We keep hearing about how bad sitting is for your health, but usually don't have much on the specific details. There's the sedentary element, which would be taken care of by exercise, but there's also apparent negative factors. However, not much research seems to try and nail down the specifics. Are people who are not in static positions, or bounce their leg not subject to these health effects? If so, it could be that a lot of children are naturally fighting for their health, much to the chagrin of strict teachers.
Also, do any of the negative effects apply, other than perhaps bone stress inherent to putting weight, to someone very active while sitting, such as a drummer?