Which energy system is dominant at the start of a maximal effort lasting about 10 seconds?

Which energy system is dominant at the start of a maximal effort lasting about 10 seconds?

• A. ATP-PC system
• B. Lactic acid system
• C. Aerobic system
• D. Protein system

Answer: (A)

For a very short, maximal effort, the body relies on the fastest source of energy: the ATP-PC system. It provides immediate energy by using stored ATP and phosphocreatine in the muscles, and it doesn’t require oxygen. This makes it ideal for up to roughly 10 seconds of high-power work. As phosphocreatine stores deplete, energy shifts toward other systems, like anaerobic glycolysis, which takes over a bit longer, while the aerobic system ramps up slowly and isn’t the main supplier in this brief window. The protein system isn’t used as a primary energy source for short, intense efforts.

For a very short, maximal effort, the body relies on the fastest source of energy: the ATP-PC system. It provides immediate energy by using stored ATP and phosphocreatine in the muscles, and it doesn’t require oxygen. This makes it ideal for up to roughly 10 seconds of high-power work. As phosphocreatine stores deplete, energy shifts toward other systems, like anaerobic glycolysis, which takes over a bit longer, while the aerobic system ramps up slowly and isn’t the main supplier in this brief window. The protein system isn’t used as a primary energy source for short, intense efforts.