What's the hell do you think they use to run? what a bizarre thing to say!
It isnt really, my dogs are well muscled now,but in a months time when the only excersise they get is running and working,the muscle will not be any were near as defined.So are they fitter now than when there lamping 4 5 nights a week.
If i was going to run a marthon i wouldnt go weight training.Think big muscles are cool becouse of the bull cross.
Any one walking there dogs for 2 hours a day are wasting there time,becouse the dog dosnt need it.
so strengthening muscles isn't an important part of fitness?