Which are the three energy systems and when does each contribute most during performance?

• A. Aerobic, Phosphagen, and Lipid oxidation; Aerobic for 0–10 s
• B. Phosphagen (ATP-CP) for ~0–10 s; Glycolytic (anaerobic) for ~10–60 s; Aerobic for longer beyond ~60 s
• C. Glycolytic first, then Phosphagen, then Aerobic
• D. Lipid oxidation dominates all efforts

Answer: (B)

Energy supply during performance comes from three systems, each dominating at different durations and intensities. The phosphagen system (ATP-CP) provides energy immediately at the start and for short bursts, lasting roughly up to 10 seconds, because its stores are limited and are depleted quickly. After that, the glycolytic anaerobic system takes over for high‑intensity efforts, typically lasting about 10 to 60 seconds, delivering ATP quickly but producing lactate as a byproduct and having a finite capacity. For longer efforts, the aerobic system becomes the main source, supporting energy production beyond about 60 seconds and continuing as long as the activity lasts, though it ramps up more slowly and uses carbohydrates and fats as fuel. These systems overlap in practice, and exact boundaries vary by individual and activity, but this sequence reflects how most performance is supplied across increasing duration. Lipid oxidation is part of the aerobic process and does not dominate all efforts, and the order described here is not glycolytic first nor an all‑encompassing lipid-dominant pattern.