Without a doubt rounded back back movements, deadlifts and rows being tops, and pulldowns. How is it so hard to do PULLDOWNS correctly? I remember one time, some jackass was training with his kid, kid had to be 13 or so, and this jerk has his kid doing pulldowns to his STOMACH, totally fucking up his rotator cuffs. After a couple sets of agony, the kid sits there rubbing his shoulders and says "dad my shoulders realllllly hurt" and jerkoff #1 says "dont worry son, we'll fix those shoulders. Up the weight, thatll fix'em" OMFG. I actually thought about saying something, so I kept my mouth shut, then about 2 days later theyre in there again, and asshole has his kid doing overhand rows with his back totally, completely rounded, as far as it will go. I make a comment under my breath, but loud enough that he could hear, about how your lats cant contract, and its bad for your spine to do movements like rows with your back rounded, so asshole STARES at me, like he wants to take it outside or something. I ignore him and go to do some small movements for my rotator cuffs, and the fucker comes over and mocks me! I'm just doing my own thing, trying to strengthen my shoulders, and he walks over and starts flailing his arms around like a chicken right behind me! WHAT A JERK. This had to be the biggest jerk i ever saw, and if it weren't for his fat dejected kid sitting there rubbing his back and shoulders in pain, I would've put that idiot in the hospital. Who are these people?!