Are back extensions worth actually doing if you want to build a strong back? I do starting strength, so I squat 3 times a week and deadlift often. But I feel like my back is the limiting factor in my squat, and my low back rounds a bit on the deadlifts too which I think indicates a week low back. Should I pring in hyperextensions at the end of my workouts? Mark Rippetoe said they are useless and are more likely to actually hurt your back. But I feel like my low back is actually a limiting factor for me. Any suggestions?