Abstract: Described here are devices and methods for strengthening the thenar muscles of the hand. Generally, a device comprises a base shaped to be held in the hand, a thumb rest having a hinge attached to the base such that one end of the thumb rest can be pivoted relative to the base, and an elastic member attached to the base and the thumb rest, which resists the pivoting motion of the thumb rest relative to the base. The user can place the device in his or her hand, and place his or her thumb on the thumb rest. When the user presses the thumb rest toward the base with his or her thumb, the elastic member supplies a force resisting the pressing motion, which exercises the thenar muscles.