Fast or Slow: It’s time to test your muscle fibres

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So there I was doing my monthly read of all my New Scientists when I found it. A piece called What’s Your Superpower by Catherine de Lange  (sorry you might have to pay for it). In it, was a section on whether you were born to exercise and within that was a fairly simple comparison test to determine whether you have predominantly fast-twitch muscle fibres (which makes you good at power sports like sprinting or weightlifting) or slow-twitch ones that make you better at endurance exercise like, erm running half marathons perhaps.

How to Test if you Have Fast or Slow Twitch fibres

It’s actually pretty simple

1) Do a simple wall squat for as long as you can. If you don’t know what that is. Stand up straight against a wall, now walk your feet forward and squat down as if you were going to sit in a chair. Stop when your thighs are parallel with the floor and make sure your knees and ankles are in a straight line, support your back against the wall and hold it until your thighs cry.  Anything over 30 seconds is good and probably means you have a high percentage of slow-twitch fibres

2) Do a vertical jump test. This sees you standing side on against a wall and reaching up. Mark that point. Now, with your hand in the air jump as high as you can from a standing position. Measure that point. Now calculate the difference. Anything over 20 inches (50cm) means you probably have mostly fast-twitch fibres,

I, of course, couldn’t wait to try this out, My score….

Wall squats – 55 seconds

Reach test – a pathetic 15cm (poor).

Hmmm, so according to this, I have a higher proportion of slow-twitch fibres that are good for marathon running. That’s handy isn’t it considering it’s 100 days to the Dumbo Double Dare, however, I do seem to have missed out on whatever genetic gifts allow you to run said half marathons in less than 2 hours. In fact my fastest ever ever time for a half was 2.06 – I was thrilled. Then the winner of the men’s marathon, which started at the same time as the half crossed the finish line and threw up by my trainers! Thanks, you’ve just proved my time was actually hopeless – and I also need to wash my shoes!

So, how do you do in the test? You know you want to try it. Oh, and don’t panic if you get the ‘wrong’ score for your sport – doesn’t mean you can’t do it, you can counteract your fibres with the right training.




  1. Arian

    Ha ha, I remember that moment in our running history very well!

    1. healthehelen

      I still look nervous near a finish line.

      Reply this thing on? Talk to me, it's lonely down here

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