Knee muscle strength, gait performance, and perceived participation after stroke.

OBJECTIVE To assess the relation between knee muscle strength, gait performance, and perceived participation in subjects with chronic mild to moderate poststroke hemiparesis. DESIGN Descriptive analysis of convenience sample. SETTING University hospital. PARTICIPANTS Fifty men and women (mean age, 58+/-6.4y) 6 to 46 months poststroke. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Isokinetic concentric knee extension and flexion strength was measured at 60 degrees /s. Gait performance was assessed by Timed Up & Go, comfortable and fast gait speed, stair climbing ascend and descend, and 6-minute walk test. Perceived participation was assessed with the Stroke Impact Scale. RESULTS There was a significant correlation (P < .01) between knee muscle strength and gait performance for the paretic but not for the nonparetic lower limb. Strength for the paretic limb explained 34% to 50% of the variance in gait performance; the addition of strength for the nonparetic limb explained at most a further 11% of the variance in gait performance. There was a significant correlation (P < .01) between gait performance and perceived participation; gait performance explained 28% to 40% of the variance in perceived participation. CONCLUSIONS Knee muscle strength is a moderate to strong predictor of walking ability in individuals with chronic mild to moderate poststroke hemiparesis. Walking ability influences perceived participation, but the strengths of the relations indicate that other factors are also important.