How does resistance training affect muscle fibers?

Resistance training significantly influences muscle fibers, primarily leading to hypertrophy, which is the increase in size and strength of the muscle fibers. When individuals engage in resistance training, especially with heavier weights and progressive overload, it stimulates the muscle fibers, particularly type II fibers (fast-twitch fibers), which are more responsive to strength training.

During this process, damage occurs to the muscle fibers, and the body repairs this damage by fusing muscle cells together, leading to an increase in cross-sectional area of the muscle fibers. This adaptation not only enhances muscle size but also improves strength, allowing muscles to generate more force. The increased size and strength from hypertrophy are crucial for athletic performance and functional activities.

Other options highlight different potential effects of resistance training, such as atrophy or endurance enhancement, but these do not accurately reflect the primary outcomes associated with consistent resistance training routines.