Which energy system is predominantly utilized during high-intensity, short-duration exercise?

The phosphagen system is predominantly utilized during high-intensity, short-duration exercise due to its ability to rapidly produce energy. This energy system primarily relies on stored ATP (adenosine triphosphate) and creatine phosphate (CP) to swiftly regenerate ATP for immediate use in muscle contractions.

During activities that require maximum effort for a short period, such as sprinting or weightlifting, the demand for energy is immediate and significant. The phosphagen system can supply energy almost instantaneously, making it ideal for these types of explosive movements. This system can sustain intense exercise for about 10 seconds or more before fatigue sets in, after which the body begins to rely more on other energy systems, particularly the glycolytic and aerobic systems.

In contrast, the aerobic system operates at lower intensities and requires time to ramp up its energy production, while the glycolytic system, although providing energy in somewhat higher intensity efforts, is still not as immediate as the phosphagen system. The oxidative system is even slower to respond and is more suited for prolonged, steady-state activities. Thus, the phosphagen system is the correct answer when considering the primary energy pathway for high-intensity, short-duration exercise.