Testing procedures
closed-eye
A force plate (Zebris FDM-S, Zebris Medical GmbH, Germany) was used in this study. The sampling frequency of the Zebris force platform was set at 100 Hz. The change in center of pressure (COP) shifting was used to evaluate the neuromuscular balance ability of the lower extremities. This study was conducted in a single-leg stance, with the dominant leg as the supportive leg. The dominant leg was defined as the leg that steps up first when climbing stairs and the leg that is used to kick a ball. There were four test conditions in this study: (1) open-eye, barefoot, single-leg standing; (2) closed-eye, barefoot, single-leg standing; (3) open-eye, single-leg standing on a soft mat; and (4) closed-eye, single-leg standing on a soft mat. The measurement variables included time spent standing on one leg, area of body sway, path length of body sway, and velocity of body sway (Fig. (