What causes a muscle to tear away from bone?

A muscle tearing away from the bone is called an avulsion fracture. It occurs when a powerful muscle contraction or an external force causes the tendon that attaches the muscle to the bone to pull away a small piece of bone. This type of injury is most commonly seen in sports that involve sudden, explosive movements, such as basketball, football, and weightlifting. It can also occur as a result of a traumatic event, such as a car accident.