title: Association between vitamin D receptor gene polymorphisms, falls, balance and muscle power: results from two independent studies (APOSS and OPUS) Velocity training induces power-specific adaptations in highly functioning older adults. A Comparison of High-Speed Power Training and Traditional Slow-Speed Resistance Training in Older Men and Women Effects of High-Speed Power Training on Muscle Performance and Braking Speed in Older Adults Gait Speed and Decline in Gait Speed as Predictors of Incident Dementia Effects of Testosterone Supplementation for 3 Years on Muscle Performance and Physical Function in Older Men Optimal load for increasing muscle power during explosive resistance training in older adults. The effects of strength and power training on single-step balance recovery in older adults: a preliminary study The effects of exercise and protein-energy supplements on body composition and muscle function in frail elderly individuals: a long-term controlled randomised study. Which impairments are most associated with high mobility performance in older adults? Implications for a rehabilitation prescription. Effect of power-training intensity on the contribution of force and velocity to peak power in older adults. Whole-body vibration training increases muscle strength and mass in older women: a randomized-controlled trial. Age differences in knee extension power, contractile velocity, and fatigability. Injuries during the one repetition maximum assessment in the elderly. Lower extremity power training in elderly subjects with mobility limitations: a randomized controlled trial Comparative effects of light or heavy resistance power training for improving lower extremity power and physical performance in mobility-limited older adults. Is grip strength a useful single marker of frailty? The relationship between leg power and physical performance in mobility-limited older people. Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women. Multicomponent exercises including muscle power training enhance muscle mass, power output, and functional outcomes in institutionalized frail nonagenarians Once weekly combined resistance and cardiovascular training in healthy older men. Strength versus muscle power-specific resistance training in community-dwelling older adults. Association of muscle power with functional status in community-dwelling elderly women. Concurrent strength and endurance training exercise sequence does not affect neuromuscular adaptations in older men Are changes in leg power responsible for clinically meaningful improvements in mobility in older adults? Muscle mass, muscle strength, and muscle fat infiltration as predictors of incident mobility limitations in well-functioning older persons. Increased velocity exercise specific to task training versus the National Institute on Aging's strength training program: changes in limb power and mobility. Effects of Strength Training on Physical Function: Influence of Power, Strength, and Body Composition Increased trunk extension endurance is associated with meaningful improvement in balance among older adults with mobility problems. High-speed circuit training vs hypertrophy training to improve physical function in sarcopenic obese adults: A randomized controlled trial Weighted stair climbing in mobility-limited older people: a pilot study. Lower extremity muscle function after strength or power training in older adults. Efficacy of whey protein supplementation on resistance exercise-induced changes in lean mass, muscle strength, and physical function in mobility-limited older adults. What is a Clinically Meaningful Improvement in Leg-Extensor Power for Mobility-limited Older Adults? Power training improves balance in healthy older adults. Effect of high versus low-velocity resistance training on muscular fitness and functional performance in older men High-Speed Power Training in Older Adults: A Shift of the External Resistance at Which Peak Power Is Produced Physical performance measures in the clinical setting. Changes in Function and Disability After Resistance Training: Does Velocity Matter?: A Pilot Study High-velocity resistance training increases skeletal muscle peak power in older women. Effect of Rest Interval Length on Repeated 1 Repetition Maximum Back Squats Beef and soy-based food supplements differentially affect serum lipoprotein-lipid profiles because of changes in carbohydrate intake and novel nutrient intake ratios in older men who resistive-train. Power training induced change in bradykinesia and muscle power in Parkinson's disease. High-Speed Resistance Training Modifies Load-Velocity and Load-Power Relationships in Parkinson's Disease
abstract: Summary Fall prevention is a key strategy for reducing  osteoporotic fractures . We investigated the association between vitamin D receptor ( VDR ) polymorphisms and reported  falls in postmenopausal women . Bsm1 polymorphisms were associated with falls , balance and muscle power measurements . These results may explain some of the excess fracture risk associated with VDR in some studies . Introduction Fall prevention is a key strategy for reducing osteoporotic fractures . It has been suggested that vitamin D supplementation may reduce the incidence of falls by reducing body sway and increasing muscle power . The vitamin D receptor gene is a well-studied c and i date gene for osteoporosis . We investigated the association between VDR polymorphisms and reported  falls in postmenopausal women . Methods Falls data were collected in two separate population cohorts . Five polymorphisms of the VDR gene were analysed ( Cdx-2 , Fok-1 , BsmI , Taq1 and Apa1 ) in the Aberdeen Prospect i ve Osteoporosis Screening Study ( APOSS ) cohort . Results found in APOSS were then vali date d in an independent cohort — the Osteoporosis and Ultrasound ( OPUS ) study ( Bsm1 and Fok1 only ) , where muscle power and balance were also measured . Results Carriers of the ‘ B ’ allele ( Bsm1 ) showed an increased risk for falls . In APOSS , this was statistically significant for visit 3 multiple falls ( p = 0.047 ) and for recurrent falls ( p = 0.043 ) . Similar results were found in OPUS for visit 1 falls ( p = 0.025 ) and visit 1 multiple falls ( p = 0.015 ) . Bsm1 polymorphisms were also associated with balance and muscle power measurements . Conclusions In conclusion , these results demonstrate an association between the Bsm1 polymorphism and risk of falling that may explain some of the excess fracture risk associated with VDR in some studies OBJECTIVE To test the efficacy of high-velocity training in healthy older persons . DESIGN A 12-week r and omized trial , with subjects blocked for gender and residence , comparing high-velocity resistance training with a self-paced walking program . SETTING Retirement community . PARTICIPANTS Forty-three volunteers over the age of 70 years . INTERVENTION Power group : high-velocity leg exercises 3 times weekly with weekly increases in resistance combined with 45 minutes of moderate , nonresistance exercise weekly . Walking group : moderate intensity exercise 30 minutes daily , 6 days weekly . MAIN OUTCOME MEASURES Variables measured included leg press peak power and leg extensor strength . Functional performance outcomes included : 6-minute walk distance , Short Physical Performance Battery , Physical Performance Test , and Medical Outcomes Study Short-Form Health Survey . RESULTS Peak power improved 22 % ( p = .004 ) in the power group ( 3.7 + /- 1.0 W/kg to 4.5 + /- 1.4 W/kg ) but did not change in the walking group ( 3.99 + /-.76 W/kg to 3.65 + /-.94 W/kg ) . Leg extensor power at resistance of 50 % , 60 % , and 70 % of body weight increased 50 % , 77 % , and 141 % , respectively , in the power group ( p < .0001 , repeated- measures analysis of variance ) . Strength improved 22 % in the power-trained individuals and 12 % in the walkers ( p < .0001 ) . Training did not improve functional task performance in either group . One subject developed a radiculopathy during training . CONCLUSIONS Resistance training focusing on speed of movement improved leg power and maximal strength substantially , but did not improve functional performance in healthy high-functioning older volunteers Sayers , SP and Gibson , K. A comparison of high-speed power training and traditional slow-speed resistance training in older men and women . J Strength Cond Res 24(12 ) : 3369 - 3380 , 2010-Muscle power , the product of force × velocity , is a critical determinant of function in older adults . Resistance training ( RT ) at high speed has been shown to improve peak muscle power in this population ; however , different functional tasks may benefit from the improvement of power at values other than “ peak ” values , for example , tasks that require a greater velocity component or a greater force component . This study compared the effect of high-speed RT on muscle performance ( peak power [ PP ] and its components [ PP force and PP velocity ] and overall peak velocity [ VEL ] ) across a broad range of external resistances . Thirty-eight older men and women were r and omized  to high-speed power training at 40 % of the 1-repetition maximum ( 1RM ) ( n = 13 [ 74.1 ± 6.4 years ] ) ; traditional RT at 80 % 1RM ( n = 13 [ 70.1 ± 7.0 years ] ) ; or control ( n = 12 [ 72.8 ± 4.1 years ] ) . Measures of muscle performance were obtained at baseline and after the 12-week training intervention . Muscle power and 1RM strength improved similarly with both high-speed and traditional slow-speed RT . However , speed-related muscle performance characteristics , PP velocity and overall VEL , were most positively impacted by high-speed power training , especially at lower external resistances . Because gains in speed-related measures with high-speed training compared to traditional RT do not come at the expense of other muscle performance outcomes , we recommend using an RT protocol in older adults that emphasizes high-speed movements at low external resistances We examined whether high-speed power training ( HSPT )  improved muscle performance and braking speed using a driving simulator . 72 older adults ( 22 m , 50 f ; age = 70.6 ± 7.3 yrs ) were r and omized to HSPT at 40 % one-repetition maximum ( 1RM ) ( HSPT : n = 25 ; 3 sets of 12–14 repetitions ) , slow-speed strength training at 80%1RM ( SSST : n = 25 ; 3 sets of 8–10 repetitions ) , or control ( CON : n = 22 ; stretching ) 3 times/week for 12 weeks . Leg press and knee extension peak power , peak power velocity , peak power force/torque , and braking speed were obtained at baseline and 12 weeks . HSPT  increased peak power and peak power velocity across a range of external resistances ( 40–90 % 1RM ; P < 0.05 ) and improved braking speed ( P < 0.05 ) . Work was similar between groups , but perceived exertion was lower in HSPT ( P < 0.05 ) . Thus , the less strenuous HSPT exerted a broader training effect and improved braking speed compared to SSST Background Slow gait is common in dementia , but it remains unknown whether the slowing happens many years prior to dementia onset . We therefore examined the relationship between slow baseline gait speed ( GS ) , change in GS , and the hazard of incident dementia  in a community dwelling of elderly people . Methods A total of 3,663 participants dementia-free at baseline ( mean age , 73.5 years ) were followed up for 9 years from a prospect i ve cohort ( Three-City study , France ) for incident dementia ( all-cause , Alzheimer 's disease , vascular dementia , and other causes ) .  GS  over 6 m was assessed 4 times over the follow-up using two photoelectric cells . We used a multistate model to estimate the hazard ratio ( HR ) of dementia for baseline GS and tested a washout period of 4 to 7 years . The role of GS change between 65 and 85 years was examined using linear mixed models and joint models for survival and longitudinal data . Results A total of 296 participants developed dementia  during the follow-up . In age/sex-adjusted models , 1-SD ( 0.204 m/s ) lower GS was associated with an increased hazard of dementia ( HR = 1.59 , 95 % confidence interval [ CI ] = 1.39 , 1.81 , p < .001 ) , with associations evident when gait assessment s were taken from 4 years ( HR = 1.46 ; CI = 1.26 , 1.68 ) and 7 years ( HR=1.30 ; CI = 1.00 , 1.70 ) prior to dementia onset . Independently of baseline GS , those with a steeper decline had a higher hazard of dementia ( HR per 1 SD [ 0.007 m/s/year ] decrease = 3.39 [ 1.37 - 8.43 ] , p = .009 ) . Conclusions Gait is slower up to 7 years prior to clinical onset of dementia . Decline in GS is also more accelerated , suggesting strong links between cognitive and motor function in older adults Context : Findings of studies of testosterone ’s effects on muscle strength and physical function  in older men have been inconsistent ; its effects on muscle power and fatigability have not been studied . Objective : To determine the effects of testosterone administration for 3 years in older men on  muscle strength , power , fatigability , and physical function . Design , Setting , and Participants : This was a double-blind , placebo-controlled , r and omized trial of healthy men ≥60 years old with total testosterone levels of 100 to 400 ng/dL or free testosterone levels < 50 pg/mL. Interventions : R and om assignment to 7.5 g of 1 % testosterone or placebo gel daily for 3 years . Outcome Measures : Loaded and unloaded stair-climbing power , muscle strength , power , and fatigability in leg press and chest press exercises , and lean mass at baseline , 6 , 18 , and 36 months . Results : The groups were similar at baseline . Testosterone administration for 3 years was associated with significantly greater performance in unloaded and loaded stair-climbing power  than placebo ( mean estimated between-group difference , 10.7 W [ 95 % confidence interval ( CI ) , −4.0 to 25.5 ] , P = 0.026 ; and 22.4 W [ 95 % CI , 4.6 to 40.3 ] , P = 0.027 ) , respectively . Changes in chest-press strength ( estimated mean difference , 16.3 N ; 95 % CI , 5.5 to 27.1 ; P < 0.001 ) and power ( mean difference 22.5 W ; 95 % CI , 7.5 to 37.5 ; P < 0.001 ) , and leg-press power were significantly greater in men r and omized to testosterone than in those r and omized to  placebo . Lean body mass significantly increased more in the testosterone group . Conclusion : Compared with placebo , testosterone replacement in older men for 3 years was associated with modest but significantly greater improvements in stair-climbing power , muscle mass , and power . Clinical meaningfulness of these treatment effects and their impact on disability in older adults with functional limitations remains to be studied BACKGROUND Muscle power ( force x velocity ) recedes at a faster rate than strength with age and may also be a stronger predictor of fall risk and functional decline . The optimal training paradigm for improving muscle power in older adults is not known , although some literature suggests high velocity , low load training is optimal in young adults . METHODS One hundred twelve healthy older adults ( 69 + /- 6 years ) were r and omly assigned to either explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) one repetition maximum ( 1RM ) for 8 - 12 weeks or to a nontraining control group ( CON ) . Participants trained twice per week ( five exercises ; three sets of eight rapidly concentric and slow eccentric repetitions ) using pneumatic resistance machines . Repeated- measures analysis of variance and covariance ( ANOVA and ANCOVA ) were used to determine the effects of training . RESULTS Average peak power increased significantly and similarly in G80 ( 14 + /- 8 % ) , G50 ( 15 + /- 9 % ) , and G20 ( 14 + /- 6 % ) compared to CON ( 3 + /- 6 % ) ( p < .0001 ) . By contrast , a positive dose-response relationship with training intensity was observed for relative changes in average strength ( r = .40 , p = .0009 ) and endurance ( r = .43 , p = .0005 ) . Average strength increased in G80 ( 20 + /- 7 % ) , G50 ( 16 + /- 7 % ) , and G20 ( 13 + /- 7 % ) compared to CON ( 4 + /- 4 % ) ( p < .0001 ) . Average muscle endurance increased in G80 ( 185 + /- 126 % , p < .0001 ) , G50 ( 103 + /- 75 % , p = .0004 ) , and G20 ( 82 + /- 57 % , p = .0078 ) compared to CON ( 28 + /- 29 % ) . CONCLUSION Peak muscle power may be improved similarly using light , moderate , or heavy resistances , whereas there is a dose-response relationship between training intensity and muscle strength and endurance changes . Therefore , using heavy loads during explosive resistance training may be the most effective strategy to achieve simultaneous improvements in muscle strength , power , and endurance in older adults Improving muscle strength and power may mitigate the effects of sarcopenia , but it is unknown if this improves an older adult ’s ability to recover from a large postural perturbation . Forward tripping is prevalent in older adults and lateral falls are important due to risk of hip fracture . We used a forward and a lateral single-step balance recovery task to examine the effects of strength training ( ST ) or power ( PT ) training on single-step balance recovery in older adults . Twenty older adults ( 70.8±4.4 years , eleven male ) were r and omly assigned to either a 6-week ( three times/week ) lower extremity ST or PT intervention . Maximum forward ( FLeanmax ) and lateral ( LLeanmax ) lean angle and strength and power in knee extension and leg press were assessed at baseline and follow-up . Fifteen participants completed the study ( ST = 7 , PT = 8) . Least squares means ( 95 % CI ) for ΔFLeanmax ( ST : + 4.1 ° [ 0.7 , 7.5 ] ; PT : + 0.6 ° [ −2.5 , 3.8 ] ) and ΔLLeanmax ( ST : + 2.2 ° [ 0.4 , 4.1 ] ; PT : + 2.6 ° [ 0.9 , 4.4 ] ) indicated no differences between groups following training . In exploratory post hoc analyses collapsed by group , ΔFLeanmax was + 2.4 ° ( 0.1 , 4.7 ) and ΔLLeanmax was + 2.4 ° ( 1.2 , 3.6 ) . These improvements on the balance recovery tasks ranged from ~15%–30 % . The results of this preliminary study suggest that resistance training  may improve balance recovery performance , and that , in this small sample , PT did not lead to larger improvements in single-step balance recovery compared to ST Fighting against inactivity and inadequate nutritional intake are of utmost importance in the elderly . To our knowledge , the few studies which have been performed were conducted for only a short period and the results do not permit formal conclusions to be drawn . We therefore tried to fill this gap in our knowledge by determining whether an intervention combining an acceptable progressive exercise programme and nutritional supplements would be feasible for a long-term period in the very frail elderly , and would bring about concomitant benefits in body composition and muscle power . Accordingly , this exercise and nutritional combination was assessed in the frail elderly in a 9-month r and omised trial with a factorial design . Fifty-seven elderly volunteers over 72 years , from sixteen retirement homes in Lyon , France participated in the study .  Dietary supplements were compared with placebo , and physical exercise was compared with memory training . Main outcome measures were fat-free mass ( FFM ) and muscle power . FFM was determined by labelled water , and muscle power was measured by a leg-extensor machine . At 9 months , the compliance was 63 % for exercise sessions , and 54 % for nutritional supplements . In patients with dietary supplements , muscle power increased by 57 % at 3 months ( P=0.03 ) , and showed only a tendency at 9 months ; although FFM increased by 2.7 % at 9 months , the difference was not significant ( P=0.10 ) . Exercise did not improve muscle power at 9 months , but improved functional tests ( five-time-chair rise , P=0.01 ) . BMI increased with supplements ( + 3.65 % ) , but decreased with placebo ( -0.5 % ) at 9 months ( P=0.007 ) . A long-term combined intervention is feasible in frail elderly individuals with a good rate of compliance . Nutritional supplements and exercise may improve muscle function . Despite no significant results on FFM , due to the limited number of volunteers , combined intervention should be suggested to counteract muscle weakness in the frail elderly OBJECTIVE To test which rehabilitative impairments are associated with higher mobility performance among community-dwelling , mobility-limited older adults . DESIGN Cross-sectional analysis of baseline data from participants within a r and omized controlled trial . SETTING Outpatient rehabilitation research center . PARTICIPANTS Community-dwelling older adults ( N=138 ; mean age , 75.4 y ) with mobility limitations as defined by the Short Physical Performance Battery ( SPPB ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Balance measured via the Berg Balance Scale , leg strength , leg velocity , submaximal aerobic capacity , body mass index ( BMI ) , and mobility performance as measured by the SPPB . RESULTS Each of the 5 physiologic attributes ( unipedal balance , leg strength , leg velocity , submaximal aerobic capacity , BMI ) was categorized into tertiles by using lower values as reference for impairment status . Within an adjusted model , measures associated with higher SPPB performance ( > 9 ) included a BBS score greater than or equal to 54 ( odds ratio [OR]=4.54 ; 95 % confidence interval [ CI ] , 1.11 - 18.60 ) , leg strength greater than or equal to 21.5 N/kg ( OR=30.35 ; 95 % CI , 5.48 - 168.09 ) , leg velocity .0101 to .0129 m.s(-1).kg(-1 ) ( OR=5.31 ; 95 % CI , 1.25 - 22.57 ) , and leg velocity greater than or equal to .0130 m.s(-1).kg(-1 ) ( OR=22.86 ; 95 % CI , 3.88 - 134.75 ) . CONCLUSIONS Our investigation highlights the importance of rehabilitative impairments in leg strength , leg velocity , and balance as being associated with mobility status as measured by the SPPB . In our sample of participants within an exercise trial , submaximal aerobic capacity and BMI status were not associated with mobility performance . These findings suggest that the augmentation of not only leg strength and balance but also leg velocity may be important in the rehabilitative care of mobility-limited older adults OBJECTIVE To determine the effect of training intensity on the contributions of force and velocity to improvements in peak power ( PP ) after explosive resistance training in older adults . METHODS 112 healthy older adults ( 69 + /- 6 yr ) were r and omized to explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) maximal strength ( 1-repetition maximum ) for 8 - 12 wk ( twice weekly , 5 exercises , 3 sets of 8 explosive concentric/slow eccentric repetitions ) using pneumatic resistance machines or a nontraining control group ( CON ) . RESULTS Force at peak power ( FPP ) increased significantly and similarly among training groups compared with CON . Velocity at peak power ( VPP ) did not improve significantly and remained similar between all groups . Force contributed significantly more to PP production in G80 and G50 than in CON . The change in PP was independently predicted by changes in fat-free mass in G80 and by changes in both FPP and VPP in G50 and G20 . CONCLUSION Explosive resistance training in older adults results in the ability to produce higher PP outputs with heavier loads without loss of movement velocity . Moderate- to high-intensity training induced a greater relative contribution of force to PP production in this cohort To determine whether 10 weeks of whole-body vibration ( WBV ) training has a significant effect on strength , muscle mass , muscle power , and mobility in older women , 26 subjects were r and omly assigned to a  WBV training group ( n=13 ; mean age 79 years ) and a control ( CON ) group ( n=13 ; mean age 76 years ) . Maximal voluntary isometric contraction ( MVIC ) increased 38.8 % in the WBV group , without changes in the CON group . Electromyographic activity of the vastus medialis ( VM ) , the vastus lateralis , and the biceps femoris ( BF ) did not change in either group . Thigh muscle cross-sectional area increased significantly after training in VM ( 8.7 % ) and BF ( 15.5 % ) . Muscle power at 20 % , 40 % , and 60 % MVIC decreased from pre-test to post-test in the CON group ; however , WBV training prevented the decrease in the WBV group . Consequently , mobility , measured by the Timed Up and Go test , increased significantly after training ( 9.0 % ) only in the WBV group . Ten weeks of lower limb WBV training in older women produces a significant increase in muscle strength induced by thigh muscle hypertrophy , with no change in muscle power . The adaptations to WBV found in the present study may be of use in counteracting the loss of muscle strength and mobility associated with age-induced sarcopenia The purpose s of this study were to examine age and gender differences in knee extensor strength , power , and fatigue using open- and closed-chain testing procedures . We tested the hypothesis that specific strength ( strength/unit muscle mass ) would not differ by age , whereas age differences in specific power and fatigue would remain consequent to blunted maximal contractile velocity . Skeletal muscle performance was examined in 28 young ( 26.9 + /- 0.7 yr ) and 24 older ( 63.6 + /- 0.8 yr ) men and women . Assessment s included one-repetition maximum strength for knee extension , leg press , and squat ; concentric knee extensor peak power , velocity , and fatigability ; and  sit-to-st and power , fatigability , and relative neural activation ( electromyograph activity during sit-to-st and movement normalized to electromyograph activity during isometric maximum voluntary contraction ) . Thigh lean mass ( TLM ; kg ) was assessed by dual-energy X-ray absorptiometry . Specific strength ( N/kg TLM ) and specific power ( W/kg TLM ) were estimated by dividing absolute values by TLM . Age differences in specific strength were observed for knee extension only ( young , 41.2 + /- 1.0 N/kg TLM ; older , 32.4 + /- 1.0 N/kg TLM ; P < 0.05 ) . Adjustment for TLM did not negate age differences in knee extension specific power ( 25 - 41 % lower in older ; P < 0.05 ) across loads tested . Older adults experienced fatigue across 10 repetitions of knee extension as peak velocity fell by 24 % ( P < 0.05 ) . Deficits in concentric power persist after adjustment for TLM as maximum contractile velocity falls markedly with aging . Older adults are less capable of sustaining maximum concentric velocity during repetitive contractions . These findings suggest that velocity impairments are a possible contributor to mobility loss and falls risk among older adults . Interventions for improving contractile velocity should be pursued PURPOSE A decrease in strength , and its associated loss of functional ability is common among the elderly . Although resistance training can reverse this decline , associated injuries with frequently used strength assessment s may present a greater risk . METHODS To evaluate the injuries associated with maximal strength evaluations , 83 relatively healthy elderly subjects ( 40 men and 43 women , 65.8 + /- 6.2 years ) with and without prior weight training experience performed 1 repetition maximum testing ( 1 RM ) involving 5 different exercises : chest press , leg extension , abdominal curl , arm curl , and seated calf raise . Subjects were separated into three groups depending on weight training experience , Group 1 had no weight training experience ( n = 32 ) , Group 2 had < 6 months of training ( n = 24 ) , and Group 3 had > 6 months of training ( n = 27 ) . Injury assessment was made 30 minutes , 2 days , and 7 days posttesting . RESULTS Two Group 1 subjects sustained an injury ( 2.4 % of total subjects , 8 % of Group 1 ) . Eighty-one subjects safely completed the 1 RM assessment without injury ( 97.6 % of total ) . Forty-eight of the 83 subjects complained of muscle soreness after testing ( 58 % of total ) . This complaint alone was not sufficient to be categorized as an injury . CONCLUSIONS These results indicate that 1 RM testing is an acceptable tool in strength evaluations in the elderly . Additional pre caution s may be needed in inexperienced , elderly individuals to prevent injury Background and aims : This study investigated whether high-velocity high-power training ( POW )  improved lower extremity muscle power and quality in functionally-limited elders greater than traditional slow-velocity progressive resistance training ( STR ) . Methods : Fifty-seven community-dwelling older adults aged 74.2±7 ( range 65–94 yrs ) , Short Physical Performance Battery score 7.7±1.4 , were r and omized to either POW ( n=23 ) ( 12 females ) , STR ( n=22 ) ( 13 females ) or a control group of lower extremity stretching ( CON ) ( n=12 ) ( 6 females ) . Training was performed three times per week for 12 weeks and subjects completed three sets of double leg press and knee extension exercises at 70 % of the one repetition maximum ( 1RM ) . Outcome measures included 1RM strength and peak power ( PP ) . Total leg lean mass was determined using dual-energy X-ray absorptiometry to estimate specific strength and specific PP . Results : During training , power output was consistently higher in POW compared to STR for knee extension ( ∼2.3-fold ) and leg press ( ∼2.8-fold ) exercises ( p<0.01 ) . Despite this , PP and specific PP of the knee extensors increased similarly from baseline in POW and STR compared to CON ( p<0.01 ) , and no significant time-group interaction occurred for PP of the leg extensors . However , gains in leg press specific PP were significantly greater in POW compared to both STR and CON ( p<0.05 ) . Total leg lean mass did not change within any group . Conclusions : A short-term intervention of high-velocity power training and traditional slow-velocity progressive resistance training yielded similar increases of lower extremity power in the mobility-impaired elderly . Neuromuscular adaptations to power training , rather than skeletal muscle hypertrophy , may have facilitated the improvements in muscle quality . Additional studies are warranted to test the efficacy of power training in older individuals with compromised physical functioning BACKGROUND We compared the effects of two uniquely different lower extremity power training interventions on changes in muscle power , physical performance , neuromuscular activation , and muscle cross sectional area in mobility-limited older adults . METHODS Fifty-two subjects ( 78±5 years , short physical performance battery score : 8.1±1 ) were r and omized to either 16 weeks of progressive high velocity resistance training performed at low external resistance ( 40 % of the 1-repetition maximum [ 1-RM ] [ LO ] ) or high external resistance ( 70 % of 1RM [ HI ] ) . Both groups completed three sets of leg and knee extension exercises at maximum voluntary velocity , two times per  week . Neuromuscular activation was assessed  using surface electromyography and muscle cross sectional area ( CSA ) was measured using computed tomography . RESULTS At 16 weeks , LO and HI exhibited significant and similar within-group increases of leg extensor peak power ( ~34 % vs ~42 % ) , strength ( ~13 % vs ~19 % ) , and SPPB score ( 1.4±0.3 vs 1.8±0.3 units ) , respectively ( all P < .03 ) . Improvements in neuromuscular activation occurred in LO ( P = .03 ) while small gains in mid-thigh muscle CSA were detected in LO ( 1.6 % , P = .35 ) and HI ( 2.1 % , P = .17 ) . No significant between-group differences were evident for any measured parameters ( all P > .25 ) . CONCLUSIONS High velocity resistance training with low external resistance yields similar improvements in muscle power and physical performance compared to training with high external resistance in mobility-limited elders . These findings may have important implication s for optimizing exercise interventions for older adults with mobility limitations BACKGROUND chronological age is widely used as a marker of frailty in clinical practice . However there can be wide variation in frailty between individuals of a similar age .  Grip strength is a powerful predictor of disability , morbidity and mortality which has been used in a number of frailty scores but not as a single marker of frailty . OBJECTIVE to investigate the potential of  grip strength  as a single marker of frailty in older people of similar chronological age . DESIGN cross-sectional study with prospect i ve collection of mortality data . SETTING North Hertfordshire , UK . SUBJECTS 717 men and women , aged 64 - 74 , born and still living in North Hertfordshire , who took part in a previous study to investigate the relationship between size at birth and ageing processes in later life . METHODS the number of significant associations between grip strength and the ageing markers was compared with numbers between chronological age and the ageing markers . RESULTS in men , lower grip strength correlated significantly with ten ageing markers compared to chronological age which was significantly associated with seven . In women , there were six significant relationships for grip compared to three for age . The greater number of relationships between grip strength and ageing markers was not explained by the association between grip strength and age , and remained after adjustment for adult size . CONCLUSIONS grip strength was associated with more markers of frailty than chronological age within the narrow age range studied . Grip strength may prove a more useful single marker of frailty for older people of similar age than chronological age alone . Its validity in a clinical setting needs to be tested OBJECTIVES The purpose of this study was to assess the influence of leg power and leg strength on the physical performance of community-dwelling mobility-limited older people . DESIGN Cross-sectional analysis of baseline data from a 12-week r and omized controlled exercise-intervention study . SETTING Exercise laboratory within the Department of Health Science of an urban university . PARTICIPANTS Forty-five community-dwelling mobility-limited people ( 34 women , 11 men ) , aged 65 to 83 . MEASUREMENTS Health status , depression , cognition , physical activity , and falls efficacy ; physiological measures of lower extremity strength and power ; and measures of physical performance . RESULTS Through bivariate analyses , leg power  was significantly associated with physical performance as measured by stair-climb time , chair-st and time , t and em gait , habitual gait , maximal gait , and the short physical performance battery describing between 12 % and 45 % of the variance ( R2 ) . Although leg power and leg strength were greatly correlated ( r = .89 ) in a comparison of bivariate analyses of strength or power with physical performance , leg power modeled up to 8 % more of the variance for five of six physical performance measures . Despite limitations in sample size , it appeared that , through quadratic modeling , the influence of leg power on physical performance was curvilinear . Using separate multivariate analyses , partial R2 values for leg power and leg strength were compared , demonstrating that leg power accounted for 2 % to 8 % more of the variance with all measures of physical performance . CONCLUSION Leg power  is an important factor influencing the physical performance of mobility-limited older people . Although related to strength , it is a separate attribute that may exert a greater influence on physical performance . These findings have important implication s for clinicians practicing geriatric rehabilitation OBJECTIVES To evaluate a dynamic form of weighted vest exercise suitable for home use and design ed to enhance muscle power , balance , and mobility . DESIGN A single-blind , r and omized , controlled trial . SETTING Outpatient exercise research facility situated within an academic long-term care center . PARTICIPANTS Twenty-one community-dwelling women aged 70 and older with a Short Physical Performance Battery ( SPPB ) score between 4 and 10 ( out of 12 ) . INTERVENTIONS Subjects were r and omized into a progressive resistance-training program using weighted vests for resistance with exercises design ed to be specific to mobility tasks and have a component performed at the fastest possible velocity ( Increased Velocity Exercise Specific to Task ( InVEST ) , n=11 ) or a control exercise group ( control , n=10 ) , which performed slow-velocity , low-resistance exercise . Both groups exercised three times a week for 12 weeks . MEASUREMENTS Changes in muscle power , balance , and physical performance were compared . RESULTS In comparison to control group , InVEST group manifested significant improvements ( P<.05 ) in leg power across measurements obtained at 75 % to 90 % of the one-repetition maximum . Both groups demonstrated significant improvements in chair st and and SPPB score from baseline , and the InVEST group showed significant improvements in gait speed and chair st and from baseline ( P<.05 ) . InVEST produced significantly greater changes in chair st and time than control ( P<.05 ) . CONCLUSION InVEST training appears be an effective means of enhancing leg power and chair rise in this population and is worthy of further investigation as a means of enhancing balance and mobility This r and omized controlled trial examined the effects of multicomponent training on muscle power output , muscle mass , and muscle tissue attenuation ; the risk of falls ; and functional outcomes in frail nonagenarians . Twenty-four elderly ( 91.9 ± 4.1 years old ) were r and omized into intervention or control group . The intervention group performed a twice-weekly , 12-week multicomponent exercise program composed of muscle power training ( 8–10 repetitions , 40–60 % of the one-repetition maximum ) combined with balance and gait retraining .  Strength and power tests were performed on the upper and lower limbs . Gait velocity was assessed using the 5-m habitual gait and the time-up- and -go ( TUG ) tests with and without dual-task performance . Balance was assessed using the FICSIT-4 tests . The ability to rise from a chair test was assessed , and data on the incidence and risk of falls were assessed using question naires . Functional status was assessed before measurements with the Barthel Index . Midthigh lower extremity muscle mass and muscle fat infiltration were assessed using computed tomography . The intervention group showed significantly improved TUG with single and dual tasks , rise from a chair and balance performance ( P < 0.01 ) , and a reduced incidence of falls . In addition , the intervention group showed enhanced muscle power and strength ( P < 0.01 ) . Moreover , there were significant increases in the total and high-density muscle cross-sectional area in the intervention group . The control group significantly reduced strength and functional outcomes . Routine multicomponent exercise intervention should be prescribed to nonagenarians because overall physical outcomes are improved in this population PURPOSE To compare the effects of the 16-wk training period ( 2 d.wk(-1 ) ) of resistance training alone ( S ) , endurance training alone ( E ) , or combined resistance ( once weekly ) and endurance ( once weekly ) training ( SE ) on muscle mass , maximal strength and power of the leg and arm extensor muscles , and maximal workload ( Wmax ) by using a incremental cycling test in older men . METHODS Thirty-one healthy men ( 65 - 74 yr ) were divided into three treatment groups to train 2x wk(-1 ) for 16 wk : S ( N = 10 ) , E ( N = 11 ) , or SE ( N = 10 ; 1x wk(-1 ) S + 1x wk(-1 ) E ) . The subjects were tested at 8-wk intervals ( i.e. , weeks 8 and 16 ) . RESULTS There were no significant differences between  S- and SE-induced muscle hypertrophy ( 11 % and 11 % ) and maximal strength ( 41 % and 38 % ) gains of the legs as well as between E- and SE-induced Wmax ( 28 % and 23 % ) gains . The increase in arm strength in S ( 36 % ) was greater than that recorded in SE ( 22 % ) and greater than that recorded in E ( 0 % ) . CONCLUSIONS Prolonged combined resistance and endurance training in older men seemed to lead to similar gains in muscle mass , maximal strength , and power of the legs as resistance training alone and to similar gains in maximal peak power output measured in an incremental cycling test as endurance training alone . These findings may have an effect on how resistance exercise is prescribed to older adults BACKGROUND Loss of muscle power due to normal aging has greater functional impact than loss of strength alone . The present study compared two resistance training programs , one aim ed at enhancing muscle power and one at increasing muscle strength , on muscle function and functional performance in older adults . METHODS Sixty-seven healthy , independent older adults ( 65 - 84 years ) were r and omized to a high-velocity varied resistance ( HV ) , constant resistance ( ST ) , or nontraining control ( CO ) group . Participants trained twice weekly for 24 weeks using six exercises .  Dynamic and isometric muscle strength , muscle power , movement velocity , muscle endurance , and a battery of functional performance tasks were assessed . Secondary outcomes included body composition , quality of life , and balance confidence . RESULTS Muscle strength increased significantly ( p < .001 ) and similarly in the training groups compared to controls ( HV , 51.0 + /- 9.0 % ; ST , 48.3 + /- 6.8 % ; CO , 1.2 + /- 5.1 % ) . Peak muscle power also increased with training ( p < .05 ) , with no difference between training groups . The change in peak power was 50.5 + /- 4.1 % , 33.8 + /- 3.8 % , and -2.5 + /- 3.9 % in the HV , ST , and CO groups , respectively . Training also improved selected functional performance tasks in the HV and ST groups compared to controls ( p < .05 ) , and the HV group reported improved quality of life ( p = .018 ) . CONCLUSION Muscle power and muscle strength improved similarly using either resistance training protocol , and these changes were accompanied by improvements in several functional performance tasks . However , improvements in the HV group occurred with less total work performed per training session BACKGROUND Identification of the physiologic factors most relevant to functional independence in the elderly population is critical for the design of effective interventions . It has been suggested that muscle power may be more directly related to impaired physical performance than muscle strength in elderly persons . We tested the hypothesis that peak muscle power is closely associated with self-reported functional status in sedentary elderly community-dwelling women . METHODS We used baseline data that were collected as part of a 1-year r and omized controlled clinical trial of a combined program of strength , power , and endurance training in 80 elderly women ( mean age 74.8 + /- 5.0 years ) with 3.2 + /- 1.9 chronic diseases , selected for baseline functional impairment and /or falls . RESULTS Functional status at baseline was related in univariate analyses to physiologic capacity , habitual physical activity level , neuropsychological status , and medical diagnoses . Leg power had the strongest univariate correlation to self-reported functional status ( r = -.47 , p < .0001 ) of any of the physiologic factors we tested . In a forward stepwise regression model , leg press power and habitual physical activity level were the only two factors that contributed independently to functional status ( r = .64 , p < .0001 ) , accounting for 40 % of the variance in functional status . CONCLUSIONS Leg power is a strong predictor of self-reported functional status in elderly women Concurrent training is an effective method for increasing skeletal muscle performance in aging individuals , but controversy exists as to whether chronic neuromuscular and functional adaptations are affected by the intra-session exercise sequence . Therefore the aim of this study was to evaluate the effect of concurrent endurance and power-like strength training exercise sequence on muscular and functional adaptations of older participants . Thirty-six healthy older men not engaged in systematic exercise training programs for at least 6 months were divided into a control group ( CON ; 65.8±5.3 years ) , or in the training  groups : endurance-strength ( ES ; 63.2±3.3 years ) , or strength-endurance ( SE ; 67.1±6.1 years ) . Training groups underwent 12 weeks of concurrent endurance and power-like strength training , starting every exercise session with either endurance ( in ES ) or strength ( in SE ) exercises . Measurements included knee extension one repetition maximum ( 1RM ) , knee extension power , 30 second sit-to-st and test ( 30SS ) , maximum vastus lateralis surface electromyographic activity , and rectus femoris echo intensity ( RFEI ) . Significant increases in maximal strength ( ES + 18±11.3 % ; SE + 14.2±6.0 % ; p≤0.05 ) , peak power ( ES + 22.2±19.4 % ; SE + 26.3±31.3 % ; p≤0.05 ) , and 30SS performance ( ES + 15.2±7.2 % ; SE + 13.2±11.8 % ; p≤0.05 ) were observed only in the training groups , with no differences between ES and SE . Maximum muscular activity was greater after 12weeks at training groups ( p≤0.05 ) , and reductions in RFEI were found only in ES and SE ( p≤0.05 ) . These results demonstrate that concurrent strength and endurance training performed twice a week effectively increases muscular performance and functional capacity in older men , independent of the intra-session exercise sequence . Additionally , the RFEI decreases indicate an additional adaptation to concurrent training OBJECTIVES From among physiological attributes commonly targeted in rehabilitation , to identify those in which changes led to clinical ly meaningful differences ( CMDs ) in mobility outcomes . DESIGN Secondary analysis of data collected for a r and omized controlled trial of exercise using binary outcomes defined by recording a large CMD ( Short Physical Performance Battery (SPPB)=1 unit ; gait speed (GS)=0.1 m/s ) . Iterative models were performed to evaluate possible confounding between physiological variables and relevant covariates . SETTING Outpatient rehabilitation centers . PARTICIPANTS Community-dwelling mobility-limited older adults ( n=116 ) participating in a 16-week r and omized controlled trial of two modes of exercise .  MEASUREMENTS Physiological measures included leg power , leg strength , balance as measured according to the Performance-Oriented Mobility Assessment ( POMA ) , and rate pressure product at the maximal stage of an exercise tolerance test . Outcomes included GS and SPPB . Leg power and leg strength were measured using computerized pneumatic strength training equipment and recorded in Watts and Newtons , respectively . RESULTS Participants were 68 % female , had a mean age of 75.2 , a mean of 5.5 chronic conditions , and a baseline mean SPPB score of 8.7 . After controlling for age , site , group assignment , and baseline outcome values , leg power was the only attribute in which changes were significantly associated with a large CMD in SPPB ( odds ratio (OR)=1.48 , 95 % confidence interval (CI)=1.09 - 2.02 ) and GS ( OR=1.31 , 95 % CI=1.01 - 1.70 ) . CONCLUSION Improvements in leg power , independent of strength , appear to make an important contribution to clinical ly meaningful improvements in SPPB and GS BACKGROUND Lower muscle mass has been correlated with poor physical function ; however , no studies have examined this relationship prospect ively . This study aims to investigate whether low muscle mass , low muscle strength , and greater fat infiltration into the muscle predict incident mobility limitation . METHODS Our study cohort included 3075 well-functioning black and white men and women aged 70 - 79 years participating in the Health , Aging , and Body Composition study . Participants were followed for 2.5 years . Muscle cross-sectional area and muscle tissue attenuation ( a measure of fat infiltration ) were measured by computed tomography at the mid-thigh , and knee extensor strength by using a KinCom dynamometer .  Incident mobility limitation was defined as two consecutive self-reports of any difficulty walking one-quarter mile or climbing 10 steps . RESULTS Mobility limitations were developed by 22.3 % of the men and by 31.8 % of the women . Cox 's proportional hazards models , adjusting for demographic , lifestyle , and health factors , showed a hazard ratio of 1.90 [ 95 % confidence interval ( CI ) , 1.27 - 2.84 ] in men and 1.68 ( 95 % CI , 1.23 - 2.31 ) in women for the lowest compared to the highest quartile of muscle area ( p < .01 for trend ) . Results for muscle strength were 2.02 ( 95 % CI , 1.39 - 2.94 ) and 1.91 ( 95 % CI , 1.41 - 2.58 ) , p < .001 trend , and for muscle attenuation were 1.91 ( 95 % CI , 1.31 - 2.83 ) and 1.68 ( 95 % CI , 1.20 - 2.35 ) , p < .01 for trend . When included in one model , only muscle attenuation and muscle strength independently predicted mobility limitation ( p < .05 ) . Among men and women , associations were similar for blacks and whites . CONCLUSION Lower muscle mass ( smaller cross-sectional thigh muscle area ) , greater fat infiltration into the muscle , and lower knee extensor muscle strength are associated with increased risk of mobility loss in older men and women . The association between low muscle mass and functional decline seems to be a function of underlying muscle strength BACKGROUND This study was design ed to evaluate the benefits of InVEST ( Increased Velocity Specific to Task ) training on limb power and mobility among mobility-limited older adults . METHODS We conducted a single blinded , r and omized controlled trial among 138 mobility-limited community-dwelling older adults , evaluating two 16-week supervised exercise programs . The intervention group participated in InVEST training , and the control group participated in the National Institute on Aging 's ( NIA ) strength training program . Primary outcomes were changes in limb power per kilogram and mobility performance as measured by the Short Physical Performance Battery ( SPPB ) . RESULTS After 16 weeks , InVEST produced significantly greater improvements in limb power than NIA ( p=.02 ) . There was no significant difference in strength improvements . Both groups had significant changes in SPPB of greater than 1 unit . Self-reported function was also significantly improved in both groups . Differences between groups were not statistically different . In a post hoc analysis when participants were categorized by the manifestation of baseline leg velocity impairments ( N=68 ) , InVEST training produced effect size differences in SPPB that were clinical ly meaningful ( SPPB Group x Time difference 0.73 units , p=.05 ) . CONCLUSIONS Among mobility-limited older adults , both NIA and InVEST produce robust changes in observed physical performance and self-reported function . These improvements were not meaningfully different by statistical or clinical criteria . Compared with NIA , InVEST training produced greater improvements in limb power and equivalent improvements in strength . Observed differences between NIA and InVEST based upon baseline leg impairment status are informative for futures studies Hanson , ED , Srivatsan , SR , Agrawal , S , Menon , KS , Delmonico , MJ , Wang , MQ , and Hurley , BF . Effects of strength training on physical function : influence of power , strength , and body composition . J Strength Cond Res 23(9 ) : 2627 - 2637 , 2009-The purpose of this study was to determine ( a ) the effects of strength training ( ST ) on physical function and ( b ) the influence of strength , power , muscle volume ( MV ) , and body composition on physical function . Healthy , inactive adults ( n = 50 ) aged 65 years and older underwent strength , power , total body composition ( % fat and fat free mass [ FFM ] ) , and physical function testing before and after 22 weeks of ST . Physical function testing consisted of tasks design ed to mimic common physical activities of daily living ( ADL ) . To improve internal validity of the assessment of mid-thigh intermuscular fat , subcutaneous fat , and knee extensors MV , a 10-week unilateral ST program using the untrained leg as an internal control preceded 12 weeks of whole-body ST . Strength , power , and FFM increased significantly with ST ( all p < 0.05 ) , whereas rapid walk , 5 chair st and s , and get up and go time decreased significantly with ST in the overall group ( all p < 0.05 ) . Women improved significantly in both walking test times ( both p < 0.05 ) but not in the stair climb test , whereas men improved in the stair climb test ( p < 0.05 ) but not in walking test times . Multiple regression analysis revealed the highest R2 ( 0.28 ) for the change in chair st and s time , followed by stair climb and usual walk at 0.27 and 0.21 , respectively . ST improves performance in functional tasks important for ADLs . Changes in strength , power , and FFM are predictors of ST-induced improvements in these tasks OBJECTIVE To determine whether trunk extension endurance changes with training are associated with clinical ly meaningful improvements in balance among mobility-limited older adults . DESIGN Longitudinal data from a r and omized controlled trial . SETTING Outpatient rehabilitation research center . PARTICIPANTS Community-dwelling older adults ( N=64 ; mean age , 75.9y ) with mobility limitations as defined by a score of 4 to 10 on the Short Physical Performance Battery . INTERVENTIONS Sixteen weeks of progressive resistance training . MAIN OUTCOME MEASURES Outcomes were the Berg Balance Scale ( BBS ) and the Unipedal Stance Time ( UST ) . Predictors included leg strength , leg power , trunk extension endurance , and the product of heart rate and blood pressure ( RPP ) at the final stage of an exercise tolerance test . We performed an analysis of data from participants who completed 16 weeks of training by using binary outcomes defined by a clinical ly meaningful change ( CMC ) from baseline to completion of the intervention ( BBS=4 units ; UST=5s ) . The association of predictor variables with balance outcomes was examined separately and together in multivariate adjusted logistic regression models . RESULTS Trunk extension endurance in seconds ( 1.04 [ 1.00 - 1.09 ] ) was independently associated with CMC on the BBS . Trunk extension endurance ( 1.02 [ 1.00 - 1.03 ] ) was independently associated with CMC on the UST . Other physical attributes were not associated with meaningful change in balance . CONCLUSIONS Improvements in trunk extension endurance were independently associated with CMCs in balance in older adults . Leg strength , leg power , and RPP were not associated with CMC in balance . Poor trunk extension endurance may be a rehabilitative impairment worthy of further study as a modifiable factor linked to balance among older adults BACKGROUND Progressive loss of muscle and strength with age is often coincident with increases in adiposity , leading to a condition called sarcopenic obesity . Studies have shown sarcopenic obese adults to be at higher risk for declines in physical function . Despite this rising public health concern , no intervention studies currently exist in this population . METHODS A total of 21 sarcopenic obese adults , 60 years or older , were r and omized into two groups , strength/hypertrophy ( SH , n=9 ) and high-speed circuit ( HSC , n=8 ) and were trained for 15 weeks . The primary outcome was the SPPB modified as a measure of physical function , assessed by assessors blinded to r and omization . Secondary outcomes were lower body and upper body power and strength , instrumental activities of daily living ( IADL ) , ratings of perceived exertion ( RPE ) , body fat % ( BF% ) , skeletal muscle index ( SMI ) , and grip strength ( GRP ) . RESULTS For the SPPB results favored HSC over SH ( 1.1 , 95 % CI ( -.1 to 2.4 ) , p=.08 ) and showed a moderate effect size ( Hedge g=0.6 , 95 % CI ( -0.4 , 1.6 ) ) . For secondary outcomes , lower body power ( mean difference=158 W , 95 % CI ( 2 , 315 ) ; p=.01 ) and RPE ( mean difference=-1.5 , 95 % CI ( -2.9 , -0.12 ) ; p=.04 ) also favored HSC . IADL , SMI , BF% , upper and lower body strength and upper body power , showed no statistically significant differences between groups . CONCLUSIONS Considering the moderate effect size , the large treatment effect shown by the upper limit of the 95 % CI , the low perceived exertion , and no adverse effects , HSC training should be further investigated with a larger sample size in sarcopenic obese adults OBJECTIVES To evaluate weighted stair climbing exercise ( SCE ) as a means of increasing lower extremity muscle power in mobility-limited older people . DESIGN Single-blinded , r and omized controlled pilot study . SETTING Human physiology laboratory of a metropolitan university . PARTICIPANTS Forty-five community-dwelling people aged 65 and older who had baseline mobility limitations manifested by scores of 11 or lower on the Short Physical Performance Battery ( SPPB ) . INTERVENTIONS Subjects were r and omized into one of two 12-week exercise programs . The intervention group ( SCE ) ( n = 23 ) ascended and descended stairs , at a set pace , while wearing a weighted vest . The control group ( WALK ) ( n = 22 ) participated in a st and ardized walking program . MEASUREMENTS Primary and secondary outcomes included measures of muscle power and strength , submaximal aerobic capacity , and physical performance . RESULTS SCE produced 17 % improvement in double leg press peak power in comparison with WALK ( P = .013 ) and significant improvement in stair climbing power from baseline ( 12 % ) . Improvement in submaximal aerobic performance was equivalent for both groups . Although not statistically significant , effect size estimates suggest that SCE can potentially influence knee extension power and strength . Stair climb time was improved in both groups , whereas SCE produced significant improvements from baseline SPPB score in a subcohort of participants . CONCLUSIONS These findings suggest that SCE maybe a useful component of a home exercise program design ed to enhance lower extremity muscle power , aerobic capacity , and functional performance . Further investigation is needed involving larger sample sizes and direct comparisons with other forms of resistance training It is unclear whether strength training ( ST ) or power training ( PT ) is the more effective intervention at improving muscle strength and power and physical function in older adults . The authors compared the effects of lower extremity PT with those of ST on muscle strength and power in 45 older adults ( 74.8 + /- 5.7 yr ) with self-reported difficulty in common daily activities . Participants were r and omized to 1 of 3 treatment groups : PT , ST , or wait-list control . PT and ST trained 3 times/wk for 12 wk using knee-extension ( KE ) and leg-press ( LP ) machines at approximately 70 % of 1-repetition maximum ( 1RM ) . For PT , the concentric phase of the KE and LP was completed " as fast as possible , " whereas for ST the concentric phase was 2 - 3 s. Both PT and ST paused briefly at the midpoint of the movement and completed the eccentric phase of the movement in 2 - 3 s. PT and ST groups showed significant improvements in KE and LP 1RM compared with the control group . Maximum KE and LP power increased approximately twofold in PT compared with ST . At 12 wk , compared with control , maximum KE and LP power were significantly increased for the PT group but not for the ST group . In older adults with compromised function , PT leads to similar increases in strength and larger increases in power than ST BACKGROUND Whey protein supplementation may augment resistance exercise-induced increases in muscle strength and mass . Further studies are required to determine whether this effect extends to mobility-limited older adults . The objectives of the study were to compare the effects of whey protein concentrate ( WPC ) supplementation to an isocaloric control on changes in whole-body lean mass , mid-thigh muscle cross-sectional area , muscle strength , and stair-climbing performance in older mobility-limited adults in response to 6 months of resistance training ( RT ) . METHODS Eighty mobility-limited adults aged 70 - 85 years were r and omized to receive WPC ( 40g/day ) or an isocaloric control for 6 months . All participants also completed a progressive high-intensity RT intervention . Sample sizes were calculated based on the primary outcome of change in whole-body lean mass to give 80 % power for a 0.05-level , two-sided test . RESULTS Lean mass increased 1.3 % and 0.6 % in the WPC and control groups , respectively . Muscle cross-sectional area was increased 4.6 % and 2.9 % in the WPC and control groups , respectively , and muscle strength increased 16%-50 % in WPC and control groups . Stair-climbing performance also improved in both groups . However , there were no statistically significant differences in the change in any of these variables between groups . CONCLUSIONS These data suggest that WPC supplementation at this dose does not offer additional benefit to the effects of RT in mobility-limited older adults BACKGROUND Muscle power is a key predictor of physical function in older adults ; however , clinical ly meaningful improvements in leg-extensor muscle power have yet to be identified . The purpose of this study is to establish the minimal clinical ly important improvement ( MCII ) and substantial improvement ( SI ) for leg-extensor power and muscle contraction velocity in mobility-limited older adults . METHODS Data were extracted from three r and omized trials of leg-extensor muscle power training interventions ( 3- to 6-month duration ) .  Measurements of leg-extensor power and velocity were obtained using dynamic bilateral leg press at 40 % and 70 % of the one-repetition maximum . Anchor-based MCIIs were calculated using selected items extracted from the Late Life Function and Disability Instrument . St and ard error of measurement and effect size methods were used to calculate the distribution-based MCII . RESULTS Data from 164 participants ( mean age : 76.6 ± 5.6 years ; Short Physical Performance Battery score : 7.8 ± 1.3 ) were used in this analysis . The respective MCII and SI estimates for 40 % leg-extensor power were 18.3 ( 9 % ) and 30.5 ( 15 % ) W , and 23.1 ( 10 % ) and 41.6 ( 18 % ) W for 70 % leg-extensor power . The respective MCII and SI estimates for 40 % average velocity were 0.03(7 % ) and 0.08(18 % ) m/s , and 0.02(6 % ) and 0.05(15 % ) m/s for 70 % average velocity . CONCLUSIONS This is the first study to establish a clinical ly meaningful improvement of leg-extensor power ( 9%-10 % ) and velocity ( 6%-7 % ) in mobility-limited older adults . These findings should be used to aid in the design and interpretation of clinical trials and interventions that target improvements in muscle power in this high-risk population BACKGROUND Age-related decline in muscle power may be an early indicator of balance deficits and fall risk , even in nonfrail adults . This study examined the dose-dependent effect of power training on balance performance in healthy older adults . METHODS One hundred twelve community-dwelling healthy older adults ( 69 + /- 6 years ) were r and omized to 8 - 12 weeks of power training at 20 % ( LOW ) , 50 % ( MED ) , or 80 % ( HIGH ) of maximal strength , or a nontraining control ( CON ) group . Participants trained twice weekly ( five exercises ; three sets of eight rapid concentric/slow eccentric repetitions ) using pneumatic resistance machines .  Balance , muscle performance ( strength , power , endurance , contraction velocity ) , and body composition were measured . RESULTS Power training significantly improved balance performance ( p = .006 ) in participants who underwent power training compared to controls . Low intensity power training produced the greatest improvement in balance performance ( p = .048 ) . Average contraction velocity at low load ( 40 % one repetition maximum [ 1RM ] ) at baseline independently predicted improvement in balance following training ( r = -.29 , p = .004 ) . CONCLUSIONS Power training improves balance , particularly using a low load , high velocity regimen , in older adults with initial lower muscle power and slower contraction . Further studies are warranted to define the mechanisms underlying this adaptation , as well as the optimum power training intensity for a range of physiological and clinical outcomes in older adults with varying levels of health status and functional independence This study investigated the effect of a 10-week power training ( PT ) program versus traditional resistance training ( TRT ) on functional performance , and muscular power and strength in older men . Twenty inactive volunteers ( 60–76 years old ) were r and omly assigned to a PT group ( three 8–10 repetition sets performed as fast a possible at 60 % of 1-RM ) or a TRT group ( three 8–10 repetition sets with 2–3 s contractions at 60 % of 1-RM ) . Both groups exercised 2 days/week with the same work output . Outcomes were measured with the Rikli and Jones functional fitness test and a bench and leg press test of maximal power and strength ( 1-RM ) . Significant differences between and within groups were analyzed using a two-way analysis of variance ( ANOVA ) . At 10 weeks there was a significantly ( P < 0.05 ) greater improvement in measures of functional performance in the PT group . Arm curling improved by 50 versus 3 % and a 30 s chair-st and improved by 43 versus 6 % in the PT and TRT groups , respectively . There was also a significantly greater improvement in muscular power ( P < 0.05 ) in the PT group . The bench press improved by 37 versus 13 % , and the leg press by 31 and 8 % in the PT and TRT groups , respectively . There was no significant difference between groups in improved muscular strength . It appears that in older men there may be a significantly greater improvement in functional performance and muscular power with PT versus low velocity resistance training Abstract Sayers , SP and Gibson , K. High-speed power training in older adults : A shift of the external resistance at which peak power is produced . J Strength Cond Res 28(3 ) : 616–621 , 2014— Studies have shown that power training increases peak power ( PP ) in older adults . Evaluating the external resistance ( % 1 repetition maximum [ 1RM ] ) at which PP is developed is critical given that changes in the components of PP ( force and velocity ) are dependent on the % 1RM at which PP occurs . The purpose of this study was to compare the changes in PP ( and the external resistance at which PP occurred ) after 12 weeks of high-speed power training ( HSPT ) vs. traditional slow-speed strength training ( SSST ) .  Seventy-two older men and women were r and omized to HSPT at 40 % of the 1RM ( HSPT : n = 24 [ 70.8 ± 6.8 years ] ) ; traditional resistance training at 80 % 1RM ( SSST : n = 22 [ 68.6 ± 7.8 years ] ) ; or control ( CON : n = 18 [ 71.5 ± 6.1 years ] ) . Measures of muscle performance were obtained at baseline and after the 12-week training intervention . Changes in muscle power and 1RM strength improved similarly with both HSPT and SSST , but HSPT shifted the external resistance at which PP was produced to a lower external resistance ( from 67 % 1RM to 52 % 1RM ) compared with SSST ( from 65 % 1RM to 62 % 1RM ) ( p ⩽ 0.05 ) , thus increasing the velocity component of PP ( change : HSPT = 0.18 ± 0.21 m·s−1 ; SSST = −0.03 ± 0.15 m·s−1 ) ( p ⩽ 0.05 ) . Because sufficient speed of the lower limb is necessary for functional tasks related to safety ( crossing a busy intersection , fall prevention ) , HSPT should be implemented in older adults to improve power at lower external resistances , thus increasing the velocity component of power and making older adults safer in their environment . These data provide clinicians with the necessary information to tailor exercise programs to the individual needs of the older adult , affecting the components of power OBJECTIVES To assess the ability of gait speed alone and a three-item lower extremity performance battery to predict 12-month rates of hospitalization , decline in health , and decline in function in primary care setting s serving older adults . DESIGN Prospect i ve cohort study . SETTING Primary care programs of a Medicare health maintenance organization ( HMO ) and Veterans Affairs ( VA ) system . PARTICIPANTS Four hundred eighty-seven persons aged 65 and older . MEASUREMENTS  Lower extremity performance Established Population for Epidemiologic Studies of the Elderly ( EPESE ) battery including  gait speed , chair st and s , and t and em balance tests ; demographics ; health care use ; health status ; functional status ; probability of repeated admission scale ( Pra ) ; and primary physician 's hospitalization risk estimate . RESULTS Veterans had poorer health and higher use than HMO members . Gait speed alone and the EPESE battery predicted hospitalization ; 41 % ( 21/51 ) of slow walkers ( gait speed < 0.6 m/s ) were hospitalized at least once , compared with 26 % ( 70/266 ) of intermediate walkers ( 0.6 - 1.0 m/s ) and 11 % ( 15/136 ) of fast walkers ( > 1.0 m/s ) ( P < .0001 ) . The relationship was stronger in the HMO than in the VA . Both performance measures remained independent predictors after accounting for Pra . The EPESE battery was superior to gait speed when both Pra and primary physician 's risk estimate were included . Both performance measures predicted decline in function and health status in both health systems . Performance measures , alone or in combination with self-report measures , were more able to predict outcomes than self-report alone . CONCLUSION Gait speed and a physical performance battery are brief , quantitative estimates of future risk for hospitalization and decline in health and function in clinical population s of older adults . Physical performance measures might serve as easily accessible " vital signs " to screen older adults in clinical setting Sayers SP , Bean J , Cuoco A , LeBrasseur NK , Jette A , Fielding RA : Changes in function and disability after resistance training : Does velocity matter ? A pilot study . Am J Phys Med Rehabil 2003;82:605–613 . Objective To compare the effects of high- and low-velocity resistance training on functional performance and disability outcomes in physically limited older women . Design A total of 16 wk of high-velocity resistance training or traditional low-velocity resistance training consisting of knee extension and leg press exercises was performed three times per week by 30 women with self-reported disability to compare their effect on functional performance and disability . Tests of dynamic balance , stair-climb time , chair-rise time , and gait velocity were used to assess changes in functional performance . Changes in disability were assessed using the Medical Outcomes Study Short Form . Results Dynamic balance and stair-climb time improved 8 % and 10 % , respectively , with training . Self-reported disability , physical functioning , role physical , and mental health improved 11 , 9 , and 5 % with training , respectively . There were no significant differences between high- and low-velocity training groups . Conclusions High- and low-velocity training achieved similar improvements in functional performance and disability . Improvements in functional performance and disability were modest compared with robust increases in strength and power . Specific modes of training or behavioral strategies may be necessary to optimize improvements in these outcomes OBJECTIVES Peak power declines more precipitously than strength with advancing age and is a reliable measure of impairment and a strong predictor of functional performance . We tested the hypothesis that a high-velocity resistance-training program ( HI ) would increase muscle power more than a traditional low-velocity resistance-training program ( LO ) . DESIGN R and omized controlled trial . SETTING University-based human physiology laboratory . PARTICIPANTS Thirty women with self-reported dis-ability ( aged 73 + 1 , body mass index 30.1 + 1.1 kg/mn ) . INTERVENTION We conducted a r and omized trial comparing changes in skeletal muscle power and strength after 16 weeks of HI or LO . Training was performed three times per week , and subjects completed three sets ( 8 - 10 repetitions ) of leg press ( LP ) and knee extension ( KE ) exercises at 70 % of the one-repetition maximum ( IRM ) . MEASUREMENTS One-repetition maximum ( 1 RM ) and peak power for KE and LP . RESULTS LP and KE relative training force and total work were similar between groups ( P > .05 ) . However , HI generated significantly higher power during training sessions than LO for LP ( 3.7-fold greater , P < .001 ) and KE ( 2.1-fold greater , P < .001 ) . Although LP and KE 1RM muscle strength increased similarly in both groups asa result of the training ( P < .001 ) , LP peak power increased significantly more in HI than in LO ( 267 W vs 139 W , P < .001 ) . Furthermore , HI result ed in a significantly greater improvement in LP power at 40 % , 50 % , 60%,70 % , 80 % , and 90 % of the 1 RM than did LO ( P < .05 ) . CONCLUSIONS HI improved 1RM strength similarly and was more effective in improving peak power than was traditional LO in older women . Improvements in lower extremity peak power may exert a greater influence on age-associated reductions in physical functioning than other exercise interventions To examine the effects of different rest intervals on the repeatability of 1 repetition maximum ( 1RM ) efforts in the free-weight back squat exercise , 17 weight-trained men served as subjects ( mean age 22.0 years ) . One repetition maximum was tested on each of the first 2 days of testing to establish a stable baseline ( 1RM = 184.9 kg ) . Each of the next 3 sessions involved performing 2 1RM back squats , with the rest interval between attempted lifts being either 1 , 3 , or 5 minutes , assigned in a counterbalanced fashion . For the 1-minute rest interval , 13 of 17 subjects successfully completed the second lift ; for the 3-minute rest interval , 16 of 17 were successful ; and for the 5-minute rest interval , 15 of 17 were successful . Cochran Q analysis determined no significant difference ( p > 0.05 ) in the ability to repeat a successful maximal-effort back squat when different rest intervals were used . These findings are consistent with the literature for the bench-press exercise and indicate that 1-minute rest intervals are sufficient for recovery between attempted lifts during 1RM testing or training for the free-weight back squat when involving lifters of this caliber OBJECTIVE We examined if the predominant source of dietary protein influenced the lipoprotein-lipid profile in older men who performed resistive exercise training ( RT ) . DESIGN This is a 14-week , r and omized , repeated- measures study with a 12-week period of RT with supplementation of different sources of dietary protein ( beef and soy ) . SETTING Nutrition , Metabolism , and Exercise Laboratory , Central Arkansas Veteran 's Healthcare System , North Little Rock , Ark. Subjects Twenty-six healthy men were recruited , and 21 men ( age 65 + /- 5 years , body mass index 28.2 + /- 2.6 kg/m 2 ) completed the study . Interventions For 14 weeks , all men were counseled to self-select a lacto-ovo-vegetarian diet . For 2 weeks ( baseline ) , all men also consumed 0.6 g-protein/kg per day from portioned quantities of soy-based texturized vegetable protein foods . For the next 12 weeks , 11 men were r and omized to continue with texturized vegetable protein foods ( VEG group ) , whereas 10 men were r and omized to receive 0.6 g-protein/kg per day from portioned quantities of beef ( BEEF group ) and continue their otherwise lacto-ovo-vegetarian diet . All men participated in RT 3 d/wk during this 12-week period . Assessment s of upper and lower body muscle strength and power , serum lipoprotein-lipid profile , and dietary nutrient intakes were made at baseline and week 12 of RT ( POST ) . RESULTS The BEEF and VEG groups increased ( P < .05 ) overall muscle strength and muscle power with RT , with no differences between groups . From baseline to POST , the BEEF group had increased concentrations of high-density lipoprotein cholesterol ( P = .025 ; HDL-C ) , low-density lipoprotein cholesterol ( P = .027 ; LDL-C ) , and total cholesterol ( P = .015 : CHOL ) , with no changes ( P > .05 ) in triacylglycerol ( TG ) , the CHOL/HDL-C ratio , or the TG/HDL-C ratio . The VEG group did not experience within-group changes ( P > .05 ) in any lipoprotein-lipid parameter . At POST , the concentrations of HDL-C , LDL-C , and CHOL were greater in the BEEF group compared with the VEG group . There were significant interaction effects for HDL-C ( P = .004 ) and the TG/HDL-C ratio ( P = .022 ) . Multiple regression analysis determined that , regardless of intervention , change in the saturated fat/fiber ratio ( SF/fiber ) predicted CHOL ( adjusted R 2 = 0.34 ) ; the SF/fiber ratio predicted LDL-C ( adjusted R 2 = 0.36 ) ; the cholesterol/fiber intake ratio predicted HDL-C ( adjusted R 2 = 0.26 ) , and the change in carbohydrate intake predicted the CHOL/HDL-C ratio ( adjusted R 2 = 0.37 ) and TG ( adjusted R 2 = 0.44 ) . CONCLUSIONS These results suggest that the lipoprotein-lipid profile in these older men was differentially affected by supplementation with beef versus soy-based foods during RT . Regardless of group , the lipoprotein-lipid changes were predicted by differences in the SF/fiber ratio and cholesterol/fiber ratio and increases in carbohydrate intake over time UNLABELLED Power-based resistance training ( PWT ) , using low load and high velocity , can improve physical function and quality of life in older persons . Patients with Parkinson 's disease ( PD ) , exhibiting muscular weakness and reduced movement speed , have been shown to be benefit from resistance training ; however , little is known about the advantages of PWT for PD . PURPOSE To evaluate the effects of PWT on bradykinesia and muscular performance in older patients with PD . METHODS Twenty-six patients with mild to moderate PD were r and omly assigned to a PWT or control group ( CON ) . The PWT program was three months , incorporating two sessions/wk of high-speed resistance training combined balance and agility drills . Outcome measures included : upper and lower limb bradykinesia scores , one repetition maximums ( 1RM ) and peak powers on biceps curl , chest press , leg press , hip abduction and seated calf , and quality of life ( PDQ-39 ) . RESULTS The PWT group produced significant improvement in both upper and lower limbs bradykinesia scores , 1RM and muscle peak power ( p < .05 ) , which surpassed the CON group except for power during the seated calf exercise . No significant correlations between changes in clinical measure of bradykinesia and muscle peak power were observed after training . Significant improvements were seen in the PDQ-39 overall score , subsections for mobility , activities of daily living and social support for the PWT group . CONCLUSION The 3-month PWT program significantly reduced bradykinesia and increased muscle strength and power in older patients with PD . Power training is an effective training modality to improve physical function and quality of life for PD Abstract Ni , M and Signorile , JF . High-speed resistance training modifies load-velocity and load-power relationships in Parkinson 's disease . J Strength Cond Res 31(10 ) : 2866–2875 , 2017—Muscle power is a major neuromuscular factor affecting motor function and independence in patients with Parkinson 's disease ( PD ) , and it is commonly targeted using high-speed exercise . This study examined the changes in velocities ( Vpp ) and percent loads ( % 1RMpp ) at peak power and load-velocity ( L-V ) and load-power ( L-P ) relationships , result ing from resistance training because of exercise choice and loading in older patients with PD . Fourteen older adults with mild to moderate PD participated in a 12-week r and omized controlled power training trial . Changes in L-V and L-P relationships for the biceps curl , chest press , leg press , hip abduction , and seated calf were assessed using pneumatic resistance machines at loads ranging from 30 through 90 % of subjects ' 1 repetition maximum for each exercise . Significant increases in Vpp were seen for biceps curl , leg press , hip abduction , and seated calf and decreases in % 1RMpp were noted for biceps curl and hip abduction . Additionally , unique patterns of change were seen in these relationships across exercises , with biceps curl , chest press , and leg press showing the greatest shifts at the lower load end of the loading spectrum , and hip abduction and seated calf showing greatest responses at the higher end . The patterns of change in L-V and L-P relationships provide evidence for the unique responses of the specific muscle groups and joints to the exercises evaluated and offer a framework for more exacting exercise prescriptions in patients with PD
target: Finally , muscle power testing was found to be safe in older people with a broad range of health and functional states
background: Background Muscle power has been proposed to be the primary therapeutic target for resistance training interventions aim ed at enhancing physical function in older adults .
  However , no recommendations exist on ideal testing protocol s to assess muscle power in older adults , and the safety of this procedure has not been adequately evaluated in the literature .
  Methods A systematic review was conducted to identify studies evaluating muscle power exerted by older people in resistance exercises through May 2017 .