Effects of adding torque at 50% of gait on joint kinematics. a. The 3 levels of assistive torques applied on a subject's ankle (S13) by the EHO during push off (dark lines) are superimposed on Baseline (grey band); outside of the force field application zone, the EHO applied a null field to minimize its influence on the subject's walking pattern. b. Superimposed knee angular displacements for baseline (grey band) and the 3 levels of assistance. c. Superimposed ankle angular displacements for baseline (grey band) and the 3 levels of assistance. d. Ankle angular velocities for the same traces as in 'c'. Grey bands represent mean value ± 2 STD. For all conditions, data were synchronized on heel strike. Abbrev. WA: weight acceptance; MS: mid-stance; PO: push-off; HS: heel strike.