The term for the ability to sustain an amount of weight over time is known as what?

The ability to sustain an amount of weight over time is referred to as muscular endurance. This term specifically describes the muscles' capacity to perform repeated contractions over an extended period without fatigue. Muscular endurance is crucial for activities that require prolonged effort, such as cycling, running, or repetitive weight training.

In contrast, muscular strength focuses on the maximum amount of weight that can be lifted in a single effort, which is a different aspect of physical fitness. Flexibility pertains to the range of motion of muscles and joints rather than their ability to sustain weight. Cardiovascular endurance relates to the efficiency of the heart, lungs, and vascular system during prolonged physical activity, which also doesn't involve the sustained use of muscle strength in the same context. Thus, muscular endurance is the most fitting term for the described ability.