You're running as nimbly as a deer in the forest when you notice a slight cramp in your right side. You keep running, hoping it will just disappear, when it rebels and gets worse. More than likely you've developed a side-stitch, which is nothing to worry about, but they're painful enough to put your running to a halt. If you get one in your right side, try exhaling as your left foot hits the ground. This has worked for me in the early stages of a stitch. If the stitch has gotten so bad that you're doubled over in pain, it's best to slow way down or stop and walk it off. Bending over and practicing some deep belly breathing sometimes helps, although this might not be an option if you're in the middle of a race. Remember the phrase, "this too shall pass." It will. To prevent side stitches from sabotaging your run or race in the first place, strengthen your abs. Strong abs can keep your organs more firmly in place so that they don't tug so hard on your diaphragm, which is generally what causes the stitch.