[nycfem]

Thanks for posting the video, Kelt. That's definitely been my experience. The arc trainer feels so much better on my feet and knees than the elliptical. I also do the arc trainer that has the arms on it (so that it appears like an elliptical but isn't). My feet always stay flat on the arc trainer, and unless I am doing a manual program where I add too much resistance, my knees do fine too.

It's true that there are a surreal number of different pieces of cardio equipment these days. Since I'm relatively short (5'4"), I think some sort of fit me, and others don't. Right now it's really only the Arc Trainer that I am finding does not cause me knee twinges or back pain in doing lengthy sessions. I also find that I must do a minimum of 30 minutes of yoga and stretching after a long use of a cardio machine in order to get the repetitive motions of the cardio machine out of my body. If I don't then that night I get the stiffness from the session still stuck in my body. It's been a lot of trial and error over the years. So much of exercise is finding what doesn't cause injury or discomfort.