between. One trial was performed in the unfatigued state (CTRL) and one following electrically induced quadriceps muscle fatigue (FTNMES). Peripheral fatigue was quantified by comparing pre- with postexercise changes in potentiated quadriceps twitch force (?Qtw-pot) evoked by supramaximal magnetic stimulation of the femoral nerve. Central fatigue was estimated by comparing pre- with postexercise voluntary activation of quadriceps motor units. The root mean square (RMS) of the vastus lateralis and vastus medialis EMG normalized to maximal M-wave amplitude (RMS.Mmax (-1)) was also calculated during sprints. Compared with CTRL condition, pre-existing quadriceps muscle fatigue in FTNMES (?Qtw-pot = -29 ± 4%) resulted in a significant (P < 0.05) reduction in power output (-4.0 ± 0.9%) associated with a reduction in RMS.Mmax (-1). However, ?Qtw-pot postsprints decreased by 51% in both conditions, indicating that the level of peripheral fatigue was identical and independent of the degree of pre-existing fatigue. Our findings show that power output and cycling EMG are adjusted during exercise in order to limit the development of peripheral fatigue beyond a constant threshold. We hypothesize that the contribution of peripheral fatigue to exercise limitation involves a reduction in central motor drive in addition to the impairment in muscular function. PMID:24728680
Hureau, Thomas J; Olivier, Nicolas; Millet, Guillaume Y; Meste, Olivier; Blain, Gregory M
Assessing quadriceps muscles recruitment order using rectified averaged surface EMG in young normals and 'weak' and healthy elderly subjects
The purpose of this study was to investigate whether measurement of the surface electromyogram (EMG) reveals a specific quadriceps femoris (QF) recruitment pattern during various activities and whether this pattern is affected by age and QF wasting.Surface EMG from the rectus femoris (RF1, vastus lateralis (VL) and vastus medialis oblique (VMO) was recorded in 24 subjects (eight young normals, eight
GP Smith; TE Howe; JA Oldham; T. Petterson; RC Tallis; GA Vickers
Hamstring exercises for track and field athletes: injury and exercise biomechanics, and possible implications for exercise selection and primary prevention.
Hamstring strain injuries are the most prevalent muscle injuries in track and field (TF). These injuries often cause prolonged symptoms and a high risk of re-injury. Strengthening of the hamstring muscles has been recommended for injury prevention. The authors review the possible role of eccentric training in TF hamstring injury prevention and introduce exercise classification criteria to guide clinicians in designing strengthening programmes adapted to TF. The principles exposed may serve as a foundation for future development and application of new eccentric programmes to decrease the high incidence of this type of injury in other sports. PMID:22685125
Malliaropoulos, Nikos; Mendiguchia, Jurdan; Pehlivanidis, Hercules; Papadopoulou, Sofia; Valle, Xavier; Malliaras, Peter; Maffulli, Nicola
Prevalence of abnormal patellofemoral congruence in elite American football players and association with quadriceps isokinetic testing.
Abnormal patellofemoral joint alignment has been discussed as a potential risk factor for patellofemoral disorders and can impact the longevity of any elite athlete's career. The prevalence of abnormal patellofemoral congruence in elite American football athletes is similar to the general population and does not have a relationship with quadriceps isokinetic testing. A total of 125 athletes (220 knees) from the 2011 National Football League (NFL) Combine database who had radiographic and isokinetic studies were reviewed. Congruence angles (CA) and lateral patellofemoral angles (LPA) were calculated on a Merchant radiographic view. Isokinetic testing was used to determine quadriceps-to-hamstring strength (Q/H) ratio and side-to-side deficits. The relationships between abnormal CA and LPA with Q/H ratios, side-to-side deficits, and body mass index (BMI) were examined in separate logistic regression models. A Chi-square test was used to examine the association between CA and player position. Of all, 26.8% of the knees (95% CI: 21.1-33.2%) had an abnormal CA. Knees with normal CA (n?=?161) did not significantly differ from those with an abnormal CA (n? = 59) in Q/H ratios (mean: 0.699 vs. 0.728, p?=?0.19) or side-to-side quadriceps deficits (mean: 4.0 vs. 1.24, p? = 0.45). For each point increase in BMI, the odds ratio (OR) of abnormal congruence increased by 11.4% (p?=?0.002). Of all the knees, 4.1% (95% CI: 1.9-7.6%) had an abnormal LPA, and this was not associated with Q/H ratios (p? = ?0.13). For each point increase in BMI, the odds of abnormal LPA increased by 16% (p? = 0.036). CA abnormality had much higher odds of having an abnormal LPA (OR: 5.96, p = 0.014). We found that abnormal patellofemoral radiographic alignment in elite American football players is relatively common and there was no association with isokinetic testing. PMID:23925950
Brown, Christopher A; Carragee, Cat; Sox-Harris, Alex; Merchant, Alan C; Mcadams, Timothy R
Effects of a short proprioceptive neuromuscular facilitation stretching bout on quadriceps neuromuscular function, flexibility, and vertical jump performance.
The inclusion of relatively long bouts of stretching (repeated static stretches of ?30 seconds) in the warm-up is usually associated with a drop in muscle performance. The purpose of this study was to assess the effect of a novel self-administered proprioceptive neuromuscular facilitation (PNF) paradigm with short periods of stretching and contraction on quadriceps neuromuscular function, vertical jump performance, and articular range of motion (ROM). Twelve healthy men (age: 27.7 ± 7.3 years, height: 178.4 ± 10.4 cm, weight: 73.8 ± 16.9 kg) volunteered to participate in a PNF session and a control session separated by 2-7 days. The PNF stretching lasted 2 minutes and consisted of 4 sets of 5-second isometric hamstring contraction immediately followed by 5 seconds of passive static stretch of the quadriceps immediately followed by 5 seconds isometric quadriceps contraction for each leg. For the control session, the participants were asked to walk at a comfortable speed for 2 minutes. Active ROM of knee flexion, vertical jump performance, and quadriceps neuromuscular function were tested before, immediately after, and 15 minutes after the intervention. The PNF stretching procedure did not affect ROM, squat jump, and countermovement jump performances. Accordingly, we did not observe any change in maximal voluntary contraction force, voluntary activation level, M-wave and twitch contractile properties that could be attributed to PNF stretching. The present self-administered PNF stretching of the quadriceps with short (5-second) stretches is not recommended before sports where flexibility is mandatory for performance. PMID:22505131
Place, Nicolas; Blum, Yannick; Armand, Stéphane; Maffiuletti, Nicola A; Behm, David G
MuRF-1 and Atrogin-1 Protein Expression and Quadriceps Fiber Size and Muscle Mass in Stable Patients with COPD
Introduction Animal studies demonstrate the importance of the E3 ubiquitin ligases, Muscle RING-Finger Protein 1 (MuRF-1) and atrogin-1, in muscle protein degradation during acute muscle atrophy. Small clinical studies suggest MuRF-1 and atrogin-1 expression in the quadriceps muscle is also increased in stable patients with Chronic Obstructive Pulmonary Disease compared to controls. However, it remains unclear whether these ligases have a role in maintaining a muscle-wasted state in COPD patients. Methods 32 stable COPD patients (16 with a low fat-free mass index (FFMI), 16 with a normal FFMI) and 15 controls underwent lung function and quadriceps strength tests and a percutaneous quadriceps biopsy. Quadriceps MuRF-1 and atrogin-1 protein were quantified with western blotting. Quadriceps fiber cross-sectional area (CSA) and fiber proportions were determined by immunohistochemistry on muscle sections. MuRF-1 and atrogin-1 levels were compared between COPD patients with and without a low FFMI, and between patients and controls, and correlations between MuRF-1 and atrogin-1 levels and quadriceps fiber CSA in the patients were investigated. Results Atrogin-1 protein levels were lower in patients than controls, but similar in patients with a low and normal FFMI. MuRF-1 levels did not differ between any groups. MuRF-1 and atrogin-1 levels were not associated with quadriceps fiber CSA or quadriceps strength in patients. Conclusions Chronic upregulation of ubiquitin ligases was not evident in the quadriceps muscle of stable COPD patients with a low muscle mass. This does not exclude the possibility of transient increases in ubiquitin ligases during acute catabolic episodes.
Natanek, Samantha A.; Riddoch-Contreras, Joanna; Marsh, Gemma S.; Hopkinson, Nicholas S.; Moxham, John; Man, William D.-C.; Kemp, Paul R.; Polkey, Michael I.
Adaptive force regulation of muscle strengthening rehabilitation device with magnetorheological fluids.
In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based on the lowest level of torque that is produced by a muscle group. Resistance that varies with joint angle can be achieved with isokinetic devices in which angular velocity is held constant and variable torque is generated when the patient attempts to move faster than the device but are ineffective if a patient cannot generate torque rapidly. In this paper, we report the development of a versatile rehabilitation device that can be used to strengthen different muscle groups based on the torque generating capability of the muscle that changes with joint angle. The device is low cost, is smaller than other commercially available machines, and can be programmed to apply resistance that is unique to a particular patient and that will optimize strengthening. The core of the device, a damper with smart magnetorheological fluids, provides passive exercise force. A digital adaptive control is capable of regulating exercise force precisely following the muscle strengthening profile prescribed by a physical therapist. The device could be programmed with artificial intelligence to dynamically adjust the target force profile to optimize rehabilitation effects. The device provides both isometric and isokinetic strength training and can be developed into a small, low-cost device that may be capable of providing optimal strengthening in the home. PMID:16562632
Dong, Shufang; Lu, Ke-Qian; Sun, Jian Qiao; Rudolph, Katherine
Adaptive Force Regulation of Muscle Strengthening Rehabilitation Device With Magnetorheological Fluids
In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based on the lowest level of torque that is produced by a muscle group. Resistance that varies with joint angle can be achieved with isokinetic devices in which angular velocity is held constant and variable torque is generated when the patient attempts to move faster than the device but are ineffective if a patient cannot generate torque rapidly. In this paper, we report the development of a versatile rehabilitation device that can be used to strengthen different muscle groups based on the torque generating capability of the muscle that changes with joint angle. The device is low cost, is smaller than other commercially available machines, and can be programmed to apply resistance that is unique to a particular patient and that will optimize strengthening. The core of the device, a damper with smart magnetorheological fluids, provides passive exercise force. A digital adaptive control is capable of regulating exercise force precisely following the muscle strengthening profile prescribed by a physical therapist. The device could be programmed with artificial intelligence to dynamically adjust the target force profile to optimize rehabilitation effects. The device provides both isometric and isokinetic strength training and can be developed into a small, low-cost device that may be capable of providing optimal strengthening in the home.
Dong, Shufang; Lu, Ke-Qian; Sun, Jian Qiao; Rudolph, Katherine
Does quadriceps neuromuscular activation capability explain walking speed in older men and women?
Age-related impairment of neuromuscular activation has been shown to contribute to weakness in older adults. However, it is unclear to what extent impaired neuromuscular activation independently accounts for decline of mobility function. The hypothesis of this study is that the capability to produce rapid neuromuscular activation during maximal effort leg muscle contractions will be shown to be an independent predictor of mobility function in older men and women after accounting for muscle size and adiposity, body composition and age. Twenty six older men and eighteen older women (aged 70-85years) participated in this study. Mobility function was assessed by the 400-m walk test. Neuromuscular activation of the quadriceps muscle group was assessed by surface electromyography ("rate of EMG rise"). Thigh muscle cross sectional area and adiposity were assessed by computed tomography. In males, univariate regression analysis revealed strong associations between walking speed and a number of predictors including age (p<0.01), muscle area (p<0.01), intermuscular adipose tissue area (p<0.01), and rate of EMG rise (p<0.001). Subsequent multiple regression analysis with all variables accounted for 72% of the variability in walking speed (p<.0001), with age and rate of EMG rise as the dominant variables in the model. In females, univariate analysis showed a significant association only between walking speed and subcutaneous adipose tissue area (p<0.05). Multiple regression analysis accounted for only 44% of the variability in walking speed, and was not statistically significant (p=0.18). The present findings indicate that the capability to rapidly activate the quadriceps muscle group is an important factor accounting for inter-individual variability of walking speed among older men, but not among older women. This research is important for informing the design of assessments and interventions that seek to detect and prevent impairments that contribute to age-related mobility disability. PMID:24703887
Clark, David J; Reid, Kieran F; Patten, Carolynn; Phillips, Edward M; Ring, Sarah A; Wu, Samuel S; Fielding, Roger A
Exercise echocardiography has been used for 30 years. It is now considered a consolidated technique for the diagnosis and risk stratification of patients with known or suspected coronary artery disease (CAD). Of the stress echocardiography techniques, it represents the first choice for patients who are able to exercise. Given that the cost-effectiveness and safety of stress echocardiography are higher than those of other imaging techniques, its use is likely to be expanded further. Recent research has also proposed this technique for the evaluation of cardiac pathology beyond CAD. Although the role of new technology is promising, the assessment of cardiac function relies on good quality black and white harmonic images.
Peteiro, Jesus; Bouzas-Mosquera, Alberto
NASA Technical Reports Server (NTRS)
Viewgraphs on daily exercise routines are presented. Topics covered include: daily exercise and periodic stress testings; exercise equipment; physiological monitors; exercise protocols; physiological levels; equipment control; control systems; and fuzzy logic control.
Anderson, Patrick L.; Amoroso, Michael T.
Peripheral fatigue limits endurance exercise via a sensory feedback-mediated reduction in spinal motoneuronal output.
This study sought to determine whether afferent feedback associated with peripheral muscle fatigue inhibits central motor drive (CMD) and thereby limits endurance exercise performance. On two separate days, eight men performed constant-load, single-leg knee extensor exercise to exhaustion (85% of peak power) with each leg (Leg1 and Leg2). On another day, the performance test was repeated with one leg (Leg1) and consecutively (within 10 s) with the other/contralateral leg (Leg2-post). Exercise-induced quadriceps fatigue was assessed by reductions in potentiated quadriceps twitch-force from pre- to postexercise (?Qtw,pot) in response to supramaximal magnetic femoral nerve stimulation. The output from spinal motoneurons, estimated from quadriceps electromyography (iEMG), was used to reflect changes in CMD. Rating of perceived exertion (RPE) was recorded during exercise. Time to exhaustion (?9.3 min) and exercise-induced ?Qtw,pot (?51%) were similar in Leg1 and Leg2 (P > 0.5). In the consecutive leg trial, endurance performance of the first leg was similar to that observed during the initial trial (?9.3 min; P = 0.8); however, time to exhaustion of the consecutively exercising contralateral leg (Leg2-post) was shorter than the initial Leg2 trial (4.7 ± 0.6 vs. 9.2 ± 0.4 min; P < 0.01). Additionally, ?Qtw,pot following Leg2-post was less than Leg2 (33 ± 3 vs 52 ± 3%; P < 0.01). Although the slope of iEMG was similar during Leg2 and Leg2-post, end-exercise iEMG following Leg2-post was 26% lower compared with Leg2 (P < 0.05). Despite a similar rate of rise, RPE was consistently ?28% higher throughout Leg2-post vs. Leg2 (P < 0.05). In conclusion, this study provides evidence that peripheral fatigue and associated afferent feedback limits the development of peripheral fatigue and compromises endurance exercise performance by inhibiting CMD. PMID:23722705
Amann, Markus; Venturelli, Massimo; Ives, Stephen J; McDaniel, John; Layec, Gwenael; Rossman, Matthew J; Richardson, Russell S
Exercise for fitness does not decrease the muscular inactivity time during normal daily life.
The time spent in sedentary behaviors has been shown to be independent of exercise in epidemiological studies. We examined within an individual whether exercise alters the time of muscular inactivity within his/her normal daily life. Quadriceps and hamstring muscle electromyographic activities and heart rate were measured during 1 to 6 days of normal daily living of ordinary people. Of 84 volunteers measured, 27 (15 men, 12 women, 40.7 years?±?16.5 years) fulfilled the criteria of having at least 1 day with and 1 day without exercise for fitness (total of 87 days analyzed, 13.0?h?±?2.5?h/day). Reported exercises varied from Nordic walking to strength training and ball games lasting 30?min-150?min (mean 83?min?±?30?min). Exercise increased the time spent at moderate-to-vigorous muscle activity (6%?±?4% to 9%?±?6%, P?0.01) and energy expenditure (13%?±?22%, P?0.05). Muscular inactivity, defined individually below that measured during standing, comprised 72%?±?12% of day without and 68%?±?13% of day with exercise (not significant). Duration of exercise correlated positively to the increase in moderate-to-vigorous muscle activity time (r?=?0.312, P?0.05) but not with inactivity time. In conclusion, exercise for fitness, regardless of its duration, does not decrease the inactivity time during normal daily life. This is possible by slight modifications in daily nonexercise activities. PMID:22417280
Finni, T; Haakana, P; Pesola, A J; Pullinen, T
NASA Technical Reports Server (NTRS)
An apparatus and method for exercising whereby the user is supported by various mechanisms in such as way that the user's shoulder area is free to translate and rotate; the user's pelvic area is free to translate and rotate; or in any combination.
Schaffner, Grant (Inventor); Bentley, Jason R. (Inventor); Loehr, James A. (Inventor); Gundo, Daniel P. (Inventor)
... such as muscles, tendons, bursae, cartilage, bones, and nerves. Repetitive stress can leads to microtraumas — minor injuries that would typically heal with enough rest. When you exercise too frequently, your body never has a chance to repair these microtraumas. As microtraumas build up over time, ...
NSDL National Science Digital Library
This homework exercise, developed for an undergraduate geology course at Tulane University, leads students through the steps involved in determining the probability that a flood of a given discharge will occur in any given year. Students retrieve discharge data from U.S. Geological Services Internet sites for Dry Creek, LA, Rapid Creek, SD and Red River, ND to make their calculations.
Nelson, Stephen
Treadmill exercise induces neutrophil recruitment into muscle tissue in a reactive oxygen species-dependent manner. An intravital microscopy study.
Intense exercise is a physiological stress capable of inducing the interaction of neutrophils with muscle endothelial cells and their transmigration into tissue. Mechanisms driving this physiological inflammatory response are not known. Here, we investigate whether production of reactive oxygen species is relevant for neutrophil interaction with endothelial cells and recruitment into the quadriceps muscle in mice subjected to the treadmill fatiguing exercise protocol. Mice exercised until fatigue by running for 56.3±6.8 min on an electric treadmill. Skeletal muscle was evaluated by intravital microscopy at different time points after exercise, and then removed to assess local oxidative stress and histopathological analysis. We observed an increase in plasma lactate and creatine kinase (CK) concentrations after exercise. The numbers of monocytes, neutrophils, and lymphocytes in blood increased 12 and 24 hours after the exercise. Numbers of rolling and adherent leukocytes increased 3, 6, 12, and 24 hours post-exercise, as assessed by intravital microscopy. Using LysM-eGFP mice and confocal intravital microscopy technology, we show that the number of transmigrating neutrophils increased 12 hours post-exercise. Mutant gp91phox-/- (non-functional NADPH oxidase) mice and mice treated with apocynin showed diminished neutrophil recruitment. SOD treatment promoted further adhesion and transmigration of leukocytes 12 hours after the exercise. These findings confirm our hypothesis that treadmill exercise increases the recruitment of leukocytes to the postcapillary venules, and NADPH oxidase-induced ROS plays an important role in this process. PMID:24798414
Nunes-Silva, Albená; Bernardes, Priscila T T; Rezende, Bárbara M; Lopes, Fernando; Gomes, Elisa C; Marques, Pedro E; Lima, Paulo M A; Coimbra, Cândido C; Menezes, Gustavo B; Teixeira, Mauro M; Pinho, Vanessa
Treadmill Exercise Induces Neutrophil Recruitment into Muscle Tissue in a Reactive Oxygen Species-Dependent Manner. An Intravital Microscopy Study
Intense exercise is a physiological stress capable of inducing the interaction of neutrophils with muscle endothelial cells and their transmigration into tissue. Mechanisms driving this physiological inflammatory response are not known. Here, we investigate whether production of reactive oxygen species is relevant for neutrophil interaction with endothelial cells and recruitment into the quadriceps muscle in mice subjected to the treadmill fatiguing exercise protocol. Mice exercised until fatigue by running for 56.3±6.8 min on an electric treadmill. Skeletal muscle was evaluated by intravital microscopy at different time points after exercise, and then removed to assess local oxidative stress and histopathological analysis. We observed an increase in plasma lactate and creatine kinase (CK) concentrations after exercise. The numbers of monocytes, neutrophils, and lymphocytes in blood increased 12 and 24 hours after the exercise. Numbers of rolling and adherent leukocytes increased 3, 6, 12, and 24 hours post-exercise, as assessed by intravital microscopy. Using LysM-eGFP mice and confocal intravital microscopy technology, we show that the number of transmigrating neutrophils increased 12 hours post-exercise. Mutant gp91phox-/- (non-functional NADPH oxidase) mice and mice treated with apocynin showed diminished neutrophil recruitment. SOD treatment promoted further adhesion and transmigration of leukocytes 12 hours after the exercise. These findings confirm our hypothesis that treadmill exercise increases the recruitment of leukocytes to the postcapillary venules, and NADPH oxidase-induced ROS plays an important role in this process.
Nunes-Silva, Albena; Bernardes, Priscila T. T.; Rezende, Barbara M.; Lopes, Fernando; Gomes, Elisa C.; Marques, Pedro E.; Lima, Paulo M. A.; Coimbra, Candido C.; Menezes, Gustavo B.; Teixeira, Mauro M.; Pinho, Vanessa
Effect of Exercise Training and +Gz Acceleration Training on Men
NASA Technical Reports Server (NTRS)
Countermeasures for reduction in work capacity (maximal oxygen uptake and strength) during spaceflight and enhanced orthostatic intolerance during re-entry, landing and egress from the return vehicle are continuing problems. The purpose for this study was to test the hypothesis that passive-acceleration training; supine, interval, exercise plus acceleration training and exercise combined with acceleration training would improve orthostatic tolerance in ambulatory men; and that addition of the aerobic exercise conditioning would not alter this improved tolerance from that of passive-acceleration training. Seven men (24-38 yr) underwent "Passive" training on the Ames human-powered centrifuge (HPC) for 30 min, "Exercise" training on the cycle ergometer with constant +Gz acceleration; and "Combined" exercise training at 40% to 90% of the HPC +Gz(max) exercise level. Maximal supine exercise loads increased significant (P<0.05) by 8.3% (Passive), 12.6% (Exercise), and by 15.4% (Combined) after training, but their post-training maximal oxygen uptakes and maximal heart rates were unchanged. Maximal time to fatigue (endurance) was unchanged with Passive was increased (P<0.05) with Exercise and Combined training. Thus, the exercise in the Exercise and Combined training Phases resulted in greater maximal loads and endurance without effect on maximal oxygen uptake or heart rate. There was a 4% to 6% increase (P<0.05) in all four quadriceps muscle volumes (right and left) after post-Combined training. Resting pre-tilt heart rate was elevated by 12.9% (P<0.05) only after Passive training suggesting that the exercise training attenuated the HR response. Plasma volume (% Delta) was uniformly decreased by 8% to 14% (P<0.05) at tilt-tolerance pre- vs. post-training indicating essentially no effect of training on the level of hypovolemia. Post-training tilt-tolerance time and heart rate were increased (P<0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training appeared to attenuate the increased Passive tilt-tolerance.
Greenleaf, John E.; Simonson, Shawn R.; Stocks, Jodie M.; Evans, Joyce; Knapp, Charles F.; Cowell, Stephenie A.; Pemberton, Kendra N.; Wilson, Heather W.; Vener, Jamie M.; Evetts, Simon N.
Effect of Exercise Speed and Isokinetic Feedback on the Middle and Lower Serratus Anterior Muscles during Push-up Exercises
[Purpose] This study assessed the use of different exercise speeds and isokinetic feedback on the middle and lower serratus anterior muscles during push-up exercises. [Subjects] Ten male workers voluntarily consented to participate in the study. [Methods] The subjects performed push-up exercises under three conditions. Surface electrodes were placed on the dominant right side of the middle and lower serratus anterior muscles. [Results] The middle and lower SA muscle activities under condition 2 were significantly decreased when compared with those under conditions 1 and 3. The middle SA activity under condition 3 was significantly increased when compared with that under condition 1. [Conclusion] This study suggests that proper selection of push-up exercise speed may be necessary for selective strengthening of the SA and that isokinetic feedback information obtained using an accelerator can help in selective strengthening of the middle SA.
Yoo, Won-gyu
Effect of expiratory muscle fatigue on exercise tolerance and locomotor muscle fatigue in healthy humans.
High-intensity exercise (> or =90% of maximal O(2) uptake) sustained to the limit of tolerance elicits expiratory muscle fatigue (EMF). We asked whether prior EMF affects subsequent exercise tolerance. Eight male subjects (means +/- SD; maximal O(2) uptake = 53.5 +/- 5.2 ml.kg(-1).min(-1)) cycled at 90% of peak power output to the limit of tolerance with (EMF-EX) and without (CON-EX) prior induction of EMF and for a time equal to that achieved in EMF-EX but without prior induction of EMF (ISO-EX). To induce EMF, subjects breathed against an expiratory flow resistor until task failure (15 breaths/min, 0.7 expiratory duty cycle, 40% of maximal expiratory gastric pressure). Fatigue of abdominal and quadriceps muscles was assessed by measuring the reduction relative to prior baseline values in magnetically evoked gastric twitch pressure (Pga(tw)) and quadriceps twitch force (Q(tw)), respectively. The reduction in Pga(tw) was not different after resistive breathing vs. after CON-EX (-27 +/- 5 vs. -26 +/- 6%; P = 0.127). Exercise time was reduced by 33 +/- 10% in EMF-EX vs. CON-EX (6.85 +/- 2.88 vs. 9.90 +/- 2.94 min; P < 0.001). Exercise-induced abdominal and quadriceps muscle fatigue was greater after EMF-EX than after ISO-EX (-28 +/- 9 vs. -12 +/- 5% for Pga(tw), P = 0.001; -28 +/- 7 vs. -14 +/- 6% for Q(tw), P = 0.015). Perceptual ratings of dyspnea and leg discomfort (Borg CR10) were higher at 1 and 3 min and at end exercise during EMF-EX vs. during ISO-EX (P < 0.05). Percent changes in limb fatigue and leg discomfort (EMF-EX vs. ISO-EX) correlated significantly with the change in exercise time. We propose that EMF impaired subsequent exercise tolerance primarily through an increased severity of limb locomotor muscle fatigue and a heightened perception of leg discomfort. PMID:18323465
Taylor, Bryan J; Romer, Lee M
Current ISS Exercise Countermeasures: Where are we now?
NASA Technical Reports Server (NTRS)
Current International Space Station (ISS) crew schedules include 1.5 h/d for completion of resistive exercise and 1 h/d of aerobic exercise , 6 d/wk. While ISS post flight decrements in muscle strength, bone m ineral density, and aerobic capacity improved in some crewmembers, de conditioning was still evident even with this volume of exercise. Res ults from early ISS expeditions show maximum loss in bone mineral density of the lumbar spine and pelvis in excess of 1.5% per month, with all crewmembers demonstrating significant bone loss in one or more re gions. Similarly, post flight muscle strength losses in the hamstring and quadriceps muscle groups exceeded 30% in the immediate post miss ion period in some crewmembers. Measures of aerobic capacity early in the mission show average decrements of 15%, but with onboard aerobic exercise capability, the crew has been able to "train up" over the co urse of the mission. These findings are highly variable among crewmem bers and appear to be correlated with availability and reliability of the inflight resistive exercise device (RED), cycle ergometer, and t readmill. This suite of hardware was installed on ISS with limited op erational evaluation in groundbased test beds. As a result, onorbit hardware constraints have resulted in inadequate physical stimulus, d econditioning, and increased risk for compromised performance during intra and extravehicular activities. These issues indicate that the c urrent ISS Countermeasures System reliability or validity are not ade quate for extendedduration exploration missions. Learning Objective: A better understanding of the status of ISS exercise countermeasures , their ability to protect physiologic systems, and recommendations for exploration exercise countermeasures.
Hayes, J. C.; Loerch, L.; Davis-Street, J.; Haralson, Cortni; Sams, C.
Severity of arterial hypoxaemia affects the relative contributions of peripheral muscle fatigue to exercise performance in healthy humans
We examined the effects of hypoxia severity on peripheral versus central determinants of exercise performance. Eight cyclists performed constant-load exercise to exhaustion at various fractions of inspired O2 fraction (FIO2 0.21/0.15/0.10). At task failure (pedal frequency < 70% target) arterial hypoxaemia was surreptitiously reversed via acute O2 supplementation (FIO2 = 0.30) and subjects were encouraged to continue exercising. Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force (?Qtw,pot) as measured pre- versus post-exercise in response to supramaximal femoral nerve stimulation. At task failure in normoxia (haemoglobin saturation (SpO2) ?94%, 656 ± 82 s) and moderate hypoxia (SpO2 ?82%, 278 ± 16 s), hyperoxygenation had no significant effect on prolonging endurance time. However, following task failure in severe hypoxia (SpO2 ?67%; 125 ± 6 s), hyperoxygenation elicited a significant prolongation of time to exhaustion (171 ± 61%). The magnitude of ?Qtw,pot at exhaustion was not different among the three trials (?35% to ?36%, P = 0.8). Furthermore, quadriceps integrated EMG, blood lactate, heart rate, and effort perceptions all rose significantly throughout exercise, and to a similar extent at exhaustion following hyperoxygenation at all levels of arterial oxygenation. Since hyperoxygenation prolonged exercise time only in severe hypoxia, we repeated this trial and assessed peripheral fatigue following task failure prior to hyperoxygenation (125 ± 6 s). Although Qtw,pot was reduced from pre-exercise baseline (?23%; P < 0.01), peripheral fatigue was substantially less (P < 0.01) than that observed at task failure in normoxia and moderate hypoxia. We conclude that across the range of normoxia to severe hypoxia, the major determinants of central motor output and exercise performance switches from a predominantly peripheral origin of fatigue to a hypoxia-sensitive central component of fatigue, probably involving brain hypoxic effects on effort perception.
Amann, Markus; Romer, Lee M; Subudhi, Andrew W; Pegelow, David F; Dempsey, Jerome A
Severity of arterial hypoxaemia affects the relative contributions of peripheral muscle fatigue to exercise performance in healthy humans.
We examined the effects of hypoxia severity on peripheral versus central determinants of exercise performance. Eight cyclists performed constant-load exercise to exhaustion at various fractions of inspired O2 fraction (FIO2 0.21/0.15/0.10). At task failure (pedal frequency < 70% target) arterial hypoxaemia was surreptitiously reversed via acute O2 supplementation (FIO2 = 0.30) and subjects were encouraged to continue exercising. Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force (DeltaQ(tw,pot)) as measured pre- versus post-exercise in response to supramaximal femoral nerve stimulation. At task failure in normoxia (haemoglobin saturation (SpO2) approximately 94%, 656 +/- 82 s) and moderate hypoxia (SpO2) approximately 82%, 278 +/- 16 s), hyperoxygenation had no significant effect on prolonging endurance time. However, following task failure in severe hypoxia (SpO2) approximately 67%; 125 +/- 6 s), hyperoxygenation elicited a significant prolongation of time to exhaustion (171 +/- 61%). The magnitude of DeltaQ(tw,pot) at exhaustion was not different among the three trials (-35% to -36%, P = 0.8). Furthermore, quadriceps integrated EMG, blood lactate, heart rate, and effort perceptions all rose significantly throughout exercise, and to a similar extent at exhaustion following hyperoxygenation at all levels of arterial oxygenation. Since hyperoxygenation prolonged exercise time only in severe hypoxia, we repeated this trial and assessed peripheral fatigue following task failure prior to hyperoxygenation (125 +/- 6 s). Although Q(tw,pot) was reduced from pre-exercise baseline (-23%; P < 0.01), peripheral fatigue was substantially less (P < 0.01) than that observed at task failure in normoxia and moderate hypoxia. We conclude that across the range of normoxia to severe hypoxia, the major determinants of central motor output and exercise performance switches from a predominantly peripheral origin of fatigue to a hypoxia-sensitive central component of fatigue, probably involving brain hypoxic effects on effort perception. PMID:17317739
Amann, Markus; Romer, Lee M; Subudhi, Andrew W; Pegelow, David F; Dempsey, Jerome A
Electromyographic analysis of the three subdivisions of gluteus medius during weight-bearing exercises
BACKGROUND: Gluteus medius (GM) dysfunction is associated with many musculoskeletal disorders. Rehabilitation exercises aimed at strengthening GM appear to improve lower limb kinematics and reduce pain. However, there is a lack of evidence to identify which exercises best activate GM. In particular, as GM consists of three distinct subdivisions, it is unclear if GM activation is consistent across these subdivisions
Kieran O'Sullivan; Sharon M Smith; David Sainsbury
Effects of quadriceps and anterior tibial muscles electrical stimulation on the feet and ankles of patients with spinal cord injuries
Study design:Controlled clinical test.Objectives:The purpose of this study was to assess the effects of quadriceps and anterior tibial muscles electrical stimulation on the feet and ankles of patients with spinal cord injuries and to compare them with able-bodied individuals and a group of patients who did not undergo neuromuscular electrical stimulation (NMES).Setting:This study was conducted at the Hospital das Clínicas
C K Bittar; A Cliquet
Isokinetic hamstrings-to-quadriceps peak torque ratio: The influence of sport modality, gender, and angular velocity
The purpose of this study was to determine differences in hamstrings-to-quadriceps (H\\/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52
Marilia Dos Santos Andrade; Claudio Andre Barbosa De Lira; Fabiana De Carvalho Koffes; Naryana Cristina Mascarin; Ana Amélia Benedito-Silva; Antonio Carlos Da Silva
Quadriceps tendon rupture: a biomechanical comparison of transosseous equivalent double-row suture anchor versus transosseous tunnel repair.
Quadriceps rupture off the patella is traditionally repaired by a transosseous tunnel technique, although a single-row suture anchor repair has recently been described. This study biomechanically tested a new transosseous equivalent (TE) double-row suture anchor technique compared with the transosseous repair for quadriceps repair. After simulated quadriceps-patella avulsion in 10 matched cadaveric knees, repairs were completed by either a three tunnel transosseous (TT = 5) or a TE suture anchor (TE = 5) technique. Double-row repairs were done using two 5.5 Bio-Corkscrew FT (fully threaded) (Arthrex, Inc., Naples, FL, USA) and two 3.5 Bio-PushLock anchors (Arthrex, Inc., Naples, FL, USA) with all 10 repairs done with #2 FiberWire suture (Arthrex, Inc., Naples, FL). Cyclic testing from 50 to 250 N for 250 cycles and pull to failure load (1 mm/s) were undertaken. Gap formation and ultimate tensile load (N) were recorded and stiffness data (N/mm) were calculated. Statistical analysis was performed using a Mann-Whitney U test and survival characteristics examined with Kaplan-Meier test. No significant difference was found between the TE and TT groups in stiffness (TE = 134 +/- 15 N/mm, TT = 132 +/- 26 N/mm, p = 0.28). The TE group had significantly less ultimate tensile load (N) compared with the TT group (TE = 447 +/- 86 N, TT = 591 +/- 84 N, p = 0.04), with all failures occurring at the suture eyelets. Although both quadriceps repairs were sufficiently strong, the transosseous repairs were stronger than the TE suture anchor repairs. The repair stiffness and gap formation were similar between the groups. PMID:23150161
Hart, Nathan D; Wallace, Matthew K; Scovell, J Field; Krupp, Ryan J; Cook, Chad; Wyland, Douglas J
Vitamin D deficiency associates with ?-tocopherol and quadriceps weakness but not inflammatory cytokines in subjects with knee osteoarthritis
Knee osteoarthritis (OA) is a degenerative joint condition and a leading cause of physical disability in the United States. Quadriceps weakness and inflammatory cytokines contribute to the pathogenesis of knee OA, and both of which, increase with vitamin D deficiency. Other micronutrients, such as vitamins C and E and ?-carotene, modulate inflammatory cytokines and decrease during inflammation. The purpose of this study was to test the hypothesis that vitamin D deficiency associates with quadriceps weakness, an increase in serum cytokines, and a decrease in circulating micronutrients in subjects with knee OA. Subjects (age, 48±1 y; serum 25(OH)D, 25.8±1.1 ng/mL) with knee OA were categorized as vitamin D deficient (n=17; serum 25(OH)D?20 ng/mL), insufficient (n=21; serum 25(OH)D 20–29 ng/mL), or sufficient (n=18; serum 25(OH)D?30 ng/mL). Single-leg strength (concentric knee extension–flexion contraction cycles at 60 °/s) and blood cytokine, carotene (? and ?), ascorbic acid, and tocopherol (? and ?) concentrations were measured. Quadriceps peak torque, average power, total work, and deceleration were significantly (all p<0.05) impaired with vitamin D deficiency. Serum ?-tocopherol concentrations were significantly (p<0.05) increased with vitamin D deficiency. In the vitamin D sufficient group, ?-tocopherol inversely correlated (r=?0.47, p<0.05) with TNF-?, suggesting a pro-inflammatory increase with a ?-tocopherol decrease despite a sufficient serum 25(OH)D concentration. We conclude that vitamin D deficiency is detrimental to quadriceps function, and in subjects with vitamin D sufficiency, ?-tocopherol could have an important anti-inflammatory role in a pathophysiological condition mediated by inflammation.
Barker, Tyler; Henriksen, Vanessa T.; Rogers, Victoria E.; Aguirre, Dale; Trawick, Roy H.; Lynn Rasmussen, G.; Momberger, Nathan G.
SolidPhase Microextraction and Cuticular Hydrocarbon Differences Related to Reproductive Activity in Queenless Ant Dinoponera quadriceps
We extracted the cuticular hydrocarbons from live Dinoponera quadriceps ants (10 colonies collected from Brazil) with the solventless solid-phase microextraction (SPME) technique. Gas chromatography of the SPME samples (N = 233 measurements) compared with pentane extracts (N = 10) resulted in similar profiles. Eighty-one compounds belonging to the main long-chain hydrocarbon families were identified by GC-MS. There is no morphologically
Thibaud Monnin; Christian Malosse; Christian Peeters
M. Quadriceps femoris of Man, a muscle with an unusual enzyme activity pattern of energy supplying metabolism in mammals
1.The following enzyme activities were estimated in needle-biopsy samples of the lateral part of the human quadriceps femoris muscle: triosephosphate dehydrogenase (TPDH), lactate dehydrogenase (LDH), NAD: glycerol-3-phosphate dehydrogenase (GPDH), hexokinase (HK), NAD: malate dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase.2.Although the enzyme activities in muscle of women were lesser than in those of men, no difference was found in
Arno?t Bass; Karel Vondra; Ratmír Rath; Václav Vítek
Arterial oxygenation influences central motor output and exercise performance via effects on peripheral locomotor muscle fatigue in humans.
Changing arterial oxygen content (C(aO(2))) has a highly sensitive influence on the rate of peripheral locomotor muscle fatigue development. We examined the effects of C(aO(2)) on exercise performance and its interaction with peripheral quadriceps fatigue. Eight trained males performed four 5 km cycling time trials (power output voluntarily adjustable) at four levels of C(aO(2)) (17.6-24.4 ml O(2) dl(-1)), induced by variations in inspired O(2) fraction (0.15-1.0). Peripheral quadriceps fatigue was assessed via changes in force output pre- versus post-exercise in response to supra-maximal magnetic femoral nerve stimulation (DeltaQ(tw); 1-100 Hz). Central neural drive during the time trials was estimated via quadriceps electromyogram. Increased C(aO(2)) from hypoxia to hyperoxia resulted in parallel increases in central neural output (43%) and power output (30%) during cycling and improved time trial performance (12%); however, the magnitude of DeltaQ(tw) (-33 to -35%) induced by the exercise was not different among the four time trials (P > 0.2). These effects of C(aO(2)) on time trial performance and DeltaQ(tw) were reproducible (coefficient of variation = 1-6%) over repeated trials at each F(IO(2)) on separate days. In the same subjects, changing C(aO(2)) also affected performance time to exhaustion at a fixed work rate, but similarly there was no effect of Delta C(aO(2)) on peripheral fatigue. Based on these results, we hypothesize that the effect of C(aO(2)) on locomotor muscle power output and exercise performance time is determined to a significant extent by the regulation of central motor output to the working muscle in order that peripheral muscle fatigue does not exceed a critical threshold. PMID:16793898
Amann, Markus; Eldridge, Marlowe W; Lovering, Andrew T; Stickland, Michael K; Pegelow, David F; Dempsey, Jerome A
Quadriceps tendon free graft augmentation for a midsubstance tear of the medial collateral ligament during total knee arthroplasty.
Primary repair of a disrupted midsubstance MCL during TKA can provide satisfactory stability. However, in cases with poor soft tissue quality or a gap between the ligament ends, primary repair may not be feasible. In these cases, we have used an augmented repair. The purpose of this study is to describe the technique of augmented repair using a quadriceps tendon free graft and present our experience of five patients. A total of five patients underwent augmented repair of a transected MCL substance using a quadriceps tendon free graft. The patients were followed-up for a mean of 16 months. Augmented repair of the transected MCL substance was successful in all five patients, with a mean additional surgery time of 17 min, no coronal instability, a mean Knee Society Score of 87.0+/-2.7 (range, 85 to 90), and a mean function score of 85.0+/-3.5 (range, 80 to 90). There were no complications associated with the extensor mechanism. This data suggests that quadriceps tendon free graft augmentation might be a useful alternative for repairing midsubstance tears of the MCL in special situations, where the quality of the remaining tendon is poor, there is suspicion of stretching, and there is a small gap between both the repaired ligament ends resulting in late laxity. PMID:19464185
Jung, Kwang Am; Lee, Su Chan; Hwang, Seung Hyun; Jung, Soong Hyun
Postural response to vibration of triceps surae, but not quadriceps muscles, differs between people with and without knee osteoarthritis.
Although proprioceptive impairments are reported in knee osteoarthritis (OA), there has been little investigation of the underlying causes. Muscle spindles make an important contribution to proprioception. This study investigated whether function of quadriceps, triceps surae, and tibialis anterior muscle spindles is altered in individuals with knee OA. Thirty individuals with knee OA (17 females, 66?±?7 [mean?±?SD] years) and 30 healthy asymptomatic controls (17 females, 65?±?8 years) stood comfortably and blindfolded on a force plate. Mechanical vibration (60?Hz) was applied bilaterally over the quadriceps, triceps surae, or tibialis anterior muscles for the middle 15?s (Vibration) of a 45?s trial (preceded and followed by 15?s Baseline and Recovery periods). Two trials were recorded for each muscle site. Mean anterior-posterior displacement of centre of pressure was analysed. Although there were no differences between groups for trials with vibration applied to the quandriceps or tibialis anterior, participants with knee OA were initially perturbed more by triceps surae vibration and accommodated less to repeated exposure than controls. This indicates that people with knee OA have less potential to detect or compensate for disturbed input to triceps surae, possibly due to an inability to compensate using muscles spindles in the quadriceps muscle. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:989-996, 2014. PMID:24797419
Shanahan, Camille J; Wrigley, Tim V; Farrell, Michael J; Bennell, Kim L; Hodges, Paul W
Purpose/Background: A reduction in the maximal force output of muscles following pre-performance stretching has been reported. Several studies have suggested that localized vibration may enhance or replace stretching for gaining flexibility. It is important to know if localized vibration may also compromise muscle output. The purpose of this investigation was to determine the immediate effects of localized hamstring vibration on hamstrings (HAM) and quadriceps (QUAD) performance. Methods: Thirty asymptomatic participants, 19 female and 11 male, mean age 25.4 years (±SD 2.7) received either five minutes of localized vibration to the right hamstrings at 30 Hz and 6 mm amplitude, or sham. One week later, each participant received the alternate treatment. Following treatments, right (R) and left (L) isometric HAM and QUAD strength was measured twice by handheld dynamometer and maximal horizontal hop distance of each lower extremity was measured by single leg hop test (SLH). Treatment outcomes were compared using paired t-tests. Treatment order effect was measured by independent T-test. Pre-study intrarater reliability for dynamometry was established using ICC(3,2). Results: Mean (±SD) values for strength following vibration were 58.7 kg (15.7), 60.4 kg (14.0), 45.5 kg (14.2), 45.8 kg (13.2) for R QUAD, L QUAD, R HAM, L HAM respectively. SLH mean values were R SLH 153.8 cm (35 cm) and L SLH 155.4 cm (36 cm). There were no significant differences in means between vibration and sham treatment for any outcomes on either leg (p-values ranged .412-.971); p<.001 for all comparisons. Order had no significant effect (p-values .370–1.0). Intrarater ICCs were .888, .762, .884, .960 for R HAM, L HAM, R QUAD, L QUAD. Conclusions: Unilateral application of localized vibration to the hamstrings at a duration previously reported to increase flexibility did not diminish the isometric performance of the hamstrings or quadriceps of either leg. Level of Evidence: 1b
Gabler, Geoff; Hopper, Kim; Kirk, David; McGregor, Cindy J.
Creatine supplementation does not decrease oxidative stress and inflammation in skeletal muscle after eccentric exercise.
Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48 h). Cr supplementation was administered as a solution of 300 mg · kg body weight(-1) · day(-1) in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h(-1) until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1?), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1?, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P < 0.05). There are positive correlations between Cr kinase and TBARS and TNF-? 48 hours after eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction. PMID:23560674
Silva, Luciano A; Tromm, Camila B; Da Rosa, Guilherme; Bom, Karoliny; Luciano, Thais F; Tuon, Talita; De Souza, Cláudio T; Pinho, Ricardo A
Orthostasis: exercise and exercise training
NASA Technical Reports Server (NTRS)
There are two major problems here that are not independent. One is the more practically oriented problem of determining the effect of various modes of exercise training on gravitational tolerances, i.e., the point of syncope (unconsciousness) usually estimated from the time of appearance of presyncopal signs and symptoms. The other is more theoretical and concerns the mechanism of blood pressure failure that results in syncope. In many experimental designs these two problems or purposes have been intermingled, with equivocal results.
Geelen, G.; Greenleaf, J. E.
Glutathione homeostasis in response to exercise training and nutritional supplements
Glutathione plays a central role in the maintenance of tissue antioxidant defenses and in the regulation of redox sensitive signal transduction. In muscle cells, the level and redox status of GSH regulates activity of the redox sensitive transcription factor NF-?B. Physical exercise may cause oxidation of GSH in tissues such as the blood, skeletal muscle and liver. Endurance training strengthened
Chandan K. Sen
Functional analysis of limb recovery following autograft treatment of volumetric muscle loss in the quadriceps femoris.
Severe injuries to the extremities often result in muscle trauma and, in some cases, significant volumetric muscle loss (VML). These injuries continue to be challenging to treat, with few available clinical options, a high rate of complications, and often persistent loss of limb function. To facilitate the testing of regenerative strategies for skeletal muscle, we developed a novel quadriceps VML model in the rat, specifically addressing functional recovery of the limb. Our outcome measures included muscle contractility measurements to assess muscle function and gait analysis for evaluation of overall limb function. We also investigated treatment with muscle autografts, whole or minced, to promote regeneration of the defect area. Our defect model resulted in a loss of muscle function, with injured legs generating less than 55% of muscle strength from the contralateral uninjured control legs, even at 4 weeks post-injury. The autograft treatments did not result in significant recovery of muscle function. Measures of static and dynamic gait were significantly decreased in the untreated, empty defect group, indicating a decrease in limb function. Histological sections of the affected muscles showed extensive fibrosis, suggesting that this scarring of the muscle may be in part the cause of the loss of muscle function in this VML model. Taken together, these data are consistent with clinical findings of reduced muscle function in large VML injuries. This new model with quantitative functional outcome measures offers a platform on which to evaluate treatment strategies designed to regenerate muscle tissue volume and restore limb function. PMID:24280565
Li, Mon Tzu A; Willett, Nick J; Uhrig, Brent A; Guldberg, Robert E; Warren, Gordon L
Inhibition of ?-adrenergic tone disturbs the distribution of blood flow in the exercising human limb.
The role of neuronal regulation of human cardiovascular function remains incompletely elucidated, especially during exercise. Here we, by positron emission tomography, monitored tissue-specific blood flow (BF) changes in nine healthy young men during femoral arterial infusions of norepinephrine (NE) and phentolamine. At rest, the ?-adrenoceptor agonist NE reduced BF by ~40%, similarly in muscles (from 3.2 ± 1.9 to 1.4 ± 0.3 ml·min(-1)·100 g(-1) in quadriceps femoris muscle), bone (from 1.1 ± 0.4 to 0.5 ± 0.2 ml·min(-1)·100 g(-1)) and adipose tissue (AT) (from 1.2 ± 0.7 to 0.7 ± 0.3 ml·min(-1)·100 g(-1)). During exercise, NE reduced exercising muscle BF by ~16%. BF in AT was reduced similarly as rest. The ?-adrenoceptor antagonist phentolamine increased BF similarly in the different muscles and other tissues of the limb at rest. During exercise, BF in inactive muscle was increased 3.4-fold by phentolamine compared with exercise without drug, but BF in exercising muscles was not influenced. Bone and AT (P = 0.055) BF were also increased by phentolamine in the exercise condition. NE increased and phentolamine decreased oxygen extraction in the limb during exercise. We conclude that inhibition of ?-adrenergic tone markedly disturbs the distribution of BF and oxygen extraction in the exercising human limb by increasing BF especially around inactive muscle fibers. Moreover, although marked functional sympatholysis also occurs during exercise, the arterial NE infusion that mimics the exaggerated sympathetic nerve activity commonly seen in patients with cardiovascular disease was still capable of directly limiting BF in the exercising leg muscles. PMID:23666670
Heinonen, Ilkka; Wendelin-Saarenhovi, Maria; Kaskinoro, Kimmo; Knuuti, Juhani; Scheinin, Mika; Kalliokoski, Kari K
Muscle ultrastructural changes from exhaustive exercise performed after prolonged restricted activity and retraining in dogs
NASA Technical Reports Server (NTRS)
The effect of exhaustive treadmill exercise on ultrastructural changes in the quadriceps femoris muscle was studied in 7 normal, healthy dogs, before and after restricted activity (RA), and following a subsequent 2 month treadmill exercise retraining period for the 5 mo group. Mean time to exhaustion in the 2 mo group decreased from 177 + or - 22 min before to 90 + or - 32 min after RA. Retraining increased tolerance to 219 + or - 73 min; 24 pct. above the before RA and 143 pct. above the after RA time. After RA exhaustion time in the 5 mo group was 25 and 45 min. Before RA, pre-exercise muscle structure was normal and post exercise there was only slight swelling of mitochondria. After RA, pre-exercise, numerous glycogen granules and lipid droplets appeared in the muscle fibers, mitochondria were smaller, and sarcoplasmic reticulum channels widened; post exercise these changes were accentuated and some areas were devoid of glycogen, and there was fiber degradation. After 5 mo RA pre-exercise there were more pronounced changes; mitochondria were very small and dense, there were many lipid droplets, myofibrils were often separated, and the fibers appeared edematous and degenerating; post exercise the sarcoplasmic reticulum was swollen, no glycogen was present, and there was marked swelling and deformation of mitochondria. After retraining, both pre-exercise and post exercise there was still evidence of fiber degeneration. Thus, susceptibility of active skeletal muscle structures and subcellular elements, e.g., mitochondria, to the action of damaging factors occurring during exhaustive exercise is enhanced considerably by prolonged disuse.
Nazar, K.; Greenleaf, J. E.; Philpott, D.; Pohoska, E.; Olszewska, K.; Kaciuba-Uscilko, H.
HIV Communication Capacity Strengthening: A Critical Review.
: HIV communication is most effective and sustainable when it is designed and implemented locally and tailored to the local context. This requires capacity strengthening at national, subnational, and community levels. Through a review of the published and selected "grey" literature, we examine HIV communication capacity strengthening: definitions, measurements, implementation, and effects. We found limited documentation of HIV communication capacity needs or systematic approaches to address them. Most HIV communication capacity strengthening to date has focused on building individual competencies to design and manage social and behavior change communication programs through training courses, often coupled with networking opportunities for participants, post-training mentoring, and technical assistance. A few of these efforts have been evaluated through pre- and post-training tests and qualitative interviews with participants and have shown potential for improvement in individual skills and knowledge. Health communication capacity assessment tools that measure individual and organizational competencies exist, but they have most often been used to identify capacity building needs, not for evaluating capacity strengthening efforts. A new definition of capacity strengthening, grown out of recent efforts to improve effectiveness of international health and development programs, focuses on improving organizational and societal systems that support performance and individual competencies. We propose a holistic model for HIV communication capacity strengthening and call for rigorous documentation and evaluation to determine and scale-up optimal capacity building interventions for strengthening social and behavior change communication for HIV prevention, care, and treatment in developing countries. PMID:25007200
Lettenmaier, Cheryl; Kraft, Joan Marie; Raisanen, Keris; Serlemitsos, Elizabeth
Effects of supplemental carbohydrate ingestion during superimposed electromyostimulation exercise in elite weightlifters.
The purpose of this investigation was to test the effects of carbohydrate supplementation on blood parameters and force output during superimposed electromyostimulation (SEMS) single-leg isometric contractions. We hypothesized that carbohydrate ingestion before and during muscle contractions would lead to greater glucose availability and greater total force output for the session. Six elite resistance trained male subjects participated in a randomized, counterbalanced, double-blind study. The subjects were randomly assigned to placebo (PL) or carbohydrate (CHO). The subjects in CHO consumed 1 g of carbohydrate per kilogram of body mass loading dose and 0.17 g of carbohydrate · per kilogram of body mass every 6 minutes during the exercise protocol. The PL received an equal volume of a solution made of saccharin and aspartame. The exercise protocol consisted of repeated 20-second isometric contractions of quadriceps muscle at 50% maximal voluntary contraction followed by 40 seconds of rest until failure occurred. Importantly, quadriceps maximal voluntary contraction with SEMS was performed in the beginning and then every 5 minutes during the last 3 seconds of isometric contractions throughout the exercise protocol. Venous blood samples were taken preexercise, immediately postexercise, and at 5 minutes postexercise and analyzed for glucose, nonesterified fatty acids, and glycerol. Our results indicate that CHO ingestion increased (p < 0.05) plasma glucose, but no significant differences (p > 0.05) were detected for nonesterified fatty acids or glycerol. Importantly, total force output during exercise protocol was higher (p < 0.05) in CHO compared with that in PL. Therefore, our data suggest that CHO supplementation before and during exercise may be beneficial for individuals performing high-volume resistance training. PMID:23442284
Wax, Benjamin; Kavazis, Andreas N; Brown, Stanley P
Exercise-Induced Bronchoconstriction
Share | « Back to A to Z Listing Exercise-Induced Bronchoconstriction Exercise-Induced Bronchoconstriction, (EIB), often known as exercise-induced asthma, is a narrowing of the airways causing difficulty moving air out ...
... EKG - exercise treadmill; Stress ECG; Exercise electrocardiography; Stress test - exercise treadmill ... This test is done at a medical center or health care provider's office. The technician will place 10 flat, ...
A preliminary, randomized trial of aerobic exercise for alcohol dependence.
Interventions targeting physical activity may be valuable as an adjunct to alcohol treatment, but have been relatively untested. In the current study, alcohol dependent, physically sedentary patients were randomized to: a 12-week moderate-intensity, group aerobic exercise intervention (AE; n=25) or a brief advice to exercise intervention (BA-E; n=23). Results showed that individuals in AE reported significantly fewer drinking and heavy drinking days, relative to BA-E during treatment. Furthermore adherence to AE strengthened the beneficial effect of intervention on alcohol use outcomes. While high levels of moderate-intensity exercise appeared to facilitate alcohol recovery regardless of intervention arm, attending the group-based AE intervention seemed to further enhance the positive effects of exercise on alcohol use. Study findings indicate that a moderate intensity, group aerobic exercise intervention is an efficacious adjunct to alcohol treatment. Improving adherence to the intervention may enhance its beneficial effects on alcohol use. PMID:24666811
Brown, Richard A; Abrantes, Ana M; Minami, Haruka; Read, Jennifer P; Marcus, Bess H; Jakicic, John M; Strong, David R; Dubreuil, Mary Ella; Gordon, Alan A; Ramsey, Susan E; Kahler, Christopher W; Stuart, Gregory L
Mechanisms for slow strengthening in granular materials
Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F(max) experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time tau. The layer strength increases roughly logarithmically with tau only if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement measurements, and by imaging of particle motion in the shear zone. Granular matter can strengthen due to a slow shift in the particle arrangement under shear stress. Humidity also leads to strengthening, but is found not to be its sole cause. In addition to these time dependent effects, the static friction coefficient can also be increased by compaction of the granular material under some circumstances, and by a cycling of the applied shear stress. PMID:11088198
Losert; Geminard; Nasuno; Gollub
Do Twin Boundaries Always Strengthen Metal Nanowires?
It has been widely reported that twin boundaries strengthen nanowires regardless of their morphology—that is, the strength of nanowires goes up as twin spacing goes down. This article shows that twin boundaries do not always strengthen nanowires. Using classical molecular dynamics simulations, the authors show that whether twin boundaries strengthen nanowires depends on the necessary stress for dislocation nucleation, which in turn depends on surface morphologies. When nanowires are circular cylindrical, the necessary stress of dislocation nucleation is high and the presence of twin boundaries lowers this stress; twin boundaries soften nanowires. In contrast, when nanowires are square cylindrical, the necessary stress of dislocation nucleation is low, and a higher stress is required for dislocations to penetrate twin boundaries; they strengthen nanowires.
Manufacturing Methods for Dispersion Strengthened Copper.
National Technical Information Service (NTIS)
Oxide-strengthened copper forms were processed from powders prepared by spray drying, calcining, and selective hydrogen reduction. The powders were compacted, sintered, and hot consolidated. Two major problems were encountered in the preparation of consol...
N. E. Kopatz W. Scheithauer R. F. Cheney
Strengthening State Library Administrative Agency (Territoral Library).
National Technical Information Service (NTIS)
The document describes the Basic State Plan Amendments for the Library Services and Construction Act in Guam and the regulations promulgated thereunder. The major projects described under the plan are: Strengthening State Library Administrative Agency; St...
Strengthening of Glass by an Electroionic Technique.
National Technical Information Service (NTIS)
An electroionic strengthening process for glass which produces a relatively deep surface compressive layer to preserve this strength has been examined. The process consists of using an electric field to drive large alkali ions from a molten salt bath into...
D. A. Kubose H. A. Perry J. E. Tydings
Emergency exercise methodology
Competence for proper response to hazardous materials emergencies is enhanced and effectively measured by exercises which test plans and procedures and validate training. Emergency exercises are most effective when realistic criteria is used and a sequence of events is followed. The scenario is developed from pre-determined exercise objectives based on hazard analyses, actual plans and procedures. The scenario should address findings from previous exercises and actual emergencies. Exercise rules establish the extent of play and address contingencies during the exercise. All exercise personnel are assigned roles as players, controllers or evaluators. These participants should receive specialized training in advance. A methodology for writing an emergency exercise plan will be detailed.
Klimczak, C.A.
Emergency exercise methodology
Competence for proper response to hazardous materials emergencies is enhanced and effectively measured by exercises which test plans and procedures and validate training. Emergency exercises are most effective when realistic criteria is used and a sequence of events is followed. The scenario is developed from pre-determined exercise objectives based on hazard analyses, actual plans and procedures. The scenario should address findings from previous exercises and actual emergencies. Exercise rules establish the extent of play and address contingencies during the exercise. All exercise personnel are assigned roles as players, controllers or evaluators. These participants should receive specialized training in advance. A methodology for writing an emergency exercise plan will be detailed.
Klimczak, C.A.
Augmentation of deglutitive thyrohyoid muscle shortening by the Shaker Exercise.
Earlier studies of the effect of 6 weeks of the Shaker Exercise have shown significant increase in UES opening and anterior excursion of larynx and hyoid during swallowing in patients with upper esophageal sphincter (UES) dysfunction, resulting in elimination of aspiration and resumption of oral intake. This effect is attributed to strengthening of the suprahyoid muscles, as evidenced by comparison of electromyographic changes in muscle fatigue before and after completion of the exercise regime. The effect of this exercise on thyrohyoid muscle shortening is unknown. Therefore the aim of this study was to determine the effect of the exercise on thyrohyoid muscle shortening. We studied 11 dysphagic patients with UES dysfunction. Six were randomized to traditional swallowing therapy and five to the Shaker Exercise. Videofluoroscopy was used to measure deglutitive thyrohyoid shortening before and after completion of assigned therapy regimen. Maximum thyrohyoid muscle shortening occurred at close temporal proximity to the time of maximal thyroid cartilage excursion. The percent change in thyrohyoid distance from initiation of deglutition to maximal anterior/superior hyoid excursion showed no statistically significant difference between the two groups prior to either therapy (p = 0.54). In contrast, after completion of therapy, the percent change in thyrohyoid distance in the Shaker Exercise group was significantly greater compared to the traditional therapy (p = 0.034). The Shaker Exercise augments the thyrohyoid muscle shortening in addition to strengthening the suprahyoid muscles. The combination of increased thyrohyoid shortening and suprahyoid strengthening contributes to the Shaker Exercise outcome of deglutitive UES opening augmentation. PMID:18685891
Mepani, Rachel; Antonik, Stephen; Massey, Benson; Kern, Mark; Logemann, Jerilyn; Pauloski, Barbara; Rademaker, Alfred; Easterling, Caryn; Shaker, Reza
Resistance Versus Aerobic Exercise
OBJECTIVE In type 1 diabetes, small studies have found that resistance exercise (weight lifting) reduces HbA1c. In the current study, we examined the acute impacts of resistance exercise on glycemia during exercise and in the subsequent 24 h compared with aerobic exercise and no exercise. RESEARCH DESIGN AND METHODS Twelve physically active individuals with type 1 diabetes (HbA1c 7.1 ± 1.0%) performed 45 min of resistance exercise (three sets of seven exercises at eight repetitions maximum), 45 min of aerobic exercise (running at 60% of Vo2max), or no exercise on separate days. Plasma glucose was measured during and for 60 min after exercise. Interstitial glucose was measured by continuous glucose monitoring 24 h before, during, and 24 h after exercise. RESULTS Treatment-by-time interactions (P < 0.001) were found for changes in plasma glucose during and after exercise. Plasma glucose decreased from 8.4 ± 2.7 to 6.8 ± 2.3 mmol/L (P = 0.008) during resistance exercise and from 9.2 ± 3.4 to 5.8 ± 2.0 mmol/L (P = 0.001) during aerobic exercise. No significant changes were seen during the no-exercise control session. During recovery, glucose levels did not change significantly after resistance exercise but increased by 2.2 ± 0.6 mmol/L (P = 0.023) after aerobic exercise. Mean interstitial glucose from 4.5 to 6.0 h postexercise was significantly lower after resistance exercise versus aerobic exercise. CONCLUSIONS Resistance exercise causes less initial decline in blood glucose during the activity but is associated with more prolonged reductions in postexercise glycemia than aerobic exercise. This might account for HbA1c reductions found in studies of resistance exercise but not aerobic exercise in type 1 diabetes.
Yardley, Jane E.; Kenny, Glen P.; Perkins, Bruce A.; Riddell, Michael C.; Balaa, Nadia; Malcolm, Janine; Boulay, Pierre; Khandwala, Farah; Sigal, Ronald J.
Specific training improves skeletal muscle mitochondrial calcium homeostasis after eccentric exercise.
There is limited understanding of the mitochondrial adaptation following repeated eccentric exercise bouts, a model resulting in muscle adaptation known as the repeat bout effect. It was hypothesized that downhill training would reduce mitochondrial calcium content (MCC) post an acute eccentric bout with concurrent improvements in mitochondrial respiratory function. Thirty-four Sprague-Dawley rats were divided into four groups: control (N), control with acute eccentric exercise (N (ecc)), trained control (X) and trained with acute eccentric exercise (X (ecc)). Training for X and X (ecc) consisted of 30 min per day for five consecutive days of downhill treadmill running. The acute eccentric exercise bout was a -14° treadmill exercise for 90 min performed 2 weeks after the training period. Animals were killed 48 h post-exercise. Isolated mitochondria from the red quadriceps allowed for the measure of mitochondrial respiratory indices and MCC. Calpain activity and heat shock protein 72 expression (HSP72) were also measured. MCC dramatically increased following the acute bout of eccentric exercise in N (ecc) (p < 0.001), but did not change in X (ecc). Mitochondrial respiratory function tended to be slightly depressed in N (ecc) (state 3 respiration, p = 0.053; respiratory control ratio, p = 0.098) and unaltered in X (ecc). Previous training altered the calpain and heat shock protein response to an acute bout of eccentric exercise. The results suggest that downhill exercise training improves mitochondrial calcium homeostasis following an acute bout of prolonged eccentric exercise and may stabilize mitochondrial respiratory function. These improvements coincide with a reduction in calpain activity and heat shock protein upregulation. PMID:22777498
Rattray, Ben; Thompson, Martin; Ruell, Patricia; Caillaud, Corinne
Effect of fluid ingestion on neuromuscular function during prolonged cycling exercise
Objectives: To investigate the effects of fluid ingestion on neuromuscular function during prolonged cycling exercise. Methods: Eight well trained subjects exercised for 180 minutes in a moderate environment at a workload requiring ?60% maximal oxygen uptake. Two conditions, fluid (F) and no fluid (NF) ingestion, were investigated. Results: During maximal voluntary isometric contraction (MVC), prolonged cycling exercise reduced (p<0.05) the maximal force generating capacity of quadriceps muscles (after three hours of cycling) and root mean square (RMS) values (after two hours of cycling) with no difference between the two conditions despite greater body weight loss (p<0.05) in NF. The mean power frequency (MPF) for vastus lateralis muscle was reduced (p<0.05) and the rate of force development (RFD) was increased (p<0.05) only during NF. During cycling exercise, integrated electromyographic activity and perceived exertion were increased in both conditions (p<0.05) with no significant effect of fluid ingestion. Conclusions: The results suggest that fluid ingestion did not prevent the previously reported decrease in maximal force with exercise duration, but seems to have a positive effect on some indicators of neuromuscular fatigue such as mean power frequency and rate of force development during maximal voluntary contraction. Further investigations are needed to assess the effect of change in hydration on neural mechanisms linked to the development of muscular fatigue during prolonged exercise.
Vallier, J; Grego, F; Basset, F; Lepers, R; Bernard, T; Brisswalter, J
Technical note: double tibial tunnel using quadriceps tendon in anterior cruciate ligament reconstruction.
To avoid complications related to the use of patellar tendon and hamstring (semitendinosus and gracilis) tendon and to create a more anatomic reconstruction, we present a new technique based on the use of quadriceps tendon placed in a single half femoral tunnel and double tibial tunnels. The graft, harvested by a central longitudinal incision, possesses the following characteristics: (1) a bone plug 20 mm long and 10 mm in diameter; (2) a tendon component 7 to 8 cm long, 10 mm wide, and 8 mm thick; and (3) division of the tendon longitudinally into 2 bundles while maintaining the patellar insertion. Every bundle has a width and thickness of approximately 5 mm and 8 mm, respectively. The total length of the graft is 9 to 10 cm. A 10-mm half femoral tunnel is drilled through a low anteromedial portal with the knee flexed at 120 degrees. A suture loop is left in place in the half tunnel. A double tibial tunnel is drilled in a convergent manner (from outside to inside) obtaining an osseous bridge between the 2 tunnels. Two suture loops are passed trough the tibial tunnels and retrieved in a plastic cannula (10 mm) positioned in the anteromedial portal to allow the passage of the 2 bundles in the tibial tunnels. The suture loop left in the half tunnel permits the transportation of the bone plug in the femoral tunnel. Fixation is achieved by an interference screw at the femoral side and by 2 absorbable interference screws (1 for each tunnel). The advantages of this technique are a more cross-sectional area (80 mm(2)), greater bone-tendon interface, and a more anatomic reconstruction. Theoretically, easier bone incorporation, decreased windshield wiper and bungee effect, fewer donor site problems, and less tunnel enlargement can also be possible. PMID:10882460
Pederzini, L; Adriani, E; Botticella, C; Tosi, M
Quadriceps and patellar tendon pie-crusting as a treatment for limited flexion in total knee arthroplasty.
The pie-crusting method of ligament and tendon lengthening has been used successfully in various tissues but is not reported in the literature as an option for patellar or quadriceps tendons to address flexion limitation. Our case report discusses a patient with longstanding flexion limitation who underwent primary total knee arthroplasty. The report reviews the literature on intraoperative treatments, which primarily pertains to the condition of patella baja, and demonstrates that the pie-crusting technique should be included as a treatment option for a tight extensor mechanism while having some advantages over tibial tubercle osteotomy or Z-plasty. PMID:24730010
Burge, J Ross; Sanchez, Hugo B; Wagner, Russell A
Rapid Hamstrings/Quadriceps Strength Capacity in Professional Soccer Players with Different Conventional Isokinetic Muscle Strength Ratios
Muscle strength imbalance can be an important factor in hamstrings muscle strain. A hamstrings/quadriceps (H/Q) strength ratio based on concentric peak torque values (Hcon:Qcon) has traditionally been used to describe the potential for knee-joint destabilization. Because certain standard actions in soccer are explosive, the analysis of the H/Q strength ratio based on the rate of torque development (Hrtd:Qrtd) might also be useful in the evaluation of joint stability. The objective of this study was to compare the Hrtd:Qrtd between professional soccer players with heterogeneous values of Hcon:Qcon. Thirty-nine professional soccer players took part in the following procedures on different days: 1) Familiarization session with the isokinetic dynamometer, and 2) Two maximal isometric actions and five maximal concentric actions at 60°·s-1 for hamstrings (H) and quadriceps (Q). Participants were ranked according to their Hcon:Qcon ratio. The median third was excluded to form a high torque group (HTG), and a low torque group (LTG). Peak isometric (H) and concentric (H and Q) torques and rate of torque development (H) were significantly greater in the HTG group. Similarly, Hcon:Qcon (0.68 ± 0.02 vs. 0.52 ± 0.03) and Hrtd:Qrtd (0.54 ± 0.12 vs. 0.43 ± 0.16) were significantly greater in the HTG group than in the LTG group. There was no significant correlation between Hcon:Qcon and Hrtd:Qrtd. It can be concluded that Hcon:Qcon and Hrtd:Qrtd are determined, but not fully defined, by shared putative physiological mechanisms. Thus, the physiologic and clinical significance of Hcon:Qcon and Hrtd:Qrtd to an athlete's individual evaluation might be different. Key pointsSoccer players with high (0.66-0.70) and low (0.50-0.54) conventional concentric hamstrings:quadriceps ratios (Hcon:Qcon) tend to demonstrate similar profiles (i.e., high and low, respectively) in their rate of the torque development H/Q ratio (Hrtd:Qrtd).The lack of a significant relationship between Hcon:Qcon and Hrtd:Qrtd suggests that these ratios are determined, but not fully defined, by shared putative physiological mechanisms.Preseason screening programs that monitor hamstrings:quadriceps ratios should recognize that the physiologic and clinical significance of Hcon:Qcon and Hrfd:Qrfd to an athlete's individual evaluation might be different.
Greco, Camila C.; Da Silva, Wendell L.; Camarda, Sergio R.A.; Denadai, Benedito S.
Resting and active motor thresholds versus stimulus-response curves to determine transcranial magnetic stimulation intensity in quadriceps femoris
Background Transcranial magnetic stimulation (TMS) is a widely-used investigative technique in motor cortical evaluation. Recently, there has been a surge in TMS studies evaluating lower-limb fatigue. TMS intensity of 120-130% resting motor threshold (RMT) and 120% active motor threshold (AMT) and TMS intensity determined using stimulus–response curves during muscular contraction have been used in these studies. With the expansion of fatigue research in locomotion, the quadriceps femoris is increasingly of interest. It is important to select a stimulus intensity appropriate to evaluate the variables, including voluntary activation, being measured in this functionally important muscle group. This study assessed whether selected quadriceps TMS stimulus intensity determined by frequently employed methods is similar between methods and muscles. Methods Stimulus intensity in vastus lateralis, rectus femoris and vastus medialis muscles was determined by RMT, AMT (i.e. during brief voluntary contractions at 10% maximal voluntary force, MVC) and maximal motor-evoked potential (MEP) amplitude from stimulus–response curves during brief voluntary contractions at 10, 20 and 50% MVC at different stimulus intensities. Results Stimulus intensity determined from a 10% MVC stimulus–response curve and at 120 and 130% RMT was higher than stimulus intensity at 120% AMT (lowest) and from a 50% MVC stimulus–response curve (p?0.05). Stimulus intensity from a 20% MVC stimulus–response curve was similar to 120% RMT and 50% MVC stimulus–response curve. Mean stimulus intensity for stimulus–response curves at 10, 20 and 50% MVC corresponded to approximately 135, 115 and 100% RMT and 180, 155 and 130% AMT, respectively. Selected stimulus intensity was similar between muscles for all methods (p?>?0.05). Conclusions Similar optimal stimulus intensity and maximal MEP amplitudes at 20 and 50% MVC and the minimal risk of residual fatigue at 20% MVC suggest that a 20% MVC stimulus–response curve is appropriate for determining TMS stimulus intensity in the quadriceps femoris. The higher selected stimulus intensities at 120-130% RMT have the potential to cause increased coactivation and discomfort and the lower stimulus intensity at 120% AMT may underestimate evoked responses. One muscle may also act as a surrogate in determining optimal quadriceps femoris stimulation intensity.
Muscle glycogen and blood glucose are important substrates for contracting skeletal muscle during exercise and fatigue often coincides with depletion of these carbohydrate reserves. Carbohydrate utilization during exercise is influenced by several factors including exercise intensity and duration, training status, diet, environment and gender. In view of the importance of carbohydrates for exercise performance, active individuals should ensure their diet
Mark Hargreaves
ERIC Educational Resources Information Center
Suggests that exercise should be the first-line therapy for preventing and treating many common diseases; however, physicians need more training in how best to use exercise therapy. The paper explains the power of exercise and discusses how to motivate individuals to start safe, enjoyable, and life-saving exercise routines. (SM)
Elrick, Harold
Effect of resistance training on muscle use during exercise
NASA Technical Reports Server (NTRS)
This study examined the effect of resistance training on exercise-induced contrast shift in magnetic resonance (MR) images. It was hypothesized that a given load could be lifted after training with less muscle showing contrast shift, thereby suggesting less muscle was used to perform the exercise. Nine males trained the left quadriceps femoris (QF) muscle 2 days/wk for 9 wk using 3-6 sets of 12 knee extensions each day. The right QF served as a control. Exercise-induced contrast shifts in MR images evoked by each of three bouts of exercise (5 sets of 10 knee extensions with a load equal to 50, 75, and 100% of the maximum pretraining load that could be lifted for 5 sets of 10 repetitions) were quantified pre- and posttraining. MR image contrast shift was quantified by determining QF cross-sectional area (CSA) showing increased spin-spin relaxation time. One repetition maximum increased 14% in the left trained QF and 7% in the right untrained QF. Left QF CSA increased 5%, with no change in right QSF CSA. Left QF CSA showing contrast shift was less after each bout of the exercise test posttraining. This was also true, to a lesser extent, for the right QF at the higher two loads. The results suggest that short-term resistance training reduces MR image contrast shift evoked by a given effort, thereby reflecting the use of less muscle to lift the load. Because this response was evident in both trained and contralateral untrained muscle, neural factors are suggested to be responsible. The consequence of this adaptation could be to increase 'stress' per unit area of active muscle during the course of training and thereby evoke hypertrophy.
Ploutz, Lori L.; Tesch, Per A.; Biro, Ronald L.; Dudley, Gary A.
p38 mitogen-activated protein kinase is not activated in the quadriceps of patients with stable chronic obstructive pulmonary disease.
Quadriceps weakness is associated with a poor prognosis in COPD. Several data suggest that immobility and muscle wasting may be related through up-regulation of the p38 Mitogen associated protein kinase (MAPK) signalling pathway. We therefore hypothesised that this might occur in the quadriceps of COPD patients. We studied 105 stable COPD outpatients (mean FEV(1) 43.9% predicted) and 27 age and gender matched controls. We measured fat-free mass, quadriceps strength and daily physical activity using triaxial accelerometry. A quadriceps biopsy was obtained in which components of the p38-MAPK signalling pathway were examined. Patients had reduced fat-free mass index (16.1 (2.2) kg/m(2) vs 17.2 (2.2) kg/m(2), p = 0.02) and exhibited quadriceps weakness (mean (SD) maximal voluntary contraction force 72.1% (18.7) predicted and 82.3% (7.1) predicted for patients and controls respectively, p = 0.01). Physical activity was significantly reduced in the patient group; in particular mean (SD) locomotion time was 101 (48) minutes/12 hours in controls and 48 (31) minutes in patients (p < 0.0001). However, in biopsies obtained from these patients, no differences were observed for total or phosphorylated HSP27 or p38 MAPK protein or p38 MAPK mRNA (MAPK14); of the downstream products both GADD45? and c-jun mRNA were reduced in COPD patients while c-myc was not different from controls. No parameter correlated with physiological data within the patient group. We conclude that, despite the presence of reduced fat-free mass, quadriceps weakness and inactivity, p38 MAPK signalling was not up-regulated in skeletal muscle of stable out-patients with COPD. PMID:22409248
Riddoch-Contreras, Joanna; George, Tomasz; Natanek, Samantha A; Marsh, Gemma S; Hopkinson, Nicholas S; Tal-Singer, Ruth; Kemp, Paul; Polkey, Michael I
Muscle-damaging exercise affects isokinetic torque more at short muscle length.
The aim of this study was to investigate the differences in the length-dependent changes in quadriceps muscle torque during voluntary isometric and isokinetic contractions performed after severe muscle-damaging exercise. Thirteen physically active men (age = 23.8 ± 3.2 years, body weight = 77.2 ± 4.5 kg) performed stretch-shortening cycle (SSC) exercise comprising 100 drop jumps with 30-second intervals between each jump. Changes in the voluntary and electrically evoked torque in concentric and isometric conditions at different muscle lengths, muscle soreness, and plasma creatine kinase (CK) activity were assessed within 72 hours after SSC exercise. Isokinetic knee extension torque decreased significantly (p < 0.05) at all joint angles after SSC exercise. At 2 minutes and at 72 hours after SSC exercise, the changes in knee torque were significantly smaller at 80° (where 180° = full knee extension) than at 110-130°. At 2 minutes after SSC exercise, the optimal angle for isokinetic knee extension torque shifted by 9.5 ± 8.9° to a longer muscle length (p < 0.05). Electrically induced torque at low-frequency (20-Hz) stimulation decreased significantly more at a knee joint angle of 130° than at 90°. The subjects felt acute muscle pain and CK activity in the blood increased to 1,593.9 ± 536.2 IU·L?ą within 72 hours after SSC exercise (p < 0.05). This study demonstrates that the effect of muscle-damaging exercise on isokinetic torque is greatest for contractions at short muscle lengths. These findings have practical importance because the movements in most physical activities are dynamic in nature, and the decrease in torque at various points in the range of motion during exercise might affect overall performance. PMID:21273917
Skurvydas, Albertas; Brazaitis, Marius; Kamandulis, Sigitas
The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.
Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C. [Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering; Carleton, R.L.; George, E.P. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
Association of Serum Bicarbonate Levels With Gait Speed and Quadriceps Strength in Older Adults
BACKGROUND Metabolic acidosis is associated with skeletal muscle proteolysis, and alkali supplementation has demonstrated improvements in lean body mass and urinary nitrogen wasting in several studies. However, the association of acidosis with functional outcomes has not been examined on a population-based level. STUDY DESIGN Cross-sectional study. SETTING & PARTICIPANTS 2,675 nationally representative adults 50 years of age and older in the National Health and Nutrition Examination Survey 1999 – 2002. FACTOR Serum bicarbonate level. OUTCOMES Low gait speed (gait speed) and low peak torque (peak torque) were defined as being in the lowest sex-specific quartile of gait speed and peak torque, respectively. MEASUREMENTS Serum bicarbonate was measured in all participants. gait speed was determined from a 20-foot timed walk. peak torque was calculated using peak isokinetic knee extensor force. RESULTS Serum bicarbonate <23 mEq/L was present in 22.7% of the cohort. Compared to participants with bicarbonate ?23 mEq/L, those with bicarbonate <23 mEq/L had higher body-mass index and serum albumin, were more likely to have low socioeconomic status, a diagnosis of diabetes mellitus, or glomerular filtration rate <60 mL/min/1.73 m2, and were less likely to use diuretics. Serum bicarbonate <23 mEq/L, compared with ?23 mEq/L, was associated with low gait speed (OR, 1.43; 95% confidence interval (CI), 1.04 – 1.95) and low peak torque (OR, 1.36; 95% CI, 1.07 – 1.74) after multivariable adjustment. The association with low peak torque was modified by race/ethnicity among women but not men (ORs of 1.52 (95% CI 1.08 – 2.13) for men, 2.33 (95% CI 1.23 – 4.44) for non- white women, and 0.93 (95% CI 0.47 – 1.82) for white women). LIMITATIONS Cross-sectional study using a single measurement of bicarbonate. CONCLUSIONS Lower serum bicarbonate levels are associated with slower gait speed and reduced quadriceps strength in older adults. Further studies should examine the effect of alkali therapy on functional outcomes.
Abramowitz, Matthew K.; Hostetter, Thomas H.; Melamed, Michal L.
Effects of therapeutic percutaneous electrical stimulation of atrophic human quadriceps on muscle composition, protein synthesis and contractile properties.
The effects of percutaneous electrical stimulation (70 V, 300 microseconds pulses at 30 Hz) on muscle composition and rate of protein synthesis were studied in seven patients with quadriceps atrophy secondary to unilateral osteoarthritis of the knee (stimulated group). Quadriceps were stimulated on the affected side for 1 h per day. The results were compared to those from seven patients who did not use a muscle stimulator (control group), in whom muscle biopsy at surgery provided evidence of wasting of tissue protein on the side of osteoarthritis (normal leg 608 +/- 266 micrograms protein micrograms-1 DNA, affected leg 256 +/- 100 micrograms protein micrograms-1 DNA, means +/- SD, P less than 0.05; type I fibre diameters: normal 53.2 +/- 6.7 microns, affected 43.8 +/- 4.0 microns, P less than 0.05). In patients who had received stimulation there was no residual difference between the legs in either muscle protein concentration (normal 411 +/- 168 micrograms protein micrograms-1 DNA, affected 373 +/- 112 micrograms protein micrograms-1 DNA) or fibre diameter (type I diameters: normal 56.1 +/- 7.8 microns, affected 58.0 +/- 10.7 microns). Stimulation did not influence the ratios of muscle force elicited by acute stimulation at 20 and 50 Hz (normal 75 +/- 15%, affected 79 +/- 15%), or rates of muscle relaxation (percentage losses of tetanic force 10 ms-1: normal 7.66 +/- 1.2%, affected 8.67 +/- 2.2%).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2499480
Gibson, J N; Morrison, W L; Scrimgeour, C M; Smith, K; Stoward, P J; Rennie, M J
Extended Healing Validation of an Artificial Tendon to Connect the Quadriceps Muscle to the Tibia: 180-day Study
Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to nonliving materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contra lateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1400± 93N (vs. 1179± 61 N), linear stiffnesses were 33± 3 N/mm (vs. 37 ± 4N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p = 0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p = 0.3). We believe this technology will yield improved procedures for clinical challenges in orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.
Melvin, Alan J.; Litsky, Alan S.; Mayerson, Joel L.; Stringer, Keith; Juncosa-Melvin, Natalia
Polio eradication: strengthening the weakest links.
Polio eradication, like all eradication efforts, is a gamble. If it fails, much of the money spent will have been wasted. If it succeeds, the world will reap a dividend. Success or failure and the magnitude of the dividend depend on a long chain of "weakest links." In this paper I identify these links and explain how the chain can be strengthened. A crucial vulnerability is the current plan to halt vaccination using the live-attenuated oral polio vaccine in the post-eradication era. This weakest link can be strengthened by efforts that lower the cost to poor countries of vaccinating with the inactivated poliovirus vaccine. PMID:19597207
Barrett, Scott
PGC-1? Is Required for Exercise- and Exercise Training-Induced UCP1 Up-Regulation in Mouse White Adipose Tissue
Background The aim of the present study was to test the hypotheses that 1) a single exercise bout increases UCP1 mRNA in both inguinal (i)WAT and epididymal (e)WAT, 2) UCP1 expression and responsiveness to exercise are different in iWAT and eWAT, 3) PGC-1? determines the basal levels of UCP1 and PRDM16 in WAT and 4) exercise and exercise training regulate UCP1 and PRDM16 expression in WAT in a PGC-1?-dependent manner. Methods Whole body PGC-1? knockout (KO) and wildtype (WT) littermate mice performed a single treadmill exercise bout at 14 m/min and 10% slope for 1 hour. Mice were sacrificed and iWAT, eWAT and quadriceps muscle were removed immediately after, 2, 6 and 10 hours after running, and from sedentary mice that served as controls. In addition, PGC-1? KO mice and WT littermates were exercise trained for 5 weeks with sedentary mice as untrained controls. Thirty-six-37 hours after the last exercise bout iWAT was removed. Results UCP1 mRNA content increased 19-fold in iWAT and 7.5-fold in eWAT peaking at 6 h and 0? of recovery, respectively, in WT but with no changes in PGC-1? KO mice. UCP1 protein was undetectable in eWAT and very low in iWAT of untrained mice but increased with exercise training to 4.4 (AU) in iWAT from WT mice without significant effects in PGC-1? KO mice. Conclusion The present observations provide evidence that exercise training increases UCP1 protein in iWAT through PGC-1?, likely as a cumulative effect of transient increases in UCP1 expression after each exercise bout. Moreover, the results suggest that iWAT is more responsive than eWAT in exercise-induced regulation of UCP1. In addition, as PRDM16 mRNA content decreased in recovery from acute exercise, the present findings suggest that acute exercise elicits regulation of several brown adipose tissue genes in mouse WAT.
Ringholm, Stine; Grunnet Knudsen, Jakob; Leick, Lotte; Lundgaard, Anders; Munk Nielsen, Maja; Pilegaard, Henriette
Imbalance in SOD/CAT activities in rat skeletal muscles submitted to treadmill training exercise.
The association between physical exercise and oxidative damage in the skeletal musculature has been the focus of many studies in literature, but the balance between superoxide dismutase and catalase activities and its relation to oxidative damage is not well established. Thus, the aim of the present study was to investigate the association between regular treadmill physical exercise, oxidative damage and antioxidant defenses in skeletal muscle of rats. Fifteen male Wistar rats (8-12 months) were randomly separated into two groups (trained n=9 and untrained n=6). Trained rats were treadmill-trained for 12 weeks in progressive exercise (velocity, time, and inclination). Training program consisted in a progressive exercise (10 m/min without inclination for 10 min/day). After 1 week the speed, time and inclination were gradually increased until 17 m/min at 10% for 50 min/day. After the training period animals were killed, and gastrocnemius and quadriceps were surgically removed to the determination of biochemical parameters. Lipid peroxidation, protein oxidative damage, catalase, superoxide dismutase and citrate synthase activities, and muscular glycogen content were measured in the isolated muscles. We demonstrated that there is a different modulation of CAT and SOD in skeletal muscle in trained rats when compared to untrained rats (increased SOD/CAT ratio). TBARS levels were significantly decreased and, in contrast, a significant increase in protein carbonylation was observed. These results suggest a non-described adaptation of skeletal muscle against exercise-induced oxidative stress. PMID:17011801
Pinho, Ricardo A; Andrades, Michael E; Oliveira, Marcos R; Pirola, Aline C; Zago, Morgana S; Silveira, Paulo C L; Dal-Pizzol, Felipe; Moreira, José Cláudio F
Physiological benefits of exercise in artificial gravity: A broadband countermeasure to space flight related deconditioning
NASA Astrophysics Data System (ADS)
Current countermeasures to space flight related physiological deconditioning have not been sufficiently effective. We believe that a comprehensive countermeasure is the combination of intermittent centrifugation (artificial gravity) and exercise. We aim to test the long-term effectiveness of this combination in terms of fitness benefits. As a first-order determination of effectiveness, subjects participated in an eight-week exercise program. Three times per week, they exercised using a stair-stepper on a short-radius (2 m) centrifuge spinning at 30 RPM, maintaining a target heart rate that was systematically increased over the exercise period. During the sessions, foot forces and stepping cadence, heart rate, and perceived exertion were measured. Before and after the eight-week exercise program, measurements included: body fat percentage, bone mineral content, quadriceps extension strength, push-ups endurance, stepping cadence for a given heart rate, and maximum stepping endurance. We find that stair-stepping on a centrifuge is safe and comfortable. Preliminary fitness results indicate that stair-stepping on a centrifuge may be effective in improving aerobic fitness, body composition, and strength. These results indicate that such a combination may also be effective as a countermeasure to space flight deconditioning.
Edmonds, Jessica L.; Jarchow, Thomas; Young, Laurence R.
The Effects of Short-term Exercise Training on Peak-Torque Are Time- and Fiber-Type Dependent.
Ureczky, D, Vácz, G, Costa, A, Kopper, B, Lacza, Z, Hortobágyi, T, and Tihanyi, J. The effects of short-term exercise training on peak-torque are time- and fiber-type dependent. J Strength Cond Res 28(8): 2204-2213, 2014-We examined the susceptibility of fast and slow twitch muscle fibers in the quadriceps muscle to eccentric exercise-induced muscle damage. Nine healthy men (age: 22.5 ± 1.6 years) performed maximal eccentric quadriceps contractions at 120°·s over a 120° of knee joint range of motion for 6 consecutive days. Biopsies were taken from the vastus lateralis muscle before repeated bouts of eccentric exercise on the third and seventh day. Immunohistochemical procedures were used to determine fiber composition and fibronectin activity. Creatine kinase (CK) and lactate dehydrogenase (LDH) were determined in serum. Average torque was calculated in each day for each subject. Relative to baseline, average torque decreased 37.4% till day 3 and increased 43.0% from the day 3 to day 6 (p < 0.001). Creatine kinase and LDH were 70.6 and 1.5 times higher on day 3 and 75.5 and 1.4 times higher on day 6. Fibronectin was found in fast fibers in subjects with high CK level on day 3 and 7 after exercise, but on day 7, fibronectin seemed in both slow and fast fibers except in muscles of 2 subjects with high fast fiber percentage. Peak torque and muscle fiber-type composition measured at baseline showed a strong positive association on day 3 (r = 0.76, p < 0.02) and strong negative association during recovery between day 3 and day 6 (r = -0.76, p < 0.02), and day 1 and day 6 (r = 0.84, p < 0.001). We conclude that the damage of fast fibers preceded the damage of slow fibers, and muscles with slow fiber dominance were more susceptible to repeated bouts of eccentric exercise than fast fiber dominance muscles. The data suggest that the responses to repeated bouts of eccentric exercise are fiber-type-dependent in the quadriceps muscle, which can be the basis for the design of individualized strength training protocols. PMID:24531434
Ureczky, Dóra; Vácz, Gabriella; Costa, Andreas; Kopper, Bence; Lacza, Zsombor; Hortobágyi, Tibor; Tihanyi, József
Strengthening the Foundations for Teacher-Librarianship.
ERIC Educational Resources Information Center
This essay on means by which the profession of teacher-librarianship might be strengthened, and even enhanced, highlights the mission statement and resource center programs, role of the teacher-librarian, cooperative program planning and teaching, research and study skill development, education for school librarianship, and program advocacy. (EJS)
Haycock, Ken
Ideas for Strengthening Mathematics Skills. Greek Edition.
ERIC Educational Resources Information Center
Presented is an overview of some specific schemes that have been used successfully by teachers throughout New York State to strengthen basic mathematics skills. Components offer ideas that have been successful with primary, intermediate and secondary students. The contents of this Greek language edition are identical to the English language and…
New York State Education Dept., Albany. Bureau of Bilingual Education.
Strengthening Family Practices for Latino Families
ERIC Educational Resources Information Center
This study examined the effectiveness of a culturally adapted Strengthening Families Program (SFP) for Latinos to reduce risks for alcohol and drug use in children. Latino families, predominantly Puerto Rican, with a 9- to 12-year-old child and a parent(s) with a substance abuse problem participated in the study. Pre- and post-tests were conducted…
Chartier, Karen G.; Negroni, Lirio K.; Hesselbrock, Michie N.
Strengthening of Existing Bridges Using Epoxy Injection.
National Technical Information Service (NTIS)
A low viscosity epoxy was pressure injected between portions of the concrete slab and steel stringers of a non-composite highway bridge to determine if the structure could be strengthened by inducing composite action. The slab was jacked off the girders d...
L. F. Kahn K. M. Will P. H. Sanders J. A. Soltesz
Mechanisms for slow strengthening in granular materials
Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force Fmax experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time tau. The layer strength increases roughly logarithmically with tau only if a
W. Losert; J.-C. Géminard; S. Nasuno; J. P. Gollub
Working Together for Children: Strengthening Transition Pathways
ERIC Educational Resources Information Center
The "Working Together for Children: Strengthening Transition Pathways" Team has identified that there is a gap between the Early Childhood settings and schools within the Dubbo area. Through meetings with early childhood professionals within Dubbo the authors have identified that the current landscape of care and education within their community…
Collie, Louise; Willis, Felicity; Paine, Crystal; Windsor, Corina
Strengthening 4-H Program Communication through Technology
ERIC Educational Resources Information Center
Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…
Robideau, Kari; Santl, Karyn
Ni + ThOâ: dispersion strengthened nickel
Production methods for obtaining nickel dispersion strengthened with ; thorium oxide are discussed together with the physical and mechanical properties. ; Particular attention is given to TD-nickel which is suitable for use at ; temperatures up to 1300 deg C. This material has found application in engineering ; to replace superalloys based on nickel and cobalt matrices. (auth);
Locomotor muscle fatigue modifies central motor drive in healthy humans and imposes a limitation to exercise performance
We asked whether the central effects of fatiguing locomotor muscle fatigue exert an inhibitory influence on central motor drive to regulate the total degree of peripheral fatigue development. Eight cyclists performed constant-workload prefatigue trials (a) to exhaustion (83% of peak power output (Wpeak), 10 ± 1 min; PFT83%), and (b) for an identical duration but at 67%Wpeak (PFT67%). Exercise-induced peripheral quadriceps fatigue was assessed via changes in potentiated quadriceps twitch force (?Qtw,pot) from pre- to post-exercise in response to supra-maximal femoral nerve stimulation (?Qtw,pot). On different days, each subject randomly performed three 5 km time trials (TTs). First, subjects repeated PFT83% and the TT was started 4 min later with a known level of pre-existing locomotor muscle fatigue (?Qtw,pot?36%) (PFT83%-TT). Second, subjects repeated PFT67% and the TT was started 4 min later with a known level of pre-existing locomotor muscle fatigue (?Qtw,pot?20%) (PFT67%-TT). Finally, a control TT was performed without any pre-existing level of fatigue. Central neural drive during the three TTs was estimated via quadriceps EMG. Increases in pre-existing locomotor muscle fatigue from control TT to PFT83%-TT resulted in significant dose-dependent changes in central motor drive (?23%), power output (?14%), and performance time (+6%) during the TTs. However, the magnitude of locomotor muscle fatigue following various TTs was not different (?Qtw,pot of ?35 to ?37%, P= 0.35). We suggest that feedback from fatiguing muscle plays an important role in the determination of central motor drive and force output, so that the development of peripheral muscle fatigue is confined to a certain level.
Amann, Markus; Dempsey, Jerome A
Thigh-muscles strength training, dance exercise, dynamometry, and anthropometry in professional ballerinas.
The purpose of the present study was to assess the effects of 12 weeks of quadriceps and hamstring strength training on torque levels after a dance exercise and on selected anthropometric parameters. The sample consisted of 22 (ages, 25 +/- 1.3 years) full-time professional ballerinas who were randomly assigned into experimental (n = 12) and control (n = 10) groups. A dance routine designed to cause fatigue within 5 minutes, isokinetic dynamometry, and anthropometric assessments were conducted before and after strength training in both groups. Before strength training, the dance routine resulted in significant reductions of hamstring (p < 0.001) and quadriceps (p < 0.001) peak torques in both subject groups. However, after strength training, only control subjects demonstrated such torque decrements (p < 0.001) after the dance routine. Furthermore, the experimental group revealed greater knee extension (119 vs. 138 N.m; p < 0.001) and flexion (60 vs. 69 N.m; p < 0.001) torques, smaller sum of skinfolds (33.6 vs. 27.8 mm; p < 0.01), more fat-free mass (37.7 vs. 39.4 kg; p < 0.05), but unchanged body mass (p > 0.05) and thigh circumferences (p > 0.05). A negative relationship (p < 0.001) was found between initial strength levels and improvements measured at the end of the 12-week program. These results suggest that supplementary strength training for hamstring and quadriceps muscles is beneficial to professional ballerinas and their dancing; weaker individuals are more likely to benefit from such regimens than their stronger counterparts, whereas increases in thigh-muscle strength do not alter selected aesthetic components. PMID:15574072
Koutedakis, Yiannis; Sharp, N C Craig
Nitrergic Proprioceptive Afferents Originating from Quadriceps Femoris Muscle are Related to Monosynaptic Ia-Motoneuron Stretch Reflex Circuit in the Dog
1. The aim of the present study was to examine the occurrence of the neuronal nitric oxide synthase immunoreactivity in the stretch reflex circuit pertaining to the quadriceps femoris muscle in the dog.2. Immunohistochemical processing for neuronal nitric oxide synthase and histochemical staining for nicotinamide adenine dinucleotide phosphate diaphorase were used to demonstrate the presence of neuronal nitric oxide synthase
Jozef Maršala; Nadežda Luká?ová; Dalibor Kolesár; Karolína Kuchárová; Martin Maršala
Changes in Voluntary Activation Assessed by Transcranial Magnetic Stimulation during Prolonged Cycling Exercise
Maximal central motor drive is known to decrease during prolonged exercise although it remains to be determined whether a supraspinal deficit exists, and if so, when it appears. The purpose of this study was to evaluate corticospinal excitability and muscle voluntary activation before, during and after a 4-h cycling exercise. Ten healthy subjects performed three 80-min bouts on an ergocycle at 45% of their maximal aerobic power. Before exercise and immediately after each bout, neuromuscular function was evaluated in the quadriceps femoris muscles under isometric conditions. Transcranial magnetic stimulation was used to assess voluntary activation at the cortical level (VATMS), corticospinal excitability via motor-evoked potential (MEP) and intracortical inhibition by cortical silent period (CSP). Electrical stimulation of the femoral nerve was used to measure voluntary activation at the peripheral level (VAFNES) and muscle contractile properties. Maximal voluntary force was significantly reduced after the first bout (13±9%, P<0.01) and was further decreased (25±11%, P<0.001) at the end of exercise. CSP remained unchanged throughout the protocol. Rectus femoris and vastus lateralis but not vastus medialis MEP normalized to maximal M-wave amplitude significantly increased during cycling. Finally, significant decreases in both VATMS and VAFNES (?8%, P<0.05 and ?14%, P<0.001 post-exercise, respectively) were observed. In conclusion, reductions in VAFNES after a prolonged cycling exercise are partly explained by a deficit at the cortical level accompanied by increased corticospinal excitability and unchanged intracortical inhibition. When comparing the present results with the literature, this study highlights that changes at the cortical and/or motoneuronal levels depend not only on the type of exercise (single-joint vs. whole-body) but also on exercise intensity and/or duration.
Perrey, Stephane; Temesi, John; Wuyam, Bernard; Levy, Patrick; Verges, Samuel; Millet, Guillaume Y.
Exercise efficiency is reduced by mitochondrial uncoupling in the elderly.
A reduction in exercise efficiency accompanies ageing in humans. Here we evaluated the impact of changes in the contractile-coupling and mitochondrial-coupling efficiencies on the reduction in exercise efficiency in the elderly. Nine adult (mean, 38.8 years old) and 40 elderly subjects (mean, 68.8 years old) performed a cycle ergometer test to measure O2 uptake and leg power output up to the aerobic limit ( ). Reduced leg power output per unit O2 uptake was reflected in a drop in delta efficiency (?D) from 0.27 ± 0.01 (mean ± SEM) in adults to 0.22 ± 0.01 in the elderly group. Similar declines with age were apparent for both the leg power output at and the ATP generation capacity (ATPmax) determined in vivo using (31)P magnetic resonance spectroscopy. These similar declines resulted in unchanged contractile-coupling efficiency values (?C) in the adult (0.50 ± 0.05) versus the elderly group (0.58 ± 0.04) and agreed with independent measures of muscle contractile-coupling efficiency in human quadriceps (0.5). The mitochondrial-coupling efficiency calculated from the ratio of delta to contractile-coupling efficiencies in the adults (?D/?C = 0.58 ± 0.08) corresponded to values for well-coupled mitochondria (0.6); however, ?D/?C was significantly lower in the elderly subjects (0.44 ± 0.03). Conversion of ATPmax per mitochondrial volume (ATPmax/Vv[mt,f]) reported in these groups into thermodynamic units confirmed this drop in mitochondrial-coupling efficiency from 0.57 ± 0.08 in adults to 0.41 ± 0.03 in elderly subjects. Thus, two independent methods revealed that reduced mitochondrial-coupling efficiency was a key part of the drop in exercise efficiency in these elderly subjects and may be an important part of the loss of exercise performance with age. PMID:23085769
Conley, Kevin E; Jubrias, Sharon A; Cress, M Elaine; Esselman, Peter
A Comprehensive Review of the Effectiveness of Different Exercise Programs for Patients with Osteoarthritis
Exercise is recommended as a first-line conservative intervention approach for osteoarthritis (OA). A wide range of exercise programs are available, and scientific evidence is necessary for advising patients with OA on the optimal treatment strategy. The purpose of this review is to discuss the effectiveness of different types of exercise programs for OA based on trials, systematic reviews, and meta-analyses in the literature. Publications from January 1997 to July 2012 were searched in 4 electronic databases using the terms osteoarthritis, exercise, exercise program, effectiveness, and treatment outcome. Strong evidence supports that aerobic and strengthening exercise programs, both land- and water-based, are beneficial for improving pain and physical function in adults with mild to moderate knee and hip OA. Areas that require further research include examination of the long-term effects of exercise programs for OA, balance training for OA, exercise programs for severe OA, the effect of exercise programs on progression of OA, the effectiveness of exercise for joint sites other than the knee or hip, and the effectiveness of exercise for OA by such factors as age, gender and obesity. Efforts to improve adherence to evidence-based exercise programs for OA and to promote the dissemination and implementation of these programs are crucial.
Golightly, Yvonne M.; Allen, Kelli D.; Caine, Dennis J.
... light exercise and walking appear to reduce wandering, aggression and agitation. Incorporating exercise into daily routines and ... massage therapy may reduce behaviors such as wandering, aggression and agitation. ? Back EDUCATE YOURSELF Sign up here ...
... proper exercise, students should focus on getting balanced nutrition , enough water to stay hydrated, and adequate sleep . ... ON THIS TOPIC Female Athlete Triad Sports and Exercise Safety Dehydration A Guide ...
Exercise is an important part of managing your diabetes. It can help you lose weight, if you are overweight. It also helps prevent weight gain. Exercise helps lower your blood sugar without medicines . It ...
Clinical Applications for Exercise.
ERIC Educational Resources Information Center
Patients with chronic conditions such as coronary artery disease, hypertension, diabetes, and obesity might benefit from prescribed exercise. Although exercise does not reverse pathologic changes, it may play a role in disease management. (JD)
Goldstein, David
Exercise and physical activity are good for just about everyone, including older adults. There are four main ... jogging, dancing, swimming, and biking are examples. Strength exercises make your muscles stronger. Lifting weights or using ...
... Increase your chances of living longer Fitting regular exercise into your daily schedule may seem difficult at ... fine. The key is to find the right exercise for you. It should be fun and should ...
... blood sugar level may get too low (called hypoglycemia) after exercising. You may need to check your ... sugar is too low while I'm exercising? Hypoglycemia usually occurs gradually, so you need to pay ...
Assessing Exercise Limitation Using Cardiopulmonary Exercise Testing
The cardiopulmonary exercise test (CPET) is an important physiological investigation that can aid clinicians in their evaluation of exercise intolerance and dyspnea. Maximal oxygen consumption (V?O2max) is the gold-standard measure of aerobic fitness and is determined by the variables that define oxygen delivery in the Fick equation (V?O2 = cardiac output × arterial-venous O2 content difference). In healthy subjects, of the variables involved in oxygen delivery, it is the limitations of the cardiovascular system that are most responsible for limiting exercise, as ventilation and gas exchange are sufficient to maintain arterial O2 content up to peak exercise. Patients with lung disease can develop a pulmonary limitation to exercise which can contribute to exercise intolerance and dyspnea. In these patients, ventilation may be insufficient for metabolic demand, as demonstrated by an inadequate breathing reserve, expiratory flow limitation, dynamic hyperinflation, and/or retention of arterial CO2. Lung disease patients can also develop gas exchange impairments with exercise as demonstrated by an increased alveolar-to-arterial O2 pressure difference. CPET testing data, when combined with other clinical/investigation studies, can provide the clinician with an objective method to evaluate cardiopulmonary physiology and determination of exercise intolerance.
Stickland, Michael K.; Butcher, Scott J.; Marciniuk, Darcy D.; Bhutani, Mohit
Biomechanics of front and back squat exercises
NASA Astrophysics Data System (ADS)
Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee. In previous anterior cruciate ligament injuries, the mini-squats are generally used, in a knee flexion motion range from 0° to 50° because in this range the shear forces, the tibiofemoral and patellofemoral compression forces decrease related to greater flexion angles. The aim of this work is to make a comparative bidimensional study of the kinematic and dynamic variables of the excecution of the parallel squat exercise with the front and back bar. It is observed in the knee a better development of energy with the front bar, allowing a better muscular exercise with the same load. The mean power absorbed by the hip with the back bar is considerably greater, associated to the speed of the gesture.
Braidot, A. A.; Brusa, M. H.; Lestussi, F. E.; Parera, G. P.
Treatment and Prevention of Osteoarthritis through Exercise and Sports
Osteoarthritis (OA) is a degenerative joint disease with a high prevalence among older people. To date, the pathogenesis of the disease and the link between muscle function and OA is not entirely understood. As there is no known cure for OA, current research focuses on prevention and symptomatic treatment of the disorder. Recent research has indicated that muscle weakness precedes the onset of OA symptoms. Furthermore, several studies show a beneficial effect of land-based aerobic and strengthening exercises on pain relief and joint function. Therefore, current research focuses on the possibility to employ exercise and sports in the prevention and treatment of OA.
Valderrabano, Victor; Steiger, Christina
Continuous Femoral Nerve Blocks: The Impact of Catheter Tip Location Relative to the Femoral Nerve (Anterior Versus Posterior) on Quadriceps Weakness and Cutaneous Sensory Block
Background During a continuous femoral nerve block, the influence of catheter tip position relative to the femoral nerve on infusion characteristics remains unknown. Methods We inserted bilateral femoral perineural catheters in volunteers (ultrasound-guided, needle in-plane). Subjects' dominant side was randomized to have the catheter tip placed either anterior or posterior to the femoral nerve. The contralateral limb received the alternative position. Ropivacaine 0.1% was administered through both catheters concurrently for 6 hours (4 mL/h). Outcome measures included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current over to the distal quadriceps tendon. Measurements were performed at Hour 0 (baseline), and on the hour until Hour 9, as well as Hour 22. The primary endpoint was the MVIC of the quadriceps at Hour 6. Results As a percentage of the baseline measurement, quadriceps MVIC for limbs with anterior (n=16) and posterior (n=16) catheter tip placement did not differ to a statistically significant degree at Hour 6 (mean [SD] 29% [26] vs. 30% [28], respectively; 95% CI: ?22% to 20%; p=0.931), or at any other time point. However, the maximum tolerance to cutaneous electrical current was higher in limbs with anterior compared to posterior catheter tip placement at Hour 6 (20 [23] vs. 6 [4] mA, respectively; 95% CI: 1 mA to 27 mA; p=0.035), as well as at Hours 1, 7, 8, and 9 (p<0.04). Conclusions This study documents the significant (70–80%) quadriceps femoris weakness induced by a continuous femoral nerve block infusion at a relatively low dose of ropivacaine (4 mg/h) delivered through a perineural catheter located both anterior and posterior to the femoral nerve. In contrast, an anterior placement increases cutaneous sensory block compared with a posterior insertion, without a concurrent relative increase in motor block.
Ilfeld, Brian M.; Loland, Vanessa J.; Sandhu, NavParkash S.; Suresh, Preetham J.; Bishop, Michael J.; Donohue, Michael C.; Ferguson, Eliza J.; Madison, Sarah J.
Continuous Femoral Nerve Blocks: Varying Local Anesthetic Delivery Method (Bolus versus Basal) to Minimize Quadriceps Motor Block while Maintaining Sensory Block
Background Whether the method of local anesthetic administration for continuous femoral nerve blocks —basal infusion versus repeated hourly bolus doses —influences block effects remains unknown. Methods Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was administered through both catheters concurrently: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at Hour 6. Secondary end points included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation 2 cm medial to the distal quadriceps tendon in the 22 h following local anesthetic administration initiation. Results Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for limbs receiving 0.1% ropivacaine as repeated bolus doses between baseline and Hour 6 (paired t test P = 0.91). Intrasubject comparisons (left vs. right) reflected a lack of difference as well: the mean basal-bolus difference in quadriceps MVIC at Hour 6 was ?1.1% (95% CI ?22.0 to 19.8%). The similarity did not reach our a priori threshold for concluding equivalence, which was the 95% CI falling within ± 20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration. Conclusions This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration —basal infusion versus repeated bolus doses —influences continuous femoral nerve block effects to a clinically significant degree.
Charous, Matthew T.; Madison, Sarah J.; Suresh, J.; Sandhu, NavParkash S.; Loland, Vanessa J.; Mariano, Edward R.; Donohue, Michael C.; Dutton, Pascual H.; Ferguson, Eliza J.; Ilfeld, Brian M.
ERIC Educational Resources Information Center
This article discusses how to use stretch bands for improving total body fitness and quality of life. A stretch band exercise program offers a versatile and inexpensive option to motivate participants to exercise. The authors suggest practical exercises that can be used in physical education to improve or maintain muscular strength and endurance,…
Skirka, Nicholas; Hume, Donald
Advanced resistive exercise device
NASA Technical Reports Server (NTRS)
The present invention relates to an exercise device, which includes a vacuum cylinder and a flywheel. The flywheel provides an inertial component to the load, which is particularly well suited for use in space as it simulates exercising under normal gravity conditions. Also, the present invention relates to an exercise device, which has a vacuum cylinder and a load adjusting armbase assembly.
Raboin, Jasen L. (Inventor); Niebuhr, Jason (Inventor); Cruz, Santana F. (Inventor); Lamoreaux, Christopher D. (Inventor)
Supraspinal fatigue after normoxic and hypoxic exercise in humans.
Inadequate cerebral O? availability has been proposed to be an important contributing factor to the development of central fatigue during strenuous exercise. Here we tested the hypothesis that supraspinal processes of fatigue would be increased after locomotor exercise in acute hypoxia compared to normoxia, and that such change would be related to reductions in cerebral O? delivery and tissue oxygenation. Nine endurance-trained cyclists completed three constant-load cycling exercise trials at ?80% of maximal work rate: (1) to the limit of tolerance in acute hypoxia; (2) for the same duration but in normoxia (control); and (3) to the limit of tolerance in normoxia. Throughout each trial, prefrontal cortex tissue oxygenation and middle cerebral artery blood velocity (MCAV) were assessed using near-infrared spectroscopy and trans-cranial Doppler sonography, respectively. Cerebral O? delivery was calculated as the product of arterial O? content and MCAV. Before and immediately after each trial, twitch responses to supramaximal femoral nerve stimulation and transcranial magnetic stimulation were obtained to assess neuromuscular and cortical function, respectively. Exercise time was reduced by 54%in hypoxia compared to normoxia (3.6 ± 1.3 vs. 8.1 ± 2.9 min; P<0.001). Cerebral O? delivery,cerebral oxygenation and maximum O? uptake were reduced whereas muscle electromyographic activity was increased in hypoxia compared to control (P <0.05).Maximum voluntary force and potentiated quadriceps twitch force were decreased below baseline after exercise in each trial;the decreases were greater in hypoxia compared to control (P<0.001), but were not different in the exhaustive trials (P>0.05). Cortical voluntary activation was also decreased after exercise in all trials, but the decline in hypoxia (?18%) was greater than in the normoxic trials (?5-9%)(P <0.05). The reductions in cortical voluntary activation were paralleled by reductions in cerebral O? delivery. The results suggest that curtailment of exercise performance in acute severe hypoxia is due, in part, to failure of drive from the motor cortex, possibly as a consequence of diminished O? availability in the brain. PMID:22473785
Goodall, Stuart; González-Alonso, José; Ali, Leena; Ross, Emma Z; Romer, Lee M
Comparison of Active and Electrostimulated Recovery Strategies After Fatiguing Exercise
The purpose of this study was to compare an electrostimulated to an active recovery strategy after a submaximal isometric fatiguing exercise. Nineteen healthy men completed three sessions (separated by at least 4 weeks) which included a knee extensors provocation exercise consisting of 3 sets of 25 isometric contractions. Contraction intensity level was fixed respectively at 60%, 55% and 50% of previously determined maximal voluntary contraction for the first, second and third sets. This provocation exercise was followed by either an active (AR) recovery (25 min pedaling on a cycle ergometer), an electrostimulated (ESR) recovery (25-min continuous and non-tetanic (5 Hz) stimulation of the quadriceps) or a strictly passive recovery (PR). Peak torques of knee extensors and subjective perception of muscle pain (VAS, 0-10) were evaluated before (pre-ex), immediately after the provocation exercise (post-ex), after the recovery period (post-rec), as well as 75 minutes (1h15) and one day (24h) after the exercise bout. Time course of peak torque was similar among the different recovery modes: ~ 75% of initial values at post-ex, ~ 90% at post-rec and at 1h15. At 24h, peak torque reached a level close to baseline values (PR: 99.1 ± 10.7%, AR: 105.3 ± 12.2%, ESR: 104.4 ± 10.5%). VAS muscle pain scores decreased rapidly between post-ex and post-rec (p < 0.001); there were no significant differences between the three recovery modes (p = 0.64). In conclusion, following a submaximal isometric knee extension exercise, neither electrostimulated nor active recovery strategies significantly improved the time course of muscle function recovery. Key points Three sets of submaximal isometric contractions at 60%, 55% and 50% of MVC induced an early fatigue without DOMS but did not lead to exhaustion. In comparison with passive recovery, active and electrostimulated recovery did not lead to significantly higher MVC torques 24h after the exercise bout. No significant differences were demonstrated between the effects of passive, active and electrostimulated recoveries on muscle pain after repeated submaximal isometric contractions.
Vanderthommen, Marc; Makrof, Souleyma; Demoulin, Christophe
Effect of Therapeutic Exercise for Hip Osteoarthritis Pain: Results of a Meta-Analysis
Objective Recommendations for lower extremity osteoarthritis (OA) and exercise have been primarily based on knee studies. To provide more targeted recommendations for the hip, we gathered evidence for the efficacy of exercise for hip OA from randomized controlled trials. Methods A bibliographic search identified trials that were randomized, controlled, completed by ?60% of subjects, and involved an exercise group (strengthening and/or aerobic) versus a nonexercise control group for pain relief in hip OA. Two reviewers independently performed the data extraction and contacted the authors when necessary. Effect sizes (ES) of treatment versus control and the I2 statistic to assess heterogeneity across trials were calculated. Trial data were combined using a random-effects meta-analysis. Results Nine trials met the inclusion criteria (1,234 subjects), 7 of which combined hip and knee OA; therefore, we contacted the authors who provided the data on hip OA patients. In comparing exercise treatment versus control, we found a beneficial effect of exercise with an ES of ?0.38 (95% confidence interval [95% CI] ?0.68, ?0.08; P = 0.01), but with high heterogeneity (I2 = 75%) among trials. Heterogeneity was caused by 1 trial consisting of an exercise intervention that was not administered in person. Removing this study left 8 trials (n = 493) with similar exercise strategy (specialized hands-on exercise training, all of which included at least some element of muscle strengthening), and demonstrated exercise benefit with an ES of ?0.46 (95% CI ?0.64, ?0.28; P < 0.0001). Conclusion Therapeutic exercise, especially with an element of strengthening, is an efficacious treatment for hip OA.
Hernandez-Molina, Gabriela; Reichenbach, Stephan; Zhang, Bin; LaValley, Michael; Felson, David T.
Effect of triceps surae and quadriceps muscle fatigue on the mechanics of landing in stepping down in ongoing gait.
The aim of this study was to evaluate the effects of muscle fatigue of triceps surae and quadriceps muscles in stepping down in ongoing gait. We expected that the subjects would compensate for muscle fatigue to prevent potential loss of balance in stepping down. A total of 10 young participants walked over a walkway at a self-selected velocity to step down a height difference of 10-cm halfway. Five trials were performed before and after a muscle fatigue protocol. Participants performed two fatigue protocols: one for ankle muscle fatigue and another for knee muscle fatigue. Kinematics of and ground reaction forces on the leading leg were recorded. Fatigue did not cause a change in the frequency of heel or toe landing. Our results indicate that in stepping down fatigue effects are compensated by redistributing work to unfatigued muscle groups and by gait changes aimed at enhancing balance control, which was however only partially successful. PMID:24697241
Barbieri, F A; Gobbi, L T B; Lee, Y J; Pijnappels, M; van Dieën, J H
Anatomic Reconstruction of the Medial Patellofemoral Ligament in Children and Adolescents Using a Pedicled Quadriceps Tendon Graft
Reconstruction of the medial patellofemoral ligament (MPFL) has recently become a popular procedure for children and adolescents with patellofemoral instability. Nevertheless, high complication rates of up to 26% have been reported. The traditionally used technique requires patellar bone tunnels that may place the proportionately smaller patella at higher risk of fracture. Because of the adjacent physis of the femoral insertion, anatomic reconstruction of the MPFL has the risk of injury to the growth plate. This technical report therefore presents a technique for anatomic reconstruction of the MPFL in a skeletally immature population using a pedicled superficial quadriceps tendon graft, hardware-free patellar graft attachment, and anatomic femoral fixation distal to the femoral physis. The advantages of this technique include avoidance of bony patellar complications, an anatomically truer reconstruction, a single incision, and sparing of the hamstring tendons for reconstruction of any future ligamentous injuries.
Nelitz, Manfred; Williams, Sean Robert M.
Hypnotically Assisted Diaphragmatic Exercises in the Treatment of Stuttering: A Preliminary Investigation
This preliminary study investigates the combined effect of intensive hypnotherapy and diaphragmatic exercises in the management of stuttering. Fifty-nine clients with stuttering were trained to practice abdominal weightlifting to strengthen their respiratory muscles and to improve their diaphragmatic movements. The weightlifting exercises involved lifting a dumbbell (2.0–4.0 kg) with the abdomen for 2 hours daily for 8 consecutive days. Hypnotherapy
Yalcin Kaya; Assen Alladin
NSDL National Science Digital Library
This site contains model class exercises which instructors may find useful as class assignments to accompany class trips to the Wallace Creek site. These exercises are designed for college-level students who have had some background in geology and a general background of fault mechanics and earthquake geology. Particular questions in these exercises requires the students to conduct certain exercises or participate in appropriate discussions regarding geomorphology and slip rates. Five figures necessary to complete certain parts of the exercises are available for downloading.
NSDL National Science Digital Library
In this activity you will learn about components of a basic exercise program. You will also find some tips for making exercise a regular part of your life. Finally you will create a simple exercise program that includes the FIT formula. Doggonit!! You really wanted to just sit on the couch, watch another TV program, and eat a bag of chips. Your conscience, on the other hand, is telling you that you really need to get some exercise. What will you do? Hopefully, you are thinking seriously about some exercise. There are ...
The Strengthening Effect of Percutaneous Vertebroplasty
AIM: To examine whether single-needle vertebroplasty is effective in strengthening vertebrae.MATERIALS AND METHODS: Four adjacent intact lumbar vertebrae were removed from each of nine adult post-mortem subjects. One or two vertebra of each set was injected with low viscosity acrylic bone cement using a single-track posterolateral approach. Vertebral strength was measured during constant rate axial compression.RESULTS: Single-needle injection delivered different
Mechanisms for slow strengthening in granular materials
Several mechanisms cause a granular material to strengthen over time at low\\u000aapplied stress. The strength is determined from the maximum frictional force\\u000aF_max experienced by a shearing plate in contact with wet or dry granular\\u000amaterial after the layer has been at rest for a waiting time \\\\tau. The layer\\u000astrength increases roughly logarithmically with \\\\tau -only- if a
W. Losert; J.-C. Géminard; S. Nasuno; J. P. Gollub
Exercise: the first prescription for Cubans of all ages.
Regular physical exercise improves quality of life and benefits the body's organs and systems: it tones and strengthens muscles; improves joint function; contributes to healthier heart and lungs; increases resistance to fatigue, and thus capacity for both physical and mental exertion; helps combat anxiety, depression and stress; improves sleep patterns; and is an important factor in maintaining healthy weight. It also provides a simple way of sharing with family and friends, even an opportunity for improving intergenerational communication and relations. PMID:24487676
García, Osvaldo
Strengthening care of injured children globally
Abstract Part of the solution to the growing problem of child injury is to strengthen the care that injured children receive. This paper will point out the potential health gains to be made by doing this and will then review recent advances in the care of injured children in individual institutions and countries. It will discuss how these individual efforts have been aided by increased international attention to trauma care. Although there are no major, well-funded global programmes to improve trauma care, recent guidance documents developed by WHO and a broad network of collaborators have stimulated increased global attention to improving planning and resources for trauma care. This has in turn led to increased attention to strengthening trauma care capabilities in countries, including needs assessments and implementation of WHO recommendations in national policy. Most of these global efforts, however, have not yet specifically addressed children. Given the special needs of the injured child and the high burden of injury-related death and disability among children, clearly greater emphasis on childhood trauma care is needed. Trauma care needs assessments being conducted in a growing number of countries need to focus more on capabilities for care of injured children. Trauma care policy development needs to better encompass childhood trauma care. More broadly, the growing network of individuals and groups collaborating to strengthen trauma care globally needs to engage a broader range of stakeholders who will focus on and champion the improvement of care for injured children.
Abantanga, Francis; Goosen, Jacques; Joshipura, Manjul; Juillard, Catherine
Dispersion-strengthened copper-niobium composites
GlidCop dispersion-strengthened copper is a family of engineered alloys which combine high strength, high thermal and electrical conductivities, and outstanding resistance to softening following exposure to elevated temperatures. A proprietary process based on GlidCop dispersion-strengthened copper technology improves mechanical properties through the addition of niobium. Two grades have been developed: Al-60 + NB1000 and Al-15 + NB1000. Each composite contains 10% niobium by weight, in the form of uniformly dispersed particles. The technology produces a uniform distribution of niobium in the internally oxidized, dispersion-strengthened copper powder. This powder can be consolidated in the same manner as conventional GlidCop Powder to produce a variety of mill shapes. The addition of 10% niobium to the Al-60 matrix increases strength and hardness with only minimal reduction in electrical conductivity. The room-temperature properties of Al-60 + NB1000 following exposure to 980 C (1,800 F), are compared with the properties of some commonly used RWMA welding materials which have also been exposed to elevated temperatures. While Al-60 + NB1000 has outstanding as-extruded mechanical properties, the cold workability of this material is limited. A cold-workable composite using the lower aluminum oxide Al-15 + NB1000 indicate that the properties of the as-extruded bar are improved by cold work, specifically drawing.
Troxell, J. [SCM Metal Products Inc., Research Triangle Park, NC (United States)
Exercise induced hypoglycaemic hyperinsulinism
BACKGROUND—Hyperinsulinism in childhood is often caused by genetic defects involving the regulation of insulin secretion leading to recurrent episodes of hypoglycaemia. We report two patients with exercise induced hypoglycaemia.?METHODS—Standardised short exercise tests with frequent blood glucose and plasma insulin measurements were performed in the patients and young healthy controls.?RESULTS—Short term exercise resulted in insulin induced hypoglycaemia 15 to 50 minutes after the end of exercise. A massive burst of insulin secretion was observed within a few minutes of the start of exercise in both patients. By contrast glucose and insulin concentrations remained unchanged in healthy controls.?CONCLUSIONS—Hyperinsulinaemic hypoglycaemia after moderate physical exercise represents a rarely described phenotype of hyperinsulinism with an as yet unknown defect in the regulation of insulin secretion. It should be suspected in individuals with recurrent exercise related syncope or disturbance of consciousness.??
Meissner, T; Otonkoski, T; Feneberg, R; Beinbrech, B; Apostolidou, S; Sipila, I; Schaefer, F; Mayatepek, E
Muscle-Strengthening and Conditioning Activities and Risk of Type 2 Diabetes: A Prospective Study in Two Cohorts of US Women
Background It is well established that aerobic physical activity can lower the risk of type 2 diabetes (T2D), but whether muscle-strengthening activities are beneficial for the prevention of T2D is unclear. This study examined the association of muscle-strengthening activities with the risk of T2D in women. Methods and Findings We prospectively followed up 99,316 middle-aged and older women for 8 years from the Nurses' Health Study ([NHS] aged 53–81 years, 2000–2008) and Nurses' Health Study II ([NHSII] aged 36–55 years, 2001–2009), who were free of diabetes, cancer, and cardiovascular diseases at baseline. Participants reported weekly time spent on resistance exercise, lower intensity muscular conditioning exercises (yoga, stretching, toning), and aerobic moderate and vigorous physical activity (MVPA) at baseline and in 2004/2005. Cox regression with adjustment for major determinants for T2D was carried out to examine the influence of these types of activities on T2D risk. During 705,869 person years of follow-up, 3,491 incident T2D cases were documented. In multivariable adjusted models including aerobic MVPA, the pooled relative risk (RR) for T2D for women performing 1–29, 30–59, 60–150, and >150 min/week of total muscle-strengthening and conditioning activities was 0.83, 0.93, 0.75, and 0.60 compared to women reporting no muscle-strengthening and conditioning activities (p<0.001 for trend). Furthermore, resistance exercise and lower intensity muscular conditioning exercises were each independently associated with lower risk of T2D in pooled analyses. Women who engaged in at least 150 min/week of aerobic MVPA and at least 60 min/week of muscle-strengthening activities had substantial risk reduction compared with inactive women (pooled RR?=?0.33 [95% CI 0.29–0.38]). Limitations to the study include that muscle-strengthening and conditioning activity and other types of physical activity were assessed by a self-administered questionnaire and that the study population consisted of registered nurses with mostly European ancestry. Conclusions Our study suggests that engagement in muscle-strengthening and conditioning activities (resistance exercise, yoga, stretching, toning) is associated with a lower risk of T2D. Engagement in both aerobic MVPA and muscle-strengthening type activity is associated with a substantial reduction in the risk of T2D in middle-aged and older women. Please see later in the article for the Editors' Summary
Gr?ntved, Anders; Pan, An; Mekary, Rania A.; Stampfer, Meir; Willett, Walter C.; Manson, JoAnn E.; Hu, Frank B.
Effectiveness of muscle strengthening and description of protocols for preventing falls in the elderly: a systematic review.
Background: Falls are a geriatric syndrome that is considered a significant public health problem in terms of morbidity and mortality because they lead to a decline in functional capacity and an impaired quality of life in the elderly. Lower limb muscle strengthening seems to be an effective intervention for preventing falls; however, there is no consensus regarding the best method for increasing lower limb muscle strength. Objectives: To analyze the effectiveness of lower limb muscle strengthening and to investigate and describe the protocols used for preventing falls in elderly subjects. Method: We performed a systematic review of randomized and controlled clinical trials published between 2002 and 2012 in the databases PubMed, EMBASE, Scopus, Web of Science, and PEDro that cited some type of lower limb muscle strengthening protocol and that evaluated the incidence of falls as the primary outcome exclusively in elderly subjects. Twelve studies met the inclusion criteria. Qualitative analysis was performed by independent reviewers applying the PEDro scale. Results: The data obtained from the selected studies showed lower fall rates in the intervention groups compared to controls. Six studies described the lower limb muscle strengthening protocol in detail. High methodological quality was found in 6 studies (PEDro score ≥7/10 points). Conclusions: The methodological quality of the studies in this area appears to leave little doubt regarding the effectiveness of lower limb strengthening exercises for preventing falls in elderly subjects, however the interventions in these studies were poorly reported. PMID:24760166
Ishigaki, Erika Y; Ramos, Lidiane G; Carvalho, Elisa S; Lunardi, Adriana C
Muscle Adaptations Following Short-Duration Bed Rest with Integrated Resistance, Interval, and Aerobic Exercise
NASA Technical Reports Server (NTRS)
Unloading of the musculoskeletal system during space flight results in deconditioning that may impair mission-related task performance in astronauts. Exercise countermeasures have been frequently tested during bed rest (BR) and limb suspension; however, high-intensity, short-duration exercise prescriptions have not been fully explored. PURPOSE: To determine if a high intensity resistance, interval, and aerobic exercise program could protect against muscle atrophy and dysfunction when performed during short duration BR. METHODS: Nine subjects (1 female, 8 male) performed a combination of supine exercises during 2 weeks of horizontal BR. Resistance exercise (3 d / wk) consisted of squat, leg press, hamstring curl, and heel raise exercises (3 sets, 12 repetitions). Aerobic (6 d / wk) sessions alternated continuous (75% VO2 peak) and interval exercise (30 s, 2 min, and 4 min) and were completed on a supine cycle ergometer and vertical treadmill, respectively. Muscle volumes of the upper leg were calculated pre, mid, and post-BR using magnetic resonance imaging. Maximal isometric force (MIF), rate of force development (RFD), and peak power of the lower body extensors were measured twice before BR (averaged to represent pre) and once post BR. ANOVA with repeated measures and a priori planned contrasts were used to test for differences. RESULTS: There were no changes to quadriceps, hamstring, and adductor muscle volumes at mid and post BR time points compared to pre BR (Table 1). Peak power increased significantly from 1614 +/- 372 W to 1739 +/- 359 W post BR (+7.7%, p = 0.035). Neither MIF (pre: 1676 +/- 320 N vs. post: 1711 +/- 250 N, +2.1%, p = 0.333) nor RFD (pre: 7534 +/- 1265 N/ms vs. post: 6951 +/- 1241 N/ms, -7.7%, p = 0.136) were significantly impaired post BR.
Hackney, Kyle J.; Scott, Jessica M.; Buxton, Roxanne; Redd-Goetchius, Elizabeth; Crowell, J. Brent; Everett, Meghan E.; Wickwire, Jason; Ryder, Jeffrey W.; Bloomberg, Jacob J.; Ploutz-Snyder, Lori L.
Electromyographic muscle activity in curl-up exercises with different positions of upper and lower extremities.
The purpose of the study was to evaluate the electromyographic (EMG) activity of muscles in curl-up exercises depending on the position of the upper and lower extremities. From the perspective of biomechanics, different positions of the extremities result in shifting the center of gravity and changing muscular loads in abdominal strength exercises. The subjects of the research were 3 healthy students (body mass 53-56 kg and height 163-165 cm) with no history of low back pain or abdominal surgery. Subjects completed 18 trials for each of the 9 exercises (static curl-up with 3 positions of the upper and 3 position of the lower extremities). The same experiment with the same subjects was conducted on the next day. The EMG activity of rectus abdominis (RA), erector spinae (ES), and quadriceps femoris-long head (rectus femoris [RF]) was examined during the exercises. The surface electrical activity was recorded for the right and left sides of each muscle. The raw data for each muscle were rectified and integrated. The statistical analysis showed that changing the position of upper extremities in the examined exercises affects the EMG activity of RA and ES but does not significantly affect the EMG activity of RF. Additionally, it was found that curl-up exercises with the upper extremities extended behind the head and the lower extremities flexed at 90° in the hip and knee joints involve RA with the greatest intensity, whereas curl-up exercises with the upper extremities extended along the trunk and the lower extremities flexed at 90° in the hip and knee joints involve RA with the lowest intensity. PMID:20940638
Rutkowska-Kucharska, Alicja; Szpala, Agnieszka
Acute post-exercise myofibrillar protein synthesis is not correlated with resistance training-induced muscle hypertrophy in young men.
Muscle hypertrophy following resistance training (RT) involves activation of myofibrillar protein synthesis (MPS) to expand the myofibrillar protein pool. The degree of hypertrophy following RT is, however, highly variable and thus we sought to determine the relationship between the acute activation of MPS and RT-induced hypertrophy. We measured MPS and signalling protein activation after the first session of resistance exercise (RE) in untrained men (n?=?23) and then examined the relation between MPS with magnetic resonance image determined hypertrophy. To measure MPS, young men (24±1 yr; body mass index ?=?26.4±0.9 kg•m˛) underwent a primed constant infusion of L-[ring-ąłC?] phenylalanine to measure MPS at rest, and acutely following their first bout of RE prior to 16 wk of RT. Rates of MPS were increased 235±38% (P<0.001) above rest 60-180 min post-exercise and 184±28% (P?=?0.037) 180-360 min post exercise. Quadriceps volume increased 7.9±1.6% (-1.9-24.7%) (P<0.001) after training. There was no correlation between changes in quadriceps muscle volume and acute rates of MPS measured over 1-3 h (r?=?0.02), 3-6 h (r?=?0.16) or the aggregate 1-6 h post-exercise period (r?=?0.10). Hypertrophy after chronic RT was correlated (r?=?0.42, P?=?0.05) with phosphorylation of 4E-BP1(Thr37/46) at 1 hour post RE. We conclude that acute measures of MPS following an initial exposure to RE in novices are not correlated with muscle hypertrophy following chronic RT. PMID:24586775
Mitchell, Cameron J; Churchward-Venne, Tyler A; Parise, Gianni; Bellamy, Leeann; Baker, Steven K; Smith, Kenneth; Atherton, Philip J; Phillips, Stuart M
Maximal muscular vascular conductances during whole body upright exercise in humans
That muscular blood flow may reach 2.5 l kg?1 min?1 in the quadriceps muscle has led to the suggestion that muscular vascular conductance must be restrained during whole body exercise to avoid hypotension. The main aim of this study was to determine the maximal arm and leg muscle vascular conductances (VC) during leg and arm exercise, to find out if the maximal muscular vasodilatory response is restrained during maximal combined arm and leg exercise. Six Swedish elite cross-country skiers, age (mean ± s.e.m.) 24 ± 2 years, height 180 ± 2 cm, weight 74 ± 2 kg, and maximal oxygen uptake (V?O2,max) 5.1 ± 0.1 l min?1 participated in the study. Femoral and subclavian vein blood flows, intra-arterial blood pressure, cardiac output, as well as blood gases in the femoral and subclavian vein, right atrium and femoral artery were determined during skiing (roller skis) at ?76% of V?O2,max and at V?O2,max with different techniques: diagonal stride (combined arm and leg exercise), double poling (predominantly arm exercise) and leg skiing (predominantly leg exercise). During submaximal exercise cardiac output (26–27 l min?1), mean blood pressure (MAP) (?87 mmHg), systemic VC, systemic oxygen delivery and pulmonary V?O2 (?4 l min?1) attained similar values regardless of exercise mode. The distribution of cardiac output was modified depending on the musculature engaged in the exercise. There was a close relationship between VC and V?O2 in arms (r = 0.99, P < 0.001) and legs (r = 0.98, P < 0.05). Peak arm VC (63.7 ± 5.6 ml min?1 mmHg?1) was attained during double poling, while peak leg VC was reached at maximal exercise with the diagonal technique (109.8 ± 11.5 ml min?1 mmHg?1) when arm VC was 38.8 ± 5.7 ml min?1 mmHg?1. If during maximal exercise arms and legs had been vasodilated to the observed maximal levels then mean arterial pressure would have dropped at least to 75–77 mmHg in our experimental conditions. It is concluded that skeletal muscle vascular conductance is restrained during whole body exercise in the upright position to avoid hypotension.
Calbet, J A L; Jensen-Urstad, M; van Hall, G; Holmberg, H -C; Rosdahl, H; Saltin, B
Articulating Support for Horizontal Resistive Exercise
NASA Technical Reports Server (NTRS)
A versatile mechanical device provides support for a user engaged in any of a variety of resistive exercises in a substantially horizontal orientation. The unique features and versatility of the device promise to be useful in bedrest studies, rehabilitation, and specialized strength training. The device affords a capability for selectively loading and unloading of portions of the user s body through its support mechanisms, so that specific parts of the body can be trained with little or no effect on other parts that may be disabled or in the process of recovery from injury. Thus, the device is ideal for rehabilitation exercise programs prescribed by physicians and physical therapists. The capability for selective loading and support also offers potential benefits to strength and conditioning trainers and athletes who wish to selectively strengthen selected parts. The principal innovative aspect of the device is that it supports the subject s weight while enabling the subject, lying substantially horizontally, to perform an exercise that closely approximates a full standing squat. The device includes mechanisms that support the subject in such a way that the hips are free to translate both horizontally and vertically and are free to rotate about the line connecting the hips. At the same time, the shoulders are free to translate horizontally while the upper back is free to rotate about the line connecting the shoulders. Among the mechanisms for hip motion and support is a counterbalance that offsets the weight of the subject as the subject s pelvis translates horizontally and vertically and rotates the pelvis about the line connecting the hips. The counterbalance is connected to a pelvic support system that allows these pelvic movements. The subject is also supported at the shoulder by a mechanism that can tilt to provide continuous support of the upper back while allowing the rotation required for arching the back as the pelvis is displaced. The shoulder support also affords a capability for horizontal motion, and acts as the point of attachment of a load that is provided for squat and heel-raise exercises. The device is compatible with any resistive-exercise machine that provides bilateral loading via a moving cable or other mechanical linkage. The hip-translation and shoulder-translation and -rotation degrees of freedom of the supports can be locked individually or in combination in order to support the subject as necessary for exercises other than the standing squat. If necessary, for such exercises, the load can be applied directly to the subject by use of various attachments. In addition to the aforementioned heel raise, such exercises include the upright row, leg press, curls, extension of the triceps, front raise, lateral raise, and rear raise.
Gundo, Daniel; Schaffner, Grant; Bentley, Jason; Loehr, James A.
Exercise therapy for fibromyalgia.
Fibromyalgia syndrome, a chronic condition typically characterized by widespread pain, nonrestorative sleep, fatigue, cognitive dysfunction, and other somatic symptoms, negatively impacts physical and emotional function and reduces quality of life. Exercise is commonly recommended in the management of people with fibromyalgia, and interest in examining exercise benefits for those with the syndrome has grown substantially over the past 25 years. Research supports aerobic and strength training to improve physical fitness and function, reduce fibromyalgia symptoms, and improve quality of life. However, other forms of exercise (e.g., tai chi, yoga, Nordic walking, vibration techniques) and lifestyle physical activity also have been investigated to determine their effects. This paper highlights findings from recent randomized controlled trials and reviews of exercise for people with fibromyalgia, and includes information regarding factors that influence response and adherence to exercise to assist clinicians with exercise and physical activity prescription decision-making to optimize health and well-being. PMID:21725900
Busch, Angela J; Webber, Sandra C; Brachaniec, Mary; Bidonde, Julia; Bello-Haas, Vanina Dal; Danyliw, Adrienne D; Overend, Tom J; Richards, Rachel S; Sawant, Anuradha; Schachter, Candice L
Strengthening mechanisms of current dental porcelains.
Dental porcelains have a high glass content, which provides the translucency necessary for esthetic restorations. Because glasses are brittle, they fail under tension or bending by the propagation of preexisting flaws (e.g., scratches, porosities). Several approaches that are based on impeding the propagation of flaws have been used to strengthen dental porcelains, including bonding to metals, adding microcrystalline phases, and surface treatments (i.e., polishing, ion exchange, hydration). Through these methods, porcelain systems are used routinely for all-ceramic anterior restorations; however, porcelain-fused-to-metal restorations remain the most reliable for posterior applications. PMID:11199653
O'Brien, W J
Computer simulation of concentrated solid solution strengthening
NASA Technical Reports Server (NTRS)
The interaction forces between a straight edge dislocation moving through a three-dimensional block containing a random array of solute atoms were determined. The yield stress at 0 K was obtained by determining the average maximum solute-dislocation interaction force that is encountered by edge dislocation, and an expression relating the yield stress to the length of the dislocation and the solute concentration is provided. The magnitude of the solid solution strengthening due to solute atoms can be determined directly from the numerical results, provided the dislocation line length that moves as a unit is specified.
Kuo, C. T. K.; Arsenault, R. J.
Candidate Exercise Technologies and Prescriptions
NASA Technical Reports Server (NTRS)
This slide presentation reviews potential exercise technologies to counter the effects of space flight. It includes a overview of the exercise countermeasures project, a review of some of the candidate exercise technologies being considered and a few of the analog exercise hardware devices, and a review of new studies that are designed to optimize the current and future exercise protocols.
Loerch, Linda H.
Exercise for the Overweight Patient.
ERIC Educational Resources Information Center
Exercise can help patients maintain lean body mass during weight loss. Although exercise is not extremely useful in shedding excess pounds, it helps keep off weight lost through calorie restriction. This article discusses the specifics of exercise prescription, types of exercise, motivation to exercise, and special problems such as diabetes. (SM)
Work, Janis A.
[Space flight/bedrest immobilization and Bone. Exercise training for osteoporosis].
Osteoporosis is one of the main diseases of the locomotive syndrome. Exercise therapy is a basic approach for prevention and treatment of osteoporosis, and is effective for increasing bone mineral density and preventing fall. Single foothold standing with the eyes open for one minute and squatting by "rokotore" are recommended as exercises that are easy for elderly people. Strengthening of back muscles is also useful for prevention of round back due to osteoporosis. We suggest that improved outcomes may be achieved by combining some of these exercises. PMID:23187084
Sakuma, Mayumi; Endo, Naoto
Peripheral and central fatigue after muscle-damaging exercise is muscle length dependent and inversely related.
Healthy untrained men performed 10 series of 12 knee eccentric extension repetitions (EE) at 160 degrees /s. The maximal voluntary isometric contraction force of the quadriceps muscle, the maximal rate of electrically induced torque development (RTD) and relaxation (RTR), isokinetic concentric torque at 30 degrees /s, the electrostimulation-induced torque at 20 and 100Hz frequencies were established before and after EE at shorter and longer muscle lengths. Besides, voluntary activation (VA) index and central activation ratio (CAR) were tested. There was more peripheral fatigue than central after EE. We established more central fatigue as well as low frequency fatigue at a shorter muscle length compared to the longer muscle length. Relative RTD as well as relative RTR, improved after EE and did not depend on the muscle length. Finally, central fatigue is inversely significantly related with the eccentric torque reduction during eccentric exercise and with the changes in muscle torque induced by low frequency stimulation. PMID:20347333
Skurvydas, Albertas; Brazaitis, Marius; Kamandulis, Sigitas; Sipaviciene, Saule
Advanced Resistive Exercise Device
NASA Technical Reports Server (NTRS)
The advanced resistive exercise device (ARED), now at the prototype stage of development, is a versatile machine that can be used to perform different customized exercises for which, heretofore, it has been necessary to use different machines. Conceived as a means of helping astronauts and others to maintain muscle and bone strength and endurance in low-gravity environments, the ARED could also prove advantageous in terrestrial settings (e.g., health clubs and military training facilities) in which many users are exercising simultaneously and there is heavy demand for use of exercise machines.
Raboin, Jasen; Niebuhr, Jason; Cruz, Santana; Lamoreaux, chris
Exercise, Inflammation and Aging
Aging results in chronic low grade inflammation that is associated with increased risk for disease, poor physical functioning and mortality. Strategies that reduce age-related inflammation may improve the quality of life in older adults. Regular exercise is recommended for older people for a variety of reasons including increasing muscle mass and reducing risk for chronic diseases of the heart and metabolic systems. Only recently has exercise been examined in the context of inflammation. This review will highlight key randomized clinical trial evidence regarding the influence of exercise training on inflammatory biomarkers in the elderly. Potential mechanisms will be presented that might explain why exercise may exert an anti-inflammatory effect.
Woods, Jeffrey A.; Wilund, Kenneth R.; Martin, Stephen A.; Kistler, Brandon M.
... at a prescribed pace. Balance-strengthening and general fitness The success of any balance-retraining program depends in part on good general fitness. Progressive fitness programs increase energy and reduce stress. ...
Strengthening the Canadian alcohol advertising regulatory system.
Research evidence points to harmful effects from alcohol advertising among children and youth. In particular, exposure to alcohol advertising has been associated with adolescents drinking both earlier and heavier. Although current federal and provincial guidelines have addressed advertising practices to prevent underage drinking, practice has not been supported by existing policy. While protective measures such as social marketing campaigns have the potential for counteracting the effects from alcohol advertising, the effectiveness of such measures can be easily drowned out with increasing advertising activities from the alcohol industry, especially without effective regulation. Research reviewed by the European Focus on Alcohol Safe Environment (FASE) Project has identified a set of key elements that are necessary to make alcohol advertising policy measures effective at protecting children and youth from the harmful effects of alcohol marketing. Using these key elements as an evaluation framework, there are critical components in the Canadian alcohol advertising regulatory system that clearly require strengthening. To protect impressionable children and youth against the harmful effects of alcohol advertising, 13 recommendations to strengthen current alcohol advertising regulations in Canada are provided for Canadian policy-makers, advertising standard agencies, and public health groups. PMID:23618638
Heung, Carly M; Rempel, Benjamin; Krank, Marvin
Brazing of dispersion-strengthened aluminum
In recent years, the use of rapid solidification powder metallurgy has made it possible to develop a new family of aluminum alloys exhibiting unique properties. One of these materials, dispersion-strengthened (DS) aluminum, is currently being produced for commercial purposes at Raufoss Technology AS, Norway. Dispersion-strengthened aluminum derives its high strength from nanoscale AlN particles embedded in an aluminum matrix. DS Al is expected to be well suited as construction material for high-temperature applications where weight reductions are of particular concern. The present investigation has focused on the wetting behavior of DS aluminum under conditions applicable to brazing. The results from the Sessile drop experiments show that a eutectic Al-Si brazing alloy will completely wet the base metal both under high-vacuum conditions and in controlled argon atmospheres, provided that the partial pressure of oxygen is sufficiently low. The main problem appears to be the stability of the matrix grain structure. In general, the process of grain erosion and coarsening can be controlled by restricting the supply of the brazing alloy so that only a small metal volume is exposed to erosion. In addition, there is a great potential for reducing the thermodynamic driving force of the erosion reaction by proper adjustments of the brazing alloy composition and/or the brazing temperature. Sill, grain boundary liquidation may be a problem which, in turn, may require additions of surface active elements to the filler metal to control the wetting behavior.
Bjoerneklett, B.; Grong, O. [Norwegian Inst. of Technology, Trondheim (Norway). Dept. of Metallurgy; Anisdahl, L. [SINTEF Materials Technology, Oslo (Norway); Hellum, E.; Sande, V. [Raufoss Technology (Norway)
The Effects of Rest Interval on Quadriceps Torque During an Isokinetic Testing Protocol in Elderly
The purpose of this study was to compare three different intervals for a between sets rest period during a common isokinetic knee extension strength-testing protocol of twenty older Brazilian men (66.30 ± 3.92 yrs). The volunteers underwent unilateral knee extension (Biodex System 3) testing to determine their individual isokinetic peak torque at 60, 90, and 120°s-1. The contraction speeds and the rest periods between sets (30, 60 and 90 s) were randomly performed in three different days with a minimum rest period of 48 hours. Significant differences between and within sets were analyzed using a One Way Analysis of Variance (ANOVA) with repeated measures. Although, at angular velocity of 60°s-1 produced a higher peak torque, there were no significant differences in peak torque among any of the rest periods. Likewise, there were no significant differences between mean peak torque among all resting periods (30, 60 and 90s) at angular velocities of 90 and 120°s-1. The results showed that during a common isokinetic strength testing protocol a between set rest period of at least 30 s is sufficient for recovery before the next test set in older men. Key Points The assessment of muscular strength using isokinetics muscle contraction in older individuals is very important for exercise prescription and rehabilitation. The minimal time between intraset isokinetics knee extension assessment in older individuals need to be more investigated, however 30 s appear to besufficient time for strength recover.
Bottaro, Martim; Russo, Andre Faria; de Oliveira, Ricardo Jaco
The influence of ice slushy on voluntary contraction force following exercise-induced hyperthermia.
This study aimed to investigate the effect of exercise-induced hyperthermia on central fatigue and force decline in exercised and nonexercised muscles and whether ingestion of ice slushy (ICE) ameliorates fatigue. Eight participants (5 males, 3 females) completed 45 s maximal voluntary isometric contractions (MVIC) with elbow flexors and knee extensors at baseline and following an exercise-induced rectal temperature (Trec) of 39.3 ± 0.2 °C. Percutaneous electrical muscle stimulation was superimposed at 15, 30 and 44 s during MVICs to assess muscle activation. To increase Trec to 39.3 °C, participants cycled at 60% maximum power output for 42 ± 11 min in 40 °C and 50% relative humidity. Immediately prior to each MVIC, participants consumed 50 g of ICE (-1 °C) or thermoneutral drink (38 °C, CON) made from 7.4% carbohydrate beverage. Participants consumed water (19 °C) during exercise to prevent hypohydration. Voluntary muscle force production and activation in both muscle groups were unchanged at Trec 39.3 °C with ICE (knee extensors: 209 ± 152 N) versus CON (knee extensors: 255 ± 157 N, p = 0.19). At Trec 39.3 °C, quadriceps mean force (232 ± 151 N) decreased versus baseline (302 ± 180 N, p < 0.001) and mean voluntary activation was also decreased (by 15% ± 11%, p < 0.001). Elbow flexor mean force decreased from 179 ± 67 N to 148 ± 65 N when Trec was increased to 39.3 °C (p < 0.001) but mean voluntary activation was not reduced at 39.3 °C (5% ± 25%, p = 0.79). After exercise-induced hyperthermia, ICE had no effect on voluntary activation or force production; however, both were reduced from baseline in the exercised muscle group. Peripheral fatigue was greater than the central component and limited the ability of an intervention designed to alter central fatigue. PMID:24971678
Burdon, Catriona A; Easthope, Christopher S; Johnson, Nathan A; Chapman, Phillip G; O'Connor, Helen
Dissociated time course recovery between rate of force development and peak torque after eccentric exercise.
This study investigated the association between isokinetic peak torque (PT) of quadriceps and the corresponding peak rate of force development (peak RFD) during the recovery of eccentric exercise. Twelve untrained men (aged 21·7 ± 2·3 year) performed 100 maximal eccentric contractions for knee extensors (10 sets of 10 repetitions with a 2-min rest between each set) on isokinetic dynamometer. PT and peak RFD accessed by maximal isokinetic knee concentric contractions at 60° s(-1) were obtained before (baseline) and at 24 and 48 h after eccentric exercise. Indirect markers of muscle damage included delayed onset of muscle soreness (DOMS) and plasma creatine kinase (CK) activity. The eccentric exercise resulted in elevated DOMS and CK compared with baseline values. At 24 h, PT (-15·3%, P = 0·002) and peak RFD (-13·1%, P = 0·03) decreased significantly. At 48 h, PT (-7·9%, P = 0·002) was still decreased but peak RFD have returned to baseline values. Positive correlation was found between PT and peak RFD at baseline (r = 0·62, P = 0·02), 24 h (r = 0·99, P = 0·0001) and 48 h (r = 0·68, P = 0·01) after eccentric exercise. The magnitude of changes (%) in PT and peak RFD from baseline to 24 h (r = 0·68, P = 0·01) and from 24 to 48 h (r = 0·68, P = 0·01) were significantly correlated. It can be concluded that the muscle damage induced by the eccentric exercise affects differently the time course of PT and peak RFD recovery during isokinetic concentric contraction at 60° s(-1). During the recovery from exercise-induced muscle damage, PT and peak RFD are determined but not fully defined by shared putative physiological mechanisms. PMID:22487151
Molina, Renato; Denadai, Benedito S
Partial neuromuscular blockade and cardiovascular responses to static exercise in man.
In human subjects sustained static contractions of the quadriceps femoris in one leg were performed with the same absolute and the same relative intensity before and after partial neuromuscular blockade with either decamethonium or tubocurarine which reduced strength to about 50% of the control value. During the contractions performed with the same absolute force, the magnitude of the cardiovascular responses (heart rate and blood pressure) was greater during neuromuscular blockade than during control contractions. During the contractions involving the same relative force the magnitude of the cardiovascular responses was almost the same with and without neuromuscular blockade. These findings were independent of the drug used. The metabolic part of the exercise pressor reflex was assessed by the application of an arterial cuff 1/2 min before cessation of exercise and for the following 3 min of rest. Although heart rate and blood pressure decreased after cessation of exercise, application of the tourniquet resulted in higher post-exercise values and this effect was seen both with and without neuromuscular blockade. Muscle biopsies from the subjects' m. vastus lateralis were analysed for fast- and slow-twitch fibre composition showing 27-66% slow-twitch fibres. No correlation was found between cardiovascular responses to static exercise, with or without neuromuscular blockade, and fibre type predominance. The results suggest that the involvement of fast- or slow-twitch muscle fibres does not play a dominant role in the cardiovascular responses to static exercise in man. Both central command and reflex neural mechanisms are of importance, and it appears that these two control mechanisms are redundant and that neural occlusion may be operative. However, when partial neuromuscular blockade induces a disproportion between an increase in central command and a constant or decreasing muscle tension and metabolism, the larger signal arising from central command determines the magnitude of the cardiovascular responses.
Leonard, B; Mitchell, J H; Mizuno, M; Rube, N; Saltin, B; Secher, N H
Motor unit recruitment when neuromuscular electrical stimulation is applied over a nerve trunk compared with a muscle belly: quadriceps femoris.
Neuromuscular electrical stimulation (NMES) can be delivered over a nerve trunk or muscle belly and both can generate contractions through peripheral and central pathways. Generating contractions through peripheral pathways is associated with a nonphysiological motor unit recruitment order, which may limit the efficacy of NMES rehabilitation. Presently, we compared recruitment through peripheral and central pathways for contractions of the knee extensors evoked by NMES applied over the femoral nerve vs. the quadriceps muscle. NMES was delivered to evoke 10 and 20% of maximum voluntary isometric contraction torque 2-3 s into the NMES (time(1)) in two patterns: 1) constant frequency (15 Hz for 8 s); and 2) step frequency (15-100-15 Hz and 25-100-25 Hz for 3-2-3 s, respectively). Torque and electromyographic activity recorded from vastus lateralis and medialis were quantified at the beginning (time(1)) and end (time(2); 6-7 s into the NMES) of each pattern. M-waves (peripheral pathway), H-reflexes, and asynchronous activity (central pathways) during NMES were quantified. Torque did not differ regardless of NMES location, pattern, or time. For both muscles, M-waves were ?7-10 times smaller and H-reflexes ?8-9 times larger during NMES over the nerve compared with over the muscle. However, unlike muscles studied previously, neither torque nor activity through central pathways were augmented following 100 Hz NMES, nor was any asynchronous activity evoked during NMES at either location. The coefficient of variation was also quantified at time(2) to determine the consistency of each dependent measure between three consecutive contractions. Torque, M-waves, and H-reflexes were most variable during NMES over the nerve. In summary, NMES over the nerve produced contractions with the greatest recruitment through central pathways; however, considering some of the limitations of NMES over the femoral nerve, it may be considered a good complement to, as opposed to a replacement for, NMES over the quadriceps muscle for maintaining muscle quality and reducing contraction fatigue during NMES rehabilitation. PMID:22556395
Bergquist, A J; Wiest, M J; Collins, D F
Anterior cruciate ligament (ACL) reconstruction with quadriceps tendon autograft and press-fit fixation using an anteromedial portal technique
Background This article describes an arthroscopic anterior cruciate ligament (ACL) reconstruction technique with a quadriceps tendon autograft using an anteromedial portal technique. Methods A 5?cm quadriceps tendon graft is harvested with an adjacent 2?cm bone block. The femoral tunnel is created through a low anteromedial portal in its anatomical position. The tibial tunnel is created with a hollow burr, thus acquiring a free cylindrical bone block. The graft is then passed through the tibial tunnel and the bone block, customized at its tip, is tapped into the femoral tunnel through the anteromedial portal to provide press-fit fixation. The graft is tensioned distally and sutures are tied over a bone bridge at the distal end of the tibial tunnel. From the cylindrical bone block harvested from the tibia the proximal end is customized and gently tapped next to the graft tissue into the tibial tunnel to assure press fitting of the graft in the tibial tunnel. The distal part of the tibial tunnel is filled up with the remaining bone. All patients were observed in a prospective fashion with subjective and objective evaluation after 6?weeks, 6 and 12?months. Results Thirty patients have been evaluated at a 12?months follow-up. The technique achieved in 96.7% normal or nearly normal results for the objective IKDC. The mean subjective IKDC score was 86.1 ± 15.8. In 96.7% the Tegner score was the same as before injury or decreased one category. A negative or 1+ Lachman test was achieved in all cases. Pivot-shift test was negative or (+) glide in 86.7%. The mean side-to-side difference elevated by instrumental laxity measurement was 1.6 ± 1.1?mm. Full ROM has been achieved in 92.3%. The mean single one-leg-hop index was 91.9 ± 8.0 at the follow-up. Conclusions Potential advantages include minimum bone loss specifically on the femoral side and graft fixation without implants.
Stay active and exercise - arthritis
... your overall health and sense of well-being. Exercise keeps your muscles strong and increases your range ... Water exercises may be the best exercise for your arthritis. Swimming laps, water aerobics, or even just walking in ...
MedlinePLUS Videos and Cool Tools
... Last reviewed: 09/02/2013 2 • Exercise burns energy, which reduces weight and fat. • Exercise helps people ... helps prevent weight gain. • Exercise gives us more energy by increasing our endurance. Endurance is how long ...
Candidate Exercise Technologies and Prescriptions.
National Technical Information Service (NTIS)
This slide presentation reviews potential exercise technologies to counter the effects of space flight. It includes a overview of the exercise countermeasures project, a review of some of the candidate exercise technologies being considered and a few of t...
L. H. Loerch
Lab Exercises for Kinesiology.
ERIC Educational Resources Information Center
This monograph presents descriptions of various exercises and athletic activities with a kinesiological and biomechanical analysis of the muscle systems involved. It is intended as examples of laboratory activities and projects in a college course in kinesiology. A listing of the required laboratory exercises precedes the examples. Specific…
Mills, Brett D.; And Others
Heat Loss Calculation Exercise
NSDL National Science Digital Library
This class exercise from Kirk Garrison is intended for construction students learning about home insulation and heating. The class will learn to calculate heat loss in a home by using an online home heat loss calculator. This exercise document includes student worksheets. This document may be downloaded in PDF file format.
Garrison, Kirk
NSDL National Science Digital Library
Students will investigate the process of respiration by investigating the question: How does exercise affect the amount of carbon dioxide exhaled? They will use bromothymol blue to time how fast it changes color before and after exercising. They will be guided into an understanding of the process of cellular respiration.
Admin, Admin
This paper first reviews muscle growth and then considers the influence of exercise in growth. Knowledge about how muscle cells grow and some factors that may influence the growth pattern are discussed first since these effects must be considered before the influence of exercise becomes clear. Growth of muscle can occur in three ways: (1) by an increase in muscle
A. M. Pearson
ERIC Educational Resources Information Center
Describes an exercise that helps students in an interpersonal communication class to identify and understand their preferred style of bargaining while also coming to understand the ideals and practices behind other styles of bargaining. Suggests the exercise enhances their bargaining skills. (SG)
Ashwell, Douglas
Voluntary physical activity and exercise training can favorably influence brain plasticity by facilitating neurogenerative, neuroadaptive, and neuroprotective processes. At least some of the processes are mediated by neurotrophic factors. Motor skill training and regular exercise enhance executive functions of cognition and some types of learning, including motor learning in the spinal cord. These adaptations in the central nervous system have
Rod K. Dishman; Hans-Rudolf Berthoud; Frank W. Booth; Carl W. Cotman; V. Reggie Edgerton; Monika R. Fleshner; Simon C. Gandevia; Fernando Gomez-Pinilla; Benjamin N. Greenwood; Charles H. Hillman; Arthur F. Kramer; Barry E. Levin; Timothy H. Moran; Amelia A. Russo-Neustadt; John D. Salamone; Jacqueline D. Van Hoomissen; Charles E. Wade; David A. York; Michael J. Zigmond
Appropriate nutrition is an essential prerequisite for effective improvement of athletic performance, conditioning, recovery from fatigue after exercise, and avoidance of injury. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. In addition, several natural food components have been found to show physiological effects, and some of them are considered to be useful for promoting exercise performance or for prevention of injury. However, these foods should only be used when there is clear scientific evidence and with understanding of the physiological changes caused by exercise. This article describes various "functional foods" that have been reported to be effective for improving exercise performance or health promotion, along with the relevant physiological changes that occur during exercise.
Aoi, Wataru; Naito, Yuji; Yoshikawa, Toshikazu
Angle- and velocity-specific alterations in torque and semg activity of the quadriceps and hamstrings during isokinetic extension-flexion movements.
The purpose of this study was to investigate the effect of movement velocity (100 degrees, 200 degrees , 300 degrees s(-1), and 400 degrees s(-1)) and joint position (0 degrees - 15 degrees [L0], 25 degrees - 40 degees [L25], 55 degrees - 70 degrees [L55], and 75 degrees - 90 degrees [L75]) on peak torque (PT) parameters and surface electromyography (SEMG) of the knee-joint muscles during reciprocal isokinetic extension and flexion movements. Thirteen subjects (age = 22.7 +/- 2.1 years, mean height = 161.1 +/- 6.6 cm, mean weight = 63.5 +/- 5.8 kg) participated in the study. Bipolar surface electrodes were placed over the vastus medialis, vastus lateralis, biceps femoris, and medial hamstrings for determination of the root mean square (SEMGrms) and median frequency (SEMGmf) of the SEMG. Peak torque, angle of peak torque (PTang), percentage of peak torque (PTper), SEMGrms, and SEMGmf were analyzed using separate repeated measures analysis of variance (ANOVA). The following main results, significant at p < or = 0.05 or better, were found: The PTang was influenced by movement velocity (in extension there was a decrease in PTang moving from 300 degrees x s(-1) to 400 degrees x s(-1) and inflexion there was an increase in PTang moving from 300 degrees x s(-1) to 400 degrees x s(-1)). Secondly, a greater percentage of peak torque (PTper) was maintained during knee flexion than knee extension. And thirdly, both the quadriceps and hamstrings exhibited changing amplitudes and spectral frequencies based on joint position and movement velocity. There was a trend of decreasing SEMGrms for the quadriceps as the knee moved into extension, and a lower SEMGmf during early (L75) and end stages of knee extension (L0). For the hamstrings, SEMGrms was lowest at the more shortened position (L75) and highest near the mid-position (L25); the lowest SEMGmf occurred at the more lengthened position (L0) and the highest occurred at the more shortened position (L75). Finally, velocity influenced hamstrings and quadriceps muscle amplitude such that SEMGrms was highest at the slower velocities and lowest at the higher velocities. Velocity had no impact on quadriceps spectral properties (p > 0.05), but had a cyclic effect on hamstrings spectral properties. Changes in amplitude and frequency spectrum in tested muscles could be explained, in part, by neural drive to these muscles. Data support the hypothesis of lower activation levels of the quadriceps muscle in the extended position espoused by several authors as a way to protect the knee-joint in the knee-extended position. PMID:16795998
Croce, R V; Miller, J P
Manual Physical Therapy, Cervical Traction, and Strengthening Exercises in Patients With Cervical Radiculopathy: A Case Series
Study Design: A case series of consecutive patients with cervical radiculopathy. Background: A multitude of physical therapy interventions have been proposed to be effective in the management of cervical radiculopathy. However, outcome studies using consistent treatment approaches on a well-defined sample of patients are lacking. The purpose of this case series is to describe the outcomes of a consecutive series
Joshua A. Cleland; Julie M. Whitman; Julie M. Fritz; Jessica A. Palmer
Maximal peak torque as a predictor of angle-specific torques of hamstring and quadriceps muscles in man.
This study assessed the relationship between the isokinetic peak torque (PT) (speed of movement 1.05 and 3.14 rads-1) and the angle-specific torques (ASTs) at 0.26 and 1.31 rad of knee flexion in multiple contractions of the quadriceps and hamstrings in 70 individuals with a chronic anterior cruciate ligament (ACL) insufficiency and 78 individuals with a chronic medial collateral ligament (MCL) insufficiency in one knee. At every test speed, the Pearson product moment correlation coefficients (r) between the PT and ASTs were highly significant (P less than 0.001) in the uninjured knees (r = 0.61-0.93) as well as in the knees with ACL (r = 0.61-0.87) and MCL (r = 0.74-0.91) insufficiency. In addition, in both groups the majority of the correlation coefficients exceeded 0.80, which is generally regarded as the threshold for the relationship to be considered clinically significant. Furthermore, using regression analysis, both extremities showed completely non-systematic distribution of the residuals. It is concluded that in healthy knees or knees with ACL or MCL insufficiency, the predictability of ASTs from PT was good, and, therefore, that AST analyses may offer little additional information about thigh muscle function to that obtained from a simpler and more commonly used measurement, the PT analysis. PMID:1748100
Kannus, P; Järvinen, M; Lehto, M
Acute effects of static and dynamic stretching on hamstring eccentric isokinetic strength and unilateral hamstring to quadriceps strength ratios.
The main purposes of this study were to investigate the acute effects of static and dynamic lower limb stretching routines: (a) on peak torque, total external work and joint angle at peak torque of the hamstrings during maximal eccentric isokinetic leg flexion; (b) on unilateral hamstring to quadriceps (H/Q) strength ratios; as well as (c) to determine whether static and dynamic routines elicit similar responses. A total of 49 active adults completed the following intervention protocols in a randomised order on separate days: (a) non-stretching (control condition), (b) static stretching, and (c) dynamic stretching. After the stretching or control intervention, eccentric isokinetic peak torque, the angle of peak torque and total external work were assessed with participants prone at 1.04 and 3.14 rad · s(-1). Unilateral strength ratios of the knee were also recorded. Measures were compared via a fully-within-groups factorial analysis of variance (ANOVA). There were no main effects for eccentric isokinetic peak torque, angle of peak torque, total external work and unilateral H/Q strength ratios. The results suggest that dynamic and static stretching has no influence on eccentric strength profile and unilateral H/Q strength ratios and hence both forms of stretching do not reduce these two primary risk factors for muscle injury. PMID:23230900
Ayala, Francisco; De Ste Croix, Mark; Sainz De Baranda, Pilar; Santonja, Fernando
The highest antagonistic coactivation of the vastus intermedius muscle among quadriceps femoris muscles during isometric knee flexion.
Although the possibility that the vastus intermedius (VI) muscle contributes to flexion of the knee joint has been suggested previously, the detail of its functional role in knee flexion is not well understood. The purpose of this study was to examine the antagonist coactivation of VI during isometric knee flexion. Thirteen men performed 25-100% of maximal voluntary contraction (MVC) at 90°, 120°, and 150° knee joint angles. Surface electromyography (EMG) of the four individual muscles in the quadriceps femoris (QF) was recorded and normalized by the EMG signals during isometric knee extension at MVC. Cross-talk on VI EMG signal was assessed based on the median frequency response to selective cooling of hamstring muscles. Normalized EMG of the VI was significantly higher than that of the other synergistic QF muscles at each knee joint angle (all P<0.05) with minimum cross-talk from the hamstrings to VI. There were significant correlations between the EMG signal of the hamstrings and VI (r=0.55-0.85, P<0.001). These results suggest that VI acts as a primary antagonistic muscle of QF during knee flexion, and that VI is presumably a main contributor to knee joint stabilization. PMID:23489717
Saito, Akira; Watanabe, Kohei; Akima, Hiroshi
Neuro-sliding mode control with modular models for control of knee-joint angle using quadriceps electrical stimulation.
In this paper, we propose a control methodology which is based on synergistic combination of a single-neuron controller with sliding mode control (SMC) for control of knee-joint position in paraplegic subjects with quadriceps stimulation. The control law will be switched from the sliding mode control to neural control, when the state trajectory of system enters in some boundary layer around the sliding surface. The main drawback of the standard sliding modes is mostly related to the so-called chattering caused by the high-frequency control switching. The value of switching gain depends on the bounds of system uncertainties. The system with large uncertainties needs to use a higher switching gain. This will, however, result in the high-frequency control switching and chattering across the sliding surface. To avoid such a condition, it is necessary to decrease the system uncertainty. To decrease the uncertainty, an accurate model of the system is required. For this purpose, we present a modular approach to modeling the knee-joint dynamics. Extensive experiments on healthy and paraplegic subjects are provided to demonstrate the robustness, stability and tracking accuracy of the neuro-SMC. The experimental results show that the neuro-SMC provides excellent tracking control for different reference trajectories and could generate control signals to compensate the muscle fatigue. PMID:18002483
Ajoudani, Arash; Erfanian, Abbas
Anaerobic energy production and O2 deficit-debt relationship during exhaustive exercise in humans.
1. Eight subjects performed one-legged, dynamic, knee-extensor exercise, first at 10 W followed by 10 min rest, then at an intense, exhaustive exercise load (65 W) lasting 3.2 min. After 60 min recovery, exercise was performed for 8-10 min each at 20, 30, 40 and 50 W. Measurements of pulmonary oxygen uptake, heart rate, blood pressure, leg blood flow, and femoral arterial-venous differences of oxygen content and lactate were performed as well as determination of ATP, creatine phosphate (CP) inosine monophosphate (IMP) and lactate concentrations on biopsy material from the quadriceps muscle before and immediately after the intense exercise, and at 3, 10 and 60 min into recovery. 2. Individual linear relations (r = 0.95-1.00) between the power outputs for submaximal exercise and oxygen uptakes (leg and pulmonary) were used to estimate the energy demand during intense exercise. Pulmonary and leg oxygen deficits determined as the difference between energy demand and oxygen uptake were 0.46 and 0.48 l (kg active muscle)-1, respectively. Limb and pulmonary oxygen debts (oxygen uptake during 60 min of recovery - pre-exercise oxygen uptake) were 0.55 and 1.65 l (kg active muscle)-1, respectively. 3. During the intense exercise, muscle [ATP] decreased by 30% and [CP] by 60% from resting concentrations of 6.2 and 22.4 mmol (kg wet wt)-1, respectively, and [IMP] increased to 1.1 mmol (kg wet wt)-1. Muscle [lactate] increased from 2 to 28.1 mmol (kg wet wt)-1, and the concomitant net lactate release was 14.8 mmol (kg wet wt)-1 or about 1/3 of the total net lactate production. During recovery 70% of the accumulated lactate was released to the blood, and the nucleotides and CP returned to about 40 and 85% of pre-exercise values at 3 and 10 min of recovery, respectively. 4. Total reduction in ATP and CP (and elevation of IMP) during the intense exercise amounted to 16.4 mmol ATP (kg wet wt)-1, which together with the lactate production accounted for 83.1 mmol ATP (kg wet wt)-1. In addition 6-8 mmol ATP (kg wet wt)-1 are made available related to accumulation of glycolytic intermediates including pyruvate (and alanine). Estimated leg oxygen deficit corresponded to an ATP production of 94.7 mmol ATP kg-1; this value included 3.1 mmol kg-1 related to unloading of HbO2 and MbO2.(ABSTRACT TRUNCATED AT 400 WORDS)
Bangsbo, J; Gollnick, P D; Graham, T E; Juel, C; Kiens, B; Mizuno, M; Saltin, B
Plant volatile analogues strengthen attractiveness to insect.
Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of ?-ionone and benzaldehyde. The stabilities of ?-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than ?-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than ?-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety. PMID:24911460
Sun, Yufeng; Yu, Hao; Zhou, Jing-Jiang; Pickett, John A; Wu, Kongming
Plant Volatile Analogues Strengthen Attractiveness to Insect
Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of ?-ionone and benzaldehyde. The stabilities of ?-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than ?-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than ?-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety.
Sun, Yufeng; Yu, Hao; Zhou, Jing-Jiang; Pickett, John A.; Wu, Kongming
Exercise training after lung transplantation improves participation in daily activity: a randomized controlled trial.
The effects of exercise training after lung transplantation have not been studied in a randomized controlled trial so far. We investigated whether 3 months of supervised training, initiated immediately after hospital discharge, improve functional recovery and cardiovascular morbidity of patients up to 1 year after lung transplantation. Patients older than 40 years, who experienced an uncomplicated postoperative period, were eligible for this single blind, parallel group study. Sealed envelopes were used to randomly allocate patients to 3 months of exercise training (n = 21) or a control intervention (n = 19). Minutes of daily walking time (primary outcome), physical fitness, quality of life and cardiovascular morbidity were compared between groups adjusting for baseline assessments in a mixed models analysis. After 1 year daily walking time in the treated patients (n = 18) was 85 ± 27 min and in the control group (n = 16) 54 ± 30 min (adjusted difference 26 min [95%CI 8-45 min, p = 0.006]). Quadriceps force (p = 0.001), 6-minute walking distance (p = 0.002) and self-reported physical functioning (p = 0.039) were significantly higher in the intervention group. Average 24 h ambulatory blood pressures were significantly lower in the treated patients (p ? 0.01). Based on these results patients should be strongly encouraged to participate in an exercise training intervention after lung transplantation. PMID:22390625
Langer, D; Burtin, C; Schepers, L; Ivanova, A; Verleden, G; Decramer, M; Troosters, T; Gosselink, R
Evaluating the performance of skewed prestressed concrete bridge after strengthening
NASA Astrophysics Data System (ADS)
The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.
Naser, Ali Fadhil; Zonglin, Wang
"It's exercise or nothing": a qualitative analysis of exercise dependence
Objectives—To explore, using qualitative methods, the concept of exercise dependence. Semistructured interviews were undertaken with subjects screened for exercise dependence and eating disorders. Methods—Female exercisers, four in each case, were allocated a priori to four groups: primary exercise dependent; secondary exercise dependent, where there was a coincidence of exercise dependence and an eating disorder; eating disordered; control, where there was no evidence of either exercise dependence or eating disorder. They were asked about their exercise and eating attitudes and behaviour, as well as about any history of psychological distress. Their narratives were taped, transcribed, and analysed from a social constructionist perspective using QSR NUD*IST. Results—Participants classified as primary exercise dependent either showed no evidence of exercise dependent attitudes and behaviour or, if they exhibited features of exercise dependence, displayed symptoms of an eating disorder. Only the latter reported a history of psychological distress, similar to that exhibited by women classified as secondary exercise dependent or eating disordered. For secondary exercise dependent and eating disordered women, as well as for controls, the narratives largely confirmed the a priori classification. Conclusions—Where exercise dependence was manifest, it was always in the context of an eating disorder, and it was this co-morbidity, in addition to eating disorders per se, that was associated with psychological distress. As such, these qualitative data support the concept of secondary, but not primary, exercise dependence. Key Words: exercise dependence; eating disorders; psychological distress; anorexia; bulimia
Bamber, D; Cockerill, I; Rodgers, S; Carroll, D
Effect of inspiratory muscle fatigue on exercise performance taking into account the fatigue-induced excess respiratory drive.
Inspiratory muscle fatigue (IMF) is suggested to compromise exercise performance, possibly via a respiratory muscle metaboreflex that impairs blood flow to working muscles, thereby accelerating the development of fatigue in these muscles. Cycling with IMF has also been associated with an excess ventilatory response, which could per se impair performance. Therefore, the present study investigated whether prior-induced IMF would affect subsequent cycling performance via increased quadriceps muscle fatigue alone and whether fatigue-induced excess ventilation would contribute to this impairment. Fourteen healthy male subjects (peak oxygen uptake, 57.0 ± 5.5 ml min(-1) kg(-1)) cycled to exhaustion at 85% of their maximal work output with prior-induced IMF (PF-EX) and without prior-induced IMF (C-EX). Subjects then cycled twice for the duration of PF-EX but without prior IMF, once with spontaneous breathing (C-ISO) and once with breathing coached to match PF-EX ventilation (MATCH-ISO). Inspiratory muscle (P(tw)) and quadriceps muscle contractility (Q(tw)) was assessed via magnetic nerve stimulation before and after exercise. The time to exhaustion in the PF-EX conditions was significantly reduced by 14% compared with C-EX. The reduction in P(tw) and Q(tw) was greater after PF-EX (P(tw), 17.3 ± 9.7%; Q(tw), 32.0 ± 10.8%) than after MATCH-ISO (P(tw), 10.8 ± 10.3%; Q(tw), 23.3 ± 15.2%; P < 0.05), which may explain the increased perception of exertion and earlier task failure with prior-induced IMF. The augmented ventilatory drive had no effect on reductions in P(tw) and Q(tw) after MATCH-ISO compared with C-ISO. Thus, prior-induced IMF reduces exercise performance, probably as a result of the increased quadriceps muscle fatigue and thus greater perception of exertion independent of the excess respiratory drive when cycling with fatigued inspiratory muscles. PMID:24014807
Wüthrich, Thomas U; Notter, Dominic A; Spengler, Christina M
Response of Biochemical Markers of Bone Metabolism to Exercise Intensity in Thoroughbred Horses
We studied the response of biochemical markers of bone metabolism to exercise intensity in horses. Four horses were walked on a mechanical walker for one week (pre-exercise). Then they performed low-speed exercise on a high-speed treadmill in the first week and medium-speed exercise in the second week and high-speed exercise in the third week of training. We measured two indices of bone resorption, serum hydroxyproline concentration and the urinary deoxypyridinoline/creatinine ratio, and serum osteocalcin (OC) concentration as an index of bone formation. Both indices of bone resorption gradually decreased during the experiment. Serum OC concentration did not change in the first week but was significantly lower in the second and the third weeks compared to in the pre-exercise period and in the first week. These results suggest that the low-speed exercise decreased bone resorption but did not affect bone formation, which possibly results in increasing bone mineral content and strengthening of bones. The high-speed exercise decreased bone formation and bone resorption, i.e., bone turnover was suppressed. The low-speed exercise may be preferable for increasing bone mineral content.
INOUE, Yoshinobu; MATSUI, Akira; ASAI, Yo; AOKI, Fumiki; YOSHIMOTO, Kenji; MATSUI, Tohru; YANO, Hideo
Effect of two randomised exercise programmes on bone mass of healthy postmenopausal women.
The effect of two structured exercise programmes on the bone mass of 48 healthy postmenopausal white women aged 50-62 was studied after one year. Volunteers were randomised to group 1 (control), group 2 (aerobic exercise), or group 3 (aerobic and strengthening exercises). Before and after the training programme each subject had evaluations of bone mass (determined by neutron activation analysis and expressed as calcium bone index) and maximum oxygen uptake attained on a multistage exercise treadmill test. After one year both exercise groups had higher levels of fitness and greater bone mass than controls. Mean values (2 SEM) for changes in the calcium bone index were -0.011 (0.037), 0.039 (0.035), and 0.066 (0.036) for groups 1, 2, and 3, respectively. Analysis of variance on the observed data and analysis of covariance adjusting changes to the initial mean value for the whole group showed significant differences between each exercise group and the controls but no difference between the exercise groups themselves. Both exercise groups showed a significant improvement in maximum oxygen uptake. This study suggests that exercise may modify bone loss in healthy postmenopausal women.
Chow, R; Harrison, J E; Notarius, C
NSDL National Science Digital Library
This exercise is designed to simulate how a basic geological investigation of a site takes place. A basic geological investigation includes familiarizing yourself with the unconsolidated sediments, rocks, structural geology, and groundwater present at your site. As part of this exercise you will have to properly identify a variety of rock types and sediments, create maps that represent data you collected at each location, and complete a basic report of your findings (optional). Once completed, this exercise should give students a basic understanding of how the various concepts used throughout the semester are applied in the real world in the form of a geological investigation.
Smith, Andrew
Nanoscale Cementite Precipitates and Comprehensive Strengthening Mechanism of Steel
NASA Astrophysics Data System (ADS)
This article summarizes the state of the art of the comprehensive strengthening mechanism of steel. By using chemical phase analysis, X-ray small-angle scattering (XSAS), room temperature organic (RTO) solution electrolysis and metal embedded sections micron-nano-meter characterization method, and high-resolution transmission electron microscopy (TEM) observation, the properties of nanoscale cementite precipitates in Ti microalloyed high-strength weathering steels produced by the thin slab continuous casting and rolling process were analyzed. Except nanoscale TiC, cementite precipitates with size less than 36 nm and high volume fraction were also found in Ti microalloyed high-strength weathering steels. The volume fraction of cementite with size less than 36 nm is 4.4 times as much as that of TiC of the same size. Cementite with high volume fraction has a stronger precipitation strengthening effect than that of nanoscale TiC, which cannot be ignored. The precipitation strengthening contributions of nanoscale precipitates of different types and sizes should be calculated, respectively, according to the mechanisms of shearing and dislocation bypass, and then be added with the contributions of solid solution strengthening and grain refinement strengthening. A formula for calculating the yield strength of low-carbon steel was proposed; the calculated yield strength considering the precipitation strengthening contributions of nanoscale precipitates and the comprehensive strengthening mechanism of steels matches the experimental results well. The calculated ? s = 630 to 676 MPa, while the examined ? s = 630 to 680 MPa. The reason that "ultrafine grain strengthening can not be directly added with dislocation strengthening or precipitation strengthening" and the influence of the phase transformation on steel strength were discussed. The applications for comprehensive strengthening theory were summarized, and several scientific questions for further study were pointed out.
Fu, Jie; Li, Guangqiang; Mao, Xinping; Fang, Keming
A guide to exercise prescription.
Exercise is a fundamental component of good health. The American College of Sports Medicine and "Exercise is Medicine" recommend treating exercise as a vital sign, and assessing and prescribing physical activity at every medical visit. Meeting the recommended goals of physical activity results in a significant reduction in all-cause mortality. Physicians can improve health by prescribing exercise. PMID:24209719
Crookham, Jason
Pediatric endurance and limb strengthening for children with cerebral palsy (PEDALS) - a randomized controlled trial protocol for a stationary cycling intervention
Background In the past, effortful exercises were considered inappropriate for children with spastic cerebral palsy (CP) due to concern that they would escalate abnormalities including spasticity and abnormal movement patterns. Current scientific evidence indicates that these concerns were unfounded and that therapeutic interventions focused on muscle strengthening can lead to improved functional ability. However, few studies have examined the potential benefits of cardiorespiratory fitness exercises in this patient population. Methods/design The rationale and design of a randomized controlled trial examining the effects of a stationary cycling intervention for children with CP are outlined here. Sixty children with spastic diplegic CP between the ages of 7 and 18 years and Gross Motor Function Classification System (GMFCS) levels of I, II, or III will be recruited for this study. Participants will be randomly assigned to either an intervention (cycling) or a control (no cycling) group. The cycling intervention will be divided into strengthening and cardiorespiratory endurance exercise phases. During the strengthening phase, the resistance to lower extremity cycling will be progressively increased using a uniquely designed limb-loaded mechanism. The cardiorespiratory endurance phase will focus on increasing the intensity and duration of cycling. Children will be encouraged to exercise within a target heart rate (HR) range (70 – 80% maximum HR). Thirty sessions will take place over a 10–12 week period. All children will be evaluated before (baseline) and after (follow-up) the intervention period. Primary outcome measures are: knee joint extensor and flexor moments, or torque; the Gross Motor Function Measure (GMFM); the 600 Yard Walk-Run test and the Thirty-Second Walk test (30 sec WT). Discussion This paper presents the rationale, design and protocol for Pediatric Endurance and Limb Strengthening (PEDALS); a Phase I randomized controlled trial evaluating the efficacy of a stationary cycling intervention for children with spastic diplegic cerebral palsy.
Fowler, Eileen G; Knutson, Loretta M; DeMuth, Sharon K; Sugi, Mia; Siebert, Kara; Simms, Victoria; Azen, Stanley P; Winstein, Carolee J
Time to encourage patients to take more exercise.
Regular physical activity of moderate intensity can bring about major health benefits as well as significant cost savings for the NHS. Evidence suggests that regular exercise can produce up to a 30% reduction in all cause mortality with a 35% lower risk of cardiovascular disease, coronary heart disease and stroke. There is evidence to show that 37% of CHD deaths can be attributed to physical inactivity compared with 19% and 13% for smoking and hypertension respectively. In addition, a 40% reduction in the risk of metabolic syndrome and type 2 diabetes mellitus has been reported with moderate physical activity. Current guidelines from the CMO, for adults aged 19-64 years, recommend: 150 minutes of moderate intensity aerobic exercise per week such as fast walking or cycling plus muscle strengthening activities on two or more days a week, or 75 minutes of vigorous intensity aerobic activity such as running or singles tennis plus the same muscle strengthening regimen, or an equivalent mix of the two. Only 40% of men and 28% of women in England are achieving the recommended levels of exercise/physical activity. One way GPs can increase their patients' physical activity levels could be via an individualised tailored care pathway aiming to motivate individuals to make long-term health changes. Evidence suggests that the risks associated with physical activity at a level to promote health are low and that health benefits outweigh the risks. The 5 As system (Ask, Assess, Advise, Assist and Arrange) which is sometimes used in smoking cessation can be adapted for physical activity. Ask about the patient's current levels of physical activity using the General Practice Physical Activity Questionnaire; Assess their fitness and capabilities; Advise about appropriate exercise and the risks involved; Assist in locating places to get involved, use 'Let's Get Moving' and exercise referral schemes available; Arrange any necessary referrals. PMID:23252133
Pugh, David
Body Temperatures During Exercise in Deconditioned Dogs: Effect of NACL and Glucose Infusion
NASA Technical Reports Server (NTRS)
Infusion of glucose (Glu) into normal exercising dogs attenuates the rise in rectal temperature (Delta-Tre) when compared with delta-Tre during FFA infusion or no infusion. Rates of rise and delta-=Tre levels are higher during exercise after confinement. Therefore, the purpose of this study was to determine if Glu infusion would attenuate the exercise-induced excess hyperthermia after deconditioning. Rectal and quadricep femoris muscle temperatures (Tmu) were measured in 7 male, mongrel dogs dogs (19.6 +/- SD 3.0 kg) during 90 minutes of treadmill exercise (3.1 +/-SD 0.2 W/kg) with infusion (30ml/min/kg) of 40% Glu or 0.9% NaCL before BC) and after confinement (AC) in cages (40 x 110 x 80 cm) for 8 wk. Mean (+/-SE body wt. were 19.6 +/- 1.1 kg BC and 19.5 +/- 1.1kg AC, exercise VO2 were not different (40.0 - 42.0 mi/min/kg-1). With NaCl AC, NaCl BC, GluAC, and GluBC: Delta-Tre were, 1.8, 1.4, 1.3 and 0.9C respectively; and Delta-Tmu were 2.3, 1.9, 1.6, and 1.4C. respectively (P<0.05 from GluBC). Compared with NaCl infusion, attenuated both Delta-Tre and Delta-Tmu BC and AC, respectively. Compared with GluBC, GluAC attenuated Delta-Tmu but not Delta-Tre. Thus. with similar heat production, the mechanism for attenuation at bad body temperature with Glu infusion must affect avenues of heat dissipation.
Greenleaf, J. E.; Kruk, B.; Nazar, K.; Kaciuba-Usciko, H.
[Adaptive changes of Zebrafish (Danio rerio) to anaerobic exercise training].
To explore adaptive changes of the Zebrafish (Danio rerio) to anaerobic exercise training as well as to collect basic data of molecular mechanisms of adaption to anaerobic exercise training among this fish, we investigated the influences of 4 weeks of anaerobic exercise training on the behavior, morphology, growth, muscle biochemical components and metabolic enzyme activities of the Zebrafish. Our results indicated that individual's daily activity level declined after 4 weeks training and they preferred to swim together more frequently. Both body length and weight gain decreased, allowing the fish to adapt to the increased locomotion. Similarly, glycogen in muscles increased and exercise endurance also strengthened due to the enhancement of energy storage. Moreover, although the activity of lactate dehydrogenase (LDH) in muscle has increased, the activity of citrate synthase (CS) decreased. Taken together, these results suggest that both the ability of anaerobic exercise and anaerobic metabolism of Zebrafish can in fact be enhanced by training, and the tangible changes that we could measure were retained, but only for a limited time. PMID:23775994
Liu, Ming-jing; Wang, Zhi-jian
Effects of Estrogen Fluctuation during the Menstrual Cycle on the Response to Stretch-Shortening Exercise in Females
The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.7?yr) participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72?h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue) between the two menstrual cycle phases were small.
Sipaviciene, Saule; Daniuseviciute, Laura; Kliziene, Irina; Kamandulis, Sigitas; Skurvydas, Albertas
cAMP levels in fast- and slow-twitch skeletal muscle after an acute bout of aerobic exercise
NASA Technical Reports Server (NTRS)
The present study examined whether exercise duration was associated with elevated and/or sustained elevations of postexercise adenosine 3',5'-cyclic monophosphate (cAMP) by measuring cAMP levels in skeletal muscle for up to 4 h after acute exercise bouts of durations that are known to either produce (60 min) or not produce (10 min) mitochondrial proliferation after chronic training. Treadmill-acclimatized, but untrained, rats were run at 22 m/min for 0 (control), 10, or 60 min and were killed at various postexercise (0, 0.5, 1, 2, and 4 h) time points. Fast-twitch white and red (quadriceps) and slow-twitch (soleus) muscles were quickly excised, frozen in liquid nitrogen, and assayed for cAMP with a commercial kit. Unexpectedly, cAMP contents in all three muscles were similar to control (nonexercise) at most (21 of 30) time points after a single 10- or 60-min run. Values at 9 of 30 time points were significantly different from control (P < 0.05); i.e., 3 time points were significantly higher than control and 6 were significantly less than control. These data suggest that the cAMP concentration of untrained skeletal muscle after a single bout of endurance-type exercise is not, by itself, associated with exercise duration.
Sheldon, A.; Booth, F. W.; Kirby, C. R.
Effects of estrogen fluctuation during the menstrual cycle on the response to stretch-shortening exercise in females.
The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.7 yr) participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72 h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue) between the two menstrual cycle phases were small. PMID:24151587
Sipavi?ien?, Saul?; Daniusevi?iut?, Laura; Klizien?, Irina; Kamandulis, Sigitas; Skurvydas, Albertas
Stretching and deep and superficial massage do not influence blood lactate levels after heavy-intensity cycle exercise.
The study aimed to assess the role of deep and superficial massage and passive stretching recovery on blood lactate concentration ([La(-)]) kinetics after a fatiguing exercise compared to active and passive recovery. Nine participants (age 23 ± 1 years; stature 1.76 ± 0.02 m; body mass 74 ± 4 kg) performed on five occasions an 8-min fatiguing exercise at 90% of maximum oxygen uptake, followed by five different 10-min interventions in random order: passive and active recovery, deep and superficial massage and stretching. Interventions were followed by 1 hour of recovery. Throughout each session, maximum voluntary contraction (MVC) of the knee extensor muscles, [La(-)], cardiorespiratory and metabolic variables were determined. Electromyographic signal (EMG) from the quadriceps muscles was also recorded. At the end of the fatiguing exercise, [La(-)], MVC, EMG amplitude, and metabolic and cardiorespiratory parameters were similar among conditions. During intervention administration, [La(-)] was lower and metabolic and cardiorespiratory parameters were higher in active recovery compared to the other modalities (P < 0.05). Stretching and deep and superficial massage did not alter [La(-)] kinetics compared to passive recovery. These findings indicate that the pressure exerted during massage administration and stretching manoeuvres did not play a significant role on post-exercise blood La(-) levels. PMID:23256711
Cč, Emiliano; Limonta, Eloisa; Maggioni, Martina A; Rampichini, Susanna; Veicsteinas, Arsenio; Esposito, Fabio
Exercise training in pulmonary rehabilitation.
Exercise training remains a cornerstone of pulmonary rehabilitation (PR) in patients with chronic respiratory disease. The choice of type of exercise training depends on the physiologic requirements and goals of the individual patient as well as the available equipment at the PR center. Current evidence suggests that, at ground walking exercise training, Nordic walking exercise training, resistance training, water-based exercise training, tai chi, and nonlinear periodized exercise are all feasible and effective in (subgroups) of patients with chronic obstructive pulmonary disease. In turn, these exercise training modalities can be considered as part of a comprehensive, interdisciplinary PR program. PMID:24874127
Andrianopoulos, Vasileios; Klijn, Peter; Franssen, Frits M E; Spruit, Martijn A
Implications of group III and IV muscle afferents for high-intensity endurance exercise performance in humans.
We investigated the influence of group III/IV muscle afferents on peripheral fatigue, central motor drive (CMD) and endurance capacity during high-intensity leg-cycling. In a double-blind, placebo-controlled design, seven males performed constant-load cycling exercise (318 ± 9 W; 80% of peak power output (W(peak))) to exhaustion under placebo conditions and with lumbar intrathecal fentanyl impairing spinal ?-opioid receptor-sensitive group III/IV muscle afferents. Peripheral fatigue was assessed via changes in pre- vs. post-exercise quadriceps force in response to supramaximal magnetic femoral nerve stimulation (?Q(tw,pot)). CMD was estimated via quadriceps electromyogram. To rule out a direct central effect of fentanyl, we documented unchanged resting cardioventilatory responses. Compared to placebo, significant hypoventilation during the fentanyl trial was indicated by the 9% lower V(E)/V(CO(2)), causing a 5 mmHg increase in end-tidal P(CO(2)) and a 3% lower haemoglobin saturation. Arterial pressure and heart rate averaged 8 and 10% lower, respectively, during the fentanyl trial and these differences progressively diminished towards end-exercise. Although initially similar, the percent change in CMD was 9 ± 3% higher at end-exercise with fentanyl vs. placebo (P < 0.05). Time to exhaustion was shorter (6.8 ± 0.3 min vs. 8.7 ± 0.3 min) and end-exercise ?Q(tw,pot) was about one-third greater (-44 ± 2% vs. -34 ± 2%) following fentanyl vs. placebo. The rate of peripheral fatigue development was 67 ± 10% greater during the fentanyl trial (P < 0.01). Our findings suggest that feedback from group III/IV muscle afferents limits CMD but also minimizes locomotor muscle fatigue development by stimulating adequate ventilatory and circulatory responses to exercise. In the face of blocked group III/IV muscle afferents, CMD is less inhibited but O(2) transport compromised and locomotor muscle fatigability is exacerbated with a combined net effect of a reduced endurance performance. PMID:21878520
Amann, Markus; Blain, Gregory M; Proctor, Lester T; Sebranek, Joshua J; Pegelow, David F; Dempsey, Jerome A
Shear behavior of masonry panels strengthened by FRP laminates
The present experimental study, performed on brick masonry panels strengthened by Fiber Reinforced Polymer (FRP) laminates, was aimed to investigate the efficiency of an alternative shear reinforcement technique. A series of nine unreinforced masonry (URM) panels and 24 strengthened panels have been subjected to diagonal compression tests. Different reinforcement configurations were evaluated. Experimental results pointed out that FRP reinforcement applied
M. R. Valluzzi; D. Tinazzi; C. Modena
Shear capacity of FRP-strengthened RC beams: FRP debonding
Many studies have been undertaken on shear strengthening of reinforced concrete (RC) beams by externally bonding fibre-reinforced polymer (FRP) composites. These studies have established clearly that such strengthened beams fail in shear mainly in one of two modes: FRP rupture; and FRP debonding, and have led to preliminary design proposals. This paper is concerned with the development of a simple,
J. F. Chen; J. G. Teng
Strengthening families to support children affected by HIV and AIDS
This paper provides an overview of the arguments for the central role of families, defined very broadly, and we emphasise the importance of efforts to strengthen families to support children affected by HIV and AIDS. We draw on work conducted in the Joint Learning Initiative on Children and AIDS's Learning Group 1: Strengthening Families, as well as published data and
Linda M. Richter; Lorraine Sherr; Michele Adato; Mark Belsey; Upjeet Chandan; Chris Desmond; Scott Drimie; Mary Haour-Knipe; Victoria Hosegood; Jose Kimou; Sangeetha Madhavan; Vuyiswa Mathambo; Angela Wakhweya
Advanced composites have become one of the most popular methods of repairing and\\/or strengthening civil infrastructure in the past couple of decades. While the use of Fiber Reinforced Polymer laminates and sheets for the repair and strengthening of reinforced concrete structures is well established, research on the application of FRP composites to steel structures has been limited. The use of
Nisal Abheetha Peiris
Supporting Teachers, Strengthening Families: A Model Child Abuse Prevention Approach
ERIC Educational Resources Information Center
This article talks about a model child abuse prevention approach called, "Supporting Teachers, Strengthening Families." It is NAEYC's professional development initiative to help early childhood educators play leading roles in preventing child abuse and neglect through family strengthening efforts. It focuses on six strategies that high-quality…
Olson, Maril
Exercises in Physical Oceanography
NSDL National Science Digital Library
This site from Flinders University in Australia features two sets of exercises that accompany a course on physical oceanography. The basic exercises were originally intended to replace the need for the teacher's presence, but have since also proved useful in distance learning. Topics for these exercises include map projections ocean floor topography, properties of sea water, and water masses and tides. The advanced exercises were designed to give deeper insight into the material and to encourage investigation. Advanced topics include coastal upwelling, graphic display methods for ocean currents, averaging methods for vector time series, geostrophic currents, Rossby wave propagation, the depth of the permanent thermocline (the Sverdrup balance), Ekman layer dynamics, and the outflow of Mediterranean Water into the Atlantic Ocean. The site also features links to other oceanography websites.
Tomczak, Matthias; Flinders University, Australia
Adventures in Exercise Physiology
NSDL National Science Digital Library
The author altered the format of an exercise physiology course from traditional lecture to emphasizing daily reading quizzes and group problem-solving activities. The SALGains evaluation was used to compare the two approaches and significant improvements
Fitzpatrick, Kathleen A.
... www.nia.nih.gov/Go4Life Exercise and Osteoporosis Osteoporosis is a disease that weakens bones to the ... until a bone breaks. Ten million Americans have osteoporosis. It is more common in women, but men ...
... after exercise. Hives or "welts" are usually raised, flat bumps on the skin that are more red around the edge than in the middle. Hives may also look like red spots, blotches or blisters. They can occur on any ...
Everyday Fitness Ideas from the National Institute on Aging at NIH www.nia.nih.gov/Go4Life Exercise Tips for ... to stay fit when you travel. Pack your fitness clothes. Be prepared. Take along your sneakers or ...
... Playing organized sports (such as soccer, basketball, and football) Younger children have a shorter attention span than ... or biking. Others prefer group sports, like soccer, football, or basketball. Choose an exercise that works well ...
Home > Publications > Our publications > Our publications Publications Physical activity (exercise) fact sheet How can physical activity improve my health? How much physical activity should I do? How much physical activity do I ...
NSDL National Science Digital Library
Barbara and David Tewksbury, Hamilton College Summary In the first part of the exercise, students examine a variety of ArcMaps to work out what data sets and techniques were used and to develop a list of the ...
Tewksbury, Barb
... Risks Cancer Types Risk Factors Prevention & Early Detection Diet And Exercise Transplant recipients need to be aware ... plan that fits your needs, likes and dislikes. Diet After a Transplant After your transplant, you will ...
... Institution: NIH Library User Name Password Sign In Cardiology Patient Page Heart-Healthy Exercise Lauren Healey Mellett , ... Section Footnotes The information contained in this Circulation Cardiology Patient Page is not a substitute for medical ...
Exercise and activity - children
... about themselves Are more physically fit Have more energy Other benefits of exercise for children are: A lower risk of heart disease and diabetes Healthy bone and muscle growth Staying at a healthy weight
Muscle metabolic responses to exercise above and below the "critical power" assessed using 31P-MRS.
We tested the hypothesis that the asymptote of the hyperbolic relationship between work rate and time to exhaustion during muscular exercise, the "critical power" (CP), represents the highest constant work rate that can be sustained without a progressive loss of homeostasis [as assessed using (31)P magnetic resonance spectroscopy (MRS) measurements of muscle metabolites]. Six healthy male subjects initially completed single-leg knee-extension exercise at three to four different constant work rates to the limit of tolerance (range 3-18 min) for estimation of the CP (mean +/- SD, 20 +/- 2 W). Subsequently, the subjects exercised at work rates 10% below CP (
Jones, Andrew M; Wilkerson, Daryl P; DiMenna, Fred; Fulford, Jonathan; Poole, David C
Exercise-induced anaphylaxis has been recognized with increasing frequency since its original description in 1980. Recent\\u000a studies suggest food-induced reactions may occur frequently in this syndrome, which is a mast cell-dependent phenomenon. In\\u000a this article, the clinical manifestations of exercise-induced anaphylaxis are reviewed, and food related factors contributing\\u000a to the disorder are considered.
Mariana C. Castells; Richard F. Horan; Albert L. Sheffer
NSDL National Science Digital Library
This exercise flollows the progression of a winter weather event across the Central Plains states beginning 1200 UTC on 7 March 1999. Each forecast question is accompanied by Eta model data and includes a forecast discussion by Phil Schumacher, NWS Sioux Falls, South Dakota. This exercise compliments the Webcast, Inverted Troughs and their Associated Precipitation Regimes, based on a presentation by Phil Schumacher at the MSC Winter Weather Course, December 2002, in Boulder Colorado.
Spangler, Tim
\\u000a The consequences of physical activity on the brain can readily be integrated into a hormetic framework. Whereas low- to moderate-intensity\\u000a exercise exerts positive effects on the body, excessive exercise can be detrimental for somatic health. Here we review the\\u000a evidence linking physical activity with cellular and functional modifications in different organ systems, with a focus on\\u000a the dose-response characteristics of
Alexis M. Stranahan; Mark P. Mattson
Exercise rehabilitation after stroke
Summary Stroke is a leading cause of disability that results not only in persistent neurological deficits, but also profound physical\\u000a deconditioning that propagates disability and worsens cardiovascular risk. The potential for exercise-mediated adaptations\\u000a to improve function, fitness, and cardiovascular health after stroke has been underestimated: it represents an emerging arena\\u000a in neurotherapeutics. To define the health rationale for cardiovascular (aerobic) exercise,
Frederick M. Ivey; Charlene E. Hafer-Macko; Richard F. Macko
Exercise Therapy for Fibromyalgia
Fibromyalgia syndrome, a chronic condition typically characterized by widespread pain, nonrestorative sleep, fatigue, cognitive\\u000a dysfunction, and other somatic symptoms, negatively impacts physical and emotional function and reduces quality of life. Exercise\\u000a is commonly recommended in the management of people with fibromyalgia, and interest in examining exercise benefits for those\\u000a with the syndrome has grown substantially over the past 25 years. Research
Angela J. Busch; Sandra C. Webber; Mary Brachaniec; Julia Bidonde; Vanina Dal Bello-Haas; Adrienne D. Danyliw; Tom J. Overend; Rachel S. Richards; Anuradha Sawant; Candice L. Schachter
Brazing copper to dispersion-strengthened copper
The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail that has been possible to date. The beam is produced by using third-generation insertion devices in a 7 GeV electron/positron storage ring that is 1100 meters in circumference. The heat load from these intense high power devices is very high and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm{sup 2}. Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop{reg_sign}, a dispersion strengthened copper, is the desired material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.
Ryding, D.G.; Allen, D.; Lee, R.
Strengthening procedural memories by reactivation in sleep.
There is robust evidence that sleep facilitates procedural memory consolidation. The exact mechanisms underlying this process are still unclear. We tested whether an active replay of prior experience can underlie sleep effects on procedural memory. Participants learned a finger-tapping task in which key presses were associated with tones during practice. Later, during a consolidation interval spent either sleeping or awake, we presented auditory cues to reactivate part of the learned sequence. We show that reactivation strengthens procedural memory formation during sleep, but not during wakefulness. The improvement was restricted to those finger transitions that were cued. Thus, reactivation is a very specific process underpinning procedural memory consolidation. When comparing periods of sleep with and without reactivation, we find that it is not the time spent in a specific stage of sleep per se, but rather the occurrence of reactivation that mediates the effect of sleep on memory consolidation. Our data show that longer sleep time as well as additional reactivation by cueing during sleep can enhance later memory performance. PMID:23984946
Schönauer, Monika; Geisler, Teresa; Gais, Steffen
Precipitate strengthening of nanostructured aluminium alloy.
Grain boundaries and precipitates are the major microstructural features influencing the mechanical properties of metals and alloys. Refinement of the grain size to the nanometre scale brings about a significant increase in the mechanical strength of the materials because of the increased number of grain boundaries which act as obstacles to sliding dislocations. A similar effect is obtained if nanoscale precipitates are uniformly distributed in coarse grained matrix. The development of nanograin sized alloys raises the important question of whether or not these two mechanisms are "additive" and precipitate strengthening is effective in nanostructured materials. In the reported work, hydrostatic extrusion (HE) was used to obtain nanostructured 7475 aluminium alloy. Nanosized precipitates were obtained by post-HE annealing. It was found that such annealing at the low temperatures (100 degrees C) results in a significant increase in the microhardness (HV0.2) and strength of the nanostructured 7475 aluminium alloy. These results are discussed in terms of the interplay between the precipitation and deformation of nanocrystalline metals. PMID:23421286
Wawer, Kinga; Lewandowska, Malgorzata; Kurzydlowski, Krzysztof J
Strengthening of solidified dilute tailings slurry
Tailings produced during mineral processing contain up to 75% or more water and are pumped into settling ponds for disposal. They often become a pollution source due to acid generation. While tailings have been used in underground backfill, the use is very limited at present. This paper presents research results on direct solidification and strengthening of the dilute tailings slurry without dewatering. Two types of tailings were tested at water/binder ratios of up to 4.5 using a special high-water binder. Adequate strength was achieved by solidifying the tailings as is. To further improve the strength, sands and fly ash were used as reinforcement materials or partial replacement of the binder. For oil sands tailings, the 3-day strength was increased by up to 114% with 10--15% additives. For hard rock tailings, up to 30% strength gain was achieved with 15% fly ash addition, and the strength was increased by up to 36% at 10% binder replacement and no strength reduction was observed at 20--25% replacement. These results indicate that higher strength can be achieved with the proper amount of additives and that the backfill process can be simplified and the operation cost reduced.
Zou, D.H.; Li, L.P. [Dalhousie Univ., Halifax, NS (Canada). Dept. Mining and Metallurgical Engineering] [Dalhousie Univ., Halifax, NS (Canada). Dept. Mining and Metallurgical Engineering
Regular physical activity provides a variety of health benefits, including improvement in cardiopulmonary or metabolic status, reduction of the risk of coronary artery disease or stroke, prevention of cancer, and decrease in total mortality. Exercise-related cardiac events are occasionally reported during highly competitive sports activity or vigorous exercises. However, the risk of sudden death is extremely low during vigorous exercise, and habitual vigorous exercise actually decreases the risk of sudden death during exercise. The cause of sudden death is ischemic in older subjects (?35 years old), while cardiomyopathies or genetic ion channel diseases are important underlying pathology in younger (<35 years old) victims. The subgroup of patients who are particularly at higher risk of exercise-related sudden death may be identified in different ways, such as pre-participation history taking, physical examination and/or supplementary cardiac evaluation. Limitations exist because current diagnostic tools are not sufficient to predict a coronary artery plaque with potential risk of disruption and/or an acute thrombotic occlusion. Proper and cost-effective methods for identification of younger subjects with cardiac structural problems or genetic ion channel diseases are still controversial.
Efficacy of pre-exercise low-level laser therapy on isokinetic muscle performance in individuals with type 2 diabetes mellitus: study protocol for a randomized controlled trial
Background Type 2 diabetes, also known non-insulin-dependent diabetes, is the most prevalent type of the disease and involves defects in the secretion and action of insulin. The aim of the proposed study is to evaluate the efficacy of pre-exercise low-level laser therapy (LLLT) on muscle performance of the quadriceps femoris in individuals with type 2 diabetes. Methods/Design A double-blind, randomized, controlled clinical trial will be carried out in two treatment phases. In the first phase, quadriceps muscle performance will be evaluated using an isokinetic dynamometer and the levels of creatine kinase and lactate dehydrogenase (biochemical markers of muscle damage) will be determined. The participants will then be allocated to four LLLT groups through a randomization process using opaque envelopes: Group A (4 Joules), Group B (6 Joules), Group C (8 Joules) and Group D (0 Joules; placebo). Following the administration of LLLT, the participants will be submitted to an isokinetic eccentric muscle fatigue protocol involving the quadriceps muscle bilaterally. Muscle performance and biochemical markers of muscle damage will be evaluated again immediately after as well as 24 and 48 hours after the experimental protocol. One week after the last evaluation the second phase will begin, during which Groups A, B and C will receive the LLLT protocol that achieved the best muscle performance in phase 1 for a period of 4 weeks. At the end of this period, muscle performance will be evaluated again. The protocol for this study is registered with the World Health Organization under Universal Trial Number U1111-1146-7109. Discussion The purpose of this randomized clinical trial is to evaluate the efficacy of pre-exercise LLLT on the performance of the quadriceps muscle (peak torque, total muscle work, maximum power and fatigue index – normalized by body mass) in individuals with DM-2. The study will support the practice of evidence-based to the use of LLLT in improving muscle performance in Individuals with DM-2. Data will be published after the study is completed.
Anterior cruciate ligament reconstruction using bone plug-free quadriceps tendon autograft: intermediate-term clinical outcome after 24-36 months
Introduction Although known as a possible graft option for decades, quadriceps tendon grafts have often been termed a second-line graft option. We report a consecutive case series using this method as the primary treatment line. The rationale for this study was to evaluate the midterm results of this method in a prospective and consecutive case series. The primary study question was to determine the clinical results 24–36 months after primary anterior cruciate ligament (ACL) reconstruction using a bone plug-free quadriceps tendon autograft fixed with bioabsorbable cross-pins. Materials and methods The study population included 55 patients, of whom 24 were female (43.6%). The mean age at the index procedure was 31.7 years (15–58 years). All patients received an ACL construction using a bone block-free quadriceps tendon graft fixed with resorbable cross-pins. The postoperative regimen included partial weight-bearing for 3 weeks and flexion limited to 90° for six weeks; an orthosis was not used. The mean follow-up duration was 29.5 months (24.3–38.5 months) after the index procedure. The International Knee Documentation Committee (IKDC) subjective score and examination form was assessed, as well as the Lysholm and Gillquist score and the Tegner activity index. The Rolimeter arthrometer was used to assess the anterior laxity of the knee. Results Graft harvesting was possible in all cases; a bony extension was never required. On average, graft length was measured at 8.8 cm (7.5–10 cm). The mean IKDC subjective score at follow-up was 80.44 points (55.17–100 points, standard deviation [SD] 12.05). The mean preinjury Tegner activity index was 4.98 (2–7) compared to a mean value of 4.16 (2–7, SD 0.8) at follow-up. There was a mean loss of 0.82 index points. The average Lysholm and Gillquist score was 89 points (65–100, SD 17.7). Of the results, 89.1% were in the good or very good groups; in one case (1.8%), the result was poor, while the rest were fair. Conclusion ACL reconstruction using a bone plug-free quadriceps tendon autograft achieved satisfactory results in a midterm review.
Schulz, Arndt P; Lange, Vivien; Gille, Justus; Voigt, Christine; Frohlich, Susanne; Stuhr, Markus; Jurgens, Christian
Electromyographical Comparison of Four Common Shoulder Exercises in Unstable and Stable Shoulders
This study examines if electromyographic (EMG) amplitude differences exist between patients with shoulder instability and healthy controls performing scaption, prone horizontal abduction, prone external rotation, and push-up plus shoulder rehabilitation exercises. Thirty nine subjects were categorized by a single orthopedic surgeon as having multidirectional instability (n = 10), anterior instability (n = 9), generalized laxity (n = 10), or a healthy shoulder (n = 10). Indwelling and surface electrodes were utilized to measure EMG activity (reported as a % of maximum voluntary isometric contraction (MVIC)) in various shoulder muscles during 4 common shoulder exercises. The exercises studied effectively activated the primary musculature targeted in each exercise equally among all groups. The serratus anterior generated high activity (50–80% MVIC) during a push-up plus, while the infraspinatus and teres major generated moderate-to-high activity (30–80% MVIC) during both the prone horizontal and prone external rotation exercises. Scaption exercise generated moderate activity (20–50% MVIC) in both rotator cuff and scapular musculature. Clinicians should feel confident in prescribing these shoulder-strengthening exercises in patients with shoulder instability as the activation levels are comparable to previous findings regarding EMG amplitudes and should improve the dynamic stabilization capability of both rotator cuff and scapular muscles using exercises designed to address glenohumeral joint instability.
Sciascia, Aaron; Kuschinsky, Nina; Nitz, Arthur J.; Mair, Scott D.; Uhl, Tim L.
Improved knowledge on the swimming physiology of fish and its application to fisheries science and aquaculture (i.e., farming a fitter fish) is currently needed in the face of global environmental changes, high fishing pressures, increased aquaculture production as well as increased concern on fish well-being. Here, we review existing data on teleost fish that indicate that sustained exercise at optimal speeds enhances muscle growth and has consequences for flesh quality. Potential added benefits of sustained exercise may be delay of ovarian development and stimulation of immune status. Exercise could represent a natural, noninvasive, and economical approach to improve growth, flesh quality as well as welfare of aquacultured fish: a FitFish for a healthy consumer. All these issues are important for setting directions for policy decisions and future studies in this area. For this purpose, the FitFish workshop on the Swimming Physiology of Fish ( http://www.ub.edu/fitfish2010 ) was organized to bring together a multidisciplinary group of scientists using exercise models, industrial partners, and policy makers. Sixteen international experts from Europe, North America, and Japan were invited to present their work and view on migration of fishes in their natural environment, beneficial effects of exercise, and applications for sustainable aquaculture. Eighty-eight participants from 19 different countries contributed through a poster session and round table discussion. Eight papers from invited speakers at the workshop have been contributed to this special issue on The Swimming Physiology of Fish. PMID:21611721
Palstra, Arjan P; Planas, Josep V
The prevalence of type 2 diabetes mellitus (T2DM) has increased dramatically in the United States over the past 20 years. The American Diabetes Association recommends regular exercise and maintenance of healthy body weight as important in prevention of T2DM, and exercise is also a cornerstone of treatment regimens for persons already diagnosed with T2DM. T2DM most commonly develops via progressive insulin resistance, a state that has been shown to be caused through several pathways, three of which are discussed in this review. First, the accumulation of lipid intermediates in skeletal muscle under conditions of sustained energy surplus can impair insulin signaling downstream of insulin binding to its receptor. Second, several inflammatory mediators have been shown to negatively affect insulin signaling and gene expression of glucose transporters. Third, oxidative stress induces insulin resistance by creating an environment that interferes with insulin signaling in several ways. Exercise can improve insulin sensitivity by opposing each of these three mechanisms of insulin resistance, as well as providing an avenue for muscle glucose uptake that bypasses insulin, and as such, has the capacity to serve as an important preventative measure. Furthermore, in persons with T2DM, the capacity of muscle contraction to stimulate glucose uptake in a manner that is independent of insulin establishes exercise as a powerful "medicine" in its treatment. Exercise, therefore, serves an important role in prevention and treatment of T2DM. PMID:25034542
Buresh, R
NSDL National Science Digital Library
Founded in 1985, the American Council on Fitness is largely known for operating as a fitness certification and education provider. Fortunately for the average person looking for helpful information about exercise materials, the Council website is a treasure trove of free resources on the subject. Not surprisingly, most of these materials are contained within the "Get Fit!" section of the site. Here visitors will find free exercises, a number of healthy recipes, and discussion boards where they may ask questions of fitness professionals. Another useful area is the Operation FitKids section of the site. This section provides tips of keeping fit especially geared towards young people, along with informational fact sheets. Finally, there are a number of reports (sponsored by the ACE) that investigate various health and fitness practices, such as the best (and worst) abdominal exercises.
Exercise performance of birds.
Birds are excellent endurance athletes. Not only do many birds undertake long migratory flights, but many do so under extreme environmental conditions: excessive heat, extreme cold, and the hypoxic conditions of high altitude. We are just now starting to understand the physiological adaptations these animals possess for surviving and thriving in these environments. Still, relatively few studies have actually been performed on exercising birds, particularly on birds flying under the conditions mentioned here. Furthermore, not all birds are capable of sustained exercise in hypoxia, heat, and cold. More work is needed to increase our understanding of the differences in the physiological systems that allow some birds to be better able to exercise under such conditions. PMID:7810377
Saunders, D K; Fedde, M R
Locomotor exercise in weightlessness
NASA Technical Reports Server (NTRS)
The requirements for exercise in space by means of locomotion are established and addressed with prototype treadmills for use during long-duration spaceflight. The adaptation of the human body to microgravity is described in terms of 1-G locomotor biomechanics, the effects of reduced activity, and effective activity-replacement techniques. The treadmill is introduced as a complement to other techniques of force replacement with reference given to the angle required for exercise. A motor-driven unit is proposed that can operate at a variety of controlled speeds and equivalent grades. The treadmills permit locomotor exercise as required for long-duration space travel to sustain locomotor and cardiorespiratory capacity at a level consistent with postflight needs.
Thornton, W.; Whitmore, H.
40 CFR 141.551 - What strengthened combined filter effluent turbidity
Code of Federal Regulations, 2010 CFR
...strengthened combined filter effluent turbidity] 40 PROTECTION OF ENVIRONMENT ...strengthened combined filter effluent turbidity limits must my system meet? Your system...strengthened combined filter effluent turbidity limits. (a) The first combined...
Oxide dispersion strengthened (ODS) alloys (e.g. the INCOLOY{reg_sign} MA956 alloy) are known for their excellent high temperature properties and are prime candidate materials for the construction of very high temperature heat exchangers that will be used in Vision 21 power plants. The main limitation of these materials is their poor weldability. Commercially available ODS tubing also tends to exhibit relatively poor circumferential creep strength due to current processing practices resulting in a fine grain size in the transverse direction. Thus far, these two characteristics of the ODS tubing have restricted its use to mostly non-pressure containing applications. The objectives of this program are to develop: (a) an MA956 tube with sufficient circumferential creep strength for long term use as heat exchanger tubing for very high temperatures; (b) a welding technique(s) for producing adequate joints between an MA956 tube and an MA956 tube, and an MA956 tube and an INCONEL 601 tube; (c) the bending strain limits, below which recrystallization will not occur in a MA956 tube during normal operation; and (d) the high temperature corrosion limits for the MA956 alloy with respect to working-fluid side and fireside environments. Also, this program seeks to generate data for use by heat exchanger designers and the ASME Boiler and Pressure Vessel Code, and perform an analysis of the mechanical property, tube bending, and corrosion data in order to determine the implications on the design of a very high temperature heat exchanger (T>1093 C/2000 F). After one year, work is currently being conducted on increasing the circumferential strength of a MA956 tube, developing joining techniques for this material, determining the tube bending strain limits, and establishing the high temperature corrosion parameters for the MA956 alloy in environments expected to be present in Vision 21 power plants. Work in these areas will is continuing into the next fiscal year, with success anticipated to produce innovative developments that will allow the reliable use of ODS alloys for heat exchanger tubing, as well as a variety of applications previously not possible with metallic materials.
Harper, Mark A.
OBJECTIVES--To examine the potential of lifelong patterns of increased physical activity to prevent stroke. DESIGN--Case-control study. SETTING--11 general practices in west Birmingham. SUBJECTS--125 men and women who had just had their first stroke and were aged 35-74 and 198 controls frequency matched for age and sex recruited over 24 months during 1988-90. Exclusion criteria were a previous history of stroke, mitral valvular heart disease combined with atrial fibrillation, primary or metastatic cerebral neoplasm, or coagulation disorder or myeloproliferative disease. MAIN OUTCOME MEASURES--Odds ratios for stroke related to lifetime history of exercise after 15 years of age. RESULTS--A history of vigorous exercise during the ages 15-25 appeared to protect from stroke: odds ratio adjusted for age and sex 0.33 (95% confidence interval 0.2 to 0.6). This effect was independent of other potential risk factors. Increasing years of participation in vigorous exercise between the ages of 15 and 55 produced an increasing protection from stroke (p < 0.001). In the 65 cases and 169 controls who were free of cardiac ischaemia, peripheral vascular disease, and poor health recent vigorous exercise and walking were protective against stroke: odds ratios of 0.41 (0.2 to 1.0) for recent vigorous exercise and 0.30 (0.1 to 0.7) for recent walking. CONCLUSIONS--Appreciable protection from stroke in later life is conferred by vigorous exercise in early adulthood. This increased level of physical activity should, if possible, be continued lifelong.
Shinton, R; Sagar, G
[Metabolic intolerance to exercise].
Exercise intolerance (EI) is a frequent cause of medical attention, although it is sometimes difficult to come to a final diagnosis. However, there is a group of patients in whom EI is due to a metabolic dysfunction. McArdle's disease (type V glucogenosis) is due to myophosphorylase (MPL) deficiency. The ischemic exercise test shows a flat lactate curve. The most frequent mutations in the PYGM gene (MPL gene) in Spanish patients with MPL deficiency are R49X and W797R. Carnitine palmitoyltransferase (CPT) II deficiency is invariably associated to repetitive episodes of myoglobinuria triggered by exercise, cold, fever or fasting. The diagnosis depends on the demonstration of CPT II deficiency in muscle. The most frequent mutation in the CPT2 gene is the S113L. Patients with muscle adenylate deaminase deficiency usually show either a mild myopathy or no symptom. The diagnosis is based on the absence of enzyme activity in muscle and the lack of rise of ammonia in the forearm ischemic exercise test. The mutation Q12X in the AMPD1 gene is strongly associated with the disease. Exercise intolerance is a common complaint in patients with mitochondrial respiratory chain (MRC) deficiencies, although it is often overshadowed by other symptoms and signs. Only recently we have come to appreciate that exercise intolerance can be the sole presentation of defects in the mtDNA, particularly in complex I, complex III, complex IV, or in some tRNAs. In addition, myoglobinuria can be observed in patients under statin treatment, particularly if associated with fibrates, due to an alteration in the assembly of the complex IV of the MRC. PMID:12838448
Arenas, J; Martín, M A