In an ideal runner's world, every step of every mile would be 100 percent pain-free. No aches, no twinges, no lingering soreness from yesterday's workout. The reality is that many runners constantly deal with a slight (or not so slight) disturbance a tender foot, a tight hamstring, a whiny knee. While these nagging issues often aren't serious enough to require a time-out, they are annoying, especially when they don't let you fully enjoy your time on the roads.

Think of running pains in terms of a spectrum. At one end you have severe, full-blown injuries call it the red zone, which includes stress fractures that require time off. The other end, where you're in top form, is the green zone. Mild, transient aches that bug you one day and disappear the next sit closer to the green end. Unfortunately, many runners get stuck in the middle the not-quite-injured but not-quite-healthy yellow zone.