these have grown to be one of my favorite exercises to do, but i still have a few questions on them. r u supposed to perform these with an arched back and shoulder blades pulled together, like bench press form? also, how high r the feet supposed to be? level with the body?
I change grips on these all the time, going from as wide as a squat rack allows, to a couple inches of hand spacing. keep your abs and lower back tight, preventing any sort of sag, and you should be in perfect position.
raising the height of your feet moves the centre of gravity further towards the bar and your hands, therefore increasing difficulty. It also changed the angle of the pull, which can be what your looking for, or not, depends. I normally just put my feet up on a swiss ball, and rep out 15 or so for 3 sets.