Differences in leg muscle activity and body sway between elderly adults able and unable to maintain one-leg stance for 1 min: the effect of hand support.

BACKGROUND: One-leg stance (OLS) training is often used to prevent falls in the elderly. The burden imposed on the supporting lower limb during OLS may differ depending on whether hand support is used, particularly in patients with decreased lower-limb strength. AIMS: Here we examined the effect of hand support on leg muscle activity and body sway during OLS in elderly subjects able to maintain OLS for 1 min unaided [able group (AG), n = 13] and those who were unable to do so [unable group (UG), n = 11]. METHODS: All subjects performed OLS unaided and OLS with front support (OLS-FS) using one hand for 1 min each. We estimated leg muscle activity [mean and maximum % root mean square (%RMS)] and body sway (total, X-axis, and Y-axis path lengths) for both tests. %RMS was calculated according to the results of the maximum voluntary isometric contraction test. RESULT: The overall average mean and maximum %RMS for the tibialis anterior muscle was larger in UG than in AG. In AG, tibialis anterior muscle mean and maximum %RMS and body sway was larger during OLS than during OLS-FS. Total and X-axis path lengths were larger during the first 20 s OLS phase in AG and the first 20 s OLS-FS phase in UG. CONCLUSION: These results highlight the need to differentiate between patients able and unable to perform OLS unaided for training because of differences in leg muscle activity.