So, I'm deadlifting this morning using my normal mixed grip when one of the trainers at my gym comes over to me and explains that I should use a simple overhand grip with straps. He used to be a Soviet powerlifter, so I tend to heed his advice, but this seemed strange. He explained that the underhand in the mixed grip causes a slight drop in that shoulder, which thus produces a slight twist in the spine, and that, of course, being bad. I've never heard anything like this before. Anybody know anything about this?