But here is the thing about ACL tears: They're not just another injury. They are the Godzilla of injuries. They are painful beyond tolerance, they take eons to rehab, and they always leave a lingering doubt in the athlete's mind that he will ever be whole again. An ACL tear tests one's mettle. An ACL tear goes to the very heart of resilience and mental toughness. An ACL tear is the standard against which the athlete himself measures his determination. An ACL tear is the absolute limit.