The Achilles (uh-KILL-ease) tendon is a band of tissue in the back of your leg. This tendon links your heel bone (calcaneus, pronounced cal-KAY-nee-us) to your calf muscles. It’s also called the calcaneal tendon. You have two Achilles tendons, one in each leg. The Achilles tendons are the strongest and biggest tendons in your body. The Achilles averages about 15 centimeters (6 inches) in length, but it’s up to 26 centimeters (10 inches) long in some people. Achilles tendons can handle about four times a person’s body weight. But people commonly experience Achilles tendon injuries because of the stress put on this tendon. Almost 1 in 4 athletes have an Achilles tendon injury during their lifetime.