Do children who play sports for their school have better grades than students that don't play sports for the school?

Of couse, the two type of kids have diffrences.

The kids that play sports are more active, and they have a better bidness.

The kids that don't play sports are lazy, and there bidness is weak. That will cause them problems in their bodies when they grow up.

6 Hours/week sports are more than enough for the kids. That will assure you in the future that the kid will grow up healthy.