Just wanted to share some great exercises that i have found really work for both upper back muscles and lower back muscles. Neither need special equipment (if you haven't got!0

Upper back muscles - dumbbell rows :

As executed in the exercise library here in thefitmap [http://www.thefitmap.co.uk/exercise/tools/videos/back-exercises.htm]

This exercise REALLY benefits when you choosing a slightly lower weight, but do the exercise more slowly. Concentrate on your working muscles and almost 'clench' at the top of the pull. Don't be tempted to jerk the weight up or twist your back to get the full extent.

Lower back exercise - back extensions on floor :

Quick and simple - lie flat and then again slowly raise your chest away from the floor and hold - don't be tempted to rush this - again you will get far more benefit from slow but purposeful movement.

:) Good luck 

Those are some good exercises - but I'd have to say my favourite for upper back is still pull-ups.

Dumbbell rows are also one of the few upper back exercises you can do at home (without a machine).

"This exercise REALLY benefits when you choosing a slightly lower weight, but do the exercise more slowly."  Good advice, true for about every exercise in fact!