Muscle cramps are when a muscle gets tight (contracts) without you trying to do so. The muscle gets tight and does not relax. Cramps may involve all or part of one or more muscles.

The most commonly involved muscle groups are:

Back of the lower leg/calf

Back of the thigh (hamstrings)

Front of the thigh (quadriceps)

Cramps in the feet, hands, arms, abdomen, and along the rib cage are also very common.

Muscle cramps are common and may be stopped by stretching the muscle. The cramping muscle may feel hard or bulging.Considerations

Muscle spasms are different than muscle twitches, which are covered in a separate article.

Causes

Muscle cramps are common and often occur when a muscle is overused or injured. Working out when you haven’t had enough fluids (dehydration) or when you have low levels of minerals such as potassium or calcium can also make you more likely to have a muscle spasm.

Muscle cramps can occur while you play tennis or golf, bowl, swim, or do any other exercise.

They can also be triggered by:

Alcoholism

Hypothyroidism (underactive thyroid)

Kidney failure

Medications

Menstruation

Pregnancy