During which time period is the anaerobic glycolytic system the major source of energy?

The anaerobic glycolytic system becomes the major source of energy during high-intensity activities lasting from about 30 seconds to 2 minutes. This energy system primarily utilizes glucose to produce ATP without the need for oxygen, which supports activities that are intense but not sustainable for long periods.

During the first 10 seconds of exercise, the body primarily relies on the ATP-CP system (adenosine triphosphate - creatine phosphate), which quickly provides energy but is very short-lived. After this, as the activity continues and if the effort remains high, the anaerobic glycolytic system kicks in to supply energy for higher demands as the CP stores are depleted.

In the case of the first minute, the energy expenditure continues to draw upon the anaerobic glycolytic pathway, but it is more accurately represented as being predominant from the 30-second mark. The energy derived from this system is crucial for sustaining high-intensity efforts, making the 30 seconds the pivotal time frame where anaerobic glycolysis is maximally engaged.

Thus, the correct choice reflects this timing of energy system dominance.