ATHLEAN-X™ | Jeff Cavaliere MSPT, CSCS on Instagram: "The "headbanger" pull-up is no shallow party trick! It's an incredibly challenging but potent developer of straight arm scapular strength (S.A.S.S.) - a must for reaching your true athletic potential! In fact, untapped strength here will cost you dearly in the amount you can ultimately deadlift and the number of pull-ups you can knock out in a single set (both heavily reliant on S.A.S.S.). If you're unable to do any of these at the moment, do