, it's definitely harder the further down you go. Personally, I may not be going down as far as some because my chest hits the floor 6 inches before my stomach.
I'm not sure about the technicalities of the the muscles being used though...
, by count? Aaahhh. I would fail miserably. I think if my instructor stood over me as said 'do this now or I take away your belt,' I could maybe get to 60 at once/at a steady pace before I collapsed. I've never tried doing one side higher than the other, but I like that idea. I often put my feet on steps, but this is something to try! Thanks for the input.