What Causes Tendonitis?

achilles ankle tendon
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Tendonitis is caused by one of two problems:

  • Overuse

    Overuse injuries to tendons essentially demand too much from a tendon without allowing the tendon time to repair itself. Tendons, like most other tissues in the body, are nourished by blood flow. Certain areas of tendons have a poor blood supply, and, not surprisingly, these areas of the tendon are most prone to injury. That's why the Achilles tendon and the rotator cuff tendons are prone to injury. These tendons have an area of poor blood supply.

    When tendons are used excessively, the body needs to be able to repair these tendons. Because of the poor blood supply in some tendons, this may take too much time. When the tendons are used excessively, the amount of damage make overtake the body's ability to repair itself. That's when overuse tendonitis develops.

  • Trauma

    Tendons can also become inflamed after a traumatic injury. In this situation, a single event may cause an inflammatory reaction within a tendon. If the inflammation is significant, the tendon may remain inflamed, and the acute injury can turn into a chronic tendonitis.

    As with overuse tendonitis, if a traumatic injury is not allowed time to repair the damage and inflammation, a chronic condition can result. That is why rest is an important part of the treatment of tendonitis.

Once the problem has been properly diagnosed as tendonitis, treatment of the condition can begin. However, it is important to have this evaluated by your doctor to ensure you have the correct diagnosis before initiating a treatment plan.


Almekinders, LC. "Tendinitis and other chronic tendinopathies" J. Am. Acad. Ortho. Surg., May 1998; 6: 157 - 164.

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