Electrical stimulation can target which types of muscle?

• A. Both Innervated and Denervated Muscles
• B. Only Innervated Muscles
• C. Only Denervated Muscles
• D. Cardiac Muscle Only

Answer: (A)

Electrical stimulation works by activating muscle tissue, and the way it does so depends on whether the muscle still has a functioning nerve connection. For muscles that are innervated, stimulation depolarizes the motor nerves, which then recruit motor units to produce contraction. This is the common approach used for strengthening, re-education, or preventing atrophy in people with intact nerve supply. When a muscle is denervated—its nerve supply is lost—the nerve can’t be activated, so the stimulation must stimulate the muscle fibers directly. In that case, you use longer pulse durations and often different electrode placements to directly depolarize the muscle cell membranes and evoke a contraction. Because stimulation can adapt to both conditions, it can target both innervated and denervated muscles. Cardiac muscle is not the typical focus of this kind of therapy, since the heart’s activity is controlled by its own conduction system and specialized pacing approaches.