Im not sure if anyone here has tried this, but ive never seen anyone do it and never heard it explained. its a awesome back exercise for the lower trap and let thickness. i call it a supported t-bar one arm shrug. You have to use the homemade tbar for this exercise, with the bar shoved into a corner. but you set up a bench at a 45 degree angle to the bar sticking out from the corner. get into the same position as a one arm dumbell row with plates loaded on the side you will be lifting.
i thought of this out of necessity since our gym at gvsu doesnt go past 130 lbs dumbels. know i can have a 225lb dumbel, give or take since it is a lever. now with you in dumbell row position, grasp hold of the bar and row it to the abdomen in tbar row fashion. once you reach falure, put the bar in the fully stretch position, and shrug up and back feeling your traps stretch.
once i got to a weight i couldnt rown all the way, i put up 4 45lbs plates plus 1 25lber, i just shrug really heavy with the heaviest weight i can. This is brutal for the lats and traps. my lower traps have been so sore after doing this exercise. try it for yourselves and tell me what you think