@Ana1234 - Well, he is supposedly developing hand-eye coordination by playing video games and there are some you can get that will encourage him to move and stretch his body as well.
My friend has one of those systems and her kids are adorable when they are playing on it. They jump all over the place and mime throwing things and so forth.
It's no substitute for real exercise, but better than nothing. And there have definitely been studies which show that even on ordinary games, kids can improve their reaction times and things like that.