_____ is the primary fuel used to create ATP during a 3RM bench press test?

During a 3RM (three-repetition maximum) bench press test, the primary fuel used to create ATP is creatine phosphate. This is due to the short duration and high intensity of the activity, which relies on the immediate energy system, predominantly the phosphagen system.

In this system, creatine phosphate rapidly donates a phosphate group to ADP to regenerate ATP, allowing for quick bursts of energy that are essential for heavy lifting. This process happens almost instantly, making it ideal for activities that require maximal effort for a short duration, such as a 3RM test.

Glucose and pyruvate play more significant roles in longer-duration activities, where glycogen breakdown through glycolysis provides energy. Acetyl-CoA is primarily involved in aerobic metabolism and is utilized in longer-duration exercise after initial short bursts have transitioned into efforts requiring sustained energy. Thus, while glucose and other substrates may contribute in longer activities, they are not the primary fuels during short, maximal efforts like the 3RM bench press.