At what point is anaerobic metabolism predominantly used?

Anaerobic metabolism is primarily utilized during maximal effort activities that are high in intensity. This metabolic pathway does not require oxygen and is capable of providing energy quickly for short bursts of activity. It primarily relies on the phosphagen system and anaerobic glycolysis, which are effective for high-intensity efforts lasting from a few seconds up to about two minutes.

During such strenuous activities, the body demands energy rapidly, and the anaerobic system becomes the dominant energy source because it can mobilize energy faster than aerobic metabolism. In contrast, during low-intensity activities, the body relies mostly on aerobic metabolism, which requires oxygen and is effective for sustained, longer-duration efforts. While resting or during aerobic conditioning phases, the body primarily engages the aerobic systems for energy, as these conditions allow for efficient energy production over longer time periods without the immediate need for rapid energy.