Not running heel to toe
More on the study below. But first, I'd like to share my counterintuitive experience as a test subject in the research that lead to this paper. To the left you can see a photo of me wired up and ready to run on the treadmill in the Skeletal Biology Lab at Harvard. How did I get there and what did I learn?
I volunteered. While not fully barefoot, I've been running using POSE technique at CrossFit for nearly three years now. (For the uninitiated, POSE approximates a barefoot gait by stressing a shortened, quickened stride; pulling of the feet off the ground rather than pushing and landing forefoot/midfoot underneath your center of mass). I use minimal shoes (Nike Free, which to true barefooters are still too squishy and have too large a heel).
Nevertheless, I made the cut. The study collected data with runners moving at a 9-, 8- and 7-minute per mile pace on the treadmill both barefoot and wearing running shoes.
In my first barefoot set it was easy to know that I was striking with my forefoot. The treadmill had a very hard surface because it had a pressure plate to measure the force of foot strikes. Any heel striking would have immediately produced pain.
When I moved onto my shod set (which utilized regular cushioned running shoes), I fully believed that my foot strike remained identical to what it was running barefoot. After all, I was "pulling not pushing" and consciously looking to land forefoot/midfoot.
I was sure that I was not running heel to toe. It wasn't in my mental or prioperceptive image. After I finished, the technician replayed the video of my running. There I was barefoot with the ball of my foot hitting first and the heel gently flexing down before I pulled my foot off for the next stride. And ... there I was with shoes on hitting first on my heel and rolling across to my toe. It wasn't egregious. It was almost a flat footed strike with the middle of the foot being the impact point. But it wasn't. In slow motion you could see that the first point of impact was my heel.
Intuition and reality can easily be different. This experience reinforced the wisdom of having a coach or other objective observer gauge what you're doing to compare with what you think you're doing.
Amby Burfoot over at Runner's World has a great set of relevant links to other perspectives and an excellent executive summary provided by Daniel Lieberman, which speaks to what his paper doesn't say:
Our paper shows ONLY how and why humans can and did run comfortably without modern running shoes. We confirmed what many people knew already, that most experienced, habitual barefoot runners tend to avoid landing on the heel and instead land with a forefoot or midfoot strike. The bulk of the paper explores the collisional mechanics of different kinds of strikes. We show that forefoot and some midfoot strikes (shod or unshod) do not generate sudden, large impact transients that occur when you rearfoot strike (shod or unshod). As a result, runners who forefoot or midfoot strike don’t need shoes with elevated cushioned heels to cope with these sudden, high transient forces. If impact transient forces contribute to some forms of injury (emphasis on IF and SOME), then this style of running (shod or unshod) might have some benefits, but that hypothesis needs to be tested. That’s it! We present no data and make no arguments about how people should run, whether shoes cause some injuries, whether barefoot running causes other kinds of injuries, and so on. There is a strong need for controlled, prospective studies on these problems.
Here are links to some prior Bounce articles on barefoot running, persistence hunting and the endurance running capabilities of humans:
The Evolution of Running: Why Do You Run?
Do short toes make humans better runners?
Running Barefoot: Like humans have for thousands of years
More Barefoot Running: Modern technology and human biology