Which energy system is primarily used during high-intensity, short-duration exercises?

The ATP-CP system, also known as the phosphagen system, is primarily used during high-intensity, short-duration exercises because it provides immediate energy through the breakdown of adenosine triphosphate (ATP) and creatine phosphate (CP) stored in the muscle cells. This system is capable of generating energy very quickly (within seconds) but is limited in duration, typically supporting activities lasting up to about 10 seconds, such as sprinting, explosive weightlifting, or short bursts of high-intensity efforts.

During these short, high-intensity activities, the demand for energy exceeds the rate at which the body can deliver it through the aerobic system or the glycolytic system, making the ATP-CP system the primary source of energy. This is essential for performance in activities where quick bursts of power and strength are necessary. Other energy systems, like the aerobic and glycolytic systems, come into play for longer-duration activities, where sustained energy output is required.