A friend of mine sent me this link a few days ago and I wanted to add some of my own experience to the mix as well. In my 30+ years of coaching and teaching I have seen a trend for earlier and earlier specialization. Children 8, 9, 10 years of age are being labelled as the next phenom in a certain sport. That label can be a recipe for a very short career and also limit the level to which the child can develop.
The best thing for kids growing up is to play many sports and to be involved in as many activities as they are comfortable doing. There is a former athlete of mine who is now in the NHL and he played Volleyball, Basketball, Badminton and competed in track and field until he was 16. By the way he competed at the highest level in ALL of those sports. He also played some lacrosse in the summer. I am not advocating that every athlete needs to be as busy as this athlete was, I am pointing out that this diversity allowed him to develop more athleticism that helped to make him a better hockey player when he decided to specialize.
Mike Boyle, who is the strength coach for the Boston Red Sox, has talked about getting athletes to play many sports for years. Now this orthopaedic surgeon is confirming what many coaches have talked about for years.