You're in the middle of your run, swim or exercise class, when you begin to feel a cramp or pulling in your side. Ignoring it, you continue to exercise when all of a sudden that small ache turns into a sharp stabbing pain, forcing you to stop.
What happened? Was it something you ate or drank? Did you try too hard or not warm up properly? What you experienced is most often referred to as a stitch and is something most professional and recreational athletes feel at some point.
Researchers have only recently begun to study in detail the the causes of stitches. So far, they've discovered that both the fit and unfit can suffer from stitches and that they have little to do with training frequency or levels. Children seem to suffer more than older athletes but that doesn't mean adults are immune.
An Australian study of runners found some of the athletes also experienced pain in their shoulders. Researchers explained that when the diaphragm and tissue next to it are irritated, pain often settles in this area. Half of the runners said eating and drinking before exercise increased the likelihood of experiencing a stitch. According to another study in Medicine And Science In Sports And Exercise, drinks high in sugar and salts consumed before or during exercise can also cause stitches.
Exercising at a high intensity has also been identified as a cause. In one study, 26 per cent of runners claimed they experienced stitches more often during a race than in training.
Some previous causal theories include insufficient blood flow to the diaphragm or too much stress on the ligaments that attach the abdominal organs to the diaphragm. One recent idea suggests the peritoneum, a double-layered membrane located behind the abdominal muscles and close to the stomach, is responsible.