Yesterday this guy was screaming on every rep. I have never heard anything like it. I may yelp a little on my last rep because of the pain, but I don't yell or scream. I know another guy who yells very loud on the last few reps. He goes big, but the yelling is obnoxious. Does anyone know if it is scientific that yelling allows you to lift a weight you might fail on if you were silent? Is it like Bruce Lee or something?