Power Shrugs

I have a question about the effectiveness of “power shrugs”. My definition of a power shrug would be to shrug the weight up in a jerk movement for about ten-twelve reps with a total time under tension of twelve seconds(avg.). The people I’ve seen using this movement were usually power lifters and added power cleans and clean & jerks to their program. I can see how this would be a good assistance exercise for people wanting to train for power cleans & jerks. My particular goals are for a little more size/definition in the traps and to get my power clean poundage up by 30lbs. Can anyone give me any insight?

These are demonstrated in Ian King’s “Killer Legs” video, BTW.