An Achilles tendon rupture is a full-thickness tear of the tendon that runs along the back of the lower leg. This injury can occur in any active adult as well as in children, but it is more common in men in their 30s-40s. The classic patient is a middle-aged man who is aggressively playing sports on the weekend but is not a trained athlete.

Patients may feel a sudden pain in the posterior ankle while running or jumping and may hear or feel a large "pop."

Risk factors include the use of fluoroquinolones, the use of steroids (anabolic or anti-inflammatory), and Achilles tendonitis / tendinopathy.

Achilles tendon rupture rarely has been reported in children.