What happens to muscle fibers as a result of strength training?

Muscle fibers increase in size as a result of strength training, a process known as hypertrophy. This occurs when muscle fibers are subjected to tension and resistance during exercises such as weightlifting. The stimulus from strength training causes microscopic tears in the muscle fibers, and the body responds by repairing these fibers, leading to an increase in their cross-sectional area. This adaptation improves muscle strength and endurance.

While adaptations like increased blood vessel density can also occur as a result of consistent strength training, the primary and most direct change in muscle fibers is their size increase. This process is essential for enhancing overall muscular performance and is a fundamental principle in exercise physiology related to how muscles grow stronger and larger in response to increased load and intensity in training regimens.