US Patent 7150721 Knee brace with dynamic counterforce

Braces for applying dynamic forces and methods for applying dynamic forces on limbs are disclosed herein. In one embodiment, a brace has an upper frame, a lower frame, a hinge coupling the upper frame to the lower frame, a hydraulic pump, and a bladder. The upper frame is moveable relative to the lower frame. The hydraulic pump is coupled to the hinge, the upper frame or the lower frame. The hydraulic pump generates a fluid flow that flows into and expands the bladder. The bladder is positioned to apply a force to the limb as it expands.