Does anyone know some good exercises for back muscles? I have fairly bad posture and have actually injured my back a few times; my doctor says it's because I work in an office and sit at a desk all day, so I never use my back muscles and they've gotten really weak. My wedding dress has a key-hole back, so I want it to be toned to look good but also so my posture is good, and so I'll stop injuring my back. So many reasons to work out those muscles!
I know tons of ab exercises, butt exercises, etc. Those are easy. But what can you do for your back?