Orton is part of a growing movement of Free Your Feet rebels, who believe it's not running that causes injuries, but running form and economy of training. One of the more vocal -- and surprising -- members of this group is Gerard Hartmann, Ph.D., an exercise physiologist who works with the world's greatest marathoners and also consults for Nike. According to Hartmann, the vast majority of running-related foot injuries are a result of too much foam-injected pampering. Running shoes have become so supercushioned and motion-controlling, they allow our foot muscles to atrophy and our tendons to shorten and stiffen. Without strength and flexibility, injuries are inevitable.
"The deconditioned musculature of the foot is the greatest issue leading to injury," Hartmann explains. "If I give you a collar to wear around your neck, in 4 to 6 weeks, we'll find 40 to 60 percent atrophy of musculature. That's why this emphasis on cushioning and motion control makes no sense.
One of Hartmann's star clients, marathon world-record holder Paula Radcliffe, has been training in the Nike Free, a new, minimalist slipper designed to mimic the range of motion of a naked foot. Alan Webb, America's best miler, also works out in the Free. Webb had been hobbled by foot injuries early in his career, but after he started barefoot exercises, his injuries disappeared, and his shoe size shrank, from a 12 to a 9. "My foot muscles became so strong, they pulled my arches up," says Webb. "Wearing too much shoe prevents you from tapping into the natural gait you have when landing on the ground."