What Causes Leg Cramps in Children?

Whether called a cramp, charley horse or a growing pain, a sudden uncontrolled muscle contraction by any name translates into a painful surprise. The Nemours Foundation website Kids Health notes that 25 to 40 percent of normally developing children experience the discomfort associated with cramping, particularly during periods of rapid growth 1. Though the causes of all leg cramps are not completely understood, understanding the contributing factors can aid in prevention. A physician should be consulted regarding recurring cramps that interfere with sleep or function.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


High-intensity activities such as running and jumping, or activities that are either new to the child or that are not performed often, have the potential to trigger cramping. Muscle fibers create lactic acid as a waste product following activity, and microscopic tears can occur when muscle fibers are stressed. These factors contribute to an inflammatory response. Proper stretching prior to performing activities along with proper cool-down can decrease these effects.


Approximately 60 percent of the human body is composed of water, according to the U.S. Geological Survey. Water in the blood and organs helps transport the minerals that facilitate body functions and assists in the removal of waste products. Maintaining an adequate level of hydration is essential in controlling body temperature. Excessive perspiration can result in electrolyte imbalances and impaired regulation of body temperature, leading to abnormal muscle responses. Therefore, it is important to drink plenty of fluids, particularly during activity and in warm weather.

Electrolyte Imbalances

Calcium, magnesium, potassium and sodium are active in sending messages through the body and in assisting with cellular function. If these electrolytes are imbalanced or deficient because of a child's poor nutrition or other health issues, the signals are disrupted and leg cramps can develop. A balanced diet as well as adequate water intake help maintain electrolytes at their proper levels.

Rapid Growth

A Canadian study at the University of Calgary and Alberta Children’s Hospital found an increase in the incidence of leg muscle cramping at 12 years of age with maximum incidence between ages 16 and 18. These are times when bones grow and skeletal alignment is altered, requiring the muscles to grow, stretch and accommodate to bodily changes. This can result in abnormal responses as new forces act on the muscle fibers.

Foot and Leg Alignment

A child with flat feet or other structural disorder of the leg may experience cramping because of the imbalanced work load put upon the leg muscles. Gentle stretching, strengthening and use of orthotics can facilitate improved alignment and decrease stress on muscles and joints.

Other Factors

In rare instances, medical issues such as anemia, diabetes, hypoglycemia and thyroid or other endocrine disorders have cramping as a symptom. Some medications also contribute to leg cramps. This is generally due to the effect the disease or drug has on the body’s water and electrolyte balances.