Causes of Achilles Tendinitis
Achilles tendonitis is generally a chronic injury that occurs primarily from overuse, like from people who suddenly begin or increase an exercise regimen like running long distances. A person with Achilles tendinitis may also report a history of speedwork or hill running.

Failing to warm up your calf muscles before exercising is another potential trigger for the development of Achilles tendinitis. By failing to stretch and improve the flexibility of your calf muscles, there is more tension placed on the Achilles tendon.

Exercising in sneakers that are worn-out or are not meant to be used for aerobic exercise can also cause Achilles tendinitis, as can these other factors:

Cold weather training
Foot misalignment
Poor running form
Leg length discrepancy

Having a medical condition like psoriasis, high blood pressure, and obesity (which puts pressure on the tendon) has also been linked to a higher risk for developing Achilles tendinitis.

Another cause of Achilles tendon pain is the development of a bony growth on the back of the ankle-either a bone spur from arthritis or a Haglund's deformity from wearing poor-fitting shoes. The bony growth may rub on the Achilles tendon and cause pain and inflammation.