I had loaded 25 bags of Chow at the Home Depot in My truck , got home and started to unload them in the garage and probably 3 bags into unloading them I leaned forward and twisted to place a bag on the stack and "BOOM " pulled a muscle in My back. I was a poster child for what not to do when lifting. I do way heavier lifting at work and this 40# bag brought Me to My knees So be careful and lift with Your knees and NO TWISTING !!