Table 1.

Energy systems and their characteristics. Reproduced from Salo et al. [7] with permission

	Characteristics
Anaerobic phosphocreatine	• Fuels intense swimming lasting from 0 to 12 s
	• ATP production is limited by amount of creatine-phosphate present in the muscles
	• Generally associated with high intensity, sprint performance (e.g., 50 m)
Anaerobic glycolysis	• Fuels high intensity swimming lasting up to 2–3 min
	• Generally associated sprint and middle distance swimming events (e.g., 100- and 200-m swims)
	• An end product of anaerobic glycolysis is lactic acid
Aerobic	• Fuels performances lasting longer than 3 min
	• The percentage of energy derived from fats and carbohydrates is dependent on swimming intensity—the higher the intensity, the greater the reliance on glucose
	• Generally associated with endurance activities (e.g., 400 m and longer)