What term describes the development of muscles due to working out?

• A. Hyperplasia
• B. Hypertrophy
• C. Atrophy
• D. Metaplasia

Answer: (B)

Muscle growth from exercising is hypertrophy, which means the existing muscle fibers increase in size. Resistance training triggers more protein synthesis and adds contractile components inside the fibers, expanding their cross-sectional area. This makes the muscle thicker and stronger without creating new muscle cells. Hyperplasia would be an increase in the number of muscle cells, which isn’t the main mechanism in humans for typical training. Atrophy is a reduction in muscle size from inactivity, and metaplasia is a change from one tissue type to another, not about growing muscle.