How to Train Fast Twitch Muscles

(Last Updated On: April 12, 2017)

If you’ve heard that fast-twitch muscle fibers are the most powerful and largest muscular movers in the body, you’ve heard it right. Targeting these muscles in your training can help you build mass; however, they are also neglected in most bodybuilders’ programs.

Muscle-fiber types range from larger ones designed for power activities and strength, to smaller and endurance-based slow-twitch fibers. The larger, fast-twitch muscle fibers store a lot of carbohydrates and have physique implications.

Did you know that your body draws about three grams of water into the muscle for every gram of carbohydrates you store? Bodybuilders can thus obtain a denser and fuller look onstage if they focus on optimizing fast-twitch fiber development. And even though genetics determine the balance of slow-twitch and fast-twitch fibers in your body, you can still do plenty to maximize the strength and growth of your muscles. There are two important variables which you can affect in order to activate fast-twitch muscle fibers – fatigue management during your weightlifting sets and the amount of weight you lift.



Bicep curls

One of two surefire ways to increase the recruitment of fast-twitch muscle fiber is fatigue, so consider it your friend. Recruiting slow-twitch fibers is your body’s first impulse, but once they are fatigued, the body recruits fast-twitch fibers. Making the most of training fatigue is not a matter of what your program looks like, but rather how you train.

If you make short pauses in the middle of a set, that intra-set rest prevents the body from recruiting fast-twitch muscle fibers and decreases fatigue. So, you may be short-changing your gains if you notice that you pause when a certain movement becomes difficult.

The catch is to keep your work density high. Athletes who take 30 minutes to perform 15 sets have extremely high density, while athletes who perform 15 sets in 2 hours have very low density. The recruitment of fast-twitch muscle fiber will skyrocket and slow-twitch muscle fibers will take less to fatigue if you shorten your rest periods on traditional bodybuilding workout days.


Amount of Weight



If force demands from an exercise are smaller, then your body will use more slow-twitch fibers. The greater the force, the more work there will be for you fast-twitch fibers, because our bodies recruit muscle fibers based on the demands placed upon it.

According to this 2004 study conducted by researchers at the University of Memphis (Memphis, Tennessee), it was found that bodybuilders had lesser fast-twitch muscle-fiber development than competitive lifters (Olympic weightlifters and powerlifters).

What’s the difference between their training programs? Powerlifters train with very heavy weights in a 1-5 repetition range and 3-5 minutes of rest. On the other hand, a traditional bodybuilding program focuses lifting moderately heavy loads with an 8-12 repetition range and 60-90 seconds of rest. Those who don’t neglect training in a heavier range will most likely program their body’s nervous system to recruit its largest fast-twitch fibers more effectively.

However, powerlifters still have a smaller overall muscle size because, unlike bodybuilders, their slow-twitch muscle fibers are not drastically increased in size. If you are focused on bodybuilding and want to maximize gains, consider incorporating heavy low-repetition training sessions in addition to your traditional bodybuilding training program. This will lead to greater growth, which can be measured with a practical body measurement app (simply install in on your smartphone), or you can do it old-school by taking pictures or using tape measurements.


Prioritize Fast-Twitch Fibers

The goal is to perform a heavy training day every 2 or 3 workouts.

#1 – Compound movements, heavy, 1-5 reps and 3-5 mins rest;

#2 – Mainly compound movements, 8-12 reps, 60-90 seconds rest, and;

#3 – Compound and isolation movements, supersets, 12+ reps, 30-60 seconds rest.

Shoulder presses, bench presses, pull-ups, dips, deadlifts and squats are the movements that recruit the most muscle and should be prioritized on heavy days. Keep your workout density high on 8-12 rep days, perform repetitions one after the other, and remember not to pause in the middle of a set.

Know your goals, focus, and keep pushing even when you experience difficulties and pain. It may be hard at the moment, but the beauty of the human body is in its ability to adapt according to different situations and exertions. Don’t hesitate, start lifting heavy.


About the Author:

Mathews McGarry is passionate about many forms of strength training, and spent years lifting, dragging and flipping all manner of heavy objects. After graduating from the Faculty of Health Sciences, he started writing about his experiences, and sharing tips for better life. Check out his website and follow him on Twitter.