As the controversy raged, experts were unanimous on one point: We need more evidence, they said. Wait for the studies to produce results.
Six years after the barefoot running boom started, with claims that ditching your shoes would change how you run and reduce your risk of injury, that evidence is now trickling in. A study in the British Journal of Sports Medicine presents the most thorough comparison yet of injury rates, with and without running shoes. The results suggest there's not much difference – but the debate over what that means is far from over.
The study, by Dr. Allison Altman-Singles of the University of Delaware (now an assistant professor at Penn State Berks) and Dr. Irene Davis of Harvard Medical School, recruited 107 experienced barefoot runners and 94 runners who used ordinary running shoes, and monitored their injury status for a year. The "prospective" study design avoids some of the potential biases and inaccuracies associated with retrospective studies based on recall of past injuries.
The researchers expected that "barefoot runners would sustain a similar number or fewer injuries" than the shod runners, Altman-Singles says. Sure enough, 32 per cent of the barefoot runners were diagnosed with musculoskeletal injuries, essentially the same as the 34 per cent in the shoe group.
But there's an important caveat: The barefoot group covered just 24 kilometres a week, while the shod runners, at 41 kilometres per week, were running nearly twice as much without any increase in injury rate.
"Barefoot running attracts a particular demographic," Altman-Singles observes; they tend to be older and less competitive, which may be why they choose to run less.
Alternately, something about the act of running barefoot may tend to limit how much people run. For example, the barefoot group reported a total of 57 injuries to their soles, such as cuts, blisters, bruises and stubbed toes; those in shoes reported only eight types of injuries.
Either way, for experienced runners allowed to freely choose how much to run, the choice of footwear didn't seem to make any difference to overall injury risk. There were some differences in the type of injuries: the barefoot group appeared to be more vulnerable to calf injuries, while the shod group suffered more knee and hip injuries, but the small numbers of each type of injury make it difficult to draw any firm conclusions.
"The results don't surprise me," Dr. Maxime Paquette, an assistant professor of biomechanics at the University of Memphis and former captain of the University of Guelph cross country team, said in an e-mail. "I think that for any type of training condition, whether you study footwear, volume, intensity, surfaces, etc., the adaptation to this training condition is the most important factor."
In this case, participants in both groups had been running for an average of about 10 years, giving their bodies plenty of time to get used to the stresses imposed by their weekly mileage. (The barefoot runners had been running without shoes for an average of 1.65 years, and did three-quarters of their mileage completely barefoot with the rest in barefoot-mimicking minimalist shoes.)
If these results are confirmed by future studies (more prospective results are on the way, Altman-Singles says), what does that say about barefoot running? To some, it might be proof that the barefoot craze was just a passing fad whose benefits were vastly overstated.
But you could also make the opposite case, points out Quebec City physiotherapist and running injury specialist Blaise Dubois: "Maybe it means that we don't need shoes." After all, why pay $200 for a heavily engineered shoe loaded with patent-pending cushioning and motion control technology if it doesn't protect you from anything more serious than a stubbed toe?
In reality, the hype – or hyperbole – about barefoot running has long since become more moderate. Lighter, more minimalist shoes undoubtedly lead to changes in your running stride that may help some people, but not others. It's a tool, not a panacea.
That suggests that running shoe choice is highly personal – which, as it happens, is the conclusion that Dr. Benno Nigg, the recently retired University of Calgary shoe guru, recently advanced, also in the British Journal of Sports Medicine.
Concepts such as shoe cushioning and foot pronation have failed to reduce running injuries, Nigg argues. Instead, he advances the "comfort filter paradigm" when you choose a shoe that feels comfortable, you are selecting one that allows your foot to move along its preferred path. This "automatically reduces injury risk."
It's a bold prediction, and certainly a convenient and stress-free way of selecting shoes. Is it true? We'll have to wait for the studies to find out.
Alex Hutchinson blogs about exercise research at sweatscience.runnersworld.com. His latest book is Which Comes First, Cardio or Weights?