Simulating Ideal Assistive Devices to Reduce the Metabolic Cost of Running
The average metabolic power consumed over the running gait cycle, normalized by subject mass and averaged over 10 subjects, is shown for the ankle plantarflexors and dorsiflexors (AP and AD, red), the knee flexors and extensors (KF and KE, orange), and the hip flexors, extensors, adductors, abductors, external rotators, and internal rotators (HF and HE, blue; HD and HB, green; HX and HI, gray) when running at 2 m/s (top row) and 5 m/s (bottom row) in four assistance scenarios. The total height of each column, excluding the white regions, indicates the metabolic cost associated with the corresponding functional group in the unassisted simulation. Black and white regions indicate, respectively, reductions and increases in average metabolic power when the assistive devices were added. The greatest savings were observed in muscles actuating the assisted degrees of freedom, but substantial savings were observed in other muscle groups as well.