Unless you’ve been living under a rock the past few years, you’ve probably heard something about the barefoot running/“minimalism” debate. Spearheaded by Christopher McDougall’s bestselling Born to Run, the barefoot enthusiasts contend that modern running shoes are ineffective at preventing injuries and furthermore, are harmful to your feet and lower legs. This claim has attracted a significant amount of pushback from podiatrists, sports orthopedists, and of course, the running shoe industry. While claims of a massive conspiracy are downright loony, like many popular movements, there is a grain of truth to the claims made by McDougall in Born to Run and by other barefoot enthusiasts: running shoes don’t function like they’re supposed to.

Getting started

If you’ve ever been to a running store, the sales representative probably examined your feet, watched the way you walked, and recommended a particular shoe based on those factors. Some studies (but not all!) have connected biomechanical factors like arch height and running gait with injury risk. The different varieties of running shoes were designed to correct these issues. The logic is as follows: people with low arches need supportive shoes, and people with high arches need cushioned shoes. Supportive shoes are also purported to work best for people who pronate—that is, people whose ankles roll inward as they walk or run, as the stiff wedge of foam on the inside of the arch counteracts this inward rolling. A proper shoe, in theory, would correct your gait and prevent injury. But did this pan out in practice?

The research on finding the right running shoe

Until recently, we had to rely on the anecdotal evidence of runners, doctors, and podiatrists. But how could they reconcile their model of supportive and cushioned shoes with the rising tide of “minimalists” who found that they were able to run injury-free in thin, unsupportive shoes? And the many examples of people who were not any better off in the “right” shoe? Recently, two large-scale, randomized studies were undertaken to examine whether the “right” shoe has any effect on injury risk. A randomized study is the “gold standard” of research: it’s the best tool we have for examining, for example, whether a certain drug treats a disease or not. It removes all of the problems of anecdotal evidence.

Pronation and motion control shoes

A 2011 study1 at the University of British Columbia tested whether assigning running shoes based on pronation had any effect on injury risk in female runners. The 81 subjects were classified by the scientists as having “neutral,” “pronated,” or “highly pronated” feet. Within each group, one-third received a cushioning shoe (intended for “neutral” feet), one-third received a support shoe (intended for “pronated” feet), and one-third received a motion control shoe (intended for “highly pronated” feet). So within each group, some people go the “right” shoe for their foot type, and others got the “wrong” one. Then, all the subjects trained for a half-marathon, and the researchers monitored how many within each group and sub-group got injured. The results were a bit puzzling: people with “pronated” and “neutral” feet tended to do slightly better with the wrong shoe, but in all cases the shoe with the worst record was the motion control shoe! These findings are a bit weak, as a group of 81 subjects is not quite large enough to draw strong conclusions.

Injury risk and shoe type

Perhaps assigning shoes based on arch height would provide better results. A 2010 study 2 by the US Marine Corps did exactly this: a group of 1,400 recruits was divided into an experimental group and a control group. All Marines in the control group received a “support” type shoe regardless of their foot type, while those in the experimental group were assigned shoes based on their arch height. As in the previous study, three types of shoes were used: a motion control shoe, a stability shoe, and a cushioning shoe. These shoes were assigned to subjects with low, medium, and high arches, respectively. The recruits were followed for their 12-week basic training program. This study found no significant difference in injury risk based on shoe type, even when other factors like previous physical activity were controlled.

But how can this be? Do all shoes have the same effects on your feet? Intuition tells us “no,” and it turns out that indeed different shoe conditions affect your feet in different ways.

Shoe inserts

This has actually been established for a while in the field of biomechanics; we have to look back to 2001 to find a study on shoe comfort and injuries. This study, conducted by esteemed University of Calgary researcher Benno Nigg and coworkers3, investigated whether various shoe inserts could reduce injuries and (more relevant to our interests) whether inserts that accomplished this were subjectively more comfortable to the recruits. Some 206 military personnel were presented with a variety of shoe inserts and were instructed to choose the most comfortable one. The subjects had very different feet, which responded differently to the various shoe inserts, and this resulted in the subjects selecting different inserts as the “most comfortable.” Furthermore, the group as a whole experienced fewer injuries than a control group given a standard flat insert. If comfortable shoe inserts reduce injury, it shouldn’t be too much of a stretch to assume that comfortable shoes reduce injury as well.

Shoe comfort and performance

What’s more, it appears that comfortable shoes may increase performance too! A study in 2009, again by Benno Nigg’s research group4, investigated whether more comfortable shoes led to better running economy—a measure of how much energy a particular runner needs to maintain a given pace. Ten male runners evaluated five different pairs of shoes, ranking them from “most comfortable” to “least comfortable.” The men subsequently underwent a treadmill test to determine their running economy in the most and least-comfortable shoes. The result? A 0.7% increase in running economy in the most comfortable shoe vs. the least comfortable shoe. This might not sound like much, but that’s well over a minute off your marathon—just by swapping out shoes! What’s more, this study also controlled for the weight of the shoes, which has been shown to affect performance, and it even obscured the appearance of the shoes from the subjects so flashy designs wouldn’t deceive them. However, this study was quite small compared to the others we’ve seen, and all ten subjects happened to rank the same shoe as the “most comfortable,” so this result isn’t a sure bet.

Limitations

Now, all of these studies have their limitations. The first study we saw was only done on women. The second and third study was done on soldiers and marines, who, though they run a lot, also do plenty of crawling, marching, climbing, and so on. And the last study was rather small. No good scientist bases his conclusions on just one or two studies, but the plurality of evidence available points towards comfort as the best metric for what shoe really is the “right” one for you.

How can you use this research to find the right running shoe

All of this leads us to a profound but rather unsurprising conclusion: wearing comfortable shoes are your best bet. For some reason, nobody has bothered to replicate Benno Nigg’s study of shoe insert comfort and injury risk with shoes themselves, but I’d be floored if such a study found contradicting results. From the studies we’ve reviewed today, it’s pretty clear that the “traditional” methods of assigning shoe types based on foot shape or walking gait are outdated, and that comfort is the best method to pick out shoes as of today.

So where does this leave you, the aspiring runner, when you are staring at dozens upon dozens of shoes mounted on the wall at your local running store?

Well, there’s no better way of finding the right shoe than to try them out! I recommend trying out a lot of shoes—perhaps six or eight pairs or more if you can’t find a pair that feels great on your feet. Lace up a pair, walk around in them, and take them for a spin in the parking lot (any reputable running store should let you do this). If they don’t feel phenomenal, try on another!

Much of the common wisdom about running shoes still holds: heavier runners ought to try on larger, more cushioned models first, whereas lightweights might consider opting for a thinner, sleeker model, and it’s never a bad idea to get a new pair of shoes after you’ve logged 300 or 400 miles on your previous pair. But beware of sales representatives telling you that you’ll have to “break in” your shoes—your new shoes should feel like a second skin from the get-go. If not, do not buy them! And finally, if you’ve been running injury-free in the same shoe model for a long time, you’ve found a keeper. Stick with what works!