A charley horse is the common name for a muscle spasm. Muscle spasms can occur in any muscle in the body, but often happen in the leg. When a muscle is in spasm, it contracts without your control and does not relax.
Causes, incidence, and risk factors
Muscle spasms often occur when a muscle is overused or injured. Things that might bring on a muscle spasm include:
Exercising when you have not had enough fluids (you're dehydrated).
Having low levels of minerals such as potassium or calcium.
Some spasms occur because the nerve that connects to a muscle is irritated. One example is a herniated disk irritates the spinal nerves and causes pain and spasm in the back muscles.
Spasms in the calf often occur while kicking during swimming. They can also happen at night when you are 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.
When a muscle goes into spasm it feels very tight. It is sometimes described as a knot. The pain can be severe.
Signs and tests
To diagnose a spasm, your health care provider will look for tight or hard muscles that are very tender to the touch. There are no imaging studies or blood tests for 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 problem.
Stop your activity and try stretching and massaging the affected muscle at the first sign of a spasm.
Heat will relax the muscle at first. Ice may be helpful after the first spasm and when the pain has improved.
If the muscle is still sore after heat and ice, you can use nonsteroidal anti-inflammatory medicines to 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.
Drinking water or sports drinks when exercising can help ease cramps due to dehydration. If drinking water alone is not enough, salt tablets or sports drinks may help replace minerals in your body.
Muscle spasms will get better with rest and time. The outlook is excellent for most people. Learning how to exercise properly can prevent spasms from occurring regularly.
You might need other treatments if an irritated nerve caused the spasm. Results from these treatments can vary.
Calling your health care provider
Call your health care provider if:
You have a muscle spasm with severe pain.
You have weakness with your muscle spasm.
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.
Stretch to improve your 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.
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; 2010: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; 2010:chap 46.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.