Final answer:
Sprinters derive energy initially from stored ATP, then from creatine phosphate, and later through anaerobic glycolysis using glycogen, resulting in lactic acid as a by-product. This allows for sustained high-intensity performance even when oxygen is temporarily scarce during a sprint.
Step-by-step explanation:
Energy Sources for Sprinting
During a 100m sprint, muscle cells require a rapid supply of energy that aerobic cellular respiration cannot provide quickly enough. Initially, ATP stores in the muscles are used, which last only a few seconds. Subsequently, energy is derived from creatine phosphate, which supplies the muscles for about 8-10 seconds. As the race continues, muscles turn to glycogen reserves to produce ATP via glycolysis, a process that does not require oxygen and can support intense activity for approximately 90 seconds. Lactic acid is a by-product of this anaerobic metabolism, which can cause muscle fatigue and soreness.
After the race, heavy breathing occurs as the sprinter's body transitions back to aerobic respiration to fulfill the oxygen debt and recover from the exertion. Endurance athletes, such as marathon runners, use a different strategy by maximizing glycogen storage through carbohydrate loading, providing a longer-term energy source that is metabolized into ATP through aerobic pathways.