I took Sam up to the Canine Fitness Center and he's gained 2 centimeters of muscle on his leg! That is a great sign as it means that he is using his leg more. We have been doing the prescribed exercises every day and he is doing great. He really seems to enjoy them at least! And, I can start letting him do more normal doggy things- he is allowed to do stairs whenever he wants (in moderation) and he can have normal to moderate walking exercises. Still no 100 mph running but Sam will be a very happy boy to get more exercise. We go back again in three weeks, so hopefully he will continue to improve! Yay for Sam!