A method and apparatus include a therapeutic or developmental instrument that includes hardware and/or software for stimulating a muscle. Such an instrument may comprise, for instance, a golf club, a baseball bat, a lacrosse stick, a tennis racquet or a hockey stick, among other sports-related instruments. Still other suitable instruments may include a writing instrument, such as a pen. In the case of a golf club, a muscle of a user may be stimulated by the instrument as the golfer practices her swing. Combining such muscle stimulation with the act of practicing the movement of the swing has a synergistic effect of training the muscle as it builds strength. Similarly, a partial paralytic may regain strength in their hand by holding and writing with a pen configured to transcutaneously deliver a stimulating signal. Where desired, the instrument may include at least one electrode configured to deliver a stimulating signal to the holder of the instrument. In another or the same embodiment, wired electrodes may extend from the instrument or an adjacent signal generator to the holder of the instrument. This configuration may allow other, targeted muscles to be concurrently stimulated while the user manipulates the instrument.