Our middle son was a "high maintenance" baby and was unhappy unless he was doing whatever big sister was doing. In kindergarten, he would spin around in his seat at school when he was done before everyone else and got bored. But his private school didn't punish - they asked if we would send some quiet things for him to do when he wasn't able to run outside right away. Now, he's a busy teen getting "A"s (except in English, just like his father) and playing plenty of sports. He is constantly tossing some kind of ball in the air everywhere he goes - getting on his mother's nerves occasionally. He loves baseball and we make him play all the rest. He doesn't like soccer or basketball but we insist he play anyway. After a few mumbles, as soon as a ball enters the field of play, he's all over it.
It's a shame so many kids are not able to get outside and the ones who can are usually inside sitting around instead and are allowed to sit and eat processed carbs all afternoon.
I'm convinced that diet has a lot to do with ADD, ADHD kinds of situations. They put so much poison in our foods (under the title of preservatives) that it's no wonder the kids act out.