Current prosthetic feet produce much less peak mechanical power than the able-bodied foot/ankle and release only about half of the mechanical energy generated during gait.This leads to higher energy expenditure among amputees as compared to able-bodied individuals.In addition, the lack of prosthetic ankle range of motion negatively impacts users abilities to navigate slopes and uneven terrain.Therefore, amputees with major lower limb amputation would greatly benefit from a prosthetic foot that had a large range of motion and was able to increase the amount and timing of the power it returned during the gait cycle to improve gait efficiency.Along with our partners from College Park Industries and the University of Michigan, Liberating Technologies, Inc. proposes to develop the Compliant Adaptive Energy Storing And Return (CAESAR) foot.The CAESAR foot aims to harvest energy from the entirety of the stance phase and control of the timing of the release of this energy to allow for the optimal return of energy to assist in forward propulsion of the individual during a variety of military relevant tasks.