When I can't get to the gym and I gota use my own equiptment is it okay to do shruggs one arm at a time? See my dumbell set is only a 40lb set, and that means if I split it in between 2 dumbells its 20lbs each trap, but if I could stick all 40 on one dumbell and do each arm one at a time it would be twice the weight (which still aint much, but it's better than 20).