What is the purpose of using a return electrode in NMES?

• A. To increase battery life of the device.
• B. To deliver the main stimulation to the targeted muscle.
• C. To complete the electrical circuit, help distribute current, and improve contraction localization while reducing skin irritation.
• D. To cause proprioceptive feedback.

Answer: (C)

The essential idea is to complete the electrical circuit and shape how the current travels through the body. The return electrode provides the path back to the stimulator after the active electrode delivers the pulse to the muscle. Using a larger return pad spreads the current over a wider area, which lowers the current density at the skin, reducing irritation and discomfort. It also helps guide the current to flow in a way that concentrates the contraction in the target muscle rather than under a single point. If the return path is poorly placed or too small, current can crowd under the active electrode, causing hotspots, skin irritation, and less selective activation. So, the return electrode serves to complete the circuit, distribute current, improve localization of contraction, and minimize skin irritation.