Which energy source is most important in activities lasting less than 2 minutes?

In activities lasting less than 2 minutes, the most important energy source is the ATP-CP system. This anaerobic energy system provides immediate energy for high-intensity efforts by utilizing stored ATP (adenosine triphosphate) and creatine phosphate (CP) within the muscles. During such short durations of intense activity, the body relies primarily on these readily available energy stores, as they can supply energy very rapidly without the need for oxygen.

While glycolysis is also an anaerobic pathway that can produce energy in the form of ATP, it typically comes into play for activities that last slightly longer than around 10 seconds, as it leads to the breakdown of glucose into pyruvate, and during high-intensity efforts, it can contribute to lactic acid production. The lactic acid system, often associated with activities lasting from about 30 seconds to 2 minutes, also supports high-intensity efforts but becomes less prominent after longer durations when aerobic metabolism begins to dominate.

In summary, the ATP-CP system is the primary energy source for short bursts of high-intensity activity lasting less than 2 minutes, making it the most important source in this scenario.