SETUP: Take a D-handle in each hand then step forward, letting the cables pull your shoulders back and create an angle where your elbows naturally want to sit behind the line of your body. This places the biceps on stretch. You will not be as strong here.
REP: Keeping that elbow position, pull the cables up by squeezing your biceps hard until you can’t get them any higher.
TIP: You can even out any strength differences between your arms by doing the single-arm version of this exercise; the Behind-The-Back Cable Curl.