Shin Splints

A shin splint is pain resulting from damage to the muscles along the shin.

See the figure Shin Splints.

The usual cause is long-standing, repeated stress to the lower leg. Two groups of muscles in the shin are susceptible to shin splints. The location of the pain depends on which group is affected.

Anterolateral shin splints affect the muscles in the front (anterior) and outside (lateral) parts of the shin. This type of injury results from a natural imbalance in the size of opposing muscles. The shin muscles pull the foot up, and the larger and much stronger calf muscles pull the foot down each time the heel touches the ground during walking or running. The calf muscles exert so much force that they can injure the shin muscles.

The main symptom of anterolateral shin splints is pain along the front and outside of the shin. At first, the pain is felt only immediately after the heel strikes the ground during running, walking, skiing, or other similar exercises. If the person continues to run, the pain occurs throughout each step, eventually becoming constant. Usually by the time the person sees a doctor, the shin hurts when touched.

To allow this type of shin splint to heal, the runner must stop running temporarily and do other kinds of exercise. Exercises to stretch the calf muscles are helpful. Once the shin muscles start to heal, exercises to strengthen them, such as the bucket-handle exercise, can be done in 3 sets of 10 every other day.

Posteromedial shin splints affect the muscles in the back (posterior) and inner (medial) parts of the shin, which are responsible for lifting the heel just before the toes push off. This type of shin splint often results from running on banked tracks or crowned roads and can be worsened by rolling onto the outside of the feet (pronation) excessively or by wearing running shoes that do not adequately prevent such rolling.

The pain produced by this type of shin splint usually starts along the inside of the lower leg, about 1 to 8 inches above the ankle, and worsens when a runner rises up on the toes or rolls the ankle in. If the person continues to run, the pain moves forward, affecting the inner aspect of the ankle, and may extend up the shin to within 2 to 4 inches of the knee. The severity of the pain increases as the shin splint progresses. At first, only the muscle tendons are inflamed and painful, but if the person keeps running, the muscles themselves can be affected. Eventually, tension on the inflamed tendon can actually pull it from its attachment to bone, causing bleeding and further inflammation.

The primary treatment is to stop running and do other types of exercise until running is no longer painful. Running shoes with a rigid heel counter (the back part of the shoe) and special arch supports can keep the foot from rolling onto the outside excessively. Avoiding running on banked surfaces can help prevent shin splints from recurring. Exercises to strengthen the injured muscles are useful.

An experimental treatment consists of calcitonin (a hormone that builds bone) injected daily or alendronate (a drug that slows bone loss) given by mouth; this treatment has healed some shin splints that were unresponsive to other measures. Sometimes none of the available treatments are effective, and the runner must abandon running permanently.

See the sidebar Strengthening the Shin Muscles.