In neuromuscular electrical stimulation (NMES), what is the primary effect on muscles?

The primary effect of neuromuscular electrical stimulation (NMES) on muscles is muscle contraction. NMES utilizes electrical impulses to stimulate the motor neurons that lead to muscle fibers, resulting in contraction. This contraction mimics the natural processes of muscle activation during physical activity. NMES is often used in rehabilitation settings to prevent muscle atrophy, improve muscle strength, and enhance functional mobility after a stroke or injury. By effectively inducing muscle contractions, NMES can aid in maintaining neuromuscular function during periods when voluntary movement is limited or impaired.

The other options do not accurately reflect the primary role of NMES. Increased pain perception is not a characteristic effect of NMES; rather, effective use of NMES aims to alleviate pain through muscle contractions. Joint immobilization is not a direct outcome of NMES; instead, proper use of stimulation encourages movement and muscle engagement. Decreased range of motion is also not supported by NMES, as the goal of stimulating the muscles is often to improve mobility and flexibility rather than restrict movement.