The invention may be embodied in a physical therapy or health maintenance stretching system including a frame configured for engaging a treated leg of a user at or near the popliteal space of the treated leg to allow a knee of the treated leg to bend inwards in response to gravitational force affecting a lower portion of the treated leg. The frame may be further configured to allow a knee of the treated leg to bend inwards in response to a user force directly or indirectly applied to the lower portion of the treated leg.