A muscle spasm is an involuntary contraction of a muscle, and is frequently painful. There are many different types of muscle spasms. Some can be addressed through medical means, improvement of diet or physical therapy. Other causes of a muscle spasm may be harder to find and treat.

Some causes of muscle spasm include straining of a muscle, dehydration, trauma, diseases like cerebral palsy or multiple sclerosis (MS), as well as a reaction to certain poisons like strychnine, and damage to nerves or to the spinal cord.

The contraction that occurs during a muscle spasm is involuntary; the brain sends signals to the muscle to contract, which are not willed by the body. When we exercise, we use voluntary contractions of muscles to perform work. In a muscle spasm, the brain sends a mixed signal to the muscle to contract that is not willed by the person.

A contraction can last for a few seconds, to several minutes or hours. The familiar charley horse, for example, may contract a muscle in the legs. The muscle does not simply relax by a person wishing it would. Deep breathing and relaxation exercises may help the muscle gradually relax. Often people actually contract other muscles in response to the pain of a charley horse, which can make the duration of the muscle spasm longer.

If one frequently gets cramping of this sort, this may be the result of poor nutrition, or too much exercise. Frequently at the end of a marathon, runners may be seized with a painful muscle spasms because their body is depleted of essential electrolytes. Excessive nausea and vomiting can also cause a muscle spasm.

The first consideration in treating frequent muscle spasms of the legs and feet is to address hydration concerns. People who do not maintain proper hydration are more likely to experience cramping. As well, some studies show that magnesium and calcium depletion may result in a muscle spasm. If cramps occur frequently, one might consider supplementing one’s diet with more calcium and magnesium loaded foods, or with mineral supplements.

Should this not end painful muscle spasms, one should see a doctor to evaluate other possible causes. Exposure to certain chemicals, like pesticides may cause poisoning, which can result in spasm. As well, severe muscle spasm may be linked to conditions like MS.

Another type of muscle spasm that may occur is cramping of the stomach. This may be associated with either a stomach flu illness, or with conditions like irritable bowel syndrome (IBS). This cramping is also quite painful, but gradual control of IBS can reduce frequent muscle spasm. Infants with colic often experience muscle spasm in the abdomen as well, hence the excessive crying. This is often a brain's immature response to digestion, which is why many children with colic improve as they age.

Angina is another type of muscle spasm, caused when the heart does not get enough blood. It is associated with atherosclerosis or hardening of the arteries. The muscle spasm angina causes is usually painful cramping that may be felt in the chest, and sometimes the neck, shoulders and jaw. Treatment usually involves treating the underlying conditions causing heart disease, and also treating episodes of angina with medication.

Injured muscles may also improperly receive “work” signals from the brain, causing muscle spasm. Often as a muscle heals, such spasms become infrequent. Sometimes an injury can cause almost constant spasmodic action of the muscles, which may require muscle relaxants, as well as time, in order to heal such action.