A lower extremity exoskeleton, configurable to be coupled to a person,comprises two leg supports configurable to be coupled to the person's lowerlimbs and configured to rest on the ground during their stance phases. Eachleg support comprises a thigh link, a shank link, and two knee joints. Eachknee joint is configured to allow flexion and extension between the respectiveshank link and the respective thigh link. The lower extremity exoskeleton alsocomprises an exoskeleton trunk configurable to be coupled to the person'supper body. The exoskeleton trunk is rotatably connectable to the thigh linksof the leg supports allowing for the flexion and extension between the legsupports and the exoskeleton trunk. In this exemplary embodiment, the energyrequired for flexion and extension movement between the shank link and therespective thigh link of a leg support over a cyclic knee motion is providedby the person.
