Which of the following describes muscular endurance?

Muscular endurance is defined as the ability of a muscle or group of muscles to perform repeated contractions over a period of time without becoming fatigued. This concept highlights how muscles can sustain activity for an extended duration, making option B the correct choice.

In practical terms, muscular endurance is essential for activities that require prolonged physical effort, such as running, swimming, or high-repetition weight training. It indicates not just strength but a muscle's ability to work effectively over time without loss of performance.

The other choices focus on aspects of muscular strength or speed rather than endurance. The first option pertains to one-time maximal lifting, while the third option emphasizes maximum influence rather than ability over time. The fourth option addresses the speed of contraction, which does not directly connect to the ability to perform repeated movements. Thus, B captures the essence of muscular endurance accurately.