Ankle force and rate of force production increase following high intensity strength training in frail older adults Evidence for improved muscle activation patterns after retraining of reaching movements with the MIME robotic system in subjects with post-stroke hemiparesis Task-oriented progressive resistance strength training improves muscle strength and functional performance in individuals with stroke Single Session of Transcranial Direct Current Stimulation Transiently Increases Knee Extensor Force in Patients With Hemiparetic Stroke Bed rest promotes reductions in walking speed, functional parameters, and aerobic fitness in older, healthy adults. Hip, thigh and calf muscle atrophy and bone loss after 5-week bedrest inactivity Reliability of concentric and eccentric torque during isokinetic knee extension in post-stroke hemiparesis. Forced use of hemiplegic upper extremities to reverse the effect of learned nonuse among chronic stroke and head-injured patients Muscle, functional and cognitive adaptations after flywheel resistance training in stroke patients: a pilot randomized controlled trial Progressive resistance training increases strength after stroke but this may not carry over to activity: a systematic review. High-Intensity Resistance Training Improves Muscle Strength, Self-Reported Function, and Disability in Long-Term Stroke Survivors Motor Imagery Training on Muscle Strength and Gait Performance in Ambulant Stroke Subjects-A Randomized Clinical Trial. Change of strength and rate of rise of tension relate to functional arm recovery after stroke. Does functional strength training of the leg in subacute stroke improve physical performance? A pilot randomized controlled trial Upper extremity muscle volumes and functional strength after resistance training in older adults. Muscle strength in breast cancer patients receiving different treatment regimes Efficacy of Nintendo Wii training on mechanical leg muscle function and postural balance in community-dwelling older adults: a randomized controlled trial. Resistance training and neuromuscular performance in seniors. Randomised controlled trial of transcutaneous electrical muscle stimulation of the lower extremities in patients with chronic obstructive pulmonary disease Effects of hip extensor fatigue on lower extremity kinematics during a jump-landing task in women: a controlled laboratory study. Reliability of isokinetic normalized peak torque assessments for knee muscles in post-stroke hemiparesis. Gait Parameters Associated With Responsiveness to Treadmill Training With Body-Weight Support After Stroke: An Exploratory Study Similar effects of leucine rich and regular dairy products on muscle mass and functions of older polymyalgia rheumatica patients: A randomized crossover trial
Background and aims : The most common cause of accidental injury and death in people over age 65 results from impacts associated with falling . Balance impaired older adults have poorer balance control than healthy young adults or healthy older adults . Lack of sufficient lower extremity strength and inability to rapidly produce muscle force may contribute to diminished balance control in the elderly . This study evaluated the effect of a 10-week high intensity strength- training program targeting key lower extremity muscles for the purpose of improving postural control in frail older adults . Methods : Thirteen experimental and fourteen control subjects , all balance impaired older adults were evaluated in response to unexpected platform perturbations that simulated slips . Results : Following strength training the experimental group was significantly stronger than the control group . Mean ankle moments improved in the experimental group following strength training during forward sway ( Right : p=0.067 , Left : p=0.009 ) and backward sway ( Right : p=0.031 , Left : p=0.058 ) . For the backward sway condition the ankle rate of torque production increased significantly in the experimental group ( Right : p=0.016 , Left : p=0.031 ) . Conclusions : Enhancement of lower extremity strength contributed to improvements in balance stability demonstrated by greater ankle force production , in response to balance threats Previously , we reported that chronic stroke subjects had significant improvements in isometric strength , free reaching extent , and clinical evaluations of function after training in the  mirror-image movement enabler ( MIME ) robotic device . Our primary goal in this analysis was to investigate the hypothesis that the robotic training promoted improved muscle activation patterns . To this end , we examined the interaction forces , kinematics , and electromyograms recorded during training of eight different movement patterns in active-constrained mode . In this mode , the robot constrained the reaching movements to be toward the target , and the movement velocity was proportional to the force produced along the trajectory . Thirteen chronic stroke subjects trained in MIME for 24 1-h sessions over an eight-week period . Work output was significantly increased by week five in all eight movement patterns . Low-level subjects increased their extent of reach , while high-level subjects increased their speed . Directional errors in force production were reduced in six of eight movement patterns . Electromyographic data provided evidence for improved muscle activation patterns in the four movement patterns that started at tabletop level and ended at shoulder level . In contrast , there was no evidence of improved muscle activation patterns in any of the tabletop movements , with increased activation of antagonists in two movement patterns . This dichotomy may have been related to compensation at the shoulder girdle during movements that remained at tabletop level . A simple biomechanical model will be introduced to demonstrate the likelihood of this possibility Objective : To examine the effectiveness of task-oriented progressive resistance strength training on lower extremity strength and functional performance in chronic stroke subjects . Design : Single-blind , r and omized controlled trial . Setting : Medical centre and district hospital . Subjects : Forty-eight subjects at least one year post stroke . Interventions : Participants r and omly allocated to two groups , control  ( n-/24 ) and experimental  ( n-/24 ) . Subjects in the control group did not receive any rehabilitation training . Subjects in the experimental group were put on a four-week task-oriented progressive resistance strength training . Main measures : Lower extremity muscle strength , gait velocity , cadence , stride length , six-minute walk test , step test , and timed up and go test . Results : Muscle strength significantly improved in the experimental group for strong side muscle groups ( ranged from 23.9 % to 36.5 % ) and paretic side muscle groups ( ranged from 10.1 % to 77.9 % ) . In the control group muscle strength changes ranged from 6.7 % gain to 11.2 % decline . The experimental group showed significant improvement in all selected measures of functional performance except for the step test . In the control group , the number of repetitions of the step test significantly decreased ( -20.3 % ) with no change in other functional tests . There was a significant difference between groups for muscle strength and all functional measures . The strength gain was significantly associated with gain in the functional tests . Conclusions : The task-oriented progressive resistance strength training programme could improve lower extremity muscle strength in individuals with chronic stroke and could carry over into improvement in functional abilities Background . Transcranial direct current stimulation ( tDCS ) of the motor cortex can enhance the performance of a paretic upper extremity after stroke . Reported effects on lower limb ( LL ) function are sparse . Objective . The authors examined whether tDCS can increase the force production of the paretic quadriceps . Methods . In this double-blind , crossover , sham-controlled experimental design , 8 participants with chronic subcortical stroke performed knee extension using their hemiparetic leg before , during , and after anodal or sham tDCS of the LL motor cortex representation in the affected hemisphere . Affected h and -grip force was also recorded . Results . The maximal knee-extension force increased by 21 N ( 13.2 % , P < .01 ) during anodal tDCS compared with baseline and sham stimulation . The increase persisted less than 30 minutes . Maximal h and -grip force did not change . Conclusions . Anodal tDCS transiently enhanced knee extensor strength . The modest increase was specific to the LL . Thus , tDCS might augment the rehabilitation of stroke patients when combined with lower extremity strengthening or functional training CONTEXT The exact relationship between the bed rest-induced loss of skeletal muscle and reductions in muscle strength and physical performance in the older individuals is still unclear . OBJECTIVE We examined the effect of 10 days of bed rest on changes in regional body composition , muscle strength , and functional status , and the relationship between these variables in older individuals . DESIGN , PARTICIPANTS , AND INTERVENTION Regional body composition was measured using dual energy x-ray absorptiometry . We also determined changes in leg strength and several indices of functional status , including walking speed . RESULTS Body weight , body mass index , and total and lower extremity lean mass decreased with bed rest . There were also significant reductions in knee extension one repetition maximum , isometric knee extension , knee extension 60 ° concentric , stair ascent time , stair ascent power , stair descent time , VO2 max , floor transfer test , 5-minute walk time , and chair st and . The overall change in total and lower extremity lean mass was also directly related to bed rest-induced reductions in one repetition maximum knee extension . CONCLUSIONS Bed rest promoted overall declines in muscle mass , muscle strength , and physical function in older individuals . The changes in lean tissue were closely correlated with the bed rest-induced decline of muscle strength Unloaded inactivity induces atrophy and functional deconditioning of skeletal muscle , especially in the lower extremities . Information is scarce , however , regarding the effect of unloaded inactivity on muscle size and function about the hip . Regional bone loss has been demonstrated in hips and knees of elderly orthopaedic patients , as quantified by computerized tomography ( CT ) . This method remains to be vali date d in healthy individuals rendered inactive , including real or simulated weightlessness . In this study , ten healthy males were subjected to 5 weeks of experimental bedrest and five matched individuals served as ambulatory controls . Maximum voluntary isometric hip and knee extension force were measured using the strain gauge technique .  Cross-sectional area ( CSA ) of hip , thigh and calf muscles , and radiological density ( RD ) of the proximal tibial bone were measured using CT . Bedrest decreased ( P < 0.05 ) average ( SD ) muscle strength by 20 (8)% in knee extension , and by 22 (12)% in hip extension . Bedrest induced atrophy ( P < 0.05 ) of extensor muscles in the gluteal region , thigh and calf , ranging from 2 to 12 % . Atrophy was more pronounced in the knee extensors [ 9 (4)% ] and ankle plantar flexors [ 12 (3)% ] than in the gluteal extensor muscles [ 2 (2)% ] . Bone density of the proximal tibia decreased ( P < 0.05 ) by 3 (2)% during bedrest . Control subjects did not show any temporal changes in muscle or bone indices ( P > 0.05 ) , when examined at similar time intervals . The present findings of a substantial loss in hip extensor strength and a smaller , yet significant atrophy of these muscles , demonstrate that hip muscle deconditioning accompanies losses in thigh and calf muscle mass after bedrest . This suggests that comprehensive quantitative studies on impaired locomotor function after inactivity should include all joints of the lower extremity . Our results also demonstrate that a decreased RD , indicating bone mineral loss , can be shown already after 5 weeks of unloaded bedrest , using a st and ard CT technique BACKGROUND Emerging evidence on the velocity-dependent nature of force impairment in post-stroke hemiparesis has emphasized the complexity of strength and motor performance assessment s in this clinical population . The need to establish reliability and responsiveness of muscle performance measures across a broad range of concentric and eccentric movement speeds is therefore clear , as these metrics will provide benchmarks both for making clinical inference and evaluating meaningful clinical change following interventions . METHODS Isokinetic knee extensor strength was tested at 14 angular velocities in 17 adults with chronic post-stroke hemiparesis ( > 18 months ) , and 13 non-disabled controls . Identical tests were conducted on two occasions separated by two days . Test-retest reliability of maximal isokinetic torque was evaluated using intraclass correlation . Absolute reliability was assessed using st and ard error of measurement from which smallest real differences were derived . FINDINGS Overall , intraclass correlation coefficients were excellent for both hemiparetic ( 0.891 ) and control ( 0.937 ) groups . Intraclass correlation coefficients for each criterion speed were also high for both groups ( > 0.86 ) . Measurement error relative to the mean torque varied between 14.1 % and 26.3 % for hemiparetic subjects and 6.0 - 18.1 % for controls . The smallest real difference relative to mean torque was 39.0 - 72.7 % and 16.6 - 50.2 % for hemiparetic and control subjects , respectively . INTERPRETATION Isokinetic knee extension torque can be measured reliably in persons with chronic post-stroke hemiparesis and in non-disabled controls across a full functional range of concentric and eccentric speeds . Established measurement error and smallest real differences will aid interpretation of longitudinal observations of muscle performance in this clinical population To test the clinical counterpart of the learned nonuse theory , 25 chronic hemiplegic stroke and head-injured patients with minimal to moderate upper extremity extensor muscle function were required to keep their uninvolved upper extremities within a h and -enclosed sling during waking hours over a 2-week interval . During this forced use period and for 1 year thereafter , changes in force or time-based measures among 21 functional tasks were compared to values at the sixth baseline session , a preintervention time when relearning had plateaued . Significant ( P less than 0.05 , Friedman 's repeated measures followed by Tukey multiple comparison tests ) changes were seen in 19 of the 21 tasks with most persisting at the 1-year follow-up . There were no apparent differences between right- and left-sided involvement or between stroke versus head injury clients ( Mann-Whitney procedure ) . Ratings for quality of movement scored from videotapes presented in r and om order showed no change over time . These data suggest that learned nonuse does occur in select neurological patients and that this behavior can be reversed through application of a forced use paradigm Background Resistance exercise ( RE ) improves neuromuscular function and physical performance after stroke . Yet , the effects of RE emphasizing eccentric ( ECC ; lengthening ) actions on muscle hypertrophy and cognitive function in stroke patients are currently unknown . Thus , this study explored the effects of ECC-overload RE training on skeletal muscle size and function , and cognitive performance in individuals with stroke . Methods Thirty-two individuals with chronic stroke ( ≥6 months post-stroke ) were r and omly assigned into a training group ( TG ; n = 16 ) performing ECC-overload flywheel RE of the more-affected lower limb ( 12 weeks , 2 times/week ; 4 sets of 7 maximal closed-chain knee extensions ; < 2 min of contractile activity per session ) or a control group ( CG ; n = 16 ) , maintaining daily routines . Before and after the intervention , quadriceps femoris volume , maximal force and power for each leg were assessed , and functional and dual task performance , and cognitive functions were measured . Results Quadriceps femoris volume of the more-affected leg increased by 9.4 % in TG . Muscle power of the more-affected , trained ( 48.2 % ) , and the less-affected , untrained limb ( 28.1 % ) increased after training . TG showed enhanced balance ( 8.9 % ) , gait performance ( 10.6 % ) , dual-task performance , executive functions ( working memory , verbal fluency tasks ) , attention , and speed of information processing . CG showed no changes . Conclusion ECC-overload flywheel resistance exercise comprising 4 min of contractile activity per week offers a powerful aid to regain muscle mass and function , and functional performance in individuals with stroke . While the current intervention improved cognitive functions , the cause-effect relationship , if any , with the concomitant neuromuscular adaptations remains to be explored . Trial registration Clinical Trials QUESTION Does progressive resistance training improve strength and activity after stroke ? Does any increase in strength carry over to activity ? DESIGN Systematic review of r and omised trials with meta- analysis . PARTICIPANTS Adults who have had a stroke . INTERVENTION Progressive resistance training compared with no intervention or placebo . OUTCOME MEASURES The primary outcome was change in strength . This measurement had to be of maximum voluntary force production and performed in muscles congruent with the muscles trained in the intervention . The secondary outcome was change in activity . This measurement had to be a direct measure of performance that produced continuous or ordinal data , or with scales that produced ordinal data . RESULTS Eleven studies involving 370 participants were included in this systematic review . The overall effect of progressive resistance training on strength was examined by pooling change scores from six studies with a mean PEDro score of 5.8 , representing medium quality . The effect size of  progressive resistance training on strength was 0.98 ( 95 % CI 0.67 to 1.29 , I2=0 % ) . The overall effect of progressive resistance training on activity was examined by pooling change scores from the same six studies . The effect size of progressive resistance training on activity was 0.42 ( 95 % CI -0.08 to 0.91 , I2=54 % ) . CONCLUSION After stroke , progressive resistance training has a large effect on strength compared with no intervention or placebo . There is uncertainty about whether these large increases in strength carry over to improvements in activity . REVIEW REGISTRATION PROSPERO CRD42015025401 . [ Dorsch S , Ada L , Alloggia D ( 2018 ) Progressive resistance training increases strength after stroke but this may not carry over to activity : a systematic review . Journal of Physiotherapy 64 : 84 - 90 ] Background and Purpose — To evaluate the efficacy of supervised high-intensity progressive resistance training ( PRT ) on lower extremity strength , function , and disability in older , long-term stroke survivors . Methods — Forty-two volunteers aged 50 years and above , 6 months to 6 years after a single mild to moderate stroke , were r and omized into either a control group of upper extremity stretching or a PRT group that received a 12-week supervised high-intensity resistance training program consisting of bilateral leg press ( LP ) , unilateral paretic and nonparetic knee extension ( KE ) , ankle dorsiflexion ( DF ) , and plantarflexion ( PF ) exercises .  Functional performance was assessed using the 6-minute walk , stair-climb time , repeated chair-rise time , and habitual and maximal gait velocities . Self-reported changes in function and disability were evaluated using the Late Life Function and Disability Instrument ( LLFDI ) . Results — Single-repetition maximum strength significantly improved in the PRT group for LP ( 16.2 % ) , paretic KE ( 31.4 % ) , and nonparetic KE ( 38.2 % ) with no change in the control group . Paretic ankle DF ( 66.7 % versus −24.0 % ) , paretic ankle PF ( 35.5 % versus −20.3 % ) , and nonparetic ankle PF ( 14.7 % versus −13.8 % ) significantly improved in the PRT group compared with the control . The PRT group showed significant improvement in self-reported function and disability with no change in the control . There was no significant difference between groups for any performance-based measure of function . Conclusions — High-intensity PRT improves both paretic and nonparetic lower extremity strength after stroke , and results in reductions in functional limitations and disability INTRODUCTION The ultimate goal of physiotherapy in stroke rehabilitation is focused towards physical independence and to restore their functional ability during activities of daily living ( ADLs ) . Motor imagery ( MI ) is an active process during which a specific action is reproduced within working memory without any actual movements . MI training enhances motor learning , neural reorganization and cortical activation in stroke . The efficacy of MI training involving lower extremity mobility tasks need to be assessed . AIM To evaluate the effects of combining motor imagery with physical practice in paretic Lower Extremity Muscles Strength and Gait Performance in Ambulant Stroke subjects . MATERIAL S AND METHODS A R and omized Clinical Trial was conducted in Department of Physical Therapy , Tertiary Care Hospitals , Mangalore , India which includes 40 hemi paretic subjects ( > 3 months post-stroke ) who were ambulant with good imagery ability in both KVIQ-20 ≥ 60 and Time dependent MI screening test were recruited and r and omly allocated into task-oriented training group ( n=20 ) and task-oriented training group plus MI group ( n=20 ) . Subjects in both groups underwent task orientated training for lower extremity 45 - 60 minutes , 4 days per week for 3 weeks . In addition , the experimental group received 30 minutes of audio-based lower extremity mobility tasks for MI practice  . Isometric muscle strength of Hip , Knee and Ankle using a h and -held dynamometer and self-selected 10 m gait speed were assessed before and after 3 weeks of intervention . RESULTS Both the groups had found a significant change for all the outcome measures following 3 weeks of interventions with p < .05 . The experimental group had shown a significant improvement in paretic hip muscles ( both flexors and extensors ) , knee extensors and ankle dorsiflexors and gait speed compare to control group with p < .05 between group analyses . CONCLUSION Additional task specific MI training improves paretic muscle strength and gait performance in ambulant stroke patients OBJECTIVE To examine the relationship between individual strength parameters and functional motor ability over time during rehabilitation in stroke patients . DESIGN A multiple-baseline experiment with assessment at inclusion and after 3 and 6 weeks . SETTING Secondary -care rehabilitation center . PARTICIPANTS A convenience sample of 16 subacute stroke patients . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Maximal voluntary force and rate of rise of tension of h and grip , wrist extension , and elbow flexion and extension were recorded at all 3 times . At the same time , functional motor assessment s were evaluated by the  Action Research Arm Test ( ARAT ) , Box and Block test , and Rivermead Test . RESULTS We found no correlation between maximal voluntary force increases of various muscle contractions measurements . Neither the increase of grip strength nor that of wrist extension force correlated with improvement in ARAT score . Yet the improvement in the rate of rise of tension of h and grip ( Spearman rho=.91 ) and of wrist extension ( Spearman rho=.73 ) correlated with the improvement of the ARAT score and explained 77 % of the variance of the ARAT . CONCLUSIONS The change in the rate of rise of tension of the h and grip has a better predictive value for the functional recovery compared to the change in maximal voluntary force in patients with moderate arm and h and weakness after stroke . The rate of rise of tension of h and grip seems an adequate quantifiable parameter to detect small improvements during functional recovery Objective : To examine the effect of functional strength training in subacute stroke . Design : A single-blinded r and omized controlled trial . Setting : Two rehabilitation units . Subjects : Eighteen patients in the subacute phase post stroke , r and omly allocated to a functional strength training ( intervention ) group ( n = 8) and a training-as-usual ( comparison ) group ( n = 10 ) . Intervention : The functional strength training group participated in functional progressive strength training of the affected lower extremity . The training-as-usual group had traditional training , excessive muscle power being avoided to prevent associated reactions . All trained 50 minutes five days a week for four weeks . Main measures : Maximum weight-bearing in st and ing ( primary outcome ) , isometric muscle strength , gait speed and items of Motor Assessment Scale . Results : Maximum weight-bearing on the affected leg improved more in the functional strength training group ( mean 17.4 % of body weight ) than in the training-as-usual group ( mean 5.6 % of body weight ) , but taking test data at inclusion into consideration , the difference in change was not statistically significant ( P = 0.056 ) . More patients in the functional strength training group ( 57 % ) could weight-bear on the affected leg while stepping forward , than in the training-as-usual group ( 17 % ) . Improvement was clinical ly significant in 7 of 9 outcome measures in the functional strength training group ( effect size ≥0.80 , large ) , but in only 3 of 9 in the training-as-usual group . All patients in the functional strength training group and 70 % of the patients in the training-as-usual group rated their overall status as ` much ' or ` very much ' improved . Conclusions : This pilot study indicates that functional strength training of lower extremities improves physical performance more than traditional training Aging leads to a decline in strength and an associated loss of independence . The authors examined changes in muscle volume , maximum isometric joint moment , functional strength , and 1-repetition maximum ( 1RM ) after resistance training ( RT ) in the upper extremity of older adults . They evaluated isometric joint moment and muscle volume as predictors of functional strength . Sixteen healthy older adults ( average age 75 ± 4.3 yr ) were r and omized  to a 6-wk upper extremity RT program or control group . The RT group increased 1RM significantly ( p < .01 for all exercises ) . Compared with controls , r and omization to RT led to greater functional pulling strength ( p = .003 ) , isometric shoulder-adduction moment ( p = .041 ) , elbow-flexor volume ( p = .017 ) , and shoulder-adductor volume ( p = .009 ) . Shoulder-muscle volumes and isometric moments were good predictors of functional strength . The authors conclude that shoulder strength is an important factor for performing functional reaching and pulling tasks and a key target for upper extremity RT interventions Abstract Background Muscle dysfunction and sarcopenia have been associated with poor performance status , an increased mortality risk , and greater side effects in oncologic patients . However , little is known about how performance is affected by cancer therapy . We investigated muscle strength in breast cancer patients in different adjuvant treatment setting s and also compared it with data from healthy individuals . Methods Breast cancer patients ( N = 255 ) from two r and omized controlled exercise trials , staged 0–III and aged 54.4 ± 9.4 years , were categorized into four groups according to their treatment status . In a cross‐sectional design , muscle function was assessed bilaterally by isokinetic dynamometry ( 0 ° , 60 ° , 180 ° /s ) as maximal voluntary isometric contraction ( MVIC ) and maximal isokinetic peak torque ( MIPT ) in shoulder rotators and knee flexors and extensors .  Additionally , muscular fatigue index ( FI% ) and shoulder flexibility were evaluated . Healthy women ( N = 26 ) , aged 53.3 ± 9.8 years , were tested using the same method . Analysis of covariance was used to estimate the impact of different cancer treatments on skeletal muscle function with adjustment for various clinical and socio‐demographic factors . Results Consistently , lower muscle strength was measured in shoulder and knee strength in patients after chemotherapy . On average , patients had up to 25 % lower strength in lower extremities and 12–16 % in upper extremities in MVIC and MIPT during cancer treatment compared with healthy women . No substantial difference between patient groups in shoulder strength , but significantly lower shoulder flexibility in patients with radical mastectomy was measured . Chemotherapy‐treated patients had consistently higher FI% . No serious adverse events were reported . Conclusions Breast cancer patients showed markedly impaired muscle strength and joint dysfunctions before and after anticancer treatment . The significant differences between patients and healthy individuals underline the need of exercise therapy as early as possible in order to prevent or counteract the loss of muscle function after curative surgery as well as the consequences of neo‐/adjuvant chemotherapy BACKGROUND Older adults show increased risk of falling and major risk factors include impaired lower extremity muscle strength and postural balance . However , the potential positive effect of biofeedback-based Nintendo Wii training on muscle strength and postural balance in older adults is unknown . METHODS This r and omized controlled trial examined postural balance and muscle strength in community-dwelling older adults ( 75±6 years ) pre- and post-10 weeks of biofeedback-based Nintendo Wii training ( WII , n = 28 ) or daily use of ethylene vinyl acetate copolymer insoles ( controls [ CON ] , n = 30 ) . Primary end points were maximal muscle strength ( maximal voluntary contraction ) and center of pressure velocity moment during bilateral static stance . RESULTS Intention-to-treat analysis with adjustment for age , sex , and baseline level showed that the WII group had higher maximal voluntary contraction strength ( 18 % ) than the control group at follow up ( between-group difference = 269 N , 95 % CI = 122 ; 416 , and p = .001 ) . In contrast , the center of pressure velocity moment did not differ ( 1 % ) between WII and CON at follow-up ( between-group difference = 0.23 mm(2)/s , 95 % CI = -4.1 ; 4.6 , and p = .92 ) . For secondary end points , pre-to-post changes favoring the WII group were evident in the rate of force development ( p = .03 ) , Timed Up and Go test ( p = .01 ) , short Falls Efficacy Scale-International ( p = .03 ) , and 30-second repeated Chair St and Test ( p = .01 ) . Finally , participants rated the Wii training highly motivating at 5 and 10 weeks into the intervention . CONCLUSIONS Biofeedback-based Wii training led to marked improvements in maximal leg muscle strength ( maximal voluntary contraction ; rate of force development ) and overall functional performance in community-dwelling older adults . Unexpectedly , static bilateral postural balance remained unaltered with Wii training . The high level of participant motivation suggests that biofeedback-based Wii exercise may ensure a high degree of compliance to home- and /or community-based training in community-dwelling older adults Age-related processes in the neuromuscular and the somatosensory system are responsible for decreases in maximal and explosive force production capacity and deficits in postural control . Thus , the objectives of this study were to investigate the effects of resistance training on strength performance and on postural control in seniors . Forty healthy seniors ( 67+/-1 yrs ) participated in this study . Subjects were r and omly assigned to a resistance training ( n=20 ) and a control group ( n=20 ) . Resistance training for the lower extremities lasted for 13 weeks at 80 % of the one repetition maximum . Pre and post tests included the measurement of maximal isometric leg extension force with special emphasis on the early part of the force-time-curve and the assessment of static ( functional reach test ) and dynamic ( t and em walk test , platform perturbation ) postural control .  Resistance training result ed in an enhanced strength performance with increases in explosive force exceeding those in maximal strength . Improved performances in the functional reach and in the t and em walk test were observed . Resistance training did not have an effect on the compensation of platform perturbations . Increases in strength performance can primarily be explained by an improved neural drive of the agonist muscles . The inconsistent effect of resistance training on postural control may be explained by heterogeneity of testing methodology or by the incapability of isolated resistance training to improve postural control Background : Although exercise training improves exercise tolerance in most patients with chronic obstructive pulmonary disease ( COPD ) , some patients with severe disease may not be able to tolerate exercise training due to incapacitating breathlessness . Transcutaneous electrical muscle stimulation ( TCEMS ) has been shown to improve muscle strength , muscle mass , and performance in paraplegics , patients with knee ligament injury , and patients with peripheral vascular disease . We hypothesised that TCEMS of the lower extremities can improve muscle strength and exercise tolerance in patients with moderate to severe COPD . Methods : A r and omised controlled trial of TCEMS of the lower extremities was performed in 18 medically stable patients of mean ( SD ) age 60.0 ( 1.5 ) years with a mean forced expiratory volume in 1 second ( FEV1 ) of 1.03 ( 0.10 ) l ( 38 % predicted ) and residual volume/total lung capacity ( RV/TLC ) of 59 (2)% .  Stimulation of the lower extremities was performed three times a week , 20 minutes each session , for six continuous weeks . Quadriceps and hamstring muscle strength , exercise capacity , and peak oxygen uptake were measured at baseline and after 6 weeks of stimulation . Results : TCEMS improved both the quadriceps strength ( by 39.0 (20.4)% v 9.0 (8.1)% , p=0.046 ) and hamstring muscle strength ( by 33.9 (13.0)% v 2.9 (4.7)% , p=0.038 ) in the treated ( n=9 ) and sham treated ( n=9 ) groups , respectively . The improvement in muscle strength carried over to better performance in the shuttle walk test in the treated group ( 36.1 % v 1.6 % in the treated and sham groups respectively , p=0.007 , Mann-Whitney U test ) . There was no significant change in lung function , peak workload , or peak oxygen consumption in either group . Muscle stimulation was well tolerated by the patients with no dropouts and better than 95 % compliance with the protocol . Conclusions : TCEMS of peripheral muscles can be a useful adjunct to the comprehensive pulmonary rehabilitation of patients with COPD BACKGROUND Lower extremity kinematics may change as a result of impaired hip muscle function , thereby placing athletes at increased risk of injury . The purpose of this study was to examine whether experimentally-induced hip extensor fatigue alters lower extremity kinematics during a jump-l and ing task in women . METHODS Forty healthy women were r and omly assigned to an experimental group in which participants performed modified Biering-Sørenson tests to fatigue the hip extensors or to a sham control group in which participants performed repeated push-ups to exhaustion . Three-dimensional hip and knee kinematics and gluteus maximus electromyography ( EMG ) signals were measured during jump-l and ing tests to examine the effects of hip extensor fatigue . FINDINGS Hip extension strength decreased in the experimental group by 25 % following the intervention , thereby confirming effects of the fatigue intervention . No group × time interactions in hip and knee motions were statistically significant , indicating that hip and knee kinematics did not change following the fatigue-inducing intervention . Gluteus maximus recruitment during the post-fatigue test , however , increased by 55 % in the experimental group . INTERPRETATION A 25 % reduction in hip extensor strength did not lead to changes in hip or knee kinematics . Rather , participants accommo date d for the loss of strength by recruiting more Gmax activation to complete the task . Gmax recruitment may compensate when hip extensor strength is impaired , suggesting that improved neuromuscular control can influence motor performance when strength is diminished The purpose of this study was to establish test-retest reliability of measurement procedures for quantifying isokinetic concentric peak torque ( PT ) at the knee using normalization methods post-stroke . A second aim was to estimate the change required to show clinical ly significant improvements in knee muscles strength .  The isokinetic normalized PT ( NPT ) values for the knee extensors and flexors were measured in each participant at two different angular velocities during two sessions 1 day apart . Thirty participants with mild to moderate hemiparesis after stroke who were able to walk were tested . The normalized PT measures for the knee muscles of the affected lower extremity were highly reliable ( intraclass correlation coefficients ranged from 0.85 to 0.98 ; p<0.05 ) . Size of relative changes ( the percent smallest real difference , SRD% ) for extensors NPT ( ranged from 22.35 % to 25.68 % ) were lower than flexors NPT ( ranged from 74.01 % to 76.31 % ) , indicating that the affected isokinetic knee flexors had more r and om variation than the knee extensors . This study supports the use of isokinetic dynamometers for the assessment of knee muscle strength in participants with chronic mild to moderate post-stroke hemiparesis and to measure clinical improvements . Established measurement error and smallest real differences in normalized PT will aid interpretation of real changes in muscle strength in this clinical population Background Task-specific training programs  after stroke improve walking function , but it is not clear which biomechanical parameters of gait are most associated with improved walking speed . Objective The purpose of this study was to identify gait parameters associated with improved walking speed after a locomotor training program that included body-weight – supported treadmill training ( BWSTT ) . Design A prospect i ve , between-subjects design was used . Methods Fifteen people , ranging from approximately 9 months to 5 years after stroke , completed 1 of 3 different 6-week training regimens . These regimens consisted of 12 sessions of BWSTT alternated with 12 sessions of : lower-extremity resistive cycling ; lower-extremity progressive , resistive strengthening ; or a sham condition of arm ergometry .  Gait analysis was conducted before and after the 6-week intervention program . Kinematics , kinetics , and electromyographic ( EMG ) activity were recorded from the hemiparetic lower extremity while participants walked at a self-selected pace . Changes in gait parameters were compared in participants who showed an increase in self-selected walking speed of greater than 0.08 m/s ( high-response group ) and in those with less improvement ( low-response group ) . Results Compared with participants in the low-response group , those in the high-response group displayed greater increases in terminal stance hip extension angle and hip flexion power ( product of net joint moment and angular velocity ) after the intervention . The intensity of soleus muscle EMG activity during walking also was significantly higher in participants in the high-response group after the intervention . Limitations Only sagittal-plane parameters were assessed , and the sample size was small . Conclusions Task-specific locomotor training alternated with strength training result ed in kinematic , kinetic , and muscle activation adaptations that were strongly associated with improved walking speed . Changes in both hip and ankle biomechanics during late stance were associated with greater increases in gait speed Objectives Leucine-rich milk and whey proteins have been suggested for prevention of age related loss of muscle mass and strength i.e. sarcopenia . The effects of milk protein supplementation and low intensity home based physical exercise on body composition and muscle functions were investigated . Design A r and omized double blind crossover trial . Setting Community dwelling members of Helsinki rheumatoid association . Participants Older people ( N = 47 , mean age 69.5 years ) suffering from polymyalgia rheumatica . Intervention Patients performed as many st and ups as possible twice a day after which they ingested a regular ( Control ) or a whey protein enriched dairy product with high leucine content ( Test ) . The 8-week intervention periods were separated by a 4-week wash-out . Measurements Body composition was measured by dual x-ray absorptiometry and muscle functions by h and grip strength , force platform countermovement jump performance , chair st and test , and walking speed . Results The 16-week home-based post-exercise supplementation result ed in a 1.8 % increase ( p = 0.052 ) in lower limb muscle mass . Walking speed ( + 5.3 % , p = 0.007 ) and chair st and test performance ( −12.2 % , p < 0.001 ) were also improved . Furthermore , a tendency for increased jump power ( + 3.0 % , p = 0.084 ) was observed . However , significant and consistent differences were not found in the changes of muscle mass indices or muscle functions between supplements , but the test supplement tended to prevent accumulation of body fat . Conclusion A low intensity home based exercise program combined with post-exercise milk protein supplementation is feasible despite some gastrointestinal complaints and seems effective in improving the muscle mass and functions of older persons with a inflammatory disease . Further studies are needed to establish , whether and to what extent the use of leucine-enriched whey products prevent or treat age-associated sarcopenia and whether they are superior to the present commercial milk products
Conclusions : Age-related differences support the impact of stroke-related sarcopenia as a contributor to hemiparetic muscle dysfunction .
Abstract Background : Despite extensive study of the impact of stroke on muscle and functional performance , questions remain regarding the extent to which changes are due to the neurological injury vs. age-related loss of morphology and force production .
Objectives : To synthesize available evidence describing post-stroke changes in lower extremity muscle size and strength compared to healthy adults .