不安定面上でのバランスエクササイズが姿勢制御における感覚依存性に及ぼす即時効果

抄録

    The purpose of this study was to determine whether balance exercises on unstable support surfaces change the dependence on sensory inputs for postural control. Twenty-one healthy males were divided into two groups, Balanceboard group (B group, n＝11) and G-ball group (G group, n＝10). The subjects repeated 2 min of balance exercise twice with 1 min’s rest between executions. As the balance exercise, B group executed standing on a Balance-board and G group executed sitting on a G-ball. The subjects performed 60 s of quiet standing twice on a force platform with three sensory conditions; eyes open (EO), eyes closed (EC) and eyes closed on a foam (ECF) before (pre measurement) and after (post measurement) the balance exercises. In post measurement, 20 s of balance exercise was performed just before the first trial of each condition to maintain sensory adaptation. During quiet standing, the motion of the center of pressure (COP) was measured and sway velocity and sway area were calculated. To estimate the dependence on visual input, Romberg ratio (EC vs. pre-EO ratio) based on the sway velocity and the sway area was calculated. To estimate the dependence on somatosensory inputs from lower extremity based on the two sway parameters, the difference between ECF and pre-EC normalized by pre-EC was calculated as the increase in sway (IS). In B group, post-Romberg ratios were significantly higher than pre-values. By contrast, in G group, post-ISs were significantly lower than pre-values. We concluded that for postural control, the Balance-board exercise increases the dependence on visual input and that the G-ball exercise decreases the dependence on somatosensory inputs from lower extremities.