Fig. 9.

Perturbation to backward direction. Left - pelvis movement and interaction forces/moment associated with actuated DoF in transversal plane for unperturbed and perturbed walking over selected observation interval for single typical subject was averaged across five single responses. Right - graphical illustration of foot placement at left (approximately at 0, 100 and 200 %) and right (approximately at −50, 50, 150 and 250 %) foot strikes for unperturbed and perturbed walking over selected observation interval for a group of subjects was generated from averaged group step lengths and step widths and time-aligned at the onset of perturbation at 0 %