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More muscle tension: there is research

February 13th, 2011

A few thoughts following up on the post about Steve Magness’s muscle tension article in Running Times. Steve was kind enough to send me a copy of Marius Bakken‘s medical school thesis, which consisted of two documents: a detailed literature review on efforts to characterize and measure muscle tension, and a clinical trial investigating whether regular cross-friction massage can reduce muscle tension. It’s still a very young field of study, but it turns out there is some literature devoted to the ideas discussed in Steve’s article.

What Steve is talking about here is what you might call “passive” muscle tension — the tension that remains in your muscles even when they’re completely relaxed (i.e. receiving no neural instructions to contract). Bakken adopts the definition of “resting muscle tone” from a 1998 journal paper, which is:

the elastic and/or the viscoelastic stiffness in the absence of contractile activity.

So how do you measure this tension? Most simply, you relax your muscle and press into it to see how stiff it is. This is, obviously, a pretty crude measurement. Bakken is now using a tool developed by an Estonian company called Myoton (shown above), which measures the frequency and damping of muscle oscillations to determine muscle tone, elasticity and stiffness. That’s the tool he used for his massage study, in which five athletes received 20 minutes of massage once a week for four weeks. The Myoton showed that their resting muscle tone decreased by an average of 3.3%, and EMG measurements of nerve signals showed that the decrease was unrelated to changes in active muscle contraction.

If you poke through the references in Bakken’s literature search, you find various interesting hints — e.g. links between overtraining and muscle tension in cross-country skiers in a 2002 study. There are still some pretty big pieces missing from the puzzle, for example showing a link between resting muscle tone and performance. And the mechanisms responsible for this resting tone are still being debated (is it extracellular water pressure? cross-bridges between contractile proteins?). But the documents made for an interesting read, and show that there is some serious science behind these ideas. I’ll be following further developments in this field with interest.

  1. emark
    February 14th, 2011 at 01:19 | #1

    I don’t follow. So massage reduces muscle mass? Muscle tension? Can you dumb this down a little for me please?

  2. alex
    February 14th, 2011 at 03:23 | #2

    @emark
    Sorry, emark — I agree this is definitely confusing stuff. Basically, the massage study found that regular massage made the muscles “looser” at rest. This might seem pretty obvious; it’s what you’d expect massage to do. What’s significant about the study is the way they measured “looseness,” using a machine that basically vibrated the muscle and watched how quickly the vibrations died away.

    The hope is that, at some point in the future, we’ll use machines like this to learn more about exactly how “tight” or “loose” we want our muscles (the Running Times article speculates that we want them loose during recovery runs and tight during races). And then we’ll also figure out different ways to raise or lower the tightness/looseness on demand.

  3. Marius Bakken
    February 14th, 2011 at 13:24 | #3

    Hi emark,

    Yes, muscle tone is extremely interesting from a performance perspective – and highly underestimated. The good thing about the Myoton is that it does this quite well objectively. I have no problem doing this myself subjectively and if you gave cross friction massage the way we did to 100 athletes on one leg only I could probably determine 100 out of 100 in terms of what leg it was done to. However, from a more scientific standpoint, it is always good to have ways such as the Myoton. When we looked into this thesis, it was quite surprising how many studies it was out there – and how recent some of them were, so it will sure be more info on this in the future as well.

    Great job on your blog, I enjoyed reading through many of your posts.

    Kind regards,
    Marius Bakken MD

  4. alex
    February 16th, 2011 at 05:03 | #4

    Hi Marius — thanks very much for the comments and the insight! I enjoyed following your elite career through your blog (one of the very first among elite runners, as I recall), and I hope that you’ll be able to combine your medical career with continued research into questions like this. Definitely an interesting topic, and one that receives very little attention.

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