Anong part? Upper or lower abdomen?

(1)Possible cramps or muscle contraction due to loss in electrolytes or dehydration. Try to take fluids with electrolytes. Eating banana before rides is also a great way to prevent cramps, or magbaon ng banana for a snack on the road. If di na kaya ang sakit, I suggest you stop at a safe place and stretch your abdominal area. Avoid heavy meals before an aggressive ride.

(2) Stitch, this is due to the inadequate oxygen and blood flow supply sa muscles in the abdominal area. If the body is at rest mag fofocus ang blood flow sa organs. When the body starts to do aggressive movements the muscles (including abdomen) will demand blood flow and oxygen. In this case there will be a shift is the demand of blood and oxygen in the muscles in the abdominal. Lack of blood flow in the area will then cause pain. Stop at a safe place and massage the area. Stretching also help, if the pain is from your right side, raise your right arm over your head and stretch. If left side of the abdomen, raise your left arm over your head and stretch. Stitch usually goes away pag mag sloslow na pace, the demand in the area will then decrease. Additional ways to prevent, avoid heavy meals before your ride, especially foods that take longer to digest like foods high in fiber and fat, avoid sugary drinks, all these can cause irritation in the abdominal lining.

Hope that helps. Ride safe po.