Which energy system is predominantly engaged during activities lasting 10 seconds or less, such as a sprint?

Which energy system is predominantly engaged during activities lasting 10 seconds or less, such as a sprint?

• A. Glycolytic (anaerobic) system
• B. Lipid oxidation system
• C. Aerobic system
• D. Phosphagen (ATP-PC) system

Answer: (D)

Short, all-out efforts rely on the phosphagen (ATP-PC) system. This pathway stores ATP and phosphocreatine in muscles and can rapidly resynthesize ATP without oxygen, making it the primary energy source for maximal efforts lasting roughly 10 seconds or less. As you push beyond that brief window, phosphocreatine stores deplete and other systems start contributing more. The glycolytic system becomes more important for efforts that last a bit longer (around 10–60 seconds) and can produce lactate; lipid oxidation is a slower process used for low-intensity, longer-duration activity, and the aerobic system dominates longer-duration efforts. Therefore, for a sprint lasting about 10 seconds or less, the phosphagen system is the best fit.

Short, all-out efforts rely on the phosphagen (ATP-PC) system. This pathway stores ATP and phosphocreatine in muscles and can rapidly resynthesize ATP without oxygen, making it the primary energy source for maximal efforts lasting roughly 10 seconds or less. As you push beyond that brief window, phosphocreatine stores deplete and other systems start contributing more. The glycolytic system becomes more important for efforts that last a bit longer (around 10–60 seconds) and can produce lactate; lipid oxidation is a slower process used for low-intensity, longer-duration activity, and the aerobic system dominates longer-duration efforts. Therefore, for a sprint lasting about 10 seconds or less, the phosphagen system is the best fit.