The large tendon located on the back of your ankle is the Achilles tendon. When that tendon is irritated or becomes inflamed, it could be Achilles tendonitis (also referred to as tendinitis), which is a common injury amongst athletic individuals. The most obvious evidence of this injury is pain in the Achilles tendon followed by swelling.
Achilles tendonitis can be caused by insufficient flexibility or overpronation. Pronation refers to the natural motion of the foot, and when people go against their natural range of motion, an injury can occur. You can also develop Achilles tendonitis by suddenly increasing your physical training program or even changing your running shoes.
Achilles tendonitis can be extremely painful. If you think you are suffering from this ankle condition, consult a specialty-trained ankle doctor who will evaluate your ankle and advise you of possible treatment options.