I'll be watching this one, but I have to complain about something: having something move your body around while you're unconscious wouldn't work as exercise. Exercise works to reduce body weight by burning calories via chemical work—however, if you're not moving your body with your muscles you're not doing any chemical work. Similarly, Luke won't get any stronger this way, as strength gains are due to putting strain on your muscle cells, which causes damage to some of them, requiring that they get replaced; continuous cycles of damage and replacement will signal to the body that it needs to reinforce the area to handle the presumed upcoming strain. Because Luke isn't putting strain on his muscles and is instead being moved around by an external force, his muscles won't get any stronger.
Tl;dr it sucks but you can't cheat biomechanics, not even with magic that does the work for you.