While gaining flexibility in my knee after a total knee replacement, the rowing machine works out pretty well. The seat can be adjusted, either stationary or moving. The moving function offers me a chance to gain the most flexibility. Even when not using the handle bars (similar to using paddles or oars), the moving seat offers a pretty good leg workout. it definitely gives a good upper body workout, which helps increase the circulation.
As much as using the rowing machine helps with my knee’s flexibility, I believe the exercise bike is more beneficial. However, one makes do with what is available. 🙂