Propelled in part by the success of the bestselling book Born To Run, the decision to go barefoot has been hailed by some as a step towards minimizing the stress that running can put on the body.
As the barefoot style becomes more popular -- Americans reportedly spent $59 million on minimalist shoes last year -- questions have arisen about the injury risks faced by runners who forgo typical sneakers. The New York Times points out "anecdotal evidence, including from physicians who treat runners, indicates that some people who take up barefoot running develop entirely new aches and injuries." And new study finds evidence that's in step with these concerns.
Led by Brigham Young University Assistant Professor of Exercise Science Dr. Sarah Ridge, researchers examined the potential for injuries that can occur during shoeless running, or running while wearing so-called barefoot shoes. Participants were 36 experienced runners who typically ran between 15 and 30 miles a week in regular shoes. Half of those runners were told to add mileage in small increments while wearing Vibram Five Fingers barefoot shoes for 10 weeks.
MRI scans revealed that more than half of those wearing the minimalist shoes showed signs of bone injuries in their feet.
The authors concluded that those who want to start barefoot running "should transition very slowly and gradually in order to avoid potential stress injury in the foot."
“Transitioning to minimalist shoes is definitely stressful to the bones,” Ridge cautioned in a statement released by the university. “You have to be careful in how you transition and most people don’t think about that; they just want to put the shoes on and go.”
Running styles differ depending on how a person's foot strikes the ground. Barefoot running involves forefoot or midfoot striking, which is supposed to minimize the impact of your body colliding with a surface. Striking the ground with your heel first, on the other hand, falls in line with running in regular shoes.
Previous research has shown that striking on your heels might mean hitting the ground with three times more weight than barefoot running. Furthermore, as Wired reported last year, Daniel Lieberman, a Harvard University professor known for his research on barefoot running, has found that forefoot-striking runners have lower risks of repetitive stress injuries, and that going barefoot is more energy efficient.
The Associated Press, however, reported last spring that doctors have noticed an uptick in the number of injuries associated with barefoot running, including tendinitis in the achilles and metatarsal stress fractures. The AP also noted that those injuries were mainly said to be found in people who took up barefoot running quickly, rather than slowly building their up their mileage over time.
Ridge's study, titled "Foot Bone Marrow Edema after 10-week Transition to Minimalist Running Shoes," was published last month in Medicine and Science in Sports and Exercise.