Muscle spasms and cramps


Muscle spasms and cramps are spontaneous, often painful muscle contractions.


The rapid, uncontrolled muscle contraction, or spasm, happens unexpectedly, with either no stimulation or some trivially small one. The muscle contraction and pain last for several minutes and then slowly ease. Cramps may affect any muscle but are most common in the calves, feet, and hands. While painful, they are harmless and, in most cases, not related to any underlying disorder. Nonetheless, cramps and spasms can be manifestations of many neurological or muscular diseases.

The terms cramp and spasm can be somewhat vague, and they are sometimes used to include types of abnormal muscle activity other than sudden painful contraction. These include stiffness at rest, slow muscle relaxation, and spontaneous contractions of a muscle at rest (fasciculation). Fasciculation is a type of painless muscle spasm, marked by rapid, uncoordinated contraction of many small muscle fibers. A critical part of diagnosis is distinguishing these different meanings and allowing the patient to describe the problem as precisely as possible.


The exact incidence of muscle cramps and spasms is not known. They are more likely to occur in older children and teenagers who are participating in organized, competitive sports and strenuous aerobic activities.

Causes and symptoms


Normal voluntary muscle contraction begins when electrical signals are sent from the brain through the spinal cord along nerve cells called motor neurons. These include both the upper motor neurons within the brain and the lower motor neurons within the spinal cord and leading out to the muscle. At the muscle, chemicals released by the motor neuron stimulate the internal release of calcium ions from stores within the muscle cell. These calcium ions then interact with muscle proteins within the cell, causing the proteins (actin and myosin) to slide past one another. This motion pulls their fixed ends closer, thereby shortening the cell and, ultimately, the muscle itself. Recapture of calcium and unlinking of actin and myosin allow the muscle fiber to relax.

Abnormal contraction may be caused by unusual activity at any stage in this process. Certain mechanisms within the brain and the rest of the central nervous system help regulate contraction. Interruption of these mechanisms can cause spasm. Motor neurons that are overly sensitive may fire below their normal thresholds. The muscle membrane itself may be overly sensitive, causing contraction without stimulation. Calcium ions may not be recaptured quickly enough, causing prolonged contraction.

Structural disorders such as flat feet, hyperextended knees (genu recurvatum), and hypermobility syndrome (joints that can move beyond the normal range of motion) may predispose a person to developing leg cramps. Prolonged sitting, inappropriate leg positioning during sedentary activity, or standing on concrete flooring for prolonged periods may be associated with an increased incidence of leg cramps.

Interruption of brain mechanisms and overly sensitive motor neurons may result from damage to the nerve pathways. Possible causes include stroke , multiple sclerosis, cerebral palsy , neurodegenerative diseases, trauma, spinal cord injury , and nervous system poisons such as strychnine, tetanus , and certain insecticides. Nerve damage may lead to a prolonged or permanent muscle shortening called contracture.

Changes in muscle responsiveness may be due to or associated with the following:

  • Prolonged exercise : Curiously, relaxation of a muscle actually requires energy to be expended. The energy is used to recapture calcium and to unlink actin and myosin. Normally, sensations of pain and fatigue signal that it is time to rest. Ignoring or overriding those warning signals can lead to such severe energy depletion that the muscle cannot be relaxed, causing a cramp. The familiar advice about not swimming after a heavy meal, when blood flow is directed away from the muscles, is intended to avoid this type of cramp.
  • Exercising or participating in activities in high or humid temperatures: Copious sweating during prolonged exercise can lead to heat cramps, a condition associated with brief, painful cramps, especially in the legs, sweating, and mild fever , usually less than 102°F. Heat cramps are more likely to occur when the child has not taken in enough fluids before, during, and after the activity. Exercising in high temperatures without adequate fluid intake may increase the risk of dehydration .
  • Dehydration and salt depletion: This condition may be brought on by repeated bouts of vomiting or diarrhea or by copious sweating during prolonged exercise. Loss of fluids, salts, and minerals—especially sodium, potassium, magnesium, and calcium—can disrupt ion balances in both muscle and nerves. This imbalance can prevent the muscles and nerves from responding and recovering normally and can lead to cramping.
  • Metabolic disorders that affect the energy supply in muscle: These are inherited diseases in which particular muscle enzymes are deficient. They include deficiencies of myophosphorylase (McArdle's disease), phosphorylase b kinase, phosphofructokinase, phosphoglycerate kinase, and lactate dehydrogenase.
  • Myotonia: Myotonias include myotonic dystrophy , myotonia congenita, paramyotonia congenita, and neuromyotonia. These conditions cause stiffness due to delayed relaxation of the muscle but do not cause the spontaneous contraction usually associated with cramps. However, many patients with myotonia do experience cramping from exercise. Symptoms of myotonia are often worse in cold temperatures.

Fasciculation may be due to fatigue, cold, medications, metabolic disorders, nerve damage, or neurodegenerative disease, including amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease). Most people experience brief, mild fasciculation from time to time, usually in the calves.


The pain of a muscle cramp is intense, localized, and often debilitating. Coming on quickly, it may last for minutes and fade gradually. Contractures develop more slowly, over days or weeks, and may be permanent if untreated. Fasciculation may occur at rest or after muscle contraction and may last several minutes.

Exercising in high temperatures can lead to dehydration. Dehydration should be suspected if these symptoms are present: dry mouth or tongue, increased or excessive thirst, few or no tears when crying, decreased urination, dark yellow urine, irritability, low energy, lightheadedness or fainting, severe weakness, and sunken abdomen, eyes and cheeks.

When to call the doctor

Prompt medical attention is required if the child has any of the symptoms associated with dehydration, as listed above. Prompt medical attention also is required if the child has a high fever— of 102°F or 38.9°C, or above. Parents also should call the child's pediatrician if the following symptoms are present:

  • acute pain associated with the muscle cramp or spasm
  • prolonged muscle contractions
  • cramps or spasms that cause twisting and repetitive movement or abnormal posture
  • apparent development of muscle contractures (prolonged joint flexion in an abnormal position)


A usual bout of muscle cramps should not require a visit to the doctor. However, medical treatment is essential if the child has any symptoms of dehydration associated with the muscle cramps. In addition, any abnormal contractions or frequent muscle cramps or spasms that cause concern should be evaluated by a physician. Abnormal muscle contractions are diagnosed through a careful medical history, as well as a physical and neurological examination. In some cases when a structural abnormality is suspected, x rays may be performed.

The medical history helps the physician evaluate the presence of other conditions or disorders that might contribute to or cause the abnormal contractions. Records of previous diagnoses, surgeries, and treatments are reviewed. The child's family medical history is evaluated to determine if there is a history of muscular or neurological disorders.

Questions about the child's medical history may include:

  • When were the symptoms first noticed?
  • How long have the symptoms lasted?
  • Are the symptoms always present?
  • What muscles are affected?
  • What makes the symptoms improve?
  • What specific treatments or techniques have been tried?
  • What makes the symptoms worse?
  • Do certain activities, emotions, or events seem to aggravate the symptoms?
  • Are other symptoms present?

The physical and neurological exams may include an evaluation of the child's motor reflexes including muscle tone, mobility, strength, balance, and endurance; heart and lung function; cranial nerve function; and an examination of the child's abdomen, spine, throat, and ears. The child's height and weight and blood pressure also are checked and recorded.

When a neurological cause is suspected, a multi-disciplinary team may be consulted to provide an accurate diagnosis, so the proper treatment can be planned. Occupational and physical therapy evaluations may be helpful to determine upper and lower extremity movement patterns and passive range of motion.

In some cases, nerve conduction studies with electromyography of the affected muscles may be performed to evaluate an underlying neuromuscular disorder. These tests are useful in evaluating a child's muscular activity and provide a comprehensive assessment of nerve and muscle function.

In both tests, the examiner uses a computer, monitor, amplifier, loudspeaker, stimulator, and high-tech filters to see and hear how the muscles and nerves are responding during the test. In the nerve conduction study, small electrodes are placed on the skin over the muscles to be examined. A stimulator delivers a very small electrical current (that does not cause damage to the body) through the electrodes, causing the nerves to fire. In the electromyogram, a very thin, sterilized needle is inserted into various muscles, usually those affected most by spasticity symptoms. The needle is attached by wires to a recording machine. The patient is asked to relax and contract the muscles being examined. The electrical signals produced by the nerves and muscles during these tests are measured and recorded by a computer and displayed as electrical waves on the monitor. The test results are interpreted by a specially trained physician.


Most cases of simple cramps require no treatment other than patience and stretching. When heat cramps occur, the child should stop the activity, move to a cool or shady place, remove excess clothing, drink cool water or a sports drink with electrolytes, such as Gatorade, and rest. If the child appears nauseous or is feeling dizzy, he should lie down, with feet slightly elevated. Directing a fan on the child will help cool the child. Gently and gradually stretching and massaging the affected muscle may ease the pain and hasten recovery.

Briefly applying cold packs to cramped muscles, for about ten minutes, may help ease pain.

Acetaminophen (such as Tylenol) or ibuprofen (such as Advil or Motrin) should be used sparingly for relief of discomfort. Ask the child's doctor for specific guidelines. More prolonged or regular cramps may be treated with prescribed medications.

If the child has any signs of dehydration, generous amounts of fluids and an oral rehydrating solution containing glucose and electrolytes should be given. Oral rehydrating solutions, including brands such as Pedialyte, Infalyte, Ceralyte, and Oralyte, are available at most grocery stores and drug stores. They are essential for replacing fluids, minerals , and salts. Dehydration can upset the body's electrolyte balance, leading to potentially life-threatening problems such as heart beat abnormalities (arrhythmia). Prolonged, severe dehydration requires medical treatment with intravenous (IV) fluids and may require hospitalization .

Treatment of underlying metabolic or neurologic diseases, when possible, may help relieve symptoms.


Active motion —Spontaneous; produced by active efforts. Active range of motion exercises are those that are performed by the patient without assistance.

Acupuncture —Based on the same traditional Chinese medical foundation as acupressure, acupuncture uses sterile needles inserted at specific points to treat certain conditions or relieve pain.

Anoxia —Lack of oxygen.

Ataxia —A condition marked by impaired muscular coordination, most frequently resulting from disorders in the brain or spinal cord.

Biofeedback —A training technique that enables an individual to gain some element of control over involuntary or automatic body functions.

Central nervous system —Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.

Cerebral palsy —A nonprogressive movement disability caused by abnormal development of or damage to motor control centers of the brain.

Clonic —Referring to clonus, a series of muscle contractions and partial relaxations that alternate in some nervous diseases in the form of convulsive spasms.

Contraction —A tightening of the uterus during pregnancy. Contractions may or may not be painful and may or may not indicate labor.

Contracture —A tightening or shortening of muscles that prevents normal movement of the associated limb or other body part.

Dystonia —Painful involuntary muscle cramps or spasms.

Fasciculations —Small involuntary muscle contractions visible under the skin.

Genu recurvatum —Hyperextension of the knee.

Hyperactive reflexes —Reflexes that persist too long and may be too strong. For example, a hyperactive grasp reflex may cause the hand to stay clenched in a tight fist.

Hypermobility —Unusual flexibility of the joints, allowing them to be bent or moved beyond their normal range of motion.

Hypertonia —Having excessive muscular tone or strength.

Idiopathic —Refers to a disease or condition of unknown origin.

Motor neuron —A nerve cell that specifically controls and stimulates voluntary muscles.

Multiple sclerosis —A progressive, autoimmune disease of the central nervous system characterized by damage to the myelin sheath that covers nerves. The disease, which causes progressive paralysis, is marked by periods of exacerbation and remission.

Muscle spasm —Localized muscle contraction that occurs when the brain signals the muscle to contract.

Myoclonus —Involuntary contractions of a muscle or an interrelated group of muscles. Also known as myoclonic seizures.

Neurologist —A doctor who specializes in disorders of the nervous system, including the brain, spinal cord, and nerves.

Neurosurgeon —Physician who performs surgery on the nervous system.

Nocturnal leg cramps —Cramps that may be related to exertion and awaken a person during sleep.

Occupational therapist —A healthcare provider who specializes in adapting the physical environment to meet a patient's needs. An occupational therapist also assists patients and caregivers with activities of daily living and provide instructions on wheelchair use or other adaptive equipment.

Orthopedist —A doctor specializing in treatment of the musculoskeletal system.

Passive movement —Movement that occurs under the power of an outside source such as a clinician. There is no voluntary muscular contraction by the individual who is being passively moved.

Periodic limb movement disorder —A disorder characterized by involuntary flexion of leg muscles, causing twitching and leg extension or kicking during sleep.

Peripheral nerves —Nerves outside the brain and spinal cord that provide the link between the body and the central nervous system.

Physiatrist —A physician who specializes in physical medicine and rehabilitation.

Physical therapist —A healthcare provider who teaches patients how to perform therapeutic exercises to maintain maximum mobility and range of motion.

Range of motion (ROM) —The range of motion of a joint from full extension to full flexion (bending) measured in degrees like a circle.

Restless legs syndrome (RLS) —A disorder in which the patient experiences crawling, aching, or other disagreeable sensations in the calves that can be relieved by movement. RLS is a frequent cause of difficulty falling asleep at night.

Rigidity —A constant resistance to passive motion.

Spinal cord injury —Injury to the spinal cord, via blunt or penetrating trauma.

Stroke —Interruption of blood flow to a part of the brain with consequent brain damage. A stroke may be caused by a blood clot or by hemorrhage due to a burst blood vessel. Also known as a cerebrovascular accident.

Alternative treatment

Alternative and complementary therapies include approaches that are considered to be outside the mainstream of traditional health care. In adults, alternative treatments for cramps include gingko ( Ginkgo biloba ) or Japanese quince ( Chaenomeles speciosa ). Supplements of vitamin E, niacin, calcium, and magnesium may also help to relieve the likelihood of night cramps, especially when taken at bedtime. Indications for these treatments in children have not been documented.

There are several alternative therapies that can be useful when treating movement disorders . Among the therapies that may be helpful are acupuncture, homeopathy, touch therapies, postural alignment therapies, and biofeedback. The progress made will depend on the individual and his/her condition.

Biofeedback training may be used to teach older children how to consciously reduce muscle tension. Biofeedback uses an electrical signal that indicates when a spastic muscle relaxes. The patient may be able to use biofeedback to learn how to consciously reduce muscle tension and possibly reduce symptoms.

Before learning or practicing any particular technique, it is important for the parent or caregiver and child to learn about the therapy, its safety and effectiveness, potential side effects, and the expertise and qualifications of the practitioner. Although some practices are beneficial, others may be harmful to certain patients. Alternative therapies should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these alternative treatments with the child's doctor to determine the techniques and remedies that may be beneficial for the child.


Occasional cramps are common and have no special medical significance.


The likelihood of developing cramps may be reduced with regular exercise to build up energy reserves in the muscles. Avoiding exercising in extreme heat helps prevent heat cramps. Heat cramps can also be avoided by drinking plenty of water before and during exercise in extreme heat. Practicing proper body mechanics while sitting (sitting with both feet on the floor, back straight and legs uncrossed) can help prevent the development of leg cramps. Taking a warm bath before bedtime may increase circulation to the legs and reduce the incidence of nighttime leg cramps.

Nutritional concerns

The likelihood of developing cramps may be reduced by eating a well-balanced, healthy diet with appropriate levels of minerals. A registered dietitian can work with parents to identify a child's specific calorie needs and develop an individualized meal plan.

Fluids should be encouraged during all strenuous activities, especially in warm weather. People should aim for two to four eight-ounce glasses of fluid per hour of activity.

If an underlying neurological disorder has been identified, dietary guidelines are individualized, based on the child's age, diagnosis, overall health, caloric and energy needs, and level of functioning. Early identification, treatment, and correction of specific feeding problems will improve the health and nutritional status of the patient.

Parental concerns

Occasional muscle cramps are common. The most important concern is preventing dehydration, especially when the child is exercising in high or humid temperatures. Make sure the child drinks enough fluids before, during, and after sports and other activities. Pack a water bottle and/or sports drink for the child to have at sports practices, games, and other physical activities. Make sure the coach provides time out for water breaks. After the activity, encourage the child to continue drinking water to replace lost fluids.

If a movement disorder has been diagnosed, parents should work closely with the child's therapists and doctors to create an effective treatment plan. It is important for parents to communicate their treatment goals with the health care team. Parents should take an active role in the child's exercise program.

Raising a child with a movement disorder can be challenging. There are several support groups available to provide information and assistance.



Bradley, Walter G., et al. Neurology in Clinical Practice ,4th ed. Woburn, MA: Butterworth-Heinemann, 2003.

Martini, Frederic H. Fundamentals of Anatomy and Physiology , 6th ed. Englewood Cliffs, NJ: Prentice Hall, 2002.


National Institute of Neurological Disorders and Stroke (NINDS). National Institutes of Health. PO Box 5801, Bethesda, MD 20824. Web site:

National Rehabilitation Information Center (NARIC). 4200 Forbes Blvd., Ste. 202, Lanham, MD 20700. Web site:

Richard Robinson Angela M. Costello

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User Contributions:

Bill Doyle
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Aug 22, 2006 @ 7:07 am
My 15 Daughter has had 4 orthopedic surgery operations in an attempt to solve her knee problems in that it her right knee continues to lock at 45 degrees on a common occurrence. The report from the orthopedic surgeon is that her knee is structually sound.
Yet the problem still occurs. This week however her jaw locked after coughing. Eventually after visiting her Doctor she was taking to hospital and put under an anaesthic to to put her jaw back in place. Apparently whilst under the pain killers her jaw just went back into place but upon waking up her knee was locked. Hence she had to be put under again to resolve that problem. Two days later she suffered acute pain in her knee whilst at school . She was taken back to hospital where they manipulated her knee again under medication and spent cosiderable time in hospital with her whole body shaking uncontrolable.
I am staring to wonder if the orthopedic sugeons are right in that it is not a structual problembut but something else in the muscle area that is causing this on going problem. Is it a lack of magesium or something simiular that may be causing these locking effects that are becoming more common.
Maddison is a fit girl whom has done alot of swimming and water polo as her sport. She unfortunately cannot play sports like netball etc as her knee tends to swell up. The mystery to us is that the surgeons are convince that there is nothing structually wrong with the knee yet it continues to lock. Now her jaw has locked twice in the ast 10 months.Could they be connected?
I would love to get some feed back on this I also must add that the orthopedic surgeon that has preformed the surgery on her is recognised as one of Australia's leading orthopedic surgeon

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