title: An examination, correlation, and comparison of static and dynamic measures of postural stability in healthy, physically active adults. Interrater reliability and convergent validity of the American Academy for Cerebral Palsy and Developmental Medicine methodology for conducting systematic reviews. Gait and step training to reduce falls in Parkinson's disease. Changes in postural stability with fatigue of lower extremity frontal and sagittal plane movers. Effectiveness of aquatic and non-aquatic lower limb muscle endurance training in the static and dynamic balance of elderly people. Effects of a Short‐term Dynamic Balance Training Program in Healthy Older Women The effect of lower limb muscle fatigue on obstacle negotiation during walking in older adults. The effect of 15 weeks of exercise on balance, leg strength, and reduction in falls in 40 women aged 65 to 89 years. Effects of isokinetic ankle fatigue on the maintenance of balance and postural limits. Effect of high-intensity strength-training on functional measures of balance ability in balance-impaired older adults.
abstract: OBJECTIVE To examine the relationship and differences between static and dynamic postural stability in healthy , physically active adults . DESIGN Descriptive laboratory study . SETTING Research laboratory . PARTICIPANTS Ten females ( age : 21.6 ± 1.2 yrs , mass : 60.8 ± 7.6 kg , height : 165.0 ± 5.0 cm ) and ten males ( age : 25.1 ± 3.0 yrs , mass : 73.9 ± 8.7 kg , height : 173.5 ± 9.0 cm ) . MAIN OUTCOME MEASURES Static postural stability was measured during a single-leg st and ing task ( st and ard deviation of the ground reaction forces ) . Dynamic postural stability was measured during a single-leg l and ing task using the Dynamic Postural Stability Index . Pearson 's r-coefficients were calculated to examine relationships between the two tests and a one-way ANOVA was calculated to examine potential differences in test scores ( p < 0.05 ) . RESULTS None of the Pearson 's r-coefficients achieved statistical significance . The one-way ANOVA and post hoc comparisons demonstrated that dynamic postural stability scores were significantly higher than static postural stability scores . CONCLUSIONS A lack of a correlation between static and dynamic measures and increase in difficulty during dynamic measures indicates differences in the type and magnitude of challenge imposed by the different postural stability tasks . The more challenging dynamic measures of postural stability may be more suitable for prospect i ve studies examining risk of ankle and knee injury in healthy , physically active individuals AIM The aim of this study was to evaluate the interrater reliability and convergent validity of the American Academy for  Cerebral Palsy and Developmental Medicine  's ( AACPDM ) methodology for conducting systematic review s ( group design studies ) . METHOD Four clinicians independently rated 24 articles for the level of evidence and conduct using AACPDM methodology . Study conduct was also assessed using the Effective Public Health Practice Project scale . Raters were r and omly assigned to one of two pairs to resolve discrepancies . The level of agreement between individual raters and pairs was calculated using kappa ( α=0.05 ) and intraclass correlations ( ICCs ; α=0.05 ) . Spearman 's rank correlation coefficient was calculated to evaluate the relationship between raters ' categorization of quality categories using the two tools . RESULTS There was acceptable agreement between raters ( κ=0.77 ; p<0.001 ; ICC=0.90 ) and between assigned pairs ( κ=0.83 ; p<0.001 ; ICC=0.96 ) for the level of evidence ratings . There was acceptable agreement between pairs for four of the seven conduct questions ( κ=0.53 - 0.87 ) . ICCs ( all raters ) for conduct category ratings ( weak , moderate , and strong ) also indicated good agreement ( ICC=0.76 ) . Spearman 's rho indicated a significant positive correlation for the overall quality category comparisons of the two tools ( 0.52 ; p<0.001 ) . CONCLUSIONS The AACPDM rating system has acceptable interrater reliability . Evaluation of its study quality ratings demonstrated reasonable agreement when compared with a similar tool INTRODUCTION Frequent falls and risk of injury are evident in individuals with Parkinson 's disease ( PD ) as the disease progresses . There have been no reports of any interventions that reduce the incidence of falls in idiopathic PD . PURPOSE Assess the benefit of gait and step perturbation training in individuals with PD . DESIGN R and omized , controlled trial . SETTING Outpatient research , education and clinical center in a tertiary care Veterans Affairs Medical Center . OUTCOME MEASURES Gait parameters , 5-step test , report of falls . SUBJECTS Eighteen men with idiopathic PD in stage 2 or 3 of the Hoehn and Yahr staging . METHODS Subjects were r and omly assigned to a trained or control group . They were asked about any falls  2 weeks prior to and after an 8 week period .  Gait speed , cadence , and step length  were tested on an instrumented walkway . Subjects were timed while stepping onto and back down from an 8.8 cm step for 5 consecutive steps . Gait training consisted of walking on a treadmill at a speed greater than over ground walking speed while walking in 4 directions and while supported in a harness for safety . Step training consisted of suddenly turning the treadmill on and off while the subject stood in the safety harness facing either forwards , backwards , or sideways . Training occurred 1 hour per day , three times per week for 8 weeks . A two-factor ( time and group ) analysis of variance with repeated measures was used to compare the groups . RESULTS Substantial reduction occurred in falls in the trained group , but not in the control group . Gait speed increased in the trained group from 1.28+/-0.33 meters/sec to 1.45+/-0.37 meters/sec , but not in the control group ( from 1.26 to 1.27 m/s ) . The cadence increased for both groups : from 112.8 to 120.3 steps/min for the trained group and 117.7 to 124.3 steps/min for the control group . Stride lengths increased for the trained group , but not the control group . The 5-step test speed increased in the trained group from 0.40+/-0.08 steps/sec to 0.51+/-0.12 steps/sec , and in the control group ( 0.36+/-0.11 steps/sec to 0.42+/-0.11 steps/sec ) . CONCLUSION Gait and step perturbation training result ed in a reduction in falls and improvements in gait and dynamic balance . This is a promising approach to reduce falls for patients with PD The purpose of this study was to quantify changes in postural stability with fatigue of the frontal and sagittal movers of the lower extremities . There were four test sessions , with a r and omized order assigned according to the muscles tested and the plane of motion . Subjects were 20 healthy men ( age : 22.6+/-2.4 years , height : 173.7+/-3.6 cm , weight : 63.3+/-7.9 kg ) . During each session , one set of muscle groups was fatigued using isokinetic contractions : ankle plantar/dorsi flexors , ankle evertor/invertors , hip flexor/extensors or hip abductor/adductors . The Biodex Stability System was used to assess anterior/posterior and medial/lateral stability before and after muscle fatigue . Repeated measures ANOVAs revealed that fatigue was associated with a significant increase in all stability indices . Fatigue of the hip movers , whether in the frontal or sagittal planes , led to greater increments in stability indices than fatigue of the ankle musculature . Fatigue of the frontal movers result ed in greater increases in the medial/lateral stability index compared to fatigue of the sagittal movers . In conclusion , fatigue of proximal lower extremity muscles affects postural stability and fatigue of the frontal movers is associated with postural instability in the frontal plane BACKGROUND Aging compromises the ability of the central nervous system to maintain body balance and reduces the capacity for adaptive reactions . To prevent falls , the reception conditions for sensory information need to be improved . OBJECTIVES To evaluate the impact of a structured aquatic and a non-aquatic exercise program for lower-limb muscle endurance on the static and dynamic balance of elderly people . METHODS This was a prospect i ve r and omized clinical study in which the variables were assessed before and after the training program . Thirty-six elderly people were evaluated using four tests : the Berg Balance Scale , Dynamic Gait Index , gait speed and t and em gait . The participants were r and omized into three groups : aquatic exercise group , non-aquatic exercise group and control group . The exercise groups underwent a program for lower-limb muscle endurance that consisted of 40-minute sessions twice a week for six weeks . The participants were reevaluated after six weeks . The data were analyzed statistically using the univariate ANOVA test for comparisons between the groups before and after the intervention . RESULTS The program for lower-limb muscle endurance significantly increased balance ( p<0.05 ) in the evaluation tests after the training program . CONCLUSION The muscle endurance program provided a significant improvement in static and dynamic balance among community-dwelling elderly people . It was also possible to infer that this improvement occurred regardless of the environment , i.e. aquatic or non-aquatic . Article registered in the Australian New Zeal and Clinical Trials Registry ( ANZCTR ) under the number ACTRN 12609000780257 Purpose : Aging is associated with deterioration of the physiologic systems controlling balance . Consequently , a multitude of intervention trials has appeared in the last 2 decades attempting to improve control of balance . Effective programs often require substantial and frequent time commitments , expensive and specialized equipment , professional assistance , and clinical setting s. This investigation reports the effects of a simple , short‐term balance training program on dynamic balance in healthy older women . Methods : Subjects included 11 healthy women ( 75.6 ± 6.4 years ) who participated in biweekly , 15‐minute balance training sessions for 5 weeks , and 10 age‐matched women ( 71.2 ± 9.1 years ) who served as controls . Balance training involved medial‐lateral and anterior‐posterior movements and bilateral partial squats while st and ing on semi‐compressible foam roller‐devices . Dynamic balance was quantified using functional reach in the forward , left , and right directions , and a lower extremity reach test . Results : Significant increases were observed in the balance trained group : 25 % in functional reach right ( P = 0.014 ) and left ( P < 0.001 ) and 16 % in lower extremity reach ( P = 0.001 ) . No change was noted in the control group . Conclusions : Improvements in dynamic balance can be realized following 5 weeks of dynamic balance training using this novel , simplistic , and short‐term protocol Tripping over obstacles is a common cause of falls in older adults , and muscle fatigue , which can alter walking patterns , may add to this risk . To date , no study has examined the effect of lower limb muscle fatigue on obstacle negotiation in older adults . 30 older adults ( 13 women , aged 78.3 [ 6.2 ] years )  negotiated a 12 m obstacle course , while completing a visual secondary task , under two r and omized conditions : rested or fatigued . For the fatigue condition , participants performed a repeated sit-to-st and movement , as fast as possible , until they could no longer continue . Participants then immediately began walking trials . Kinematic and kinetic data were collected on approach to , during , and after crossing a height-adjustable target obstacle ( 10 % and 20 % of leg length ) . Repeated measures ANOVA showed a statistically significant increase in lead limb vertical loading rate after stepping over the 10 % obstacle when fatigued , relative to rested ( P=0.046 ) . No other significant between-condition differences ( > 0.05 ) were observed for the other kinematic variables when negotiating the 10 % obstacle . Furthermore , no significant between-condition differences ( P>0.05 ) were observed for any kinetic or kinematic variables when negotiating the 20 % obstacle . This study describes a feasible method for investigating the consequences of lower limb muscle fatigue on obstacle crossing . The current finding of increased vertical loading rate when fatigued supports the need for further investigation into the effect of muscle fatigue on gait under different environmental conditions , fatiguing a range of muscles , analyzing a more comprehensive array of kinetic and kinematic measures , and in healthy and clinical population OBJECTIVE Risk of falling increases as people age , and decreased leg strength and poor balance have been implicated as contributors . Our aims were to:1 ) assess the efficacy of a fall-prevention exercise program on balance and leg strength in women aged 65 to 89 years and 2 ) conduct a 1-year follow-up to determine the effect of exercise on fall rates . METHODS Forty women were classified by falling history and fear of falling and assigned to exercise and control groups using stratified r and omization . We used the Berg Balance Scale , Get-up and Go , Functional Reach , and Wall-Sit Tests to evaluate changes in balance and leg strength before and after a supervised 15-week exercise program ( 31-hr sessions/week ) . We conducted 1-year follow-up telephone interviews and compared the number of falls reported by exercise and control groups . The study used a 2 x 2 ( exercise/control by pretest/post-test ) factorial design with the testing times being a repeated factor , so we used analysis of variance ( ANOVA ) to evaluate differences between the 2 groups across testing times . Power analysis computed a priori with STPLAN software ( Version 4.2 ) showed that a sample size of 40 was necessary to determine statistical differences in balance and leg strength . RESULTS Exercise subjects showed significant improvement on 5 of 14 items ( 5.2 % , p < or = 05 to 34.4 % , p < or = .01 ) in the Berg Balance Scale and on the total score ( 6.8 % , p < or = .05 ) . Leg strength increased significantly ( p < or = .05 ) on post-test as measured by the Wall-Sit Test . Control subjects reported 6 falls and exercise subjects no falls during the follow-up year , but this difference was not significant using Fischer 's exact test ( p=.106 ) . CONCLUSION The exercise program result ed in increased balance and leg strength , but did not result in a significant difference in falls during the follow-up period . Further research with a larger and possibly older sample is needed to more adequately investigate this question . Health care providers who work with older women should provide exercise programs in which balance and leg strength are emphasized OBJECTIVE To quantify changes in balance parameters and ranges of postural control at the ankle after isokinetic fatigue . DESIGN Before-after trials , with a 5 x 6 repeated- measures design . SETTING General community . PARTICIPANTS Twenty-four men ( age , 24.9 + /- 3.92y ; height , 177.79 + /- 6.36 cm ; weight , 80.78 + /- 13.22 kg ) without ankle trauma within 2 years . INTERVENTIONS Fatigue of the plantarflexors and dorsiflexors was induced by isokinetic contractions . Balance was assessed by using a unilateral test ( 15-s quiet stance , 10-s lean test ) on a force platform immediately before and at 0 ( T0 ) , 10 ( T10 ) , 20 ( T20 ) , and 30 ( T30 ) minutes postfatigue . MAIN OUTCOME MEASURE Mediolateral ( ML ) and fore-aft ( FA ) sway as well as ML and FA displacement were analyzed by analysis of variance with repeated measures for time ( alpha = .05 ) . RESULTS In quiet stance , ML sway was greater at T0 , whereas total sway increased at all time points postfatigue ( P < .05 ) . For the lean test , FA sway increased at T0 and T10 , and total sway increased at all time points ( P < .05 ) . Both ML and FA displacement significantly differed at T0 ( P < .05 ) . All sway parameters returned to baseline within 20 minutes . CONCLUSIONS Isokinetic fatigue of ankle plantarflexors and dorsiflexors significantly influences sway parameters and ranges of postural control in healthy young men . These perturbations are transient , and recovery occurs within 20 minutes OBJECTIVE The aim of this study was to evaluate the effect of a 10-week , high-intensity strength-training program targeting key lower extremity muscles for the purpose of improving postural control in balance-impaired older adults . METHODS A quasi-experimental , delayed entry controlled design was used to evaluate balance ability in balance-impaired older adults after participation in 10 weeks of high-intensity strength training focused on the quadriceps , hamstrings , tibialis anterior , and gastrocnemius muscles . Participants were evaluated using vali date d clinical measures of functional balance ability : the Berg Balance Scale , the Timed Up and Go , and the Activities-Specific Balance Confidence Scale . RESULTS After strength training , the exercisers were significantly stronger than the control subjects . They improved significantly on the Berg Balance Scale ( P = .030 ) from a mean score of 48.8 + /- 2.4 of 56 before training to 51.2 + /- 4.3 of 56 after training . The Timed Up and Go ( P = .045 ) and the Activities-Specific Balance Confidence Scale ( P = .038 ) also improved significantly in the experimental group . These changes are associated with a decrease in fall risk . CONCLUSIONS High-intensity strength training can safely and effectively strengthen lower extremity muscles in balance-impaired older adults , result ing in significant improvements in functional balance ability and decreased fall risk
target: CONCLUSION On the basis of systematic review of relevant literature , it appears that muscle fatigue induces clear deteriorations in reactive postural control .
background: BACKGROUND Falls are the leading cause of traumatic brain injury and fractures and the No. 1 cause of emergency department visits by older adults .
  Although declines in muscle strength and sensory function contribute to increased falls in older adults , skeletal muscle fatigue is often overlooked as an additional contributor to fall risk .
  In an effort to increase awareness of the detrimental effects of skeletal muscle fatigue on postural control , we sought to systematic ally review research studies examining this issue .
  PURPOSE The specific purpose of this review was to provide a detailed assessment of how anticipatory and reactive postural control tasks are influenced by  acute muscle fatigue in healthy older individuals .