Well ..... I hang on tight and so I haven't fallen off yet, but if you asked my leg or buttock muscles after a good session, they'd scream injury!!

I used to go to yoga classes once weekly, but I got to the stage I just couldn't do it any more. My body just refused to bend the way it should.

Pilates, as already mentioned, and Tai Chi are quite popular here among MSers, and although I did try them, neither were for me.

So, I'll stick to my long walks and my several miles/Kms each day on my bike. That's my workout for now.