What is muscle hypertrophy?

Muscle hypertrophy refers specifically to the increase in muscle size, which occurs as a result of physical training, particularly resistance training. When muscles are subjected to stress, such as lifting weights, the muscle fibers undergo microscopic damage. The body responds by repairing these fibers and, in the process, increasing the size and density of the muscle fibers to better handle similar stresses in the future. This adaptation is what leads to visible growth in muscle size.

In the context of muscular adaptations, endurance refers to the ability of muscles to sustain prolonged activity, flexibility involves the range of motion in muscles and joints, and strength pertains to the maximum amount of force a muscle can exert. While all these elements can be influenced by training programs, muscle hypertrophy specifically targets the growth in size of the muscle fibers themselves, distinguishing it from the other concepts listed.