Indoctrination starts early. If they’re really that young more focus should be put on sports and fun, active things they can do in groups or alone.
Strength and nutrition for kids is good, but may be a little much for them to chew on for a few years.
If you want to get started in youth training I’d suggest summer camps. They’re a good way to get on the job experience (and as fun as a job can get).
Make it fun, make the food tasty.