Which energy system would be predominantly used during a sprint lasting about 20 seconds?

The energy system primarily utilized during a sprint lasting about 20 seconds is the ATP-CP system, also known as the phosphagen system. This system is highly efficient for short bursts of high-intensity activity, providing immediate energy through the breakdown of adenosine triphosphate (ATP) and phosphocreatine (CP) stored within the muscles.

During a sprint, the body requires rapid energy output, which is best met by the ATP-CP system. It can supply energy almost instantaneously but can only sustain it for about 10-15 seconds. Hence, for a 20-second sprint, while there might be some contribution from anaerobic glycolysis as it kicks in after the initial energy burst, the predominant energy used is still derived from the ATP-CP system because it provides the quickest energy release.

In contrast, aerobic glycolysis and fatty acid oxidation are more suited for longer, steady-state activities where oxygen is readily available, and energy is produced over a longer duration. Therefore, they play a minimal role in a high-intensity effort lasting 20 seconds. Anaerobic glycolysis also supports energy production for efforts lasting from about 30 seconds to 2 minutes, which is slightly beyond the sprint duration in question,