Which term describes a muscle's ability to sustain repeated contractions without fatigue?

The term that accurately describes a muscle's ability to sustain repeated contractions without fatigue is muscle endurance. This concept encompasses how well a muscle can perform over prolonged periods of activity, which is crucial for athletes and individuals who engage in endurance sports or activities.

Muscle endurance is essential for activities that require prolonged effort, such as running, cycling, or swimming, where maintaining a level of performance over time is key. It is distinct from muscle strength, which refers to the maximum force a muscle can exert in a single effort, and muscle power, which involves the speed of contraction in addition to force generation. Flexibility, on the other hand, pertains to the range of motion in joints and muscles, and does not relate to the capacity to perform repeated contractions. Thus, muscle endurance is the most appropriate choice in this context, as it highlights the capability of muscles to continue working effectively without succumbing to fatigue.