Roads, for the most part, are steady and predictable. Trails are not. "On the trail, every footfall is different," says Nikki Kimball, a physical therapist and ultrarunner who has won the Western States 100-Mile Endurance Run three times. "If you land on a rock or slippery moss, your body has to be able to stabilize itself." To prepare for the task, Kimball suggests adding … [Read more...]