Effect of push-off timing on metabolic cost during walking with a universal ankle-foot prosthesis emulator

Prosthesis push-off timing, isolated from push-off work, had a strong effect on metabolic cost, with optimal push-off occurring at or after opposite leg heel contact. This result roughly concurs with findings from simulations, exoskeleton experiments, and normal walking, although the optimal timing was slightly later. It is possible that a different result would be found if the prosthesis were worn by amputees, as they would not have the additional weight and leg length and are more acclimated to walking with prostheses [11]. These results confirm that the prosthesis emulator used here allows experimental tests of the influence of push-off parameters on metabolic cost. In the future a similar experimental approach could be used to optimize the assistance that amputees can get from a constrained amount of battery energy