Tuesday, June 11, 2013

The Hullabloo Over Foot Strike


If you're a runner I'm sure by this point you've heard about the ongoing debate over what foot strike is better, a forefoot (or midfoot) landing or a heel strike.  Recently there has been a growing body of research trying to prove with one is “better,” spurred along in a great part by the minimalist shoe movement. Many people have heard of the land mark study done by Harvard's Daniel Lieberman on barefoot Kalenjin Kenyan distance runners that shows them running with a forefoot strike. Recently a second study done by George Washington University researchers recently came out that looked at the habitually barefoot Daasanach Kenyans; this one found that many of them were heel strikers. And there's been a tone of other research done trying to determine if switching from one type of heel strike to another is beneficial - none of which seem to really come to any hard and fast conclusions. If you’ve trained with us here at PTI you’ll know it’s no secret that we teach runners to land with a mid or forefoot strike, so I'll go ahead an d make my bias known. But what really bothers me about all this debate is that people don’t seem to be talking about what the rest of the body is doing – which is just as important as where your foot first touches the ground. In fact, if I had to choose only one factor to “fix” in a person’s running stride (or wright a research paper on), it wouldn’t be how their foot lands; it would be the orientation of their tibia (the shin bone) to the ground upon landing.

There’s a whole continuum of foot strikes that runners use, from the most extreme heel striker to the person who’s heel never touches the ground.  Biomechanically a lot of this will have to do with how much the person plantarflexes (points toes, like in ballet) or dorsiflexes (top of foot moves up towards the shin) their foot in the milliseconds before landing. My concern is when a person’s tibia isn’t close to a 90 degree angle with the ground when they land. When your tibia is close to perpendicular your knees and hips are both flexed, allowing your leg to act more like a spring and absorb some of the impact of landing. On the other hand, the closer your knee is to straight when you land the more that leg is “putting on the breaks,” meaning more impact is going to be transmitted directly up your knee and into your hip, pelvis, and lower back instead of being dissipated over the lower joints.

The difficulty comes when you’re trying to teach someone proper running mechanics.  It’s much easier to visualize and change where your foot lands than it is to think about your tibia, and getting a person to start landing on their mid to forefoot will almost always bring their tibia closer to perpendicular than they were before. It is possible to land on your heel with an almost vertical tibia if you have a large amount of dorsiflexion available. I imagine this is what was happening in the North African study that showed the habitually barefoot people heel striking. But for those of us who grew up wearing shoes it's very unlikely that you'll have that much dorsiflexion available to you. So when the next media headline comes up proclaiming “running on your forefoot is better” or “heel landings are better” take a good look at the study and see if they were only looking at where the foot landed or if they considering the position of the entire lower leg.

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