Which energy system predominantly provides energy for a high-intensity effort lasting about 60 seconds?

• A. Phosphocreatine (ATP-PC) system.
• B. Aerobic system.
• C. Anaerobic glycolysis.
• D. Lipid oxidation.

Answer: (C)

When a task is high‑intensity and lasts around a minute, the body relies on a fast energy supply that doesn’t depend on oxygen. The ATP‑PC system delivers energy incredibly quickly, but it can only power activity for roughly the first 10 seconds before its stores are depleted. After that, the dominant source becomes anaerobic glycolysis, which breaks down glucose to produce ATP rapidly without using oxygen and produces lactate as a byproduct. This pathway is well suited to sustaining a hard effort for about a minute, matching the 60-second duration.

The aerobic system, while capable of substantial ATP production, is slower to ramp up and cannot meet the immediate energy demand of a high‑intensity burst at the start; it contributes more as the duration extends beyond that quick, intense phase. Lipid oxidation is a slower process best suited to low‑intensity, long-duration activities, not high‑intensity efforts.