Can a dog's gait be "fixed"?

My 6 year old is a finished champion and is retired and living on the sofa watching dog show reruns on Animal Planet. I'd like to get him back in condition to hopefully compete as a veteran in specialties. His gait has gone a little off from not being roadworked. His reach is terrible, but he still has a lot of drive in the rear. Are there any exercises or stretches he can do to improve the reach in the front so that his gait extends a little more nicely? He's on K9 Showstopper for muscle and coat and free runs for 35-45 mins daily but isn't getting roadworked because I no longer have a bicycle and lately I don't think I could run 2 miles anymore if my life depended on it!