Hi. I think I've got the answer for you. When I broke my foot a few years ago, I found a paraplegic work-out site. Very cool! The trainer was air boxing from her chair. Basically, just throwing punches fo 1/2 hour at a good rate using her whole upper-body strength. I tried this during the time I was waiting for my foot to heal, and it worked great! Came home after 2 weeks of Maui holidays 2 pounds lighter! Maybe not as much as I'd have liked, but I lost instead of gaining!
Hope this helps you!