***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To identify the determinants of improvement in walking capacity following therapeutic exercise in chronic stroke survivors . DESIGN A secondary analysis of data obtained from a prospect i ve , single-blind , r and omized controlled intervention trial . SUBJECTS Sixty-three community-dwelling individuals ( mean age = 65 years , age range = 50 - 87 years ) with a chronic stroke ( post-stroke duration : mean = 5.5 years , range = 1 - 28 years ) . METHODS Subjects were r and omized into a leg exercise group ( n = 32 ) or an arm exercise group ( n = 31 ) . Subjects in each group underwent 3 1-hour exercise sessions per week for 19 weeks . Walking capacity , cardiorespiratory fitness , isometric knee extensor muscle strength , balance ability , and balance confidence were evaluated before and after the interventions . Multiple regression analysis was performed to identify the determinants of improvement in walking capacity . RESULTS After controlling for age , gender , post-stroke duration , and baseline walking capacity , gain in paretic leg muscle strength and peak oxygen consumption remained independently associated with gain in walking capacity ( R2 = 0.229 ) . CONCLUSION Enhancement of cardiorespiratory fitness and paretic leg muscle strength are both significant determinants in improving walking capacity among chronic stroke survivors . However , the rather weak relationship ( R2 = 0.229 ) indicates that other factors not measured in this study may also contribute to the improvement in walking capacity This study evaluated the feasibility , safety , and findings from a protocol for exercise-bicycle ergometry in subacute-stroke survivors . Of 117 eligible c and i date s , 14 could not perform the test and 3 discontinued because of cardiac safety criteria . In the 100 completed tests , peak heart rate was 116 + /- 19.1 beats/min ; peak VO(2 ) was 11.4 + /- 3.7 ml x kg x min(-1 ) , peak METs were 3.3 + /- 0.91 , exercise duration was 5.1 + /- 2.84 min , and Borg score was 14 + /- 2.6 . Among 71 tests , anaerobic threshold was achieved in 3.0 + /- 1.7 min with a VO(2 ) of 8.6 + /- 1.7 ml x kg x min(-1 ) . After screening , this protocol is feasible and safe in subacute-stroke survivors with mild to moderate deficits . These stroke survivors have severely limited functional exercise capacity . Research and clinical practice in stroke rehabilitation should incorporate more comprehensive evaluation and treatment of endurance limitations Background and Purpose — Stroke often impairs gait thereby reducing mobility and fitness and promoting chronic disability . Gait is a complex sensorimotor function controlled by integrated cortical , subcortical , and spinal networks . The mechanisms of gait recovery after stroke are not well understood . This study examines the hypothesis that progressive task-repetitive treadmill exercise ( T-EX ) improves fitness and gait function in subjects with chronic hemiparetic stroke by inducing adaptations in the brain ( plasticity ) . Methods — A r and omized controlled trial determined the effects of 6-month T-EX  ( n=37 ) versus comparable duration stretching ( CON , n=34 ) on walking , aerobic fitness and in a subset ( n=15/17 ) on brain activation measured by functional MRI . Results — T-EX significantly improved treadmill-walking velocity by 51 % and cardiovascular fitness by 18 % ( 11 % and −3 % for CON , respectively ; P<0.05 ) . T-EX but not CON affected brain activation during paretic , but not during nonparetic limb movement , showing 72 % increased activation in posterior cerebellar lobe and 18 % in midbrain ( P<0.005 ) . Exercise-mediated improvements in walking velocity correlated with increased activation in cerebellum and midbrain . Conclusions — T-EX  improves walking , fitness and recruits cerebellum-midbrain circuits , likely reflecting neural network plasticity . This neural recruitment is associated with better walking . These findings demonstrate the effectiveness of T-EX rehabilitation in promoting gait recovery of stroke survivors with long-term mobility impairment and provide evidence of neuroplastic mechanisms that could lead to further refinements in these paradigms to improve functional outcomes BACKGROUND AND PURPOSE Rehabilitation care after stroke is highly variable and increasingly shorter in duration . The effect of therapeutic exercise on impairments and functional limitations after stroke is not clear . The objective of this study was to determine whether a structured , progressive , physiologically based exercise program for subacute stroke produces gains greater than those attributable to spontaneous recovery and usual care . METHODS This r and omized , controlled , single-blind clinical trial was conducted in a metropolitan area and 17 participating healthcare institutions . We included persons with stroke who were living in the community . One hundred patients ( mean age , 70 years ; mean Orpington score , 3.4 ) consented and were r and omized from a screened sample of 582 . Ninety-two subjects completed the trial . Intervention was a structured , progressive , physiologically based , therapist-supervised , in-home program of thirty-six 90-minute sessions over 12 weeks targeting flexibility , strength , balance , endurance , and upper-extremity function . Main outcome measures were postintervention strength ( ankle and knee isometric peak torque , grip strength ) , upper- and lower-extremity motor control ( Fugl Meyer ) , balance ( Berg and functional reach ) , endurance ( peak aerobic capacity and exercise duration ) , upper-extremity function ( Wolf Motor Function Test ) , and mobility ( timed 10-m walk and 6-minute walk distance ) . RESULTS In the intention-to-treat multivariate analysis of variance testing the overall effect , the intervention produced greater gains than usual care ( Wilk 's lambda=0.64 , P=0.0056 ) . Both intervention and usual care groups improved in strength , balance , upper- and lower-extremity motor control , upper-extremity function , and gait velocity . Gains for the intervention group exceeded those in the usual care group in balance , endurance , peak aerobic capacity , and mobility . Upper-extremity gains exceeded those in the usual care group only in patients with higher baseline function . CONCLUSIONS This structured , progressive program of therapeutic exercise in persons who had completed acute rehabilitation services produced gains in endurance , balance , and mobility beyond those attributable to spontaneous recovery and usual care Background . Aerobic treadmill exercise ( T-EX ) therapy has been shown to benefit walking and cardiorespiratory fitness in stroke survivors with chronic gait impairment even long after their stroke . The response , however , varies between individuals . Objective . The purpose of this post hoc analysis of 2 r and omized controlled T-EX trials was to identify predictors for therapy response . Methods . In all , 52 participants received T-EX for 3 ( Germany ) or 6 ( United States ) months . Improvements in overground walking velocity ( 10 m/6-min walk ) and fitness ( peak VO2 ) were indicators of therapy response . Lesion location and volume were measured on T1-weighted magnetic resonance scans . Results . T-EX significantly improved gait and fitness , with gains in 10-m walk tests ranging between + 113 % and −25 % and peak VO2 between −12 % and 88 % . Baseline walking impairments or fitness deficits were not predictive of therapy response ; 10-m walk velocity improved more in those with subcortical rather than cortical lesions and in patients with smaller lesions . Improvements in 6-minute walk velocity were greater in those with more recent strokes and left-sided lesions . No variable other than training intensity , which was different between trials , predicted fitness gains . Conclusions . Despite proving overall effectiveness , the response to T-EX varies markedly between individuals . Whereas intensity of aerobic training seems to be an important predictor of gains in cardiovascular fitness , lesion size and location as well as interval between stroke onset and therapy delivery likely affect therapy response . These findings may be used to guide the timing of training and identify subgroups of patients for whom training modalities could be optimized OBJECTIVE To evaluate whether leg cycling training in subjects with chronic stroke can improve cycling performance , aerobic capacity , muscle strength , and functional performance and to determine if electric stimulation ( ES ) to the contralateral ( paretic ) leg during cycling has additional effects over cycling without ES . DESIGN A r and omized controlled trial , with a partial double-blind design . SETTING A rehabilitation center . PARTICIPANTS Twelve stroke patients ( range , 18 - 70 y ) , more than 5 months poststroke , with lower-extremity hemiparesis . INTERVENTION Subjects were r and omly assigned to groups that performed cycling exercise , one with ES evoking muscle contractions and a control group with ES not evoking muscle contractions . Subjects , blinded for group assignment , trained twice a week for 6 weeks . MAIN OUTCOME MEASURES Changes in aerobic capacity and maximal power output , functional performance , and lower-limb muscle strength . RESULTS Aerobic capacity and maximal power output significantly increased by 13.8%+/-19.1 % and 38.1%+/-19.8 % , but muscle strength was not significantly enhanced after training . Functional performance improved ( ie , scores on the Berg Balance Scale increased by 6.9%+/-5.8 % ( P=.000 ) and the six-minute walk test improved by 14.5%+/-14.1 % ( P=.035 ) . There was no significant effect on the Rivermead Mobility Index ( P=.165 ) . Training-induced changes were not significantly different between the 2 groups . Changes in cycling performance and aerobic capacity were not significantly related to changes in functional performance . CONCLUSIONS This study showed that a short cycling training program on a semirecumbent cycle ergometer can markedly improve cycling performance , aerobic capacity , and functional performance of people with chronic stroke . The use of ES had no additional effects in this specific group of subjects with chronic stroke OBJECTIVE To evaluate the effect of an 8-week , water-based exercise program ( experimental group ) with that of an upper-extremity function program ( control group ) to increase cardiovascular fitness within a community setting for people with stroke . DESIGN Single-blind r and omized controlled trial . SETTING Public community center . PARTICIPANTS A volunteer sample of 12 community-dwelling people with stroke with mild to moderate residual motor deficits . INTERVENTION Study subjects participated in group exercise programs for 1 hour , 3 times a week for 8 weeks . The experimental group exercised in chest-deep water at targeted heart rates . The control group performed arm and h and exercises while sitting . Main outcome measures The primary outcome measure was cardiovascular fitness ( V(O2)max ) . Secondary measures were maximal workload , muscle strength , gait speed , and the Berg Balance Scale score . RESULTS The experimental group attained significant improvements over the control group in cardiovascular fitness , maximal workload , gait speed , and paretic lower-extremity muscle strength . The relatively short program ( 8 wk ) of water-based exercise result ed in a 22 % improvement in cardiovascular fitness in a small group of people with stroke who had relatively high function . CONCLUSIONS A water-based exercise program undertaken as a group program may be an effective way to promote fitness in people with stroke The purpose of this pilot study was to compare differences in motor recovery between regular rehabilitation ( REG ) , and regular rehabilitation with supported treadmill ambulation training ( STAT ) using the performance on a bicycle exercise test and the locomotor scale of the Functional Independence Measure ( FIM-L ) . Twelve patients with acute strokes were r and omly assigned to either REG or STAT for 2 to 3 weeks . The STAT group received daily gait training utilizing a treadmill with partial support of body weight . After intervention , the STAT group had higher oxygen consumption ( 11.34+/-0.88 vs 8.32+/-0.88 ml/kg/min , p=0.039 ) , total workload ( 58.75+/-7.09 vs 45.42+/-7.09 watts , p = ns ) , and total time pedaling the bike ( 288.91+/-30.61 vs 211.42+/-30.61 s , p = ns ) compared to the REG group . The FIM-L scores were not different for the two groups . This pilot study suggests that the STAT intervention is a promising technique for acute stroke rehabilitation , and that future studies with larger sample sizes are warranted to establish the effectiveness of this intervention Background and Purpose — Resting and reactive hyperemic leg blood flows are significantly reduced in the paretic compared with the nonparetic limb after disabling stroke . Our objective was to compare the effects of regular treadmill exercise ( TM ) with an active control regimen of supervised stretching ( CONTROL ) on peripheral hemodynamic function . Methods — This intervention study used a r and omized , controlled design , in which participants were r and omized with stratification according to age and baseline walking capacity to ensure approximate balance between the 2 groups . Fifty-three chronic , ischemic stroke participants ( 29 TM and 24 CONTROL ) with mild to moderate hemiparetic gait completed bilateral measurements of lower leg resting and reactive hyperemic blood flow using venous occlusion strain gauge plethysmography before and after the 6-month intervention period . Participants also underwent testing to track changes in peak aerobic fitness across time . Results — Resting and reactive hyperemic blood flows were significantly reduced in the paretic compared with 
    Output:
    
Most studies recruited participants with mild stroke , and it is possible that cardiorespiratory fitness is even more impaired after severe stroke .
Maximal oxygen uptake might have been overestimated , as less healthy and older stroke survivors may not tolerate maximal exercise testing .