What is the duration of the ATP-PC energy system?

• A. ~5-10 seconds
• B. ~30-60 seconds
• C. ~2-3 minutes
• D. ~10-20 minutes

Answer: (A)

The ATP-PC system fuels immediate, explosive efforts by using the muscle’s stored ATP and phosphocreatine. These energy stores are very limited, so they can power a maximal effort for only a short period—typically about five to ten seconds. Once those stores are depleted, energy production shifts to other systems (primarily anaerobic glycolysis, then aerobic metabolism) to continue activity. That’s why longer durations like thirty to sixty seconds, a couple of minutes, or many minutes are associated with other energy pathways. So, the duration of the ATP-PC energy system is about 5–10 seconds.