I,m convinced that the running action of a dog has a bearing on how well the dogs feet hold up to wear and tear , some dogs ,especially dogs with heavy shoulders , seem to pound the ground with their front feet and use them as anchors , other types have a smoother action they lean into bends more , the front feet are used more as balances , there is less abrupt force exerted .I will always prefer a dog with good tight feet , but I do think there are other considerations as to why some feet hold up and others don,t .