1. Sign Up, Already Chances are, no matter where you live, there’s a 5-K nearby soon. It’s the most popular race: 7,500-plus 5-Ks held in 2006 drew more than 3 million runners. Why? “It’s only three miles!” says Mike Mahan of Tullahoma, Tennessee. Well, 3.1 miles, but so as long as you’re logging three half-hour runs per … Continue reading