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Leg cramps are a serious hazard for swimmers and are often blamed on simple overexertion. While basically true, this answer is so simple as to be misleading, and it is better to look at cramps as having three separate causes.
Identification
A muscle cramp is any interference in a muscle's ability to expand or contract.
Foot Flexing
Over-flexing the feet is one cause of leg cramps. It is possible to overextend the tendons and nerves in the feet, and since these lead back into the calf muscles, they can cramp.
Overwork
Another major cause of leg cramps is the lack of oxygen in the muscles produced by doing too much work too quickly. This prevents the oxidation of lactic acid, a mild muscle toxin that can cause cramps.
Electrolytes
An uncommon cause of cramps for swimmers is electrolyte imbalance due to perspiration, but it is still possible in warm, tropical waters. As they are immersed in cool water, swimmers do not perspire as much as a runner making the same effort might, for example.
Solution
Leg cramps are so dangerous to swimmers because the loss of the use of one leg seriously impairs the ability to stay afloat. Getting out of trouble means staying calm and trying to massage the cramp out of the muscle.
Fun Fact
According to Snopes.com, the old cautionary dictum of waiting an hour after meals before going swimming for fear of stomach or other cramps has little or no medical validity.
About The Author
Richard Thomas has been writing since earning his M.A. in international affairs in 1997. A former cheap travel blogger for eHow and senior travel editor for Associated Content, he has traveled from Argentina to Vietnam. Thomas usually writes about boxing, hiking and scuba diving, as well as on the food and wine of his current home of Portugal.
