What energy system is primarily used for sprints lasting less than 10 seconds?

The energy system primarily utilized for sprints lasting less than 10 seconds is the phosphagen system, also known as the ATP-CP system. This energy system operates anaerobically, meaning it does not require oxygen, allowing for rapid energy production to meet the immediate demands of short-duration, high-intensity activities like sprinting.

During sprints of this duration, the body relies on stored adenosine triphosphate (ATP) and phosphocreatine (CP) to provide energy. These substrates are readily available in muscle cells and can be rapidly mobilized to regenerate ATP. This is crucial for performance, as the body cannot produce energy quickly enough through aerobic metabolism or other systems in such a short time frame.

The phosphagen system can sustain maximal efforts for about 6 to 10 seconds before the energy substrates are depleted. After this initial period, the body begins to rely more on other energy pathways, such as the lactic acid system, for continued performance, especially for efforts extending beyond 10 seconds. Thus, for activities that demand quick bursts of speed and power, the phosphagen system is the most effective and primary energy source.