Talk to orthopedist and they will generally tell you that kids today are getting pushed too hard, too soon. If you are trying to be an elite athlete and move on to the college game you are playing high school and club sports. It is a year round schedule.
I'm familiar with soccer where the kids typically get a two week break about twice a year. They are playing between fourty and fifty games a year and practice around 150 days annually. I'm sure basketball isn't much different.
On young bodies that are still growing they simple don't have enough recovery time. Not to mention that they sometimes push beyond their limits. Toss in a poor coach or trainer and you are set up for serious health issues down the road.