What are your Muscle Fibre Types and can you change them?

You want to be fast, you want to be strong, you want to have good endurance but what do your muscles say about you?

Our muscles are formed of several components and when you dive into exactly what those muscle fibres are, you find the myofibril, the mitochondria, the sarcoplasm, the T-Tubules and my favourite…the Sarcoplasmic Reticulum. They have very specific roles for muscle contraction to occur and these are vitally important for scientists but for you to understand what’s happening when you’re training, not so much.

What you do need to know is that all muscle contraction revolves around energy and Adenosine Triphosphate (ATP)is an important one to remember.

It is this contraction where things become to get interesting. All actions in exercise and sport rely on the muscles ability to produce energy and force.

To do this, we have THREE different types of muscle fibres. Type I (Slow twitch), Type IIa (Fast twitch) and then Type IIx. There is in fact a further fibre known as Type IIc but these are yet to be fully understood. The origin of these names come from the fact that Type I fibres reach peak tension in around 110ms whilst Type IIa take just 50ms.

Most muscles are composed of 50% Type I, 25% Type IIa and then the remaining from IIx, whilst…