Pronation. It has been the foundation for prescribing and selecting running shoes for decades and ‘over’pronation has been the purported “cause” of a dizzying array of running injuries. Overpronation to runners is what global warming is to Al Gore. It’s going to kill us all. But does the evidence really back it up?
The impetus for this article was because of what I read. The barefoot and minimalist advocates say there isn’t anything to pronation, while the shoe companies, stores and podiatrists imply it’s the bane of all running injuries. Yet, if you ask any of them to define “pronation”, you will get wildly different answers. Want to have some fun? Ask them when at what point pronation becomes “over”pronation. If they think they know the answer, they are apparently smarter than any top biomechanist researcher in the world. Not even they have figured that one out yet. So, What is a runner (or a clinician) to believe? The only way to find out is to delve into the research yourself headfirst and see what you come up with. So, that’s what I did.
I started with what was supposed to be a one or two page report on the validity on ‘over’pronation, but one month later, I emerged out the other side with a 9,000 word, 18 page paper with 55 literature references. It turned out way more technical than I had intended and now is really just for clinicians or other people who are REALLY interested in foot mechanics. A sort of magnum opus. You can find it here. It’s kind of technical, but if you really want to know your stuff, well, there it is. If you don’t want the lengthy technical version, stay on this page and read below the orange button.
Alternatively, on this page, you will find the executive summary. A much more palatable summary intended for everyone. What I say below is not off the cuff and without doing my research. If you don’t like what I have to say, it’s all backed up with references in the “Guide for Clinicians”
So enough with the hype, here you go…
Topic #1 – What is Pronation and Overpronation?
When weight bearing, pronation is what happens when the arch of the foot flattens a bit and also facilitates some inward rotation of the ankle and shin. When walking or running, our feet are supposed to pronate. This is normal!
How much we are supposed to pronate, the velocity of pronation, how long we are supposed to stay in pronation and how much the pronation actually influences the inward rotation of the tibia is debatable. Not because it hasn’t been studied. It has been studied in great detail. It’s just that the studies are inconsistent and conflicting
Thus, we can’t agree on what pronation exactly is defined as. This makes “over”pronation even more difficult to define
Topic #2 – Does ‘Over’pronation Cause Injury?
The influence of pronation on injury has been broadly and exceedingly exaggerated. There is too much emphasis placed upon pronation and injury and it needs to stop. Studies that show ‘over’pronation (which is exceedingly ambiguous and undefined at this point) are associated with injury are mostly done on measuring subjects feet in a non-weight bearing state which don’t correlate well with actual running or walking. Those studies that measure pronation when actually walking or running are very conflicting and inconsistent when associating ‘over’pronation to injury. In addition to being conflicting, the studies that link pronation and injury merely imply association – not cause.
Is there an association? Yes, for some people, but not nearly as much as the general public is lead to believe.
Topic #3 – Why all the Inconsistency in Research?
There are a few different answers to this, but I’ll focus on two of them:
a) Research methods are not consistent. Some researchers measure pronation by using markers on the shoe (your foot slides in the shoe when you walk or run, so not very accurate) some place markers on the skin (your bones slide in your skin, so some accuracy lost there too) some place pins in the bones of the subjects (study sizes are small – who wants pins stuck in their bones?) Some research uses cadaver feet, some use elite runners, some use novice runners. Get the point? If research methods are inconsistent, how can you expect results to be consistent?
b) This is probably the biggest idea I want people to get out of this paper: It appears as if control of the leg when running is from the top down, not the bottom up. In other words, the leg controls the foot, the foot doesn’t control the leg. That means that if you are going to put some orthotics in the shoes to “control” the situation, but the real “control” is coming from the lower leg muscles or the hip, you’re fighting a losing battle. Pronation research has mainly looked at the movement of the foot and the lower leg to try and see patterns, but if the control is coming from higher up, you will have inconsistency. If you don’t believe me, look at the “clinician’s guide”. It’s all laid out there.
No wonder why orthotics and shoes show a conflicting ability to control the foot and shin.
Topic #4 – What Should I Do?
a) When choosing a shoe, go with what has worked for you in the past. Don’t be lured into a shoe based on what someone tells you you need because they can “see” you ‘over’pronate. Go with what feels right and comfortable for you and if it doesn’t work, try something different. Trial and error will work it out.
b) If you are still getting injured, get a full body gait analysis. No, this statement isn’t based on research reviewed in this paper, but since the research suggests that the mechanics are “top-down”, you need to look into the stability and mobility of the hips, pelvis and core. You may have some hip or pelvic mechanics that need changing. In addition, look into the credentials of the person looking at your form. Do they know anatomy and mechanics, or did they read “chi running”?
c) If you have tried a variety of shoes, tried the gait analysis, modified your training habits and are still getting injured, you may want to try orthotics. However, it appears off the shelf orthotics are just as beneficial (and 1/5 the price) as custom made, casted orthotics, so save your money when thinking about the $500 custom orthotics.
In the end, there is only one blanket statement we can make – anatomy and biomechanics are highly variable between people. It’s not about “minimalism is great”, or “overpronation is bad”, it’s about being an individual. Don’t try and force yourself into a shoe or some running style that some guy wrote about on his blog
Ok, now that I’ve offended barefoot and minimalists, podiatrists and “Chi Runners”, I think I’ll end it there. I’d love to hear any feedback – hate mail or otherwise.