NONE OF THE ABOVE!!! I couldn't believe anyone would call those power shrugs. Shrugs are not done with the LEGS, or with MOMENTUM of an Oly movement, or with the help of old ladies in water.
POWER SHRUG:
Grab the bar from your rack, safety stops, curl stand or table.
1.) With it hanging, shoulders drooping, and a good grip, let the shoulders roll forward and the UPPER spine only, curve a bit to the front.
2.) Your head usually will be down and you're looking at the floor. As you bring your head up, pull back and up with the traps, rhomboids, and whatever else you have, and do a static hold at the top for one second.
3.) When you can't clear your gear for height, the set is over. Because this is initiated with the upper back muscles instead of just the traps, you can go bug-heavy on these.
4.) grip wide enough so you won't try to "curl" it at the elbows. A semi-wide stance helps keep the heels on the floor. Heels come up and it's not a shrug.
These are what made my traps explode at last.
I just spent a half hour looking at Utubes of "power shrugs" and couldn't find even ONE guy who knows how to do it right. Closest I found was this guy, and he's cheating with the legs, and not holding at the top very long:
http://www.youtube.com/watch?v=NjBsqMurq9s&feature=related
The point is to pull with the traps, right? A power shrug, rolling back from a forward shoulder hits the lower traps as well. I do them with up to around 405, and the only thing moving is the shoulders. Not elbows, knees, or low back. I can't believe the horrible videos I just saw, so I guess I should make one and post it.