How to Work Your Fast Twitch Muscle Fibers

Female sprinter getting ready for the run

Fast-twitch muscle fibers are key to many activities, both on athletic fields and in everyday activities. Your body uses fast-twitch fibers to sprint when running or playing a game, but also to snap a fly swatter or in similar quick movements. While some people are endowed with more fast-twitch muscle fibers than others, training is important to maintain and encourage the development of these fibers. Even an individual gifted with fast-twitch fibers needs to use those fibers constantly to keep them sharp and active.

Lift weights of moderate size for a low to moderate number of repetitions, generally between four and eight reps per set. This won't feel like you're pushing your muscles very hard, and the temptation is to add weight in order to stress the muscles and cause muscle growth as a response to stimulus. However, lifting too much volume — either too much weight, too many reps or a mix of both — can ruin your recovery period, which is the time when muscle growth and development occurs.

Keep breaks between intervals relatively short — generally between one and two minutes. This puts the focus on workout speed and intensity, and keeps your heart beating fast and muscles warm for the duration of the workout.

Aim for maximum speed in all your activities. Lift weights quickly, run fast and jump rope as rapidly as possible. Workout sets of 10 seconds tend to be the most effective way to build fast-twitch muscles, which will respond to the short bursts of work by customizing the fibers to perform best during these periods of time.

Use overtraining running workouts to test your body with faster-than-normal speeds. Running down a hill employs the help of gravity to move you down the hill faster than you otherwise would on a flat plane. When you sprint down these hills, you will be training your legs to run faster than they are accustomed to, and this will help them adapt to the new work.

Consume ample amounts of protein throughout the day to provide the necessary materials for building new muscle. You can get protein naturally through meat and dairy products, or in protein supplements like energy bars and shakes. If you are attempting to build muscle mass while training your fast-twitch muscles, aim to consume at least one gram of protein for each pound you weigh each day.


Consult your doctor before beginning any new exercise or diet regimen.