What does "muscular endurance" refer to?

Muscular endurance specifically refers to the ability of a muscle or group of muscles to perform repeated contractions over an extended period of time without fatigue. This definition emphasizes the endurance aspect, whereby muscles can sustain activity over longer durations, making it crucial for many physical activities and sports where prolonged effort is required. For instance, activities such as running, cycling, or performing multiple repetitions of resistance exercises rely heavily on muscular endurance.

In contrast to the other options, which address different aspects of fitness, muscular endurance is distinct from the total amount of weight that can be lifted (maximum strength), the overall power and capability of muscles (strength), or their range of motion (flexibility). Each of those has its own significance in physical fitness but does not capture the essence of muscular endurance. Therefore, the correct answer clearly encapsulates the concept of maintaining performance through repeated exertion without significant decline in capability over time.