Awful night. In the middle of squatting 290 I felt a tiny twinge in my back on just one rep. I reracked, considered how I felt, then belted up and tried again. Sudden sharp pain in my lower right back at the bottom of the first rep. I actually let out a grunt from the shock of it. Painfully came up and reracked, then hobbled to my chair. This is a particularly bad one. I'm estimating I'll be back to 100% in two weeks.