I'm enjoying elliptical training and the rowing machine at the gym just now.

Like the elliptical because I can really vary all the settings, from elevation and resistance to pace and whether or not I'm going "forward" or "reverse."

Also, I am back to really enjoying the rowing machine just now. It definitely uses some of the same lower body muscles, and I think also is relevant in that you have to correctly use your core and back...which is super helpful for cycling. And, using both lower body and upper gets the cardio up easily.

Also, I have been amazed at how much my ab and back work have helped my cycling this year.