Fig. 8. The pendular recovery of mechanical energy, defined by equation 1 (R_step, open circles) and by equation 6 (R_int, open squares), and the external work done per unit distance (W⁺_ext, filled circles) plotted as a function of speed during unloaded walking for the 11 European subjects of this study. Values are means ± S.D. (N is given by the numbers near the filled circles) for data grouped into the following intervals along the abscissa: <2, 2 to <2.5,...., 8.5 to <9, >9 km h^-1. Lines are fitted using a third-order polynomial fit (r²=0.98, KaleidaGraph 3.5). The crosses and the dotted line show how R_step changes when the kinetic energy of vertical motion of the centre of mass, E_kv, is taken into account in the calculation of W⁺_v and W⁺_k (see text). Note that W_ext attains a minimum at a speed lower than the speed at which the pendular recovery attains a maximum.

Return to article