AFAA Personal Trainer Certification Practice Exam 2025 – All-in-One Guide to Master Your Certification!

The principle that states resistance must be increased as muscles adapt to an exercise is known as progressive resistance exercise. This approach is essential for promoting continued strength gains and muscle growth because, over time, the muscles become accustomed to a certain level of stress. By systematically increasing the resistance—whether in weight or intensity—a trainer can ensure that the muscles continue to be challenged, thereby inducing further adaptations.

Progressive resistance exercise emphasizes the importance of gradually increasing the demands placed on the body, which is fundamental for enhancing strength and performance. This principle aligns with the body's natural adaptability—what is known as the principle of overload. By regularly adjusting the resistance, trainers can help clients avoid plateaus in their fitness journey.

In contrast, static resistance exercise may involve using fixed weights without progression, dynamic resistance exercise focuses on movement through a full range of motion often with varying degrees of load, and fixed resistance exercise typically involves machines that provide constant resistance. These approaches do not inherently include the progressive incrementing of resistance upon adaptation, which is why they do not embody the same underlying principle as progressive resistance exercise.