A leg locomotion device includes a frame having a leg coupler configured to mount the frame to a users leg, the frame also includes two frame components movable relative to one another in response to movement of the users leg, an energy harvesting device coupled to the frame and configured to harvest energy from the movement of the two frame components during a first portion of a stride, an energy storage device coupled to the energy harvesting device, the energy storage device configured to store harvested energy over more than one stride, and an assist device coupled to the frame, coupled to the energy storage device to receive energy therefrom, and configured to move the frame components relative to one another to selectively assist with movement of the users leg during a second portion of the stride.
