A brace for augmenting movement of a user's limb about a joint includes an upper arm having an engaging portion for engaging against the user's limb above the joint, and an attachment portion, a lower arm having an engaging portion for engaging against the user's limb below the joint, and an attachment portion, the lower arm being pivotable relative to the upper arm, at least one compression element disposed in fixed relation to at least one of the upper and lower arms, and a substantially inelastic tensioning element affixed to the other of the upper and lower arms over at least one tensioning element tensioning member such that a user applies a force to move the brace to a loaded position in which the at least one compression element is loaded and upon removal of the applied force the at least one compression element applies a restoring force to urge the brace out of the loaded position, the at least one compression element comprising a hydraulic tension spring disposed in fixed relation to at least the other of the upper and lower arms, comprising a pair of cylinders mounted within a frame, each cylinder having a sealed portion defining a liquid containment space, for each of the pair of cylinders, a piston comprising a piston rod, the piston rod comprising a compressing portion having a smaller diameter than the cylinder and extending axially through a hydraulic seal into the liquid containment space, and an external portion accessible from outside the liquid containment space, one of the cylinder and the piston being fixed relative to the frame and the other of the cylinder and the piston being movable axially relative to the frame, a guide for maintaining the movable one of the cylinder and the piston oriented axially relative to the frame, and a compression element tensioning member bearing against the movable one of the at least one cylinder and the piston, for compressing the at least one cylinder relative to the piston, whereby when the frame is fixed in p
