There are a bunch of exercises you can try. There are tons of different nautilus machines in gyms that can work your back, take a look around to see which ones you can use. I do two exercises, both nautilus. One is a seated row, and the other I sit with my back pressed against a pad, and I'm leaning forwards. I select a weight on the machine and try to straighten my back pushing backwards and forcing the weight up. It's a very good machine, check around your gym to see if you have one.
