Many factors can cause Achilles tendon pain. According to the website Foot Health Facts, the Achilles tendon is a thick band of tissue that runs down the back of the lower leg. The Achilles tendon links the calf muscles--the gastrocnemius and the soleus--with the heel bone or calcaneus, and it helps with walking and raising the heel off the ground. Pain in the Achilles tendon can be caused by traumatic injury, overuse injuries and certain medical conditions.
Ankylosing Spondylitis
Ankylosing spondylitis can cause pain in the Achilles tendon. According to the Spondylitis Association of America, ankylosing spondylitis is a type of arthritis that targets the spine, causing inflammation in the spinal joints that can result in chronic back pain, fusion of the vertebrae or spinal bones and reduced spine active range of motion. The SAA states that, although ankylosing spondylitis is characterized by spinal discomfort, the condition may cause pain and inflammation in other parts of the body too. In fact, many people with ankylosing spondylitis experience pain in the back of the heel where the Achilles tendon inserts into the heel bone. The location where a tendon or ligament inserts into bone is called an enthesis. Enthesitis or inflammation of the Achilles tendon is one of the hallmarks of ankylosing spondylitis.
Achilles Tendinitis
Achilles tendinitis can cause pain in the Achilles tendon. The Sports Injury Clinic website states that Achilles tendinitis--now sometimes called Achilles tendinopathy, due to the lack of inflammation in the Achilles tendon in most cases--is a common cause of running injuries. Approximately 11 percent of all running injuries are thought to be caused by acute or chronic Achilles tendinopathy.
A person with Achilles tendinopathy will often possess degenerated tissue in the affected area, which may be the cause of Achilles tendon discomfort. Possible causes of Achilles tendinopathy include reduced recovery time between bouts of exercise, an inappropriate increase in training volume and intensity and inappropriate footwear. Common signs and symptoms associated with chronic or long-term Achilles tendinopathy include pain in the Achilles tendon when walking or climbing stairs, swelling or thickening of the Achilles tendon and nodules or lumps in the Achilles tendon.
Bursitis
Bursitis can cause pain in or around the Achilles tendon. According to MedlinePlus, bursitis--retrocalcaneal bursitis, specifically--is swelling of the bursa or fluid-filled sack at the back of the heel bone or calcaneus. The retrocalcaneal bursa, which is located between the Achilles tendon and the heel bone, helps reduce friction between these two structures during movement. The most common cause of retrocalcaneal bursitis is excessive or repetitive ankle movement, which may occur when walking, running or jumping. MedlinePlus states that retrocalcaneal bursitis is often confused with Achilles tendinitis, but the conditions are separate and distinct. Common signs and symptoms associated with retrocalcaneal bursitis include heel pain with walking, running or squeezing of the heel, heel pain that's made worse by standing on the toes and skin over the heel that's red and warm to the touch.
