Figure 2.

Body sway during quiet standing. Body sway is represented here as the SD of C7 velocity during quiet standing. A, C, Group mean sway measured in X and Y directions of the laboratory coordinate system (Lab). B, D, Group mean X/Y ratio for sway. Error bars represent 95% confidence intervals of the mean. The top row of panels (A, B) shows the effect of stance width using data from experiment 1. Labels on the abscissa denote the stance width in centimeters. The bottom row of panels (C, D) shows the effect of lateral touch (experiment 3).