Is backwards the new barefoot?

This past weekend, a motley mix of Brits and citizens from all over the world toed the line at the year’s “most unusual sporting event.” The London Backward Run is just the latest manifestation of a growing trend in oddball locomotion: backwards running. Proponents of reverse running – cleverly dubbed gninnur – claim that the retro-activity increases flexibility and coordination, burns more calories than regular running, reduces back pain, and even improves peripheral vision.

The scientific community has also been quite charmed by this reverse-directional curiosity. A flurry of articles have analyzed the benefits of backwards running for people with low back pain or knee injuries, athletes in training, and even healthy people who want to cross-train their way to better fitness or a lower weight.

But before we get swept away by the retrograde motion, it might be beneficial to consider a similar tale of quirky mobility: barefoot running. Once touted as the natural way to reduce injuries and return to what evolution intended, barefoot running has come under increased scrutiny.

Running without shoes was somewhat of a peculiarity in the United States a decade ago. The trend garnered new attention and many more followers in 2005 with the publication of Born to Run, by Christopher McDougall. The book’s argument was simple and made intuitive sense – we evolved to run without shoes. So ditch the sneakers and just go bare.

McDougall’s argument wasn’t fluff – it was backed by multiple scientific studies comparing traditional shoe runners with the scantily shod. Harvard exercise scientist Daniel Lieberman (a “minimalist” runner himself) found that runners who have gone without shoes their entire lives run differently than those who put on a well-cushioned Nike. In particular, barefoot runners land on the front part of their feet, gradually rolling back their foot as they stride. Shod runners typically land on the heel, a spot normally too painful but made possible by the heel cushioning of the modern sneaker.

So it seemed logical that to get back to the “simple” form of running, all curious runners had to do was kick off their shoes. And they did, albeit not in mass quantities. But certainly enough to attract the attention of running shoe companies. Nike came out with a line of “minimal” running shoes, and the Vibram Five Fingers promised a liberating ride. Barefoot running also started appearing in the popular press (barefoot runners in Central Park were particularly well covered).

However, the wild enthusiasm towards barefoot running was premature. As of yet, there is no concrete evidence that barefoot running reduces injury rates. Even Lieberman’s 2010 Harvard study, widely touted as “proof” that barefoot running decreased injuries (by minimizing rear-foot striking, or RFS), in fact said nothing of the kind. The last sentence read: “controlled prospective studies are needed to test the hypothesis that individuals who do not predominantly RFS either barefoot or in minimal footwear, as the foot apparently evolved to do, have reduced injury rates.”

Indeed, running without shoes may make matters worse. Over the past few years evidence has been mounting (much of it from physical therapists, medical doctors and sports medicine clinics) that a bare foot may not always mean an injury-free foot. Injury rates have risen among the shoeless, and not merely because there are more shoeless out there. Plantar fasciitis, a painful inflammation to the arch of the foot, normally makes up 15 percent of all overuse injuries in runners. But according to physical therapist Darwin Fogt, it accounts for 90 percent of the barefoot running injuries he sees. This suggests that something particular about running barefoot is causing the problem.

And while shoes do change your running form, that’s not an entirely a bad thing. It’s more likely that shoes protect against some types of injuries, while raising the risk of others. Hitting the ground heel first (as shod runners do) sends quite a shock through the bones, raising the risk of stress fractures. Striking with the ball of the foot (as barefoot runners do) places more strain on the muscles and tendons, as well as more strain on the foot itself.

So what can we learn from the state of barefoot running? First, not to get carried away in “minimalist” hype. A driving underlying assumption of the barefoot running fad was the questionable notion that something so primitive couldn’t be harmful. The “au natural” factor is also invoked by those arguing that backwards running is so simple, not requiring any gadgetry or equipment, that it must be safe.

Second, any type of new movement, even if it promises to be beneficial, must be introduced very slowly. Many barefoot running injuries might have been avoided if the new exercise was added one minute at a time, according to Lieberman. He sees many excited athletes approach barefoot exercise with a running start, when they really should be inching along at a crawl.

Third, if something sounds too good to be true – take off your shoes and never get injured again! Go gninnur and say goodbye to low back pain! – it probably is. When it comes to backwards running, proceed with caution.