Muscle Fiber Types: Are you a sprinter or a marathon runner?

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What muscle fiber types are you? There are three types of muscle in the human body for different needs: striated muscle (also ‘skeletal muscle’), smooth muscle, and cardiac muscle.

Properly trained muscles allow you to do things that you never thought possible before:

You can run, bike, or swim for hours.
For a few seconds, you develop almost superhuman strength and speed.

Perhaps you have already asked yourself one of these questions:

Why are some people building muscle faster than others?
Why are there people who can run faster and longer with less training?
What role do your genes play? Could Schwarzenegger have gone from being a muscle man to a marathon man with the proper training?
Which muscle fibers should you train to reach your goal as quickly as possible?

The secret – and the answer to these questions – lies within your muscles— time to air it.

What is a muscle?

A muscle is an organ that can contract to move a part of your body. You have about 650 different muscles.

Every muscle in your body is unique and has a specific job.

There are three types of muscle for different bodily needs: striated, smooth, and cardiac.

Smooth muscle: The muscles of our intestines, such as intestines. We cannot consciously control them, yet they work tirelessly in the “background” daily.
Cardiac muscle: Although the cardiac muscle consists of striated muscles, it is otherwise entirely separately controlled. It also has another important property: It cannot cramp even with a magnesium deficiency.
Striated muscles(“skeletal muscles”): These are the muscles that interest us. We can consciously tighten and relax them; as the name suggests, they are connected to our bones.

We are interested in the type of muscle we can consciously control, the striated muscle. When I say “muscles” below, I mean this guy.

The composition of our muscles determines whether you are strong or enduring – possibly both…?

What is muscle fiber?

Your muscles are connected to the skeletal bone by tendons.

Each muscle consists of individual muscle strands separated from each other by fascial tissue. You can imagine a muscle strand as a bundle of many muscle fibers: A muscle strand combines many individual muscle fibers.

The muscle fibers can differ significantly in their properties: There are different types of muscle fibers.

Electron microscope free: Now, let’s zoom in one more level.

Muscle fiber is made up of different types of protein. These proteins form filaments, thick and thin structures that slide into one another.

When you tense your muscle, you ensure that these structures slide into each other – the muscle fiber becomes shorter. This force is transmitted to your skeleton via tendons.

This is how you lift weights, stand up, jump up or run from your apartment to the gym.

What types of muscle fibers are there?

Now it gets exciting: You have different muscle fiber types than either.

fast and powerful or
long and not quite as powerful

can contract.

There are three muscle fiber types:

Type 1 muscle fiber – slow-twitch (also called ‘slow twitch’)
Muscle fiber type 2a – fast-twitch (also called ‘fast twitch’)
Muscle fiber type 2b – very fast-twitch (also called ‘fast twitch’)

I know these terms aren’t convenient. It will soon be clearer!

The three muscle fiber types differ, among other things, in:

Color
Number of mitochondria (mitochondria are the powerhouses of the muscle cell – this is where fat and sugar are converted into the only form of energy that our muscles can use – ATP)
Speed at which the muscle fiber can contract
Volume (how “big” does the muscle fiber get as it gets stronger?)

The exciting question is…

Which muscle fiber types do sprinters make, and which marathon runners?

Marathon runners need excellently trained type 1 muscle fibers. If you like to swim or climb, you need the 2a muscle fiber. And if you want to look good naked, don’t neglect your type 2b muscle fibers.

Muscle fiber type 1 – The marathon runner (>30 min. effort)

Red color
Fatigue: very slow
Mitochondria: very many
Contraction: slow
Power: low
Volume: thinner
Type of sport: long-distance running, cycling, triathlon, marathon, Ironman (continuous exertion over 30 minutes)

This type of muscle fiber is also called slow-twitch.

Muscle fiber type 2a – The middle-distance runner (1-30 min. effort)

Red color
Fatigue: slow
Mitochondria: many
Contraction: relatively fast
Power: medium
Volume: thicker
Type of sport: middle-distance running, swimming, climbing (continuous exertion under 30 minutes)

Muscle fiber type 2b – The weight lifter (< 60 seconds load)

Color white
Fatigue: fast
Mitochondria: few
Contraction: very fast
Power: high
Volume: thicker
Type of sport: sprinting, weightlifting, gymnastics (continuous exertion under 60 seconds)

Muscle fiber type 2 is also called fast-twitch – fast contracting.

Which muscle fiber type are you: sprinter or marathon runner?

Every muscle has all three muscle fiber types. The quantity counts: the higher the proportion of a certain type of muscle fiber, the greater your potential.

The exciting question is, therefore: How well equipped are you with the respective muscle fiber type?

As is so often the case, it depends. The number of individual fibers essentially depends on two factors:

Function: What is the function of muscle tissue?
Predisposition: What distribution do your genes dictate?

In a moment, you will see why training does NOT affect this distribution – and why it is still important.

Muscle fiber type distribution #1: What is the function of the muscle?

Every muscle in your body is exposed to different loads and has to perform different tasks. And just as different is the composition of the muscle fiber types.

A muscle has more enduring or powerful muscle fibers depending on its function.

For example, the muscles that ensure an upright posture: erector spinae, hip flexors, calves, etc.

They don’t usually need a lot of force to do this, but they must be continuously under tension for hours. So Mother Nature endowed them with a large proportion of type 1 muscle fibers.

Your body is intelligent. If you use a muscle in sports or everyday life, it will only use the type of muscle fiber that does the job while using the least amount of energy:

If you exert little force, you will only contract type 1 muscle fibers – the type 2 muscle fibers remain relaxed. Example: walk.
If you need a lot of strength, the following happens: First, your body tries to cope with the load (in vain) with only type 1 muscle fibers and then switches on the type 2a and finally the type 2b muscle fibers.

Example: barbell deadlifts in the muscle-building range.

Quiz question: Can Haile Gebrselassie become Schwarzenegger if he puts his heart and soul into it?

Muscle Fiber Type Distribution #2: Can a Marathon Runner Become a Bodybuilder?

Perhaps you also know people like this in your sporting environment: the ones who, with obscenely little training, are among the fastest in the fun run.

And then there are the cardio die-hards who look at a barbell to build muscle.

Everyone is born with a certain percentage of each type of muscle fiber.

You are a sprinter, weightlifter, or long-distance runner by nature.

Science is divided on whether your body can convert one muscle fiber type into another. So we assume you can get by with what your parents gave you.

Thankfully, the story doesn’t end there!

With proper training, the muscle fiber types you are equipped with becoming more efficient.

With proper training, you don’t change the number but the proportion of fast and slow-twitch muscle fibers in the cross-sectional area of the muscle.

The more area your type 2 muscle fibers occupy in the overall muscle cross-section, the higher your maximum, and speed strength – and the better the conditions for muscle building.

To look good naked, you must train the correct muscle fiber types. To do this, you can align all factors, muscle building, endurance training, and nutrition, with your goal.

Some people – they call themselves hard gainers – have a more challenging time building muscle than others. Very few of them know that the limiting factor is not the distribution of muscle fiber types but their eating habits.

Muscle fiber types – Conclusion

Whether sprinter, weightlifter, marathon runner, or triathlete – the secret of our physical performance lies in the performance of the individual muscle fiber types.

You probably can’t change how many muscle fibers you have of each type. So you can play with the cards your parents gave you.

Maybe you’re not equipped with the Type 1 muscle fibers of an Olympic marathoner or the Type 2 fibers of a world-class sprinter or bodybuilder. But it doesn’t matter. After all, you don’t want to win an Olympic gold medal. You want to look good naked.

The good news for those who stay tuned: If you are willing to train your muscle fibers properly, you will reach your goal. If you belong to the group of hard gainers, you can put an additional focus on your diet.