This project contains experimental data and muscle-actuated tracking simulations of male subjects walking while carrying heavy load, and OpenSim simulations of these subjects wearing hypothetical ideal assistive devices. We collected motion capture data of 7 subjects walking in 4 different conditions: walking (a) without load at a freely selected speed, (b) without load at 80% of the freely selected speed, (c) while carrying 38 kg on the torso at a new freely selected speed, and (d) while carrying 38 kg at the same speed as in (a).

Based on the simulations of loaded walking (condition (c) above), we created new simulations to predict the effect of ideal assistive devices on the metabolic cost of walking. We examined 7 massless devices that each provided unrestricted torque at one degree of freedom and in one direction: hip abduction, hip flexion, hip extension, knee flexion, knee extension, ankle plantarflexion, and ankle dorsiflexion. We estimated the optimal device torques, and the devices' effect on metabolic cost and muscle activity.

Dembia CL, Silder A, Uchida TK, Hicks JL, Delp SL (2017) Simulating ideal assistive devices to reduce the metabolic cost of walking with heavy loads. PLoS ONE 12(7): e0180320. https://doi.org/10.1371/journal.pone.0180320