About Muscle Cramps
A cramp is an involuntary and forcibly contracted muscle that does not relax. Cramps can affect any muscle under your voluntary control (skeletal muscle). Muscles that span two joints are most prone to cramping. Cramps can involve part or all of a muscle, or several muscles in a group.

About Side Stitches
That sharp twinge of pain just below the rib cage on the right or left side. The infamous side stitch is believed to be a spasm or cramp in the diaphragm muscle.

Conquering Muscle Cramps
Muscle cramps can occur at the most inopportune moments, such as playing tennis, golf, bowling, swimming, and exercising. Muscle cramps also occur while sitting, walking or even when we are asleep. The most inconspicuous movement can suddenly precipitate

How to avoid swimming cramps
Perhaps more good swimmers have been drowned by cramp than by anything else, and only those who have suffered from it can conceive its fatal power.

Muscle Cramp Mechanics
THis article explains, in some detail, the causes of muscle cramps.

Swimming isn't dangerous after eating, but use common sense
The old caveat, "Don't go swimming for one hour after eating," is borderline mythology — an old wives' tale — folk medicine. There is nothing magical about water that gives a sated person stomach cramps.

What to do if you get cramps while swimming
If you get a leg cramp, try not to panic. A stomach cramp is more serious.