ACSM Personal Trainer Certification Practice Exam 2025 - Free Personal Trainer Practice Questions and Study Guide

The primary energy source utilized during anaerobic glycolysis is glucose. This metabolic process occurs when oxygen is limited, and the body needs a quick source of energy, particularly during high-intensity exercise. When glucose is broken down through anaerobic glycolysis, it is converted into pyruvate, and in the absence of sufficient oxygen, pyruvate is further converted into lactic acid. This allows for the regeneration of NAD+, which is crucial for the continuation of glycolysis, enabling the production of ATP (adenosine triphosphate), the energy currency of the cell.

Using glucose as the main fuel source in this pathway is essential because it provides the needed energy rapidly, which is particularly important during activities that demand quick bursts of energy, such as sprinting or heavy lifting. Other substrates like fats and proteins typically come into play during aerobic metabolism or under different energy demands when oxygen levels are sufficient for oxidation processes.