schensted

While I agree with previous posters that rowing is primarily an aerobic activity, my experience has been that it does build some muscle and develops strength. Rowing on an indoor ergometer can be useful cross training for cycling.

I rowed in college and have used a Concept II machine for the last thirty years. I am definitely more muscular and stronger when rowing is part of my program. Resistance training such as weight lifting is more effective at pure muscle building, but rowing also improves strength and muscular endurance. Like weight lifting, rowing can also help prevent osteoporosis, a concern for cyclists. Proper technique is critical, however, for rowing to be safe and effective. There are some excellent technique videos on the Concept II website.