Eline Lievens Profile picture
👩🏻‍🔬FWO Post-doc in Exercise Physiology & Sports Nutrition 🏆 PhD Cup & Multidisciplinary thesis award BiR&D 🎙Passionate about science communication

Sep 28, 2021, 17 tweets

Last week, I defended my Phd on 'The relevance of muscle fiber typology in sports'🎓.

Next to the PhD, I also made a practical & illustrated guide for the general public & sport coaches!

Following thread summarizes the most important findings.👇👇

#ThesisThread

What is the muscle fiber typology?

Two different types of muscle fibers are responsible for production of movements:

👉slow-twitch 🔴 & fast-twitch fibers ⭕️

Both types are present in all muscles, but their proportion differs between individuals & determines the 'myotype'.

Why are muscle fibers important?

Muscle fibers have different properties (see picture👇), which result in different characteristics.

Slow-twitch fibers 🔴 are made for low-intensity & long lasting activities

🆚

Fast-twitch fibers ⭕️ are made for fast & powerful actions.

What does the myotype look like in animals & humans?

🐭Mammals, like a rat and springbok, display more fast fibers ⭕️ as their survival strategy is to be faster than enemies.

👫Humans evolved to a slower myotype 🔴, which they used as a weapon during persistence hunting.

Humans show a big spread in their muscle fiber distribution from 20% to 90% slow-twitch fibers.

Therefore the muscle fiber distribution humans can be divided into three 'myotypes':

a slow 🔵, intermediate⚪️ or fast myotype 🟢.

What is your myotype: albatross, ape or cheetah?

The myotype follows a Gaussian distribution, indicating that most people are intermediate ⚪️ (like an ape🐒), but some are dominantly slow 🔵 (like an albatross🕊️) and others dominantly fast 🟢 (like a cheetah🐅).

How can the myotype be measured?

The gold standard is an invasive method where a small part of muscle tissue is taken with a biopsy needle, which is then analyzed and visualized under a microscope🔬

👍 Gold standard
👎 Not applicable in athletes
👎 High variation

Can the myotype be estimated in a non-invasive way?

✅Yes!
A method using an MRI-scan was invented in which calf muscles are scanned to determine the concentration of a fast-twitch metabolite, which is then translated into a myotype.

👍 Applicable in athletes
👍 Low variation

Can I discover talent based on the myotype?

✅Yes!

Data on 86 elite athletes🏃and 80 cyclists🚴show distinct profiles in between disciplines:

A slow myotype 🔵 might be favorable for endurance disciplines

🆚

A fast myotype 🟢 might be needed for explosive disciplines

What does the myotype look like in team sports?

A big spread in myotypes can be witnessed in soccer ⚽️, as both slow 🔵, intermediate ⚪️ and fast myotype 🟢 players are present.

❌No differences in myotypes were found in between different positions on the field.

Can we adapt a training program based on the myotype?

💡Results from a single training

10 slow 🔵 and 10 fast 🟢 myotype subjects performed 3 x 30 sec all-out on a 🚲.

In the fast myotype group 🟢:
➖Power drop was higher
➖Recovery took much longer

Can we adapt a training program based on the myotype?

💡Results from an overload study

16 high level runners🏃performed 3 weeks of overload training.

Runners with a faster myotype 🟢 showed a higher incidence of functional overreaching.
➡️ Fatigue accumulation was higher

Overall guidelines for myotype-based training:

Individualization of training volume, frequency, recovery and taper might be needed!

👇👇

Can we estimate the injury risk based on the muscle typology?

A study in 95 elite soccer players ⚽️ demonstrated the importance of myotypes on the risk of sustaining a hamstring strain injury

Fast myotype 🟢 players showed a 5.3 x higher risk

🆚

slow myotype players 🔵

🔥Take home message🔥:

The myotype is an important characteristic of an athlete which has multiple applications in sports:

➖ Talent identification
➖ Training individualization
➖ Injury risk

Do you want to know your myotype? 🧐

We have optimized the non-invasive scan technique, also called 'the muscle talent scan', to allow scanning on multiple scan sites. After the scan (25 min) an individualized report will be provided👇.

More info?
muscletalentscan.com

Do you want more detailed information?

📢 Contact me via twitter or e-mail elilieve.lievens@ugent.be

🔍 Read our illustrated guide
ugent.be/ge/bsw/nl/onde…

💡 Acces my PhD
biblio.ugent.be/publication/87…

Thanks to @Teamderave @FloreStassen @FWOVlaanderen and all collaborators!

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