Ok, I have a question and i want to see if you guys can point out where my flaw is... well when i deadlift sumo style i can shoot the weight up put it seems as if i just hit a wall when the bar gets a few inches above the top of my knee just before lockout, i mean the bar flys up and just dies right in that spot...i know its a flaw somewhere in my back.. anyone know a good exercise to help with this??