Cramps come in four categories: True cramps, Rest cramps, Tetanic cramps, and Dystonic cramps. The most common of these is the True cramp. While there are different causes of muscle cramps, like the involuntary contractions associated with seizures, we’ll focus on muscle cramping related to athletics, as this is the most common.
Our bodies are composed of over 700 muscles that work together. Occasionally, involuntary contractions of one or more of these muscles will cause a cramp or spasm. A muscle cramp may involve a single muscle, part of a muscle or a number of muscles that work in synergy. Although most skeletal muscle cramps occur in foot and calf muscles, other muscles such as the thighs, arms, hands, and abdomen are also prone to spasms.
No one knows for sure the exact mechanism that causes people to cramp during exercise, but there are two main theories, the second of which is generally accepted as the principle cause, though not definitively proven yet.
Although not supported by scientific evidence, dehydration is often given as an explanation for why muscle cramps occur in athletes. The lack of evidence might seem difficult to believe because every high-school sports coach preaches hydration as a way to ward them off. The truth is, the only studies showing dehydration, and by extension some of the electrolyte abnormalities associated with dehydration, is the cause of cramps have all been called in to question due to small sample sizes, or that they relied on anecdotal clinical observations. In fact, several studies have shown athletes who cramped during events have the same levels of dehydration, and the same levels of electrolyte concentrations, as those who didn’t cramp.