Achilles tendinitis occurs when the tendon that connects the back of your leg to your heel becomes swollen and painful near the bottom of the foot. This tendon is called the Achilles tendon. It allows you to push your foot down. You use your Achilles tendon when walking, running, and jumping.
There are two large muscles in the calf. These create the power needed to push off with the foot or go up on the toes. The large Achilles tendon connects these muscles to the heel.
Heel pain is most often due to overuse of the foot. Rarely, it is caused by an injury.
Tendinitis due to overuse is most common in younger people. It can occur in walkers, runners, or other athletes.
Achilles tendinitis may be more likely to occur if:
Tendinitis from arthritis is more common in middle-aged and older adults. A bone spur or growth may form in the back of the heel bone. This may irritate the Achilles tendon and cause pain and swelling. Flat feet will put more tension on the tendon.