What term refers to the ability of muscles to utilize oxygen during exercise?

The term that refers to the ability of muscles to utilize oxygen during exercise is "cardiorespiratory endurance." This concept involves the efficiency with which the heart, lungs, and muscles work together to supply oxygen during sustained physical activity. A higher level of cardiorespiratory endurance indicates that the body can deliver and use oxygen more effectively, which is crucial for activities that require prolonged exertion.

While terms like "aerobic capacity" might also relate to the utilization of oxygen, cardiorespiratory endurance encompasses the broader system involving the heart and lungs, as well as the muscular response to sustained efforts. Muscle efficiency, on the other hand, focuses specifically on how effectively muscles can perform work, but it doesn't solely capture the role of oxygen delivery and utilization. Cardiac strength is related to the heart's ability to pump blood but does not directly address the muscular aspect of using oxygen during exercise. Therefore, cardiorespiratory endurance is the most appropriate term for the overall ability of muscles to efficiently utilize oxygen during exercise.