In my experience, not many HUS horses are spur-trained, in the sense that I think you mean - which would be using a spur-stop like a western horse. They position bodies the same with your legs and such, but not quite so much is done off the feet quite like a western horse.
For the western horses, it is a lot more common because we don't have the luxury of having the horse in our hand like a hunt seat rider does. The spurs are used in a combination of other cues - shifts of weight, leg pressure, etc. It's not JUST the spur. Nailing one with spurs only is a good way to screw up a ride on an unforgiving horse.
Spurs are used to tell the horse where to put his body, to move his shoulders or hips while going down the rail, for example. Some horses are also taught to stop off the spur, and back as well. In the trail, your spurs are there to help position your horse through the course, to ask him to shorten his stride to make a distance, to sidepass, to move his hip around a back through, etc. But, always with some leg, the weight of the rider, some hand, etc.
Just sticking a horse is a good way to get him pissed off, burnt out, and sour.
Last edited by spurstop; 12-26-2012 at 01:07 AM.