Figure 4

Anteroposterior (x), mediolateral (y) and vertical (z) trajectories of the BCoM at 1.1 and 1.4 m/s (a) and corresponding SPM paired two-tailed t-test with an alpha level of 0.05 (b). For graphical purposes, the horizontal axis spans from 0 to 100% of the stride period, instead of spanning from 0 to 2π as required by Fourier analysis. In panel a, approximate double support (DS) and single support (SS) periods are shown to ease the understanding of the plots.