What is Achilles Tendonitis or Tendinitis?


The Achilles tendon is the largest tendon in the body and it connects the calf muscles to the heel bone. It is primarily used for walking and running, but can withstand more high-intensity activities such as jumping and sprinting. Although it can tolerate high stress, it is common to develop tendonitis and degeneration with overuse.

Achilles Tendonitis or Tendinitis?

“Itis” is the Latin word for disease or inflammation.  So, Tendonitis or Tendinitis are both correct spelling and they bot mean an inflammation of the tendon. The inflammatory response is triggered in the body when there is injury or a disease present. The inflammation can cause swelling, pain, and irritation at the site of injury.  There are two main types of Achilles tendonitis, both caused by overuse, Non-insertional Achilles Tendonitis and Insertional Achilles Tendonitis. 

Achilles Tendonitis JOIImage of Achilles Tendonitis 

Noninsertional tendonitis is an injury in the middle of the tendon not near the heel bone.  This happens when the fibers begin to break down (degeneration) and develop tiny tears.This type of Achilles Tendonitis commonly occurs in younger athletes that have significantly increased their activity level or perform prolonged high-stress activities such as sprinting. 

Insertional Tendonitis is an injury that involves the lower portion of the tendon close to the attachment (insertion) point on the heel bone. This Achilles tendonitis also includes degeneration of the fibers and tiny tears.  In both cases, but more common in insertional, the tears and degeneration near the insertion point can harden (calcify) and extra bone growth (bone spurs) may occur which can cause increased irritation and pain.  This type of tendonitis can be found in both active and non-active persons from everyday use or overuse.

What caused it?

There are multiple causes of Achilles tendonitis and they are often not related to a specific “sport” injury.  The common causes are as follows:

  • Sudden increase in amount of activity or exercising – example: increase of running distance and frequency without accounting for body adjusting to change
  • Wearing high heels or poorly supported shoes daily
  • Having tight calf muscles and not properly stretching before activity
  • Bone spurs
  • Playing sports that involve stopping quickly or directional changes
  • Exercising without proper warm up and stretches

All of these causes are specifically putting stresses on your Achilles tendon daily.  Some of the stress can be avoided with proper foot care and simple stretching.


The most common symptom of Achilles tendonitis is pain, but there are a few others that can help one come to the proper conclusion of tendonitis.

  • Pain and stiffness in the tendon upon waking
  • Swelling and increase in temperature along the tendon
  • Tight calf muscles
  • Thickening of the tendon
  • Creation of bone spurs
  • Pain a day after exercising or running
  • Swelling around the tendon that increases as the day goes on
  • A feeling of a pop in the tendon, which might indicate a tear, when the tendon is being stressed

The above symptoms can be reviewed by a doctor to properly diagnose and treatment can begin.

How we can help!

Here at Jacksonville Orthopedic Institute, we can help one get through Achilles tendonitis with carefully planned stretching and exercise routines that also educate our patients on proper care for when they are released back to normal activity. We make sure the patient fully understands how to perform the daily stretches and strengthening activities to decrease possibility of re-injury.  Other forms of therapy may also be used to facilitate healing in the area and are as follows:

  • Ice/heat
  • Massage/Instrument assisted soft tissue mobilization
  • Ultrasound
  • Laser

With multiple avenues for healing the injury, no matter the severity, JOI will make sure the patient gets the proper care specific to their diagnoses and previous level of activity.


By: Amelia Son PTA

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