Hi Bonnie, My father loved to exercise, too, and was most fond of rowing. When he lived in Florida, he used to have a single shell. Every weekday he would put it on top of the car, drive over to Lake Seminole, put the shell in the lake and row like crazy for about 6 miles! In fact, he began to realize something was really wrong with him when he couldn't hoist himself out of the shell onto the dock. Since then, he has bought an indoor rowing machine. Unfortunately, he's had to give that up because he would fall getting up from it. Anyway, about the Air Strider, I would think that might be a problem, too, because of the need to climb on and off of, and balance on, those slidey treads. It would probably be wise to find a way for him to try one out before buying. Let us know if you come up with a good solution! Jane Koenig (daughter of Fred, 80/1-ish)