Do you really know what a fit dog looks like? Most of us know that you should be able to just feel the dogs ribs with your finger tips but not see them. The dog should also have a tightly packed abdominal section. It is the doggy equivalent of a human six pack also known as abdominal cuts. That is the sign of a fit dog. The photo of the racing greyhounds is shown as an example of the ultimate fit dog. Notice the highly muscled hindquarters. The tummy is also tightly packed.
While I do not condone grey hound racing, I do enjoy looking at any athletic animal, domestic or wild. An athletic animal will have a better time fighting injuries if hurt, just like us humans. In order for a dog to get and remain fit, they need to run or jog each day. Just walking your dog will not get them as fit as they could be.