There is little doubt that the most frequent question I have been asked over the past year by runners is, “What do you think about this barefoot running thing?”
The idea that running au natural is, well, more natural and, therefore, more beneficial in terms of preventing injuries, is not a new one. (Way back in Article #6 I discussed a paper that appeared in the prestigious journal Medicine and Science in Sports and Exercise that was perhaps the first scientific study purporting to show that barefoot running may be less likely to cause injuries.) Since then,others have made similar arguments, but nothing has captured the general public’s interest in this topic more than the publication last year of Christopher McDougall’s best seller, Born to Run.
I think it’s worth a closer look at the “evidence” cited by the proponents of barefoot running before arriving at any conclusions as to whether there is any real basis to support this movement:
· Since 1968, when the modern running shoe first reached the market, the number of running injuries has steadily increased. This is because running shoes have become over-cushioned and/or stiffer and/or too high in the heel, etc. etc.
First of all, I’m not sure what is meant by the “modern running shoe,” but regardless, here is a prime example of a “statistic” that is a bit misleading. Since 1968, of course, the number of runners has steadily increased, so it makes perfect sense that the aggregate number of injuries has risen as well. I’ve seen no evidence indicating that the percentage of injuries per capita has increased during this period of time, so to indict the shoe for a non-existent crime seems somewhat unfair to me.
· Primitive humans did not seem to need shoes to run, chasing down animals for food. Less developed cultures today (the Turahumara Indians of Mexico are the example used by McDougall) run either barefoot or in thin-soled sandals and do so for incredible distances without incurring the number or type of injuries commonly seen in the shod population.
The last part of this statement is the most questionable: I don’t believe there have been any epidemiological (population) or controlled studies that have shown this to be true. Much of the “evidence” for this declaration appears to be based on McDougall’s observation of the Turahumaras, but observation does not equal scientific study. Perhaps researchers will soon carry out a comparison study over a suitable period of time to support this claim that barefoot runners truly sustain fewer injuries.
· Because running shoes provide so much cushioning and support,the intrinsic muscles of the foot (those within the foot itself, as opposed to muscles in the leg that control foot movements) become weakened over time and more susceptible to injury.
Leaving aside the fact that the percentage of all running injuries involving the intrinsic muscles specifically is exceedingly small,there really is no evidence to support this theory. No study has ever shown a measurable decrease in the strength of intrinsic foot muscles in shod vs.barefoot conditions, nor have any shown a relationship between the strength of these muscles and the incidence of injuries. On the other hand, there are studies that show such a relationship between the strength of extrinsic muscles and running injuries, which makes the findings of a report by Mayer et al [Br J Sp Med, 2007] relevant to this topic. This study found that the use of foot orthotic devices – which certainly provide as much, if not more, support for the foot, and would accordingly be a prime suspect for “weakening” the intrinsic muscles – actually resulted in increased strength of the calf muscles and contributed to a reduction of pain in runners with Achilles tendinopathy.
· Because running shoes provide so much cushioning and protection, runners adapt a different gait pattern that leads to increased contact of the heel, instead of at the mid- or forefoot, during the landing phase. This leads to increased impact forces which increases the incidence of injury.
There are two problems with these claims and they are the same problem – they simply are not true. A search of “barefoot running” on Google Video will bring up a few interesting examples of runners in side-by-side comparisons that appear to confirm the first statement, but they are all examining runners on treadmills. Videos of “natural” running over ground show a different story: the great majority of runners land with the foot directly beneath the body, with the point of contact at the middle of the foot. Those runners who reach forward with their foot and make initial contact at the heel are exhibiting what we would term an abnormal gait pattern and would be runners who may be, in fact, at increased risk for injury. But these folks are in the minority, contrary to what the advocates of barefoot running allege.
Regardless of whether or not one’s running form leads to increased impact, there is still no clear relationship between this and an increased incidence of injury, despite most people intuitively coming to that conclusion. Virtually all of the most common running ailments – patellofemoral pain syndrome, ITB syndrome, plantar fasciitis, shin splints – share the predominant risk factor of faulty biomechanics of the lower limb related to rotational impairments. Impact does not seem to be identified specifically as a cause for these injuries. Even stress fractures (with the possible exception of foot bones) do not appear to be related to different levels of impact.
While there is little evidence to support these indictments of running in shoes, there also is no evidence to criticize the practice of running barefoot. It is an individual choice, but one that should be made on the basis of preference, not fear that you are doing yourself harm by running in shoes. If you do decide to try it, I would urge the same cautions I have offered previously – break in your bare feet like you would break in a new pair of shoes. Start slow, don’t go far, and don’t run hard initially, increasing your mileage and intensity gradually. And most important – watch out for sharp objects on the ground.