AFAA Personal Trainer Certification 2026 – 400 Free Practice Questions to Pass the Exam

Hypertrophy refers specifically to the growth of muscle fibers, which occurs as a response to resistance training and other forms of strength training. When muscles are subjected to stress, such as lifting weights, they experience microtears. As these fibers repair, they become thicker and stronger, leading to an overall increase in muscle mass. This is a fundamental concept in bodybuilding, where the primary goal is often to increase muscle size and definition.

The other options indicate different physiological adaptations. For example, while flexibility can be a goal of certain training regimes, it does not pertain specifically to muscle fiber growth. Improvements in cardiovascular health are related to aerobic conditioning and involve different adaptations in the heart and lungs rather than muscle fiber size. Lastly, the reduction of body fat is typically associated with caloric deficit and weight loss, which can coincide with hypertrophy training but is not the definition of the term itself. Thus, understanding hypertrophy is crucial for anyone looking to enhance their muscle development effectively.