There are two theories explaining why we get the common stitch - BBC Sport Academy explains all.
Very common in long distance running.
Usually people who haven't warmed up properly and have eaten too close to exercise.
WHAT ARE THE TWO STITCH THEORIES?
During exercise, our blood moves away from the diaphragm to the limbs.
The diaphragm is the muscle that separates the stomach and abdomen from the heart and lungs.
It's one of the main muscles involved in breathing.
Most scientists believe the pain is caused by a reduction in blood supply to the diaphragm, causing it to cramp.
The stitch is caused by fluids which the body finds hard to digest.
This causes the gut to "tug" on the ligaments connecting it to the diaphragm.
WHAT KIND OF PAIN?
Sharp pain in upper part of abdomen made worse by deep breathing.
No-one knows why, but these two methods are known to work!
Stop running completely and touch your toes.
Pressure on the area will help to relieve the pain. Use your fingers to press firmly on the painful area.
You can run off a stitch easily enough but it affects you for a couple of minutes.