Which term best describes the ability of a muscle to perform repeated contractions against resistance without fatigue?

The term that best describes the ability of a muscle to perform repeated contractions against resistance without fatigue is muscular endurance. This concept refers specifically to how long a muscle can sustain repeated efforts over an extended period. In the context of physical exercise, muscular endurance is crucial for activities that involve continuous, effortful movements, such as long-distance running, cycling, or even performing multiple sets of a strength-training exercise.

Muscle strength, while related, refers to the maximum amount of force a muscle can exert in a single effort rather than its ability to maintain performance across repeated efforts. Flexibility pertains to the range of motion around joints and does not address how muscles perform over time under resistance. Power involves the ability to exert a maximal force in a short amount of time, which also differs from the endurance concept focused on sustained activity. Thus, muscular endurance captures the essence of the question more accurately than the other terms.