What is muscle hypertrophy?

Muscle hypertrophy refers to the increase in the size of muscle fibers as a result of strength training or resistance exercise. When muscles are subjected to stress, such as lifting weights, the muscle fibers experience small tears. In response, the body repairs these fibers, leading to an increase in their overall size and cross-sectional area. This process involves protein synthesis and can be influenced by various factors including nutrition, hormonal levels, and the type of training regimen. Over time, consistent strength training can significantly enhance muscle mass, contributing to overall physical strength and endurance.

The other options address different concepts that do not define hypertrophy. For instance, muscle flexibility relates to the range of motion in a joint and is not directly linked to an increase in muscle size. An increase in muscle strength can occur with or without hypertrophy, as strength also depends on factors like neuromuscular adaptations. Lastly, muscle atrophy is characterized by a decrease in muscle size, often due to disuse or other health issues, which directly contrasts with the concept of hypertrophy.