Many people are afraid strength training at a young age will injure young athletes. I don't find this to be the case if you program properly and stick within some guidelines. The young rugby league players I train are all getting much stronger, increasing their performance on the field, and reducing their risk of injury because they are correcting many weaknesses they have that could lead to injuries down the track suck as weak VMO's, hamstrings, and lower backs.
This morning Mani deadlifted 70kg for 5 reps with pretty solid technique. He has only done the lift about 11 times in his life and weighs 55kg. We don't lift maximally. This final set of the day was the heaviest he has gone and as you can see it was not a grind by any means. I think this is important for anyone training young athletes to keep in mind. We push hard but it is within their technical limits. It is about long term progress, so as a coach don't get overexcited and try to reach records in the first few years of training. We are building a foundation for years of lifting and competing to come. You must keep that in mind.
We are constantly talking and monitoring how the young blokes feel throughout a session and from week to week. We adjust training loads and nutrition accordingly. They have a lot going on with school, rugby league training both at school and club level, and rep teams, and many other sports such as OzTag. All these things have to be taken into account so that you don't burn them out and can keep them keen to train and progress safely.
Its great to see the commitment levels at such a young age. I just hope they keep enjoying their training and make it a part of their life forever.