what kind of work muscle fibers do
Type I muscle fiber is also known as slow twitch oxidative fibers. Muscle fiber types can be broken down into two main types: slow twitch (Type I) muscle fibers and fast twitch (Type II) muscle fibers.Type I fibers are used in lower-intensity exercises such as very light resistance work aimed at muscular endurance and long-duration aerobic activities such as 5K and 10K runs.ype II muscle fiber is also known as fast twitch muscle fibers. These fast twitch fibers can be further categorized into Type IIa and Type IIx fibers, which are also known as fast twitch oxidative and fast twitch glycolytic, respectively.
Type IIx are best known as fast-twitch muscle fibers. These are the muscle fibers primarily responsible for fast, explosive movements like sprinting. However, they lack the endurance-boosting ability of slow-twitch fibers and can only be used for short periods of time.Type IIa are what we call intermediate fibers. These are a blend between fast-and slow-twitch fibers.hese are the muscle fibers primarily responsible for fast, explosive movements like sprinting. However, they lack the endurance-boosting ability of slow-twitch fibers and can only be used for short periods of time. Type IIa are what we call intermediate fibers.