A 24-year-old medical student goes to the local gym to lift weights. She begins by bench-pressing 100 pounds as a warm-up procedure and then gradually increases the weight. Which of the following occurs as she adds more weight?

Question

Quizplus · Accepted Answer

As she adds more weight to the bar, the demand on her muscles increases. In order to meet this demand, the frequency of motor nerve action potentials (the signals that tell the muscles to contract) needs to increase. This allows more motor units (groups of muscle fibers controlled by a single motor neuron) to be recruited, resulting in a stronger contraction. Therefore, the best choice is C - increased frequency of motor nerve action potentials.

A 24-Year-Old Medical Student Goes to the Local Gym to Lift