Systems, methods, and apparatus provide an artificial knee. Such artificial knees may include a thigh link configured to move in unison with a thigh of the person, a shank link configured to be rotatably coupled to the thigh link, and a compression spring rotatably coupled to the thigh link at a first end and coupled to the shank link at a second end. The compression spring is configured to provide an extension torque between the thigh link and the shank link during a first range of motion of the thigh link and the shank link relative to each other. The compression spring is configured to provide a flexion torque between the thigh link and the shank link during a second range of motion of the thigh link and the shank link relative to each other.
