Causes

Muscle spasms often occur when a muscle is overused or injured. Working out when you haven't had enough fluids (you're dehydrated) or when you have low levels of minerals such as potassium or calcium can also make you more likely to have muscle spasms.

Some spasms occur because the nerve that connects to a muscle is irritated. The classic example is a herniated disk irritating spinal nerves as they exit the back, causing pain and spasm.

Spasms in the calf often occur while kicking during swimming, and can also occur at night while you're in bed. Upper leg spasms are more common with running or jumping activities. Spasm in the neck (cervical spine) can be a sign of stress.

Symptoms

When a muscle goes into spasm it feels very tight and is sometimes described as a knot. The pain can be severe.

Exams and Tests

Your health care provider can diagnose muscle spasms by the presence of tight or hard muscles that are very tender to the touch. There are no imaging studies or blood tests that can diagnose this condition. If the spasm is caused by nerve irritation, such as in the back, an MRI may be helpful to find the cause of the irritation.

Treatment

At the first sign of a muscle spasm, stop your activity and try stretching and massaging the affected muscle. Heat will relax the muscle at first, although ice may be helpful after the first spasm and when the pain has improved. If the muscle is still sore, nonsteroidal anti-inflammatory medications can help with pain. In more severe cases, your health care provider can prescribe antispasm medications.

After you get treated, your health care provider should look for the cause of the spasm so that it doesn't recur. If an irritated nerve is involved, you might need physical therapy or even surgery.

The most common cause of muscle cramps during sports activity is dehydration. Often, drinking water or sports drinks will ease the cramping. However, drinking water alone at times is not sufficient. Salt tablets or sports drinks that can replenish loss minerals can be helpful.

Outlook (Prognosis)

Muscle spasms will get better with rest and time. The outlook is excellent for most people. Proper training techniques should prevent spasms from occurring regularly. If an irritated nerve caused the spasm, you might need more treatment and results can vary.

When to Contact a Medical Professional

If you have a muscle spasm with severe pain, contact your health care provider. . If you have weakness with your muscle spasm, contact your health care provider.

Even if your spasms are not severe, your health care provider can help you change your exercise program to reduce the risk of spasms in the future.

Prevention

• Stretch to improve flexibility.
• Change your workouts so that you are exercising within your ability.
• Drink plenty of fluids while exercising and increase your potassium intake (orange juice and bananas are great sources of potassium).

References

Brinker MR, O’Connor DP, Almekinders LC, et al. Physiology of Injury to Musculoskeletal Structures: 1. Muscle and Tendon Injury. In: DeLee JC, Drez D Jr, Miller MD, eds. DeLee and Drez’s Orthopaedic Sports Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 1, section A.

Geiderman JM, Katz D. General principles of orthopedic injuries. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 46.

Ronthal M. Arm and neck pain. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann; 2008:chap 32.

Update Date: 5/1/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; and C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Dept of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.