Body sway and muscle activity during one-leg stance with help using a hand

The authors examined the effects of the direction (front or lateral) and method (light touch [LT] or support [LS]) of hand help on body sway and muscle activity during 1-leg stance (OLS). Fifteen subjects performed OLS with hand help under 4 conditions (front LT, front LS, lateral LT, lateral LS) after conducting normal OLS. Center of pressure (COP) path length and electromyography (EMG) were recorded. When using the lateral help, the COP and EMG were significantly smaller with LS than with LT. When using the front help, a difference in help methods did not affect the COP, but the EMG of gastrocnemius was significantly smaller with LS than with LT. In conclusion, body sway and muscle activity during OLS markedly decrease with lateral LS.