“A one-arm press involves the hips, obliques and lats as well as the deltoids, traps and rotator cuff muscles,” McCall says.

As O’Brien and Hart worked their way around the gym, they flexed all their major muscles: biceps, lats, and of course, the blackmail muscle.

But the lats, delts, quads, and inguinal creases that have been forged in the effort!