First off this is my first post on this forum. I never thought there was a forum dedicated to german shepards but now that I know im thankful. I have an 8 year old german shepard female and recently when play with her in my backyard I noticed that when walking she walked fine, the front legs moved left then right and the same for the rear legs, but when she ran fast the two back legs ran together sorta like hopping. Canine degenerative myelopathy was the first thing that came to mind, or the beginning to it, as she wasn't dragging her legs, there was still some motility. On reading about the disease I found out that this happens when they walk too, but when she walks it is fine. What could be the problem? Excess exercise? Whenever anyone is outside with her she will run chasing flies sort of to put on a show, she does this for hours if someone is outside for hours. Any help woudl be appreciated.