First of all when you're grabbing hold of that barbell and should be right next to your waist area. From there you'll stand up and take a couple steps forward just to make sure that that barbell path isn't blocked by any objects. Then you'll drive those shoulder blades back and try to focus that activation of your traps as you drive those shoulders up and squeeze those straps at the top.
Come back down make sure you're doing this nice and under control then when you're done we just step back, place the barbell down, and that was a behind the back barbell shrug.
