Section 5. Bone, Joint, and Muscle Disorders

Chapter 75. Sports Injuries

Topics: Introduction | Stress Fractures of the Foot | Shin Splints | Popliteus Tendinitis | Achilles Tendinitis | Runner's Knee | Hamstring Injury | Lateral Epicondylitis | Medial Epicondylitis | Rotator Cuff Tendinitis

Achilles Tendinitis

Achilles tendinitis is inflammation of the Achilles tendon, the tough band extending from the calf muscles to the heel.

The calf muscles and the Achilles tendon lower the forefoot after the heel touches the ground and raise the heel as the toes push off just before stepping to the other foot.

Achilles tendinitis occurs when stresses placed on the tendon are greater than the tendon's strength. Running downhill places extra stress on the Achilles tendon because the forefoot has farther to go before touching the ground. Running uphill also stresses this tendon because the calf muscles must exert greater force to raise the heel as the toes push off. A soft heel counter (the back part of the shoe that surrounds the heel) allows excessive movement of the heel, stressing the Achilles tendon unevenly and increasing the likelihood that it will tear. Stiff-soled shoes that do not bend where the toes join the foot place great stress on the Achilles tendon just before the toes push off.

Various functional and structural abnormalities predispose the Achilles tendon to injury. These abnormalities include rolling the feet onto the outside (pronation) excessively, the habit of landing too far back on the heel (checking the sole of the running shoe can show where the heel is most worn), bowed legs, tight hamstring and calf muscles, high arches, tight Achilles tendons, and heel deformities. The Achilles tendon is enclosed in a protective sheath; between the tendon and its sheath is a thin layer of fat, which enables the tendon to move freely. When the tendon is injured, scars form between it and its sheath, causing the tendon to pull on the sheath with each movement.

Pain, the major symptom, is usually most severe when a person starts to move. It is often relieved by continuing to walk or run despite the pain and stiffness. Continuing to walk or run relieves the pain because it increases the temperature of the sheath, making it more pliable, so that the tendon can move more freely.

If the person ignores the pain and continues to run, rigid scar tissue replaces the elastic tendon, and the tendon will always hurt during exercise, with virtually no chance of a cure. Refraining from running and from pedaling a bicycle as long as the pain persists is an important part of treatment. Other measures depend on the probable cause or predisposing conditions and include wearing shoes with flexible soles and placing heel lifts in running shoes to reduce tension on the tendon and stabilize the heel. The blood flow to the Achilles tendon is reduced when the foot is bent upwards; a heel wedge reduces this effect. Exercises to stretch the hamstring muscles can be started as soon as they can be done without pain. Exercises to strengthen the Achilles tendon, such as toe raises, are helpful. After running is resumed, the person should not run uphill or downhill at a fast pace until the tendon is fully healed--which can be weeks to years later. Surgery may be required; a procedure called lithotripsy is sometimes used as an alternative to surgery.