Yea for some reasons girls are more susceptible to knee injuries than men, not sure the exact reason why... strength?
I'll do my best, talked to the mother yesterday, she said he loved the training. I stressed to her that I want to work with him for a while because I feel he will be an excellent college athlete and he'll need to be physically ready for that beyond his natural abilities. She agreed.
One brother isn't doing it because he doesn't have much interest in training hard, but the other brother (who is looking at Duke for soccer) is all for it.