Athletes often complain about "shin splints" at the beginning of a sports season. They're describing a pain in the front of the lower leg between the knee and ankle. In their hurry to get in shape, athletes can overtrain without properly conditioning their muscles. The result can be injury to the tendons, muscles or bones in the lower leg.

Tendinitis

Tendons are tough, dense, cordlike bands of tissue that connect muscle to bone and transmit the force a muscle exerts. If they become inflamed, the condition is called tendinitis. Athletes who have been inactive for a period of time and runners who overtrain are prime candidates for tendinitis in the shin area.

One of the several muscles that pass up and through the lower leg is located directly behind the shinbone. When the tendons of this muscle become inflamed, the pain is felt along the shin.

Possible causes of tendinitis

Usually, stresses and strains in the leg cause tendinitis. But tendinitis in the shin area can also be caused by:

• Problems with the way the runner's foot strikes the ground.
• Poor conditioning.
• A strength imbalance between two muscle groups that normally work together.

Treating tendinitis

• When tendinitis strikes, take a rest or break from the activity that caused it. This is often enough to clear up the condition.
• Do some other type of activity. If the tendinitis results from a muscle imbalance, you'll need to exercise and strengthen the weaker muscle to correct the imbalance.
• To prevent the pain from recurring, apply heat before and ice after the activity.
• Use aspirin or ibuprofen to relieve symptoms.

Stress fractures

Patients with pain from stress fractures in either of the two bones in the lower leg may describe their ailment as shin splints, too. Stress fractures are another injury that results from overuse.

Repeated stresses on the bones can result in tiny, almost invisible breaks in the bone structure called microfractures. Normally, the body has time to heal the microfractures before they start to cause problems. However, overtraining and poor conditioning can aggravate the microfractures so they are unable to heal. The microfractures become larger (but still very fine) stress fractures.

Sometimes, the stress fractures are so fine that they don't show up on normal X-rays. But if the injury site is not rested, the stress fractures can continue to increase in size until a cast or other immobilization is needed.

Diagnosing stress fractures

In addition to the shin pain caused by a stress fracture, you may experience swelling and extreme tenderness over the site of the stress fracture. A bone scan is sometimes necessary to distinguish stress fractures from other conditions.

If a stress fracture is diagnosed early, resting is the only treatment required. The return to activity must be slow and careful to avoid aggravating the fracture.