There's a good discussion on RSR about how much juniors should train and how often. 

This is a frequently revisited topic because many people feel that kids get "burn-out" and stop rowing after school just when they are starting to get good.  There are some good points put and I'd commend it to anyone whose club has junior members.  

Maybe bring it up at committee and check you are providing a fun, healthy and long-term framework for youngsters in our wonderful sport.