When targeting proximal limb muscles, what anatomical considerations influence electrode placement?

• A. Proximity to motor points and nerve trunks, avoiding bones/nerve pockets; align electrodes along the muscle fibers; maintain even contact and avoid over joints or large subcutaneous tissue.
• B. Place electrodes randomly on the limb.
• C. Place electrodes over bones and joints.
• D. Place electrodes on tendons only.

Answer: (A)

Targeting proximal limb muscles with NMES is about delivering current where it most effectively depolarizes motor units within the muscle. Placing the electrodes near the muscle’s motor points, usually in or around the muscle belly, maximizes recruitment by reducing the activation threshold and directing current through the muscle rather than surrounding tissues. Aligning the electrodes along the muscle fibers helps the current travel in the same orientation as the muscle fibers, promoting a more uniform and efficient contraction. Maintaining even skin contact and avoiding large subcutaneous tissue gaps keeps impedance low and reduces hotspots, which improves comfort and steadiness of the contraction. It’s also important to avoid placing electrodes over bones or nerve trunks, as that can increase impedance, cause discomfort, or recruit unintended tissues. Placing electrodes over joints or tendons would produce poor, inconsistent contractions and less selective stimulation.