Also, make sure to set the cable at eye - lever or slightly higher as this will minimize upper trap involvement. (fitnessandpower.com)
More specifically, behind - the - back shrugs will engage more of your middle traps and help you add thickness, while front shrugs emphasize upper traps. (fitnessandpower.com)
When translated to the gym floor, this means that performing barbell shrugs with the wider - grip (i.e., snatch - grip) if you're looking to get more upper trap involvement. (nicktumminello.com)