PT Tip of the Month Archive

Achilles Tendonitis

What is Achilles tendonitis?

Problems with the Achilles tendon are often described in a variety of terms, including tendinitis/tendonitis, tendinopathy, tenopathy, tendinosis, achillodynia, etc. Achilles tendonitis is the term used to refer to a more acute condition, usually presenting with inflammatory cell indicators in the tendon itself, swelling, tendon pain/tenderness, and impaired performance. Some authors specify different stages of tendonitis. El Hawary et al suggests that symptoms present for less than 2 weeks is indicative of acute tendinitis, 2-6 weeks is subacute tendinitis, and over 6 weeks as being chronic tendinitis, however these are slightly arbitrary classifications and not based on tissue pathology or clinical guidelines. The term Achilles tendinosis, on the other hand, may refer to a more chronic condition, where there is scarring or degenerative changes in the tendon, as opposed to swelling and inflammation. Chronic tendonitis may result in tendinosis or an eventual rupture of the Achilles tendon.

Epidemiological data suggests that the occurrence of Achilles tendonitis is highest among individuals involved in middle and long-distance running, orienteering, track and field, tennis, badminton, volleyball, and soccer, with the majority of patients being men.

Besides inflammation, tenderness, and swelling, other signs and symptoms may include crepitus with ankle plantar flexion and dorsiflexion movements and pain with contraction and stretching of the gastroc/soleus complex. The most notable result of Achilles tendonitis is limitation in sports and sports-related activities due to pain. Generally, activities of daily living are unaffected. Symptoms are reported anywhere from the insertion point of the tendon, to the area where the muscle and tendon connect, usually 2-6 centimeters above the insertion.


The Achilles tendon is found in the back of the lower leg at the calf and joins the two bellies of the gastrocnemius muscle, as well as the soleus muscle, (which together, make up the triceps surae muscle), and inserts into the calcaneus bone, or the heel bone. The tendon consists of different proteins called type I collagen and elastin, which are then surrounded by other elastic extracellular matrix proteins, and give the tendon additional elastic properties. Because of the tendon attachments, the prime motion the Achilles tendon is involved in is to plantarflex the ankle, which is the “gas pedal” motion of the ankle.


There have been many hypotheses as to the etiology of Achilles problems. Sports and overuse injuries are the main causes of acute trauma to the Achilles tendon, however, biomechanical and alignment variations also play a role in the on set of Achilles tendonitis. For example, a person with tight hip flexor muscles, which brings the person’s center of mass forward and creates load in the Achilles tendon, may lead to Achilles tendonitis. A second potential cause may be due to weakness in the gluteus maximus muscle, which may result in overusing the gastroc/soleus complex to advance the person forward during activity. A third explanation includes those who hyperpronate (or roll inward onto the arches of their feet), which places more stress on the gastroc/soleus complex to keep the foot inverted when bearing weight through the foot, and thus may predispose someone to Achilles tendonitis. These are just some of many potential causes for Achilles tendonitis, but a thorough exam will be necessary to find and correct the root of the problem.


The goal of conservative treatment via physical therapy is to restore the level of activity of the patient to pre-injury status through stretching and strengthening exercises, joint or soft tissue mobilization, modifying activities that bring on pain, possibly altering or adapting footwear, and the use of modalities over the affected region. If you feel that you are experiencing signs or symptoms of Achilles tendonitis, and you would like to schedule an evaluation, call 617-232-PAIN for our Brookline office, and 617-325-PAIN for our West Roxbury office.


  1. El Hawary R, Stanish WD, Curwin SL. Rehabilitation of tendon injuries in sport. Sports Med. 1997;24:347-58.
  2. Paavola M, Kannus P, Jarvinen T, Khan K, Jozsa L, Jarvinen M. Achilles Tendinopathy. JBone Joint Surg Am. 2002;84-A(11):2062-76.
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