Fig. 8. (A) Mean sum of the positive increments in mechanical energy (E_pos) of both tarsometatarsal segments as a function of treadmill speed, in the unloaded (closed symbols) and loaded (open symbols) segments. Circles, total E_pos over the whole stride; triangles, E_pos for swing phase only. (B) Mean mechanical power of the unloaded (closed circles) and loaded (open circles) tarsometatarsal segments, calculated by dividing total E_pos for the stride by the stride duration. Values are means ± 1 s.e.m. (N=6).