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In the comments section of yesterday’s post, John Lofranco raised the topic of a subject that has been popping online and in newspapers over the past few days. You may have seen the headlines: “Running shoes are more dangerous than high heels” and so on. Here’s the press release, and here’s the full text of the study itself, “The Effect of Running Shoes on Lower Extremity Joint Torques,” by researchers at the University of Virginia. Here’s the key part of the press release:
In a study published in the December 2009 issue of PM&R: The journal of injury, function and rehabilitation, researchers compared the effects on knee, hip and ankle joint motions of running barefoot versus running in modern running shoes. They concluded that running shoes exerted more stress on these joints compared to running barefoot or walking in high-heeled shoes.
From what I can tell, this is solid research that suffered from the “broken telephone” effect, being successively distorted at each step. First, there’s the data they measured — useful stuff that sheds light on how our legs work. Then there’s the scientific paper, which in my opinion stretches the conclusions a little farther than the data currently warrant. Then there’s the press release, written by a PR person at the journal, which stretches things even further (the study, for instance, did not include any high-heeled shoes, and no direct comparisons between running shoes and high-heeled shoes were possible). Then there are the press articles, which rely on the press release… (There’s also this: “In July, [Kerrigan] left the University of Virginia to start her own company, JKM Technologies LLC, which will focus on developing her shoe in coming years.”)
Amby Burfoot of Runner’s World, in his Peak Performance blog, has written an excellent post in response to this study that is essential reading for anyone interested in running injuries and the role of shoes. As usual, it’s a nuanced point of view that neither praises nor buries the research. He points some of the leaps — the difference between measured torque in the knee and observing arthritis, the mismatched comparison between walking and running forces, the downplaying of the role of stride length. His main message is that this is a very complex field of research where little is known, so we should be open to new results but avoid gratuitous oversimplification. It’s definitely worth a read.
Thanks!
So, having read the Burfoot post, I have a couple of things.
1. Peter Coe said “We are all an experiment of one” not George Sheehan. Way to plug your friends.
2. While it is revealing to point out who runs a minimalist shoe company, how do we know which came first? Maybe they did some research and then, based on what they found, decided to go that route. Is there proof that they got involved with the shoe company first, and then went looking for some science to support that? Blablabla. Burfoot edits a magazine that makes almost all its advertising dollars off shoe companies. So should we not take that into account, too, and discount his thoughts?
3. The message I got from the study and media surrounding it was the same as the one Burfoot leaves us with: go minimalist. I’ve been running exclusively in racing flats for several years now. Since I made the move from “stability” shoes and orthotics to lighter shoes I’ve had no knee injuries (compared to chronic tight ITB syndrome before the change). I was also able to pretty much double my mileage (I’ve since cut back for non-injury related reasons).
Doing some barefoot running seems to have helped everyone I know who has tried it. It can’t hurt to make the foot stronger, can it? I know this blog is all about science, but sometimes intuition is the safest bet. It may not be provable that running shoes cause injuries, but if you can prevent injuries by doing some barefoot running and going minimalist, why not?
1. You sure about that? Sheehan wins a Google battle on the quote about 700 to 6. Sheehan was also prominent before Coe was. Of course, it’s a pretty generic sentiment, which I imagine has been expressed many times.
2. The point isn’t to “discount” anyone’s thoughts — either Kerrigan’s or Burfoot’s. It’s simply to understand the context of the information. The fact that Kerrigan is planning to sell shoes doesn’t mean her research isn’t relevant. But it may shed some light on how she interprets her data. She does a study that has no injury-related outcomes (measuring some torques that no one has ever managed to connect to any real-world outcome at all) and uses that to write a study whose last line is: “Reducing joint torques with footwear completely to that of barefoot running, while providing meaningful footwear functions, especially compliance, should be the goal of new footwear designs.” How does she come to that conclusion? The paper doesn’t really say — but knowing that she herself is developing “new footwear designs” gives us some hints.
There’s a reason all reputable scientific journals force researchers to disclose any conceivable conflicts of interest, financial or otherwise, before publishing their results. It doesn’t mean they WON’T publish results from those with a conflict of interest — but it’s essential that the reader is aware of them.
As for Burfoot’s conflict of interest, we know it. He’s writing on the Runner’s World website. We understand that there are forces acting on him — forces that, I’m sure, he’d say have no effect on him. But it’s up to us to judge how those forces act, so it’s good that we know about them.
3. You say: “I know this blog is all about science, but sometimes intuition is the safest bet.” Sure, but you can’t use your intuition and then call it science. Burfoot may reach the same conclusion, but he’s not claiming the science proves it, because that would be misleading.