Muscle fibers are categorized into three main types: Type I, Type IIa, and Type IIb. Type I fibers, also known as slow-twitch fibers, are endurance-oriented and are efficient at using oxygen for sustained activities. They are ideal for long-distance running and cycling. Type IIa fibers, or fast-twitch oxidative fibers, provide a balance between endurance and strength, making them suitable for activities like sprinting and weightlifting. Type IIb fibers, known as fast-twitch glycolytic fibers, generate quick bursts of power but fatigue rapidly, making them useful for short, intense efforts like sprinting or jumping.