What is the primary source of energy for short-duration high-intensity exercises?

The primary source of energy for short-duration high-intensity exercises is anaerobic metabolism using creatine phosphate. During such activities, the body requires immediate energy, which is best provided by the phosphagen system, where creatine phosphate is utilized to rapidly regenerate ATP (adenosine triphosphate).

This metabolic pathway is very effective for delivering quick bursts of energy, typically lasting about 10 seconds. It does not rely on oxygen, which allows for rapid ATP production without the delay associated with aerobic processes. This is essential in high-intensity activities like sprinting or heavy lifting, where muscle contractions occur at a high rate and energy demands surge.

While glycolysis also plays a role in providing energy for short-duration exercises, particularly beyond the initial seconds when creatine phosphate stores begin to deplete, it is not as immediate as the anaerobic pathway utilizing creatine phosphate. Additionally, aerobic metabolism and fat oxidation are more relevant during prolonged lower-intensity activities rather than during quick and intense bursts of effort. Thus, anaerobic metabolism via creatine phosphate is the most immediate and effective source for energy in high-intensity, short-duration exercises.