Lies, I have to admit- you're the only person that I know in person with "fast" dogs. I mean come on- 3.9sec flyball runs??
[Thinks hard to see if that would be offensive to any of his friends. No... I don't think so... Well, no offense intended to you, my local friends!
] I was going to PM you to see if we could dissect one of your dog's pedigrees for a learning experience, but I'm not sure that's fair or appropriate. I suspect Carmen can provider her own examples based on past experience.
Also- I have to admit that what you've brought up, Lies, about the sheer desire
to do to work and be rewarded by the work is something I haven't considered. I figured a fast dog is fast because of their conformation and drive alone. Take me
as an example. My conformation (read: my fat [bottom]) will never be a fast sprinter. I'm built like the dwarf from the Lord of the Rings... -short, fat, and well muscled! haha! But someone with a lot of leg, tall, slender, toned, and driven to success- that person will almost certainly be a much faster runner than me. So conformation must have a part for sure.
I attributed a great croup to speed. A long, properly angled croup allows the dog to get their rear feet under their body, stretched forward for range of motion, and give them the ability to power forward pushing their rear legs backwards with lots of range of motion. The long croup means that the muscles themselves are longer providing more strength and more flexibility. I wonder if the Thuringian dogs have an impact on rear conformation.