Children Should Be Outside

Children should do warrior-caste things so they grow up with healthy bodies. Most mental deficiencies associated with intellectual laziness can be fixed later. The brain is plastic in a way the rest of the body is not.

The few mental issues that you really need to address while they're young can easily be done during sports or whatever. Warrior tasks don't actually have 0 mental component. 

Only let the child be studious if they really insist. At some point it's not worth the bother. P.S. Don't betray your children. Don't declare war on them to try to "force" them to be healthy, you fucking idiots. 

My hips are twisted, because I spent too much time sitting, and crossed my legs. Result: I have to be very careful not to injure my back. I could have every moment of that sitting at a later age.
Imagine school was just laser tag, all day, every day. Would probably cost less. Maybe have the girls do some scavenger hunt / fiddly puzzle combo thing. 

Notice this is stupid easy. If you let small kids outside they go outside on their own. Give them a place outside to be, one they can safely get to on their own, and then don't break the habit. That's it. You're done. This is very much a [stop digging] problem.