How should you address patient fatigue during NMES sessions?

• A. Adjust the duty cycle (increase off-time), reduce amplitude, shorten on-time, vary stimulation pattern, and provide rest between sets.
• B. Increase amplitude to maximum regardless of fatigue.
• C. Prolong sessions without rest.
• D. Use continuous on-time at maximum intensity.

Answer: (A)

Fatigue during NMES comes from the muscle being asked to contract repeatedly with limited opportunity to recover, leading to reduced force and performance. The best approach is to tailor the stimulation pattern and rest so the muscle can sustain activity without tiring quickly.

Increasing the off-time in the duty cycle gives the muscle a chance to recover between contractions, improving oxygen delivery and metabolite clearance. Reducing the amplitude lowers how many motor units are recruited and how much force is produced, which decreases metabolic demand. Shortening the on-time reduces the duration of each contraction and total work per burst, helping delay fatigue. Varying the stimulation pattern can recruit different motor units and prevent rapid, repetitive fatigue from a single, predictable recruitment path. Providing rest between sets allows full recovery before the next round of contractions begins.

Using maximum amplitude, prolonging sessions without rest, or keeping continuous high-intensity on-time would heighten fatigue and hinder performance, so they’re not appropriate when fatigue is a concern.