Reading through the news, this was the first time I’ve seen someone refer to an ACL tear as a “repetitive motion” injury, and I have to say I disagree.
Repetitive motion injuries are usually caused by a wearing down of a joint or overuse of one or two particular muscles over time. Tennis Elbow is a good example. The injury is not caused by one wrong swing, but rather putting repeated torque in the elbow joint after thousands of swings. ACL injuries are usually caused when an athlete does a stopping and cutting motion. The foot stays planted, the knee turns, and POP! There goes your ACL. It only takes doing it wrong one time to tear an ACL, however, with proper body mechanics you could do it all your life without ever getting hurt.
Knowing this logic, maybe you can also understand my perplexity at “experts” who recommend that adolescents play multiple sports in order to prevent injury.
If you play soccer and take up swimming, okay, I could see how that would prevent ACL injury. You would be supplementing a fast pace, high impact sport with a low impact one. Swimming has its own potential injuries but an ACL tear is highly unlikely. However, taking up something like basketball to add to your soccer regimen isn’t going to decrease the risk for injury. Both sports are fast paced and require turning and cutting. Even though you kick in one and shoot in the other, you’re still running back and forth along the court or the field.
Real injury prevention is borne out of the ability to navigate your body in space, to have proper body mechanics so deeply engrained in your muscle memory that the minute you think about changing directions your body knows how to coordinate all lower body joint movements.