What defines anaerobic activities?

Anaerobic activities are characterized by the body's ability to generate energy without relying on oxygen. This occurs during short bursts of high-intensity exercise where energy demands surpass the capacity of the cardiovascular system to deliver oxygen to the muscles. Instead, anaerobic metabolism taps into energy sources stored in the muscles, such as glycogen, allowing for quick energy release but only for a limited duration.

Other options describe different types of exercise. Low-intensity exercises performed over lengthy periods are more related to aerobic activities, where oxygen supply adequately meets energy demands, promoting endurance. Similarly, exercises that can be sustained for long durations and steady-state activities focus on aerobic endurance rather than the short, intense bursts typical of anaerobic training. Therefore, the definition aligning with the nature of anaerobic activities is that they occur when energy needs exceed the body's oxygen supply, making the selection correct.