What is the Achilles Tendon? The Achilles tendon is a tendon that attaches our gastrocnemius (calf), plantaris and soleus to your calcaneus (heel). It is one of the strongest tendons in the body and plays a very important role in propelling our body forward. The Achilles tendon has areas of poor blood supply and has some anatomical deficiencies, which can cause overuse injuries. What is Achilles Tendinitis? Achilles tendinitis is one of the most common injuries in the lower