The Today Show had a segment on this topic yesterday, Feb. 28. In the first part of the story, you will hear from Dr. Theodore Ganley, director of sports medicine at the Children's Hospital of Philadelphia. I'm biased because I've worked directly with Dr. Ganley in the past. His insight and research are amazing.
You can view the video here: http://today.msnbc.msn.com/id/
I have to admit that I hear of knee injury after knee injury from coaches whom I've interviewed in the past. Tearing an ACL is almost commonplace these days.
Injury prevention is key, so please, do what you can to keep your child injury-free...