question: Hi! I m 54 years old and suffer from severe knee pain. I recently had x-rays of both knees to find the cartilage is gone on the insides of both knees. Hence, I am now a candidate for double knee replacement. Prior to this diagnosis, I was on a weight loss plan including walking, biking and tennis and I had lost 20 lbs with more to go. I was excited! But now because of the worsening pain, exercising is difficult. My weight has crept back up to 180 lbs! I really need suggestions on how to exercise for weight loss given the pain and situation with my knees. HELP!