Practice form.
Credit: Courtesy Ed Ayres

"I'm not a biomechanics expert," Ayres says. Still, a lifetime of running has left him with a fair share of practical observations and insights. For instance, he recommends running vertically, which means over your center of gravity, not leaning backward or lurching forward. He also suggests trying to prevent your feet from splaying out to the sides. And he notes that it's best for your arms to swing directly forward and back instead of across the body. It's important that the body overall, from your jaw to your neck to your shoulders, arms, hands, and so on, be as relaxed as possible.

Addressing today's controversy over the benefits of a forefoot versus a heel strike, Ayres is pragmatic. "The natural forefoot runners are probably going to be more successful as 5K, 10K, maybe even marathon runners," he says. "For an ultrarunner, landing on the heels may be more beneficial because it's more energy-efficient, but this will vary from person to person – you can't fight it."