I've seen different descriptions and animations of how to perform this exercise on the internet.
I am trying to find a set form to do these in. Which is the best way, and how do you do yours? Do you use an overhand or underhand grip, I've seen both in animations. Also is your back at a 90 degree angle pretty much or about 45 degrees? I am finding that if I try to do it like how the guy on exrx does it I get strain put on my lower back, anyone know why and if that is supposed to happen?