I have a Cycleops pro 3 which is a commercial quality spinning bike with the flywheel in the back. It has almost no miles on it because it's just too much like a real bike and it's boring to ride inside. I'm trying to get rid of it so I can get a recumbent model with a backrest. The muscle group is a little different but it's close enough. Some of us in the club I used to ride in got mountain bikes and rode all winter but I'm done with that. It's just too damned dangerous. Running is a lot safer but I have three herniated discs that are aggravated by it.