The New Fitness Rules

Old school: Get a sneaker that offers the most stability.

New rule: Less is more.

The shift toward minimalist footwear in the past few years has biomechanical experts rethinking what makes a good athletic shoe. "Like everyone else, I used to believe that the more motion control and cushioning a shoe had, the better," says Irene Davis, PhD, the director of the Spaulding National Running Center at the Harvard Medical School. But such training wheels, she says, can encourage runners to strike with their heel first before pushing off the forefoot -- a motion that creates a lot more impact on the joints, according to research conducted by Davis. In contrast, less built-up, minimalist sneakers and their "barefoot" counterparts, like Vibram FiveFingers, encourage a natural mid-to-forefoot strike, which creates a softer landing. A recent Penn State study suggested that minimalist footwear can help reduce injury rates among runners. Today you'll see minimalist styles by just about every sneaker brand. That said, you shouldn't become a convert to them overnight. A study from the University of Wisconsin-La Crosse found that among runners who switched to a barefootlike shoe design, those who continued to strike with their heels (as if they were in a traditionally cushioned running shoe) significantly increased the loading forces on their lower legs. So work on your forefoot strike before swapping in minimalist shoes.