Tendons are bands of fibrous tissue that connect muscle to bone. The Achilles tendon is located where the calf muscle, or gastrocnemius, attaches to the heel bone, or calcaneus. The Achilles tendon can tear or rupture during sudden activity, like jumping or sprinting, or during violent tendon stretches. The injured area will be swollen, tender, and bruised. Surgery and casting, or casting alone, may be required to repair a torn Achilles tendon.