And don't do everything the instructor tells you if you feel it isn't a good idea. The classes I took over last winter had a leader who insisted on a couple of bits of low-rpm, high-resistance seated mashing as part of the routine. That might work for some people, but it's a recipe for disaster for my aging knees, especially in the off-season when I need to work on a mileage base that's more spin-oriented. I don't mind the lower RPM mashing if it's done while standing, but for me, doing it seated is a quick trip to the hurt locker.