Muscle Fiber Types: The Basics
A single skeletal muscle contains two major fiber types: Slow twitch (Type I) and fast twitch (Type II). Slow twitch muscle fibers take approximately 110 milliseconds to reach peak tension. Fast twitch fibers can reach peak tension in about 50 milliseconds.
Slow twitch (Type I) muscle fibers are highly aerobic. These fibers are very efficient at producing ATP from the oxidation of carbohydrate and fat. ATP is a high energy compound made up of adenosine triphosphate. The ATP provides t he cells with a means of storing and conserving energy in a high energy compound. Type I fibers continually produce ATP to maintain muscular activity. Because of this, these muscle fibers are used mainly for endurance activities.
Fast twitch (Type II) muscle fibers are not as useful in endurance activities. These fibers are more useful for anaerobic activities. Type II muscle fibers generate more force than Type I muscle fibers. They are well suited for explosive bouts of exercise.
A single skeletal muscle contains two major fiber types: Slow twitch (Type I) and fast twitch (Type II). Slow twitch muscle fibers take approximately 110 milliseconds to reach peak tension. Fast twitch fibers can reach peak tension in about 50 milliseconds.
Slow twitch (Type I) muscle fibers are highly aerobic. These fibers are very efficient at producing ATP from the oxidation of carbohydrate and fat. ATP is a high energy compound made up of adenosine triphosphate. The ATP provides t he cells with a means of storing and conserving energy in a high energy compound. Type I fibers continually produce ATP to maintain muscular activity. Because of this, these muscle fibers are used mainly for endurance activities.
Fast twitch (Type II) muscle fibers are not as useful in endurance activities. These fibers are more useful for anaerobic activities. Type II muscle fibers generate more force than Type I muscle fibers. They are well suited for explosive bouts of exercise.