Interesting enough, both wife and old dog take glucosamine and MSM in liquid form, and it really makes a difference in how easily they move around. Also, changing from "designer drugs" ( the high-priced stuff like celebrex or tramadol ) to regularly-spaced doses of enteric asprin ( or for the dog, baby asprin ) has made a noticable improvement. Do note that dogs metabolize asprin differently and more slowly than humans, so don't just load your mutt up with it before consulting a vet about it.
But since she's very active, she probably will be as she gets older. All that running around and jumping stuff, and busting brush in search of ducks . . .