Fig. 5. Whole body peak GRF magnitudes and phases. Values are means ± 1 s.e.m. One phase is equal to one complete stride or two steps. (A) Normal force peaked at approximately twice body weight (broken line). (B) Peak fore–aft forces decelerated and then accelerated the COM at each step with forces about 40% of the normal forces. (C) Lateral force accelerated the COM to the right followed by an acceleration to the left.