Is there some kind of logical reason why kids get so little physical activity in school?

My son recently started a summer camp where he actually gets a reasonable amount of activity and the difference in his demeanor is huge. He is able to focus at home much better and is better behaved.I don't think this is a unique issue, yet I don't think any schools in western countries give the kids enough activity...just wondering if there is some reason why this is the case. via /r/Parenting http://ift.tt/2962XfD