There is a great article over on Slate about kids and tackle football. Basically, kids that haven’t reached puberty are especially susceptible to concussions. Their bodies haven’t developed enough to sustain the blows in tackle football. Here is what the author recommends:
“It’s not as if there aren’t alternatives. Maybe have kids play flag football wearing no pads until they’re 10, then with shoulder pads until 13. At 14 or 15, if they are determined to be physically mature, players can don helmets and wrap up opponents to bring them to ground. Any blow to the head or leading with the head is an automatic ejection. Full hitting can start on high-school varsities. Tackling can be taught over time—flag football teaches the proper entry point for contact, around the hips; rugby-style tackling might be instructive—to prepare kids for full contact when their bodies are ready, or at least readier, for it.”
If a kid has had a concussion, they probably should get checked for an atlas misalignment.