Which factor affects the dominant energy system?

Which factor affects the dominant energy system?

• A. Age
• B. Weather
• C. Diet
• D. Intensity, duration and fitness

Answer: (D)

The thing this question tests is how the body chooses which energy system to rely on during exercise. The dominant system is set mainly by how hard you work (intensity), how long you work (duration), and how trained you are (fitness). At very high intensities for only a short time, the immediate ATP supply comes from the ATP-PC system because it can release energy quickly but runs out quickly. As the duration extends a bit longer, the glycolytic system takes over to keep supplying energy, often producing lactate as a by-product. When the effort is sustained at a lower to moderate intensity, the oxidative (aerobic) system becomes the main source of energy since it can use oxygen to produce ATP for longer periods. Fitness matters because better aerobic conditioning shifts the balance toward the oxidative system and lets you sustain higher intensities for longer. Weather, age, or diet can influence performance indirectly, but the direct determinant of which system dominates is the combination of intensity, duration, and fitness.

The thing this question tests is how the body chooses which energy system to rely on during exercise. The dominant system is set mainly by how hard you work (intensity), how long you work (duration), and how trained you are (fitness). At very high intensities for only a short time, the immediate ATP supply comes from the ATP-PC system because it can release energy quickly but runs out quickly. As the duration extends a bit longer, the glycolytic system takes over to keep supplying energy, often producing lactate as a by-product. When the effort is sustained at a lower to moderate intensity, the oxidative (aerobic) system becomes the main source of energy since it can use oxygen to produce ATP for longer periods. Fitness matters because better aerobic conditioning shifts the balance toward the oxidative system and lets you sustain higher intensities for longer. Weather, age, or diet can influence performance indirectly, but the direct determinant of which system dominates is the combination of intensity, duration, and fitness.