Final answer:
The force generated by a muscle depends on the number of myofibers receiving an action potential.
Step-by-step explanation:
The force generated by a muscle depends on the number of myofibers within the muscle that receive an action potential from the controlling neuron.
When only a few myofibers respond, the force is minimal. However, when all myofibers participate, the force is closer to the maximum the muscle can produce. Increasing the frequency of action potentials can increase the force even more.