Fast Twitch vs Slow Twitch Muscle Fibers

Fast Twitch VS Slow Twitch

Do you know any HIIT athletes who constantly struggle to run a mile? How about a marathon runner who isn’t able to nail a box jump?

The difference lies in the skeletal muscles, i.e. its makeup.

Individuals have two major kinds of skeletal muscle fibers – fast twitch (Type-II) and slow-twitch(Type 1). Slow-twitch muscles will assist in long endurance activities like distance running. With regards to fast-twitch muscles provide robust bursts of movements like sprinting.

Difference Between Fast-Twitch & Slow Twitch

Fast-twitch muscles consist of two categories – moderate fast-twitch (Type lla) and fast-twitch (type llb or llx). With regards to moderate fast-twitch muscles, they are quicker to contract, thicker and wear out more easily compared to slow-twitch. In addition, fast-twitch which is quite powerful and has the lowest endurance gets activated when the body reaches to the near stage of maximum exertion.

So, how does it happen? While performing aerobic exercises like swimming or running, the slow-twitch muscles will be the first one to contract. With regard to the slow-twitch fibers, it will become tired and then the fast-twitch will start to take over.

Do you know there are significant benefits in working to the point of temporary fatigue? This will make sure that the fast-twitch fibers will get recruited. Suppose you are looking to develop your muscle mass and even improve strength, then the only way to do it is by using fast-twitch.

But on the other hand, the aerobic exercise which utilizes the slow-twitch fibers will easily increase the stamina and even the oxygen capacity of the muscles. This will easily allow the human body to burn energy for a longer period of time.

Do you know that a high proportion of slow-twitch fibers is associated with having low blood pressure? There are various research which states that women might have a greater distribution of Type I muscle fibers and even lower distribution of type II muscle fibers compared to men.

How Can You Develop Your Fast Twitch And Slow Twitch Muscles?

Frankly, there isn’t any conclusive evidence to support that muscle fibers will transform from slow-to-fast twitch or even vice-versa. So, in other words, it means that you can improve slightly at sprinting or any other kind of explosive movements, still, you might not be as you are simply converting your muscle fiber types.

The fast-twitch (Type llb) fibers can be still converted into moderate fast-twitch (Type lla), or even vice versa, by increasing the resistance training or endurance. All you have to keep in mind is that fast-twitch muscles will deplete with age when compared to the slow-twitch, thereby meaning that increasing the muscle power will be less feasible in the later stages of life.

Wrapping Up

Generally speaking, when your muscles are forced to work in a different manner and you come out of your comfort zone, you will get a good workout. So, try mixing your workouts for recruiting all kinds of muscles fibers and to get over the dreadful gym boredom.


Saravavan Nadarajan (Vanan)

Vanan, fitness expert and leader at EzFit Singapore, specializes in holistic training—home-based, boot camps, and corporate fitness—with over a decade of industry experience.