- dragging a barrel--never
- straddling a pole--never
- cantering in figure 8 with lead changes--never
Based on Blessi's reactions to things in the arena and on the trail, I believe that Blessi was ridden a lot on the trail in Icelandic before he was exported to the US. And if you have ever seen the "horse treks" in Iceland, this must have seemed like a walk in the park for Blessi.
So to Blessi extreme trail is just dressage with scary things--which is much more interesting than dressage.