Postural sway and muscle activation among younger and older adults during static balance with visual feedback

BACKGROUND: Postural sway, a measure of balance and fall risk, is often greater in older adults when compared to younger individuals. Training with visual feedback is shown to improve balance in older adults. The purpose of this study was to evaluate the differences in postural sway and muscle activation among younger and older adults during static balance with real-time visual feedback. METHODS: Forty participants, classified as younger (N.=20, age: 22.3 +/- 1.9 years) or older (N.=20, age: 71.6 +/- 5.6 years), completed three 20-s statis balance trials. Postural sway (PS) was analyzed via the Biodex((R)) Balance System (Biodex Inc, Shirley, NY, USA) and lower extremity muscle activation was measured by electromyography (EMG). RESULTS: PS was significantly greater (P<0.05) among older adults; Total Stability Index, anteroposterior sway, and mediolateral sway were 1.6-, 1.8-, and 2.0-times greater, respectively. Subsequently, muscle activation in all muscles measured was also significantly greater. Older adults demonstrated 2.0 times EMG activation of the anterior tibialis, gastrocnemius, and biceps femoris muscles, 3.5 times greater activation of the vastus medialis, and 4.0 times greater activation in the vastus lateralis compared to younger counterparts. CONCLUSIONS: The findings suggested, without allowing time for a learning effect, there is significantly greater PS and muscle activation in older adults when compared to younger adults. More specifically, older adults employed a strategy of increased muscular activity, particularly in the anterior thigh, to control their PS during static standing with real-time visual feedback.