The Achilles tendon is the largest tendon in the body, extending from the calf with the union of 3 muscles: 2 gastrocnemius muscles and soleus muscle to attach to the heel bone. In addition to performing movements such as walking, jumping, running, the Achilles tendon helps the body stand on the toes. The Achilles tendon is used in most activities, so it is also the place that is under a lot of pressure and is vulnerable.