Photo: Josiah Mackenzie/Flickr

If running makes your knees hurt, you might have a little something called, well, runner's knee. Characterized by pain around the kneecap after running, this condition is usually caused by muscular imbalance of the legs and feet, says Sarah Brown at That's Fit.ca. How's it fixed? With R.I.C.E. -- rest, ice, compression and elevation -- plus some strength training, backward running, maybe even some orthotics and a good pair of running shoes.