Well in my case I cant do *freestanding* HSPU's lol, I kip up along the wall and have my heels lightly grazing along it as I press up n down. What makes you say they don't/can't significantly aid in physique development though? I would have to beg to differ...excellent movement for delts, traps, upperback/lats, upper chest, triceps, forearms n overall strength and stability. Granted, it is not easy to add resistance as one could to chins n dips for instance, you'd have to use a weight vest, also elevating hands on boxes and dipping past parallel makes it much more intense...freestanding is probably the most difficult but that deals with added balance moreso than just strength....but for most this is not a high-rep movement in even it's simplest BW form. It moves your body through 3 dimensions under resistance and engages a great deal of musculature at once. Are dips, chins, n squats not good for physique development either?? A HSPU is basically a squat for your arms n upperbody