National Physical Therapy Examination (NPTE) Practice Exam

In managing electrical stimulation for muscle strengthening, what is typically the desired current percentage of maximal voluntary contraction?

1. 20%

2. 40%

3. 60%

4. 80%

The correct answer is: 60%

The desired current percentage of maximal voluntary contraction for electrical stimulation aimed at muscle strengthening is typically set at around 60%. This level is chosen because it is sufficient to recruit a significant number of motor units, which is essential for effective muscle strengthening. At 60% of maximal voluntary contraction, the stimulation effectively creates a contraction that is strong enough to foster muscle adaptation and growth without causing excessive fatigue. This mid-range percentage strikes a balance between intensity and sustainability, allowing for effective training sessions that can contribute to both muscle strength enhancement and endurance over time. Lower percentages, such as 20% or 40%, may not adequately stimulate the muscle fibers needed for substantial strengthening effects, while 80% might push the muscle too close to maximal levels, increasing the risk of fatigue and decreasing the overall effectiveness of the training session. Therefore, 60% is often recommended for optimal outcomes in strength training through electrical stimulation.