Which of the following best defines muscular endurance?

Muscular endurance is specifically defined as the ability of a muscle or group of muscles to repeatedly exert force over a prolonged period of time without fatigue. This definition encompasses activities that require sustained effort, such as long-distance running, cycling, or performing multiple repetitions of an exercise. It emphasizes the muscle's capacity to perform at submaximal intensities for an extended duration, making it a critical component of overall fitness, particularly for athletes involved in endurance sports or for individuals engaged in physical activities that require stamina.

The other definitions touch on different aspects of muscular function but do not accurately capture the essence of muscular endurance. For instance, the first option refers to maximum force exertion, which is more aligned with muscular strength rather than endurance. The third option relates to recovery, which is an important factor in overall fitness but does not define endurance itself. Lastly, maintaining posture throughout activity speaks to core stability and balance, which involve different muscular capabilities. This clarity on the definition of muscular endurance underlines why the chosen answer is the most appropriate.