I am sure some of you already do it. But I noticed at my gym many people sacrifice form for weight when doing standing straight bar or dumbell curls.Next time you do straight bar curls lean aginst a wall keeping your head back and butt aginst it the whole time. It makes a big difference. You will probably have to go down a little in weight but it takes the back and shoulders out of it. It Isolates the bi's very good.