Determinants of walking function after stroke: differences by deficit severity.
OBJECTIVES: To investigate the relationship of cardiovascular fitness (Vo(2)peak), neurologic deficits in balance and leg strength, and body composition to ambulatory function after stroke and to determine whether these relationships differ between those with milder versus more severe gait deficits. DESIGN: Cross-sectional correlation study. SETTING: Outpatient clinic of an academic medical center. PARTICIPANTS: Seventy-four people (43 men, 31 women; mean age +/- standard deviation, 64+/-10y) with chronic hemiparetic stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Thirty-foot (9.1-m) walk velocity, 6-minute walk distance, Vo(2)peak, Berg Balance Scale score, bilateral quadriceps eccentric torque, total and regional lean mass, and percentage of fat mass. RESULTS: Short-distance walking correlated significantly with cardiovascular fitness, balance, paretic leg strength, nonparetic leg strength, percentage of body fat, and paretic lean mass but not with nonparetic lean mass. Long-distance walking correlated significantly with cardiovascular fitness, balance, paretic leg strength, nonparetic leg strength, and paretic lean mass but not with percentage of body fat or nonparetic lean mass. Stepwise regression showed that cardiovascular fitness, balance, and paretic leg strength were independently associated with long-distance walking (r(2)=.60, P<.001). Variance in long-distance walking was largely explained by balance for those who walked more slowly (<.48m/s) for short distances (r(2)=.42, P<.001) and by cardiovascular fitness for those who walked more quickly (>.48m/s) for short distances (r(2)=.26, P=.003). CONCLUSIONS: Short-distance walking after stroke is related to balance, cardiovascular fitness, and paretic leg strength. Long-distance walking ability differs by gait deficit severity, with balance more important in those who walk more slowly and cardiovascular fitness playing a greater role in those who walk more quickly. Improved understanding of the factors that predict ambulatory function may assist the design of individualized rehabilitation strategies across the spectrum of gait deficit severity in those with hemiparetic stroke.