The stability vs. mobility question is fundamental for any runner who wants to feel better and run smoothly. The two main areas of your body where runners are told to be concerned with stability are:
- the feet, where you might be advised to wear stability shoes and/or orthotics
- the midsection, where you might be advised to work on your “core stability.”
By amazing coincidence, you have 26 bones in each of your feet and also in your spine. Or maybe it’s not a coincidence…
Having many relatively short bones clustered together permits great mobility, and that’s useful because the world is a very complex place. The more mobile and versatile you can be in how you meet it, the better you’ll function.
So naturally you need a lot of bones – and therefore a lot of joints! – in your feet, especially if you’re going to run on trails or any kind of rough and intricate terrain. Having a lot of bones means you can set your feet down many different ways and still be able to position your legs at the necessary angle to catch, support, and lever your body forward.
Shoes that provide a lot of stability for runners interfere with this adaptability and also with the spring function of your foot, and that’s actually bad for your running. The American College of Sports Medicine has actually recommended that no runner wear shoes with motion control or stability components, and instead work to strengthen their feet. I would add that improving form overall dramatically improves foot function, since it’s how your body moves over your foot that determines how your foot works.
But what about the spine? What purpose could all that potential mobility serve? Isn’t the whole point of core stability for runners to limit the movement of your spine?
Consider this: you have two legs, neither one is in the middle, and neither one comes all the way to midline (that would require your pelvis to turn 180 degrees in each running stride!). So you have to make lateral and rotational movements in your torso in order to balance your weight over each leg. And on complex terrain where your feet are landing in varied and irregular positions, you need to be able to move your trunk even more or the adaptability of your feet won’t matter – you’ll fall over anyway.
And there we come to the heart of the matter: adaptability in one area is not much good without adaptability in the other. They go together, you have both either in abundance or barely at all. Running in highly structured footwear limits the variety of ways you can use your feet and thus also your spine, which may perform the basic counterrotational movements of running okay but that’s about it. Get yourself into rough or complex terrain and you’re going to feel yourself at risk of a sprained ankle.
One day years ago I was running on the bridle path in NYC’s Central Park. My eye was drawn to two runners somewhat ahead of me, but the crowds of runners blocked my view of their legs, so I could see only their torsos. One of them just looked like a runner’s back as we’re used to seeing, shifting a bit but fairly undifferentiated. Intellectually I knew there was a spine in there but I couldn’t see it. On the other runner it was as though I could see every vertebrae moving, subtly but clearly. The back was less tense (though no less strong), and from the fluid movement I realized he must be wearing Vibram Fivefingers. Shortly I was able to see their feet, and sure enough he was.
Since that day I’ve always been able to tell from a runner’s back what they have on their feet.
So here is the question: has nature made an error in giving us mobility in these areas? Should we correct that error by trying to reduce or eliminate that mobility? Or should we try to solve any problems that may arise with the movements in these areas by making the movement healthier instead?
You can probably guess my opinion. What do you think?
And if you want to try getting the right kind of mobility in your core to also improve the function of your feet, sign up for my free one-week Mind Your Running Challenge here: