I think one of the things that work really well is swimming, it's good for the joints, builds muscle, and increases endurances. If you feel like there's no where near you to swim there are lots of places: the Y, college campuses, fitness centers, some local schools (elementary, junior and senior high schools) have pools to swim in. Just remember to eat first, lifeguard or not a pool is a very dangerous place and not eating about two hours hand can cause a person to blackout. Also, stretching will help avoid cramps.
listening to:: Helena- My chemical romance