Muscle spasms or cramps are unpleasant, often painful sensations caused by contraction or over-shortening of muscles. Cramps can be caused by cold, over-exertion, or low calcium levels in the blood (especially for adolescents, who need calcium for both blood and bone maturation). The most common reasons are low sodium and potassium levels in the blood, accompanied by excessive dehydration.

Muscle cramps may also be a symptom or complication of pregnancy, kidney disease, thyroid disease, hypokalemia, hypocalcemia (as conditions), restless-leg syndrome, varicose veins, and multiple sclerosis. Further indicated are electrolyte disturbance, particularly hypokalaemia (a low level of potassium) and hypocalcaemia (a low level of calcium). This disturbance arises as the body loses large amounts of interstitial fluid through sweat.

Muscle spasms (eg in the calves when sleeping or the feet), may result from nerve irritation in the lower back. Muscle knots in the back may be due to misalignment in the spine causing a defensive action in the muscles. Muscles may also tighten up and spasm due to repetitive strain (eg neck and shoulders) and or prolonged bad posture or awkward position.

The Myosteopractic approach is to seek the source and cause of irritation in the body, and through release and muscle reactivation, to lessen the incidence of occurrence.