Balance Ability, Not Muscle Strength and Exercise Endurance, Determines the Performance of Hemiparetic Subjects on the Timed-Sit-to-Stand Test

OBJECTIVE: To examine the contribution of balance ability, muscle strength, and exercise endurance to performance in the timed-sit-to-stand test among chronic hemiparetic subjects. DESIGN: A cross-sectional study with 68 community-dwelling stroke survivors. RESULTS: By using Pearson correlation coefficient, the five-times-sit-to-stand (FTSTS) test scores showed the highest negative correlation with Berg Balance Scale scores (r = -0.837, P < 0.001), and it showed significant moderate correlation with muscle strength index (r = -0.577, P < 0.001) and distance covered in a 6-min walk test (r = -0.598, P < 0.001). After controlling for demographic factors, significant partial correlation was identified between FTSTS scores and Berg Balance Scale scores only (r = -0.630, P < 0.001). Linear regression model, after accounting for demographics and subjective balance confidence, showed that FTSTS scores were independently associated with Berg Balance Scale scores (beta = -0.630, P < 0.001), whereas muscle strength index and distance covered in the 6-min walk test were not significant predictors of FTSTS scores. The whole model could explain 71% of the variance in FTSTS scores. CONCLUSIONS: This is the first study documenting the importance of balance ability, not muscle strength and exercise endurance, as an important determinant of performance on the FTSTS test by community-dwelling stroke patients. These findings suggest that the FTSTS test may be a more appropriate proxy indicator of balance performance in chronic community-dwelling stroke subjects.