Note: Somewhere amongst the heavy squats, bent over rows, and the dumbbell push presses I tweaked my upper back. As it was my upper back and not my lower back, my money is on either the rows or the presses. I didn’t have any problems until the second set of presses, so I’m thinking that it happened somewhere between getting up off the floor after the hip extensions and lifting the dumbbells to my shoulders for the presses.