What type of muscles fiber does aerobic training cheifly work?

Aerobic training chiefly works Type I muscle fibers, also known as slow-twitch fibers. These fibers are highly resistant to fatigue and are designed for endurance activities, utilizing oxygen to produce energy efficiently over extended periods. They are characterized by a high density of mitochondria and capillaries, allowing for sustained aerobic metabolism. This type of training enhances overall cardiovascular fitness and improves the body's ability to perform prolonged physical activities.