Lol, fucking retards. That should be called the knee-ender. Some poeple are such tools. Does that really make your quads better than a normal hack with perfect form? Please.
if i remember correctly, justin harris actually has a major, or a minor, in biomechanics. or something of that nature.

anyway.... lets get real. after years of training , nobodies goign to make improvements like that in the back just by doing a new exercise. maybe the widowmaker row helped, but, comeon... theres another much more important factor at work here.