Young athletes

First of all I thank you for your site it is very informative and the users are very helpful also. I read one of the posts that a question that was about young athletes and the length that they run. I help coach an AAU program here in Texas and I help with the young athletes 14 -18 years of age. The other coaches that have the real young from 8 - 13 have the kids running 400, 200 most of the time. I feel that is too much for them. The ones that I have on Mon, Wed, we do sprint training 80m and less and Tues, Thurs , we also do endurance training 100m and above, But the question that I have is what training program is right for young people in the age group 14 -18, (Boys, girls). 100/200 and 400m runners.

Thanks very much