But while the 6-4, 320-pounder has yet to establish himself ... recently bench pressed 600 pounds during summer workouts. That's equivalent to about 130,000 shrimps on the barbie.

Alex Rosen used to weigh 105 pounds ... "I had barely any muscle mass on me whatsoever, and barely any fat as well," he says. "If I had to guess, I was at about 5-6% body fat with no muscle ...