Re: My design for a fitness wearable.
If you really want, the mass can be made up of Ni Cad battery cells.
A good idea. Get a couple of hours life out of your iPhab/Phabdroid (or one 10 minute call), gain strength and lose weight all at the one time :)
IIRC there was once a wrist band you could buy that was largely lead weights in a nice soft fabric, but NiCad's would work just as well :)