The Achilles tendon is in the back of the ankle, connecting the calf muscles to the heel bone. This tendon is needed for walking, running and jumping. It withstands a great deal of stress during normal daily life. Achilles tendonitis occurs when the muscles and tendon are overused, causing irritation to and swelling of the tendon.
There are 2 types of Achilles tendonitis:
- Insertional Achilles tendonitis affects the lower part of the tendon where it attaches to the heel. This can occur at any age.
- Non-insertional Achilles tendonitis affects the middle part of the tendon and causes swelling and thickening in this area. This is most common among young and active people.
Hardening (calcification) of the damaged tendon fibres can occur in both types of Achilles tendonitis.