I have been rowing since 1988. I've had some excellent coaches and incredible training. I've gone to summer rowing camps for many years and I've spent hours and hours on our rowing machine. My hubby was a rowing coach. For a long time, rowing was our lives.
Rowing requires a LOT of fitness training, most of which is done on an "ERG", or rowing machine, manufactured by Concept II in Vermont. All rowing clubs have ERGs; they're the best rowing machine made. In order to determine what a rower can pull, coaches always "test" their rowers on ERGs, watching their output on a little computer-like monitor on top of the machine. The coach will then put the rower in the boat, depending on his output.
Are you following me so far?
I have put in many, MANY hours on the ERG! It's an incredible training device. All rowers have their own in their homes so they can work out when weather does not permit them to be on the water. All university crews have to train on ERGs.
Okay, here's the bottom line: it is CRUCIAL that you are TRAINED on how to use the rowing machine properly. If you do not, you can VERY easily throw your back out by "driving" with your back instead of your legs. Hubby and I have gone to many, MANY fitness centers and watched customers using their ERGs improperly, and we have grimaced each time, because we know what's happening to their backs. The proper rowing sequence is, basically: "legs, backs, arms" during the drive, then the "recovery" is just the reverse, or "arms, backs, legs." If the rower does not get this right, he can throw out his back.
Also, many rowers will open up their legs in order to get more "compaction" and will begin the "drive" with their backs because their legs are in a weak position opened up like that. Also, to be kind of gross (sorry), a person with a big tummy will of necessity open their legs up that way because their tummies get in their way. This is a BIG mistake, because, as I said, they're unable to drive with their legs, thus they use their backs instead. That's just asking for back trouble!
Another common practice is to "rush the slide." Rowers think they're getting a more strenuous workout that way, but it's a misnomer. It's the strong leg drive and slow recovery that produce the best results.
Rowing machines are fabulous exercise devices, but only when used properly, and only when the rower knows what they're doing. I don't mean to discourage you, but unless you get good training on it, I'd recommend a treadmill instead.