Body Sway and Muscle Activity during Assisted One-and Two-leg Stances in the Elderly

One-leg stance (OLS) training is recommended to prevent falls in elderly people. However, most elderly have difficulty in performing OLS for an extended period of time. Hence they need to use hand help when performing OLS training. The effects of hand help on body sway and leg muscle activity during OLS have been not been adequately investigated. This study aimed to compare the body sway and leg muscle activity during a two-leg stance (TLS) and OLS with front and lateral hand helps. Eleven elderly adults who were unable to perform OLS for 1 min (mean age, 79.6±5.3 years) participated in this study. Subjects wore electrodes on the gastrocnemius medialis, soleus, and tibialis anterior muscles of the supporting leg during TLS test, and one-leg stance with front support (OLS–FS) and lateral support (OLS–LS) for 1 min on a stabilometer. Muscle activity (mean %RMS and maximum %RMS) and body sway (total path length and X and Y axes path length) in the first, middle, and last periods were calculated and the differences among time periods (factor 1) and test methods (factor 2) were examined. All muscle activity and body sway variables showed significantly greater values during OLS–FS than during TLS. Gastrocnemius medialis and soleus muscle activity and Y axis path length during OLS–LS were significantly greater than during TLS, in a part of three time periods. Tibialis anterior muscle activity and X axis path lengths were significantly smaller during OLS–LS than during OLS–FS. In conclusion, regardless of hand help position, activity of the gastrocnemius medialis and soleus muscles during OLS with hand help is greater than during TLS. Tibialis anterior muscles activity and body sway in the left–right direction are greater during OLS–FS than during TLS and OLS–LS.