Antagonistic active knee prosthesis. A metabolic cost of walking comparison with a variable-damping prosthetic knee

This paper examines the impact of a biomimetic active knee prosthesis on the metabolic costs associated with a unilateral transfemoral amputee walking at self selected speed. In this study we compare the antagonistic active knee prosthesis developed at MIT to an electronically controlled, variable-damping commercial knee prosthesis, the Otto Bock C-leg. Use of the active knee prosthesis resulted in both, a 17% increase in an amputee's average self selected walking speed from 1.12 m/s to 1.31 m/s, and a 6.8% reduction in metabolic cost. The results of this study suggest that an agonist-antagonist active knee prosthesis design with variable impedance control can offer walking energetic advantages over commercially available systems.