May 19 (UPI) -- Quarterbacks should be shivering browsing James Harrison's Instagram account. The 39-year-old posted his latest workout Thursday.
During this insane session, Harrison sits with his back balanced on the side of a bench. He puts a bar full of weights above his groin and does several thrusts. Harrison has about 675-pounds of weights on the bar. During the amazing feat you can see the bar bend under the pressure. He does six reps of the heavy load what we can see of the footage.
The five-time Pro Bowler and two-time Super Bowl champ is entering his 15th NFL season. He had 53 tackles, five sacks and two forced fumbles in 15 games last season. Harrison, a two-time All-Pro and former Defensive Player of the Year, has 81.5 career sacks.
"Explosion shoot the hips thru," Harrison wrote on Instagram. "Shoot thru the tackle not to the tackle!"
Harrison said he wears a sweatshirt while working out so he doesn't discourage other people by exposing his massive arms.
"The whole reason I wear a sweatsuit to workout is so they can't see my arms," Harrison said in a video posted by teammate Maurkice Pouncey. "I don't want to discourage people who come in here to work out, just because my arms are so [expletive] big!"
"That's why I wear a sweatsuit."
Harrison posts workout videos on social media multiple times each week, including days before his birthday when he pushed a sled carrying 1,395 pounds.
The Steelers re-signed Harrison to a two-year deal in March worth $3.5 million.
Harrison is listed at 6-foot and 242 pounds.