What is the primary energy substrate used during a 50m sprint?

During a 50m sprint, the primary energy substrate used is creatine phosphate. This is because sprinting is a high-intensity activity that lasts for a very short duration, typically around 7-10 seconds for such a distance. The body relies on the phosphagen system, which utilizes creatine phosphate stored in muscles to rapidly regenerate adenosine triphosphate (ATP).

ATP is the immediate energy currency of the cell, and during a sprint, the demand for ATP is extremely high. Creatine phosphate donates a phosphate group to adenosine diphosphate (ADP) to form ATP, allowing for sustained high-intensity performance for short bursts.

Other options, such as glycogen, glucose, and fatty acids, are utilized primarily during longer durations of physical activity. Glycogen and glucose become significant energy substrates during moderate to high-intensity exercise that lasts more than a few seconds, while fatty acids are primarily used during lower intensity, longer duration exercise. Given the short and explosive nature of a 50m sprint, creatine phosphate provides the most immediate and efficient energy source.