The term "endurance" signifies the ability to sustain physical activity over a prolonged period. In sports, endurance is critical for athletes engaged in activities like marathons or cycling, where prolonged exertion is required. It encompasses both aerobic capacity, the heart’s ability to pump oxygen, and muscular stamina. Athletes build endurance through specific training regimens, improving their overall performance and reducing fatigue, which is vital for success in endurance-focused competitions.