I apologize for going off topic a bit, but I wanted to share.
Years ago we were traveling out west in our RV. We were at a campground in South Dakota and noticed that our nieghbors had some dogs. Later in the day, I notice him take the 3 dogs out on leashes to a very large meadow the campground was next to.
He took them off the leash and gave them some commands with a whistle and voice. The dogs began circling the meadow in a very coordinated manner. It was a very impressive display.
Later we approached him and asked about his dogs. He was there to compete in a completion. This was in the late 90's and he did say he used training collars, but did not need them to practice with them at that point. His commands were whistle, voice and hand signals. It was very impressive.