A healthy 10 year old boy should be able to knock out 10 jumping jacks in a heartbeat.
My son tried to go the 'I just want to be left alone to play my video games" route.
Much like this guy suggests, I tossed his little behind outside haha!
He had a great time that summer, cutting down saplings and building a fort in the woods.
Kids usually take the path of least resistance. The parents have to step up and push the issue.