What does "aerobic capacity" measure?

Aerobic capacity is a key measure of how well the body can take in oxygen and utilize it during prolonged physical activity. This capacity reflects the efficiency of the cardiovascular and respiratory systems in delivering oxygen to the muscles and the ability of those muscles to use that oxygen in energy production. During endurance activities such as running, cycling, or swimming, higher aerobic capacity indicates improved performance and stamina.

The other options, while related to fitness, assess different aspects: muscle mass and strength pertain to anaerobic performance, recovery speed addresses the body's ability to recover after exertion, and maximum weight lifted concerns muscular strength rather than aerobic endurance. Therefore, option A accurately captures the essence of aerobic capacity and its importance in overall fitness assessment.