So this chart is taken directly from an article on www.RunnersWorld.com
My dog is a small 9 pounder, so it doesn't surprise me that she didn't make the cut! Although she's more than okay with that.
In fact, it doesn't look like any small dogs were chosen as great runners. I guess even their fast, little strides just cant keep up with the easy long stride of a big dog.
Anyhow, see if your dog made the list!