In a previous EMG study we measured trapezius activity during behind-the-back barbell shrugs (59 percent), front barbell shrugs (54 percent) and behind-the-neck presses (41 percent). Behind-the-back barbell shrugs produced the greatest amount of EMG activity for the trapezius muscles. In our second test we measured trap activity of three more exercises, and here are the results:
1) Dumbbell shrugs, 61 percent
2) Nautilus pec deck machine,* 55 percent
3) Cable upright rows, 51 percent
Dumbbell shrugs won this round.
*Sit in the machine backward, facing the weight stack. Place your elbows against the pads, arms parallel to the floor. Use your trap and deltoid strength to move your elbows directly to the rear.