Achilles tendonitis is an injury that occurs when your Achilles tendon, the large band of tissues connecting the muscles in the back of your lower leg to your heel bone, becomes inflamed or irritated.

Symptoms

The signs and symptoms of Achilles tendonitis often develop gradually. You'll feel pain and stiffness in your Achilles (back of your ankle), especially when you first get out of bed or after sitting down for a long period of time. The inflammation is commonly at the most narrow point of your tendon, just above your heel.

The pain sometimes lessens as you do a warm-up run, and may even disappear as you continue running. But once you stop, the pain returns and may feel even worse. You may also notice a crackling or creaking sound when you touch or move your Achilles tendon. There may also be mild swelling or a small bump on your tendon. Depending on how long you've been experiencing these symptoms, you may not have swelling.

You may also notice thickening of your Achilles tendon, which is known as Achilles tendinopathy.

Causes

When you place a large amount of stress on your Achilles tendon too quickly, it can become inflamed from tiny tears that occur during the activity. Achilles tendonitis is often a result of overtraining or doing too much too soon. Excessive hill running can contribute to it. Flattening of the arch of your foot can place you at increased risk of developing Achilles tendonitis because of the extra stress placed on your Achilles tendon when walking or running.

You're more at risk for Achilles tendonitis if you're inflexible (especially in your calf muscles) or if you overpronate (feet roll inward when your run). It may also be caused by a sudden or hard contraction of your calf muscle, such as when you're sprinting.

Higher BMI is another risk factor. Changes in shoewear (such as switching to a minimalist shoe), or changing running style (transitioning to a forefoot strike pattern running on the balls of your feet) can also contribute to Achilles tendonitis risk.

Prevention

Be especially careful and don't overdo it when you introduce speed training or hill training into your regimen. Don't do a hard workout two days in a row. Strengthen your calf muscles with exercises such as toe raises. Especially if you wear a minimalist shoe, work on strengthening your intrinsic foot muscles as well. Work low-impact cross-training activities, such as cycling and swimming, into your training.

If you're just getting started with your training, be sure to stretch (especially your calves) after running, and start slowly, increasing your overall weekly mileage by no more than 10 percent per week.

Treatment

Use the R.I.C.E method of treatment when you first notice the pain. Although rest is a key part of treating tendonitis, prolonged inactivity can cause stiffness in your joints. You should definitely take a few days off from running, but make sure you move the injured ankle through its full range of motion and perform gentle calf and ankle stretches to maintain flexibility.

If self-care doesn't work, it's important to get the injury treated because if the tendon continues to sustain small tears through movement, it can rupture under excessive stress. Your doctor may suggest a temporary foot insert that elevates your heel and may relieve strain on the tendon. Other possible treatments include special heel pads or cups to wear in your shoes to cushion and support your heel, or a splint to wear at night. Physical therapy may also help allow the tendon to heal and repair itself over a period of weeks.