I found some interesting quotes from Raymond Verheijen. He is a top dog soccer fitness guru. According to him most ACL injuries can be prevented. He blames fatigue for most injuries. The injury prevention program that Verheijen introduced at Feyenoord has dramatically reduced injuries.
Raymond Verheijen:
"Nine out of 10 ACLs can be avoided, because the main reason why an ACL happens is that the knee is temporarily unprotected when the players turns or leans.
Normally, your muscles contract to stabilise the knee and nothing happens. Over the holiday period when players play so many games and have accumulated fatigue, their nervous system slows down and the signal from the brain to the muscles gets slower.
When they make explosive movements the signal arrives a millisecond too late, the player leans or turns with an unprotected knee and the ACL snaps.
You often see the ACL happens with a very simple action – something a player has done in his career one million times. On one million occasions the knee was protected and everything was in its place. On the one-million-and-first time the signal arrives too late and the ACL snaps."
Another quotes from Verheijen (can't find the link anymore though)
"If a player goes from nothing to everything he risks injury. If you haven’t played for a while you are not totally fit. Then, when you play a game when you are not top fit you will need more recovery time than normal. So a less fit player is more susceptible to injury."
I don't have a medical background so I an not sure. I do however know several people who work or have worked for (semi-)pro-soccer teams, and they all say that ACL injuries (and mustle injuries) can be prevented with better training schemes. I guess there should be a lesson in here for the NFL as well.
http://www.goal.com/en-tz/news/5786...playing-russian-roulette-with-walcotts-career