by stitching? lool

Make sure you have a regular intake of oxygen. When glucose turns itself into energy in the muscles without oxygen it forms lactic acid as well and burns your muscles and causes stitches. When it uses oxygen to make energy the only by-product is carbon dioxide which is harmless and you breathe it out. The most convenient way of doing this is breathing through your nose and out of your mouth. Eating starchy food like banana's also helps!

Hope this helps!

Bananas and potatoes help prevent cramp as they contain lots of Potassium which is used by muscles to work properly. Also, keeping hydrated not just before training or competition, but in the days before competitions and training is crucial to prevent cramps and stitches.
Making sure that you are breathing frequently enough helps prevent from muscles cramping because of a lack of oxygen.
Hope I helped =D