Attach a pair of resistance bands to a door anchor and place the door anchor at a bottom of a door. Attach the workout bar to the other ends of the resistance bands. Grab handles with shoulder width underhand grip.
With elbows to side, raise the workout bar until forearms are vertical. Lower and repeat.
When elbows are fully flexed, they can travel forward slightly allowing forearms to be no more than vertical. This additional movement allows for relative release of tension in muscles between repetitions.