I also built this one to condition bird dogs. It was designed to go 4 MPH, was built on a trailer, and had an electric motor.
Actually the best way to condition a dog is off of horseback. Put the dog in a harness and it will pull as the horse walks. I used a walking horse so this was a pretty good clip. Once the dog stopped really pulling I would let them run free for about 45 minutes. This is the way we conditioned our competition field trial dogs. They can go waaaaaaaaaay in yonder. A dog must finish as strong as it started to win and they had to be in shape for that.
