According to evolutionary biologists, humans have been running for about two million years. For most of this time, running was essential to human survival activities like hunting, warfare, and fleeing danger produced better outcomes at a faster pace. It is only in the last few hundred years that running has become a recreational skill confined to the realms of sport or diet, a trend that has increased in the western world as our daily lifestyles become more sedentary.

Despite this long history of human running, somewhere between one- and three-quarters of all runners will be injured in a given year. For physical therapist and biomechanics expert Dr. Irene Davis, the huge number of running injuries was something of a puzzle. “Running is something the human body has evolved to do over 2 million years,” explains Dr. Davis, “so it didn’t make sense to me why so many recreational runners were sidelined each year.” Over her decades–long career researching running and running injuries, Dr. Davis has come to some surprising conclusions. One key, she says, is what you wear–or don’t wear–on your feet.

Dr. Davis herself runs barefoot, but she cautions that it must be a slow transition from supportive shoes to minimal ones. The stability provided by our supportive shoes actually weakens the muscles that would normally do that job. If you jump right into running with non-supportive shoes or running barefoot, your body may not be ready and this, too, can result in injury. Before running with minimal shoes or barefoot you have to build up appropriate strength in the feet and calf muscles. To learn more, click here.