Thanks Jack for the answer.

EWO( and others), what i find difficult when doing hard work and checking the dog's recovery is; you can see the dog's breath recovers to normal, but how about muscle tiredness. Most dogs need something to go all out on the mill, especially on something with more resistance. That something can cause a dog to keep going all out and ignore weaknesses. Thats what bulldogs do. (I could place one on the mill with a broken ligament, show him a rabbit and he would sprint like a greyhound). I usually find out the next day, when its to late. How do you prevent/spot overworking the muscles, you got some tips on that?

About strength condition. I know allot of people believe in it. I also know having to much/big muscle is more likely to have a negative impact in show. How do u make sure/know the resistance training isnt causing that. Is it like u cant go wrong with light resistance training and how about dogs who are genetically heavily muscled?

Sorry for the language. Hope its understandable.