Fener, your spinal errectors (lower back) are just like any of your other muscles, and will stay quite pumped from d-bol use. The only difference is that area is part of your core and is used extensively with almost ANY excersise ! My suggestion would be to use less standing excersises and use a weight belt( I don not usually advocate weight belts) until your lumbar area is less overtrained. Hope this helps you out!