This is going to be a short question, because there's very little depth to it.
I've been bulking lately, and to have something to focus on, aesthetically, my shoulder region is getting some love. And with it; traps!
I've been doing more shrugs lately, but while doing them, I can't figure out what's best; to do rolling shrugs, or just straight up-and-down shrugs?
Do anyone have any good advice, one way or the other? Preferably backed up with some sort of study. Anecdotes are alright depending on the source.