Abstract: A rotator cuff therapeutic exercise apparatus is provided which includes a stack of weights supported on a frame for movement along a working stroke from a rest position against gravitational force to a displaced position and an actuator mechanism on the frame adapted to be gripped and rotated by a hand of a user to move the weights along the working stroke. The actuator mechanism is positionable in either first or second configurations for permitting a corresponding rotational working motion of the one of the user's arms whose hand grips the actuator mechanism. For transmitting the rotational motion of the user's arm to move the weights, a ratchet-type mechanism is provided which is connected to the actuator mechanism and allows internal and external rotation of the arm and for accomplishing positive and negative work therewith.