It's just a matter of understanding what's necessary and discipline yourself to do it.
Arthur Lydiard
No one will burn out doing aerobic running. It is too much anaerobic running, which the American scholastic athletic system tends to put young athletes through, that burns them out.
If you want to be a successful runner, you have to consider everything. It's no good just thinking about endurance and not to develop fine speed.
Encourage kids to enjoy running and play in athletics. Don't force them to run too much competition.