Not a lot of dogs go all out on a mill. Even when they are really spinning the mill look at their body composition. It is like their body is still and the legs are like pendulums swinging back and forth. The mill is turning, the dog is working and this can serve a purpose so I am not knocking the slat mil.

Then watch a dog on the ground sprinting. He lowers his body, his front legs reach out and literally grab the ground in front of him. The back legs dig in and pretty much pushes the ground away from him propelling himself forward. A dog sprinting on the ground is the better choice for me.

With that said one may see slightly faster speeds on a mill where the dog is not propelling his total body weight forward because the belt is moving from under him unlike the ground being stationary. A dog in an all out ground spring may see 14-15-16mph over short distances and maybe 16-17mph on a nice free turning mill. I have never seen a dog get to the 20mph mark, not a bulldog anyway. Although I guess it is possible for a bulldog to go 20 I just have never seen it. I am not sure I would ever be concerned with attained speed as much as would be with sustained speed.

I would like to see one on a mill hit the 20mph. It would be interesting to see. EWO