I've wondered the same thing myself. Yeah you got alot of places to inject, but thats still alot of cc's a week. They probably use all of the muscle groups(quads,calves,forearms,bis,tris,delts,glute,lats,traps) and hit each in different place each time to get around scar tissue. I know I have to work my way around my delts to find a spot b/c of scar tissueand it doesn't feel to good when I hit scar tissue in my shoulder.