Which metabolic pathway predominates during anaerobic high-intensity exercise?

During anaerobic high-intensity exercise, the predominant metabolic pathway is the phosphagen system. This system primarily utilizes stored ATP (adenosine triphosphate) and creatine phosphate to provide immediate energy for muscular contractions. It is especially crucial during short bursts of intense activity, such as sprinting or heavy lifting, where energy demands exceed what can be generated through aerobic pathways.

The phosphagen system is characterized by its rapid energy production, allowing for high-intensity efforts lasting approximately 10 seconds or less. It does not require oxygen, making it anaerobic in nature. Once the ATP stored in the muscles is depleted, the body can then rely on other pathways, such as anaerobic glycolysis, but these are less effective in terms of speed and energy output compared to the phosphagen system during the initial phases of high-intensity exercise.

Other pathways, such as oxidative phosphorylation and beta-oxidation, involve aerobic metabolism and do not kick in until the exercise intensity decreases or the duration extends beyond what the phosphagen system can support. Thus, the rapid energy demands of anaerobic high-intensity exercise are best met by the phosphagen system.