Idk 5hift, dogs back legs and humans legs are fairly similar. They both are very powerful pushing muscles, and don't really go any other direction besides forward with any real strength.(you can lean yourself against the wall and push that way, but that's more pushing up as opposed to backwards.) and dogs front legs are more human arm like, with more control and less power. Like how if you're playing with a dog and he will paw at your hands with his paws, being fairly accurate.(some dogs)
Im calling it, right side of the picture all the way.