The topic that stirs the most passion and debate among runners these days is probably shoe selection and its impact on injury rate. In case you are out of the loop on this one, the popular theory is that modern running shoes (as characterized by a cushioned-sole design employing a heel-to-toe drop often in the range of 10-14 mm) actually contribute to increasing injury rates, as opposed to providing the “protection” or “correction” that manufacturers claim. The argument now is that we should return to our roots and run more naturally – i.e. barefoot running, or, acknowledging the sensitivity our typically-shod feet have evolved to possess, with “minimalist” shoes with no heel-to-toe drop.
This debate started many years ago but really reached the “mainstream” with the publication of [amazon_link id=”0307266303″ target=”_blank” container=”” container_class=”” rel=”nofollow”]Christopher McDougal’s Born to Run[/amazon_link] in 2009 (previously reviewed). The number of studies on the impact of running shoes on form and injury rate by the likes of Dan Lieberman, Pete Larson, and other evolutionary biologists has skyrocketed. The options in minimalist shoes from existing and companies new to the running shoe market (such as Vibrams, Skora Running, Altra, etc.) have likewise multiplied.
However, as with most complex topics, the debate is becoming oversimplified. As Brian Martin points out in his preamble to a running shoe debate, there is far more involved to running injury-free than just selecting the right shoes. In fact, it’s even debatable as to how large of a role shoe selection really does play in your performance as a runner.
The “lazy” interpretation of recent thinking is:
- Cushioned running shoes encourage (or even “force”) you to land on your heel
- Heel striking increases the impact felt by your legs, thus increasing injury risk
- Moving to a midfoot or forefoot strike reduces these forces and resulting injury risk
- Minimalist shoes are necessary to become a midfoot or forefoot striker
This oversimplifies things. Now granted, more discriminating evangelists for minimalist running are careful to delineate the process for achieving injury reduction more clearly, but unfortunately they tend to get shouted over by those carrying the simpler (and wrong message).
First, what really drives the injury risk is the rate at which the loading forces at foot strike are transmitted through your legs. As Jay Dicharry so vividly portrays in his analysis of various loading rates, this isn’t entirely dictated by whether you are a heel striker or a midfoot or forefoot striker. It is more dictated by where your center of gravity is, relative to your foot, when you land. It is conceivable, if difficult, to land on your heel but to do so with a low enough loading rate to mimic the lower injury risk that a typical midfoot striker would enjoy.
Second, there is an implication that there is some sort of bimodal distribution – you are either a heel-striker, or a midfoot-striker. The reality is that the distribution is more continuous than this – there are varying degrees of heel-strike. Some runners do overstride significantly, whereas others have a more appropriate stride length and “barely” land on their heel. There is thus a “gray area” between heel- and midfoot-striking that is likely occupied by a good number of runners.
Third, heel-striking (or, more correctly, overstriding) is a symptom of running form issues, not the direct cause of the problem. It is difficult, maybe even impossible, to focus strictly on landing on your midfoot. Your efforts must focus on not just improving your form through various techniques, but also on making sure that you address strength and mobility imbalances, often through ancillary work, to remove any physical barriers you might have to achieving this form.
Finally, at least one study suggests that heel-striking may be a more efficient way to run. There are two ways to increase your speed – either increase your cadence, or increase your stride length. Heel-strikers would tend to have a longer stride, and it appears that their cadence is generally not significantly less than that of most midfoot-strikers. Thus, they produce more speed for a given level of effort. The ultimate runner, then, may be a slight heel-striker who can avoid injury.
So, the reality is that becoming a “better” (more injury-resistant) runner is not as simple as learning how to run in minimalist shoes. That may be part of the solution, but the process for getting there is more involved than the simplistic view too often espoused by minimalist advocates would portray. Like most things in life, there are no shortcuts. Yes, a shoe strategy may certainly be an element of this journey – but maybe not. If it is, it may be the third or fourth most important part of the transition. There are plenty of runners who have managed to avoid injury while running in “traditional” running shoes.
It is a confusing time for runners right now, with many conflicting messages on shoe selection. This is particularly true for runners who have faced or are facing injury. I’m in that quandary right now, having gone through two injuries the past two spring seasons. I don’t believe that either injury (hamstring strain last year, Achilles tendinitis this year) were directly “caused by” poor running form or wearing “traditional” shoes. In fact, if anything, I’d argue that maybe putting in too many longer runs in my Saucony Kinvara’s with their 4mm heel-to-toe drop (note – I do not classify this as a “minimalist” shoe) is more likely the cause of the latter, though in both cases overtraining relative to my capabilities at the time is probably the primary contributor.
This isn’t to say that low heel-to-toe drop shoes will not be a part of my routine going forward. It’s just that I, like any runner, need to be smart about how we use such shoes and whether we ultimately make a full transition to “minimalist” shoes or not. They are a valuable tool for strengthening your calves and working on your form, but they are not a shortcut. Don’t let anyone sell you otherwise.
And now for something completely different…