What happens to muscle fibers during anaerobic activities?

During anaerobic activities, such as sprinting or heavy weightlifting, muscle fibers experience a process known as hypertrophy, where they increase in size and power. This occurs because of the demand placed on the muscles during high-intensity, short-duration exercises that do not rely on oxygen for energy production.

As the muscular workload increases, muscle fibers undergo microtears, which then stimulate repair mechanisms leading to increased muscle mass and strength as the body adapts to the demands of the activity. This adaptation is primarily due to an increase in the cross-sectional area of the muscle fibers, particularly the fast-twitch fibers, which are more engaged during anaerobic efforts.

This growth not only enhances muscle size but also improves the overall power output of the muscle, enabling better performance in explosive movements.