Chair-a-cise

Hi...Wondering if anyone out there has heard of or done "Chair-a-cise" DVDs. I have really bad knees that are preventing me from doing any cardio. I got this program with the thinking that anything is better than nothing. I mean, what do people in wheel chairs or people without the use of their legs do for cardio? I went online and found this program. Starting tomorrow along with a healthy diet. Any feedback is appreciated and I'll keep you informed on how it goes for me =)