http://www.youtube.com/watch?v=f4wcNX0IAwU
A friend in S.On. sent me this link to watch. This is a 2 yr. old GSD female working in SAR. My friend has the brother of this dog. (she jokingly said, she got the wrong dog!)
This "track" is 36 hr. old, on a university campus in the U.S. It is absolutely amazing to watch!!! It is almost entirely hard surface. The difficulty of this track is astounding; to watch her work consistently along without hesitation is truly a joy to see.
Enjoy!