We recently ran a tip on “barefoot” running shoes, footwear that allows runners to mimic the movements of barefoot running, while still providing some degree of protection from dangers like broken glass, small stones and cold weather.
We advised our readers—correctly, I think—to think twice about switching to these shoes from what they have already been using and to transition very slowly if they do switch, in order to decrease the chances of injury.
But there’s a fascinating larger story and ongoing controversy behind what we so briefly touched upon.
Modern running shoes, which typically have built-up heels, stiff soles and plenty of arch support, originated in the 1970’s. I recall wondering, when I took up jogging toward the end of that decade, how anyone used to manage to run without all the heel cushioning.
Have you ever tried running without shoes on a hard surface? I tried it for a few paces using my usual running-shoe technique, and I promise you I won’t do it again. You land with a great deal of force on a very small area of your heel, and at least in my case, there’s just not enough natural padding to make it comfortable.
However, as we know, up until relatively recently, people ran without the benefit of supportive running shoes—or any shoes, for that matter. In fact, humans’ ability to run long distances was essential to early hunting. Our ancestors would chase dinner across the veldt until the unfortunate ungulate was exhausted and could be killed.
Which raises the question: how did they do all that running all those millions of years ago without injuring their heels, at least most of the time?
Fast forward to the 21st century, when a group of researchers headed by Daniel Lieberman in the Department of Human Evolutionary Biology at Harvard University in essence asked the same question. In 2010, their research findings on the issue were published in the journal Nature.
Turns out you don’t have to land on your heels to run. In fact, the Lieberman study found that runners who grow up running barefoot usually don’t land on their heels.
Instead of landing on their heels (called a heel “strike”), these runners mostly use a forefoot strike, landing on the ball of the foot behind the 4th and 5th toes in a manner similar to the way most people walk down stairs. This typically brings the heel to the ground in a controlled fashion, significantly reducing the impact of the collision between heel and ground (or stairs).
And it is the collision forces between the heel and the ground that are felt to be at the root of many running-related injuries. When Lieberman’s group measured the forces generated by runners’ feet, they found that the magnitude of the force went up and down smoothly, which spreads the forces out over time (a good thing)—except for heel strikes, which created sudden, narrow, upward spikes in force (not a good thing).
This spike was there whether or not a heel-strike runner wore running shoes, suggesting that all the cushioning of running shoes only partly eases the impact on the heel. Surprisingly, the spike completely disappeared with forefoot strike running, even when the runners were barefoot. (Lieberman’s group also measured the forces for midfoot-strike running, which—no surprise here—turned out to lie on a continuum between the two extremes.)
The implication is that you might be less likely to incur the typical acute injuries (like ankle sprains) and repetitive-stress injuries (like plantar fasciitis) of modern runners if you were to run using a forefoot (or midfoot) strike instead of a heel strike. And, like barefoot running, running in minimalist shoes is a way to act on this implication.
While this line of reasoning sounds compelling, there are significantly sized flies in the forefoot ointment. First, some barefoot runners prefer a heel strike. The number was small in the Lieberman group study, whose raised-barefoot subjects were adolescents of the Kalenjin tribe in Kenya.
However, a 2012 study of another Kenyan tribe, the Daasanach, published in PLoS One, found that most of the Daasanach barefoot runners preferred a heel strike.
The authors speculated that this preference may have something to do with the favored endurance pace (the Daasanach runners prefer a slower pace) and the hardness of the surfaces being run upon. Both would be expected to produce a less forceful landing.
It may also relate to the shorter relative distances typically run by the Daasanach or to their being generally taller and skinnier. The researchers on both studies are reported to be comparing their data.
So, what’s a runner to do? As we advised, think twice before you throw your running shoes away. Presently, the benefits of forefoot strike running are still theoretical.
For all we know, forefoot-strike running—which utilizes and stresses muscles, tendons and ligaments in ways that differ from heel-strike running—could predispose you to a whole other set of injuries. Especially if you’ve run for a long time in standard running shoes without significant problems, you might be asking for trouble if you switch.
And what if, after mulling over the potential pros and cons, you decide to dip your toe into the waters of forefoot-strike running? That brings me to our second caveat: In order to give the aforementioned muscles, tendons and ligaments sufficient time to get used to handling the different loads placed on them, it is important to transition to barefoot-style running very gradually. The Lieberman group’s website provides some reasonable, practical guidelines. The website is also a fascinating read if you wish to learn more about this subject, and it includes a link to a well-done 6-minute video overview put together by the publisher of Nature.
Finally, for a further lowdown on the forefoot vs. heel-strike controversy, see the Health and Medical Implications section of the article on barefoot running in Wikipedia.
”Forget not that the earth delights to feel your bare feet and the winds long to play with your hair.” –Khalil Gibran