Phase 1: Stop really fast
This video shows a dog who is physically capable of running at full speed and coming to a rapid stop on the ground. The dog must know how to do this and be comfortable and highly rewarded for doing this before being asked to do so on a narrow or steep board.
In this case I am using a “foot touch” behavior to start a game of fetch. This is nothing more than the basic foot touch that you see in step 4, but moved to a flat board that is a bit larger and easier to see from a great distance.