Economy of motion and future gadget :-?

I always have crazy ideas in mind;and lets see this fresh madness: correct body posture and economy of motion.Bio-mechanics has always interested me.

I had this idea with kids using lot of ear plug (ear phone whatever you call it) these days; why not develop a ear plug such that it would only sound optimal when the kid has perfect body posture.That would be a easy way to connect music with exercise.
To make things worse the so called gadget would just automatically feed in data viz height,weight and other specification of the particular kid and keep it in its temporary memory.So kid can listen to music or some short of audio lecture or whatever; and whenever the perfect posture is lost by the kid even slightly the gadget would stop sounding:I would love to call it punish and reward method if I were to provide my own words.

Also;whenever the kid has minimum set of muscles utilized he would have some leverage in loosing some degrees from perfect posture :now this thing has also turned into some short of sport here.........It is just like playing video games..You need to gain coins to spend it :P..I think it is possible but little tedious.

Not only for improving body posture of kids;it would also help athletes maintain proper posture and also help then use minimum set of muscles to do their athletic task.