The January 28th issue of Nature, one of the most prestigious scientific journals in the world, contains an article by Daniel E. Lieberman et al. titled Foot strike patterns and collision forces in habitually barefoot versus shod runners. In part, the study showed that
Habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel…. In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe…. Even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers…. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
Lieberman’s name is familiar to many runners these days, as his research was discussed at some length in the bestselling book Born to Run by Christopher McDougall. McDougall latched onto Lieberman’s work because it suggests that those crazy barefoot bipedalists may be onto something after all, and I find myself inclined to believe some of their ideas — that heavily padded shoes don’t necessarily protect you from injury, for example, and that being able to feel the ground through thin soles may help the body adjust more effectively to the terrain it’s covering. My complaint is that, in an effort to make a good story even better, McDougall and his ilk take some liberties that irk the scientist in me.
A typical example concerns injury rates among runners. With all of the high-tech shoes available to us these days, McDougall asks, why are injury rates among runners so high? It’s a very good question … but what is that alarmingly high injury rate, anyway? A recent review article by R.N. Van Gent et al. says that, according to different studies, anywhere from 19% to 79% of runners get injured in a given year. Now let’s look at how McDougall reports this in his book:
Up to eight of ten runners are hurt every year….. Next time you line up for a Turkey Trot, look at the runners on your right and left: statistically, only one of you will be back for the Jingle Bell Jog.
In other words, he takes a reasonable observation — runners do get injured a lot — and stretches it beyond belief by implying that two thirds of runners are injured every month (the approximate time between Thanksgiving and Christmas). That’s on page 9 of my copy of the book. On page 71, he uses somewhat similar language:
Every year, anywhere from 65 to 80 percent of all runners suffer an injury. That’s nearly every runner, every single year.
Has McDougall calmed down since the publication of his book last year? I’m not sure. In a January 3rd article for Parade magazine, McDougall gives the injury stat as “as many as six out of 10.” However, his zest for hyperbole resurfaces later in the article, where he says,
In a 2009 review article for the British Journal of Sports Medicine, researchers searched 30 years of studies and were unable to find one demonstrating that running shoes make people less prone to injury.
That statement — presumably referring to Is your prescription of distance running shoes evidence-based? by Craig E. Richards et al. — is not incorrect. What it omits, though, is the fact that Richards et al. could not even find a single study that quantified the impact (if any) of shoe use on injury rates. In other words, while they didn’t find any evidence that shoes helped, they didn’t find any evidence that shoes were harmful or inconsequential, either. See the difference?
Again, I suspect that the barefoot running movement has legs, and McDougall deserves credit for inspiring interest in it. I just wish that, as someone who presents himself as an investigative journalist, he wouldn’t get so carried away.
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