Rowing will improve your core, upper back, lower back, and shoulder strength, all in one grueling motion. If you haven't tried this machine before, knowing what to do and don't do will make sure the correct muscle groups are being used and you aren't causing yourself harm in the process.
The machine matters too: rowing is the most efficient full-body exercise, and suppliers like Aviron offer hundreds of different workout possibilities. For the best possible comfort, Aviron, for instance, offers a foot and hip width adjustability option and an ergonomic seat for support and enjoyment.