National Academy of Sports Medicine (NASM) Performance Enhancement Specialist (PES) Certification Practice Exam 2025 - Free Practice Questions and Study Guide

The correct choice is creatine because it has been extensively studied and shown to provide significant ergogenic effects when taken consistently over a period of weeks. Creatine works by increasing the phosphocreatine stores in muscles, which enhances the ability to perform high-intensity exercises and promotes greater gains in strength, power, and muscle mass when combined with resistance training.

While other supplements like beta-alanine, whey protein, and glutamine have their benefits, their mechanisms and timelines for demonstrating ergogenic effects vary. Beta-alanine, for example, helps buffer lactic acid in muscles and can improve performance during high-intensity activities, but it typically requires consistent use over several weeks to achieve saturation in muscle tissues. Whey protein primarily aids in muscle recovery and growth but does not directly enhance performance in the same way as creatine does. Glutamine, on the other hand, is mainly involved in recovery and immune function rather than directly enhancing exercise performance.

Creatine stands out because of its specific role in energy production for short bursts of activity, its ability to improve overall training adaptations through enhanced performance, and the substantial body of research supporting its efficacy when used over time.