Final answer:
Creatine phosphate is an energy system used for short, intense bursts of activity and can supply energy for about 8-10 seconds, whereas aerobic events lasting 90 to 120 minutes mainly rely on aerobic respiration to sustain muscle activity.
Step-by-step explanation:
For athletes participating in continuous, intense aerobic events lasting 90 to 120 minutes, the energy system predominantly utilized is aerobic respiration, not creatine phosphate. Creatine phosphate is a quick source of energy, catalyzed by creatine kinase, that allows for the generation of ATP from ADP and creatine, providing energy for about 8-10 seconds, which is ideal for short, explosive events such as weightlifting or sprinting.
As the event continues past the brief period that creatine phosphate can supply energy, the body shifts to anaerobic glycolysis, which breaks down glucose to generate ATP without the need for oxygen, lasting about 90 seconds. However, for endurance events that extend beyond this duration, such as marathon running or distance rowing, the muscles rely predominantly on aerobic respiration. This efficient process uses oxygen to break down glucose into carbon dioxide, water, and a significant amount of ATP, sustaining muscle activity for the duration of the event.