Marketed as the first extreme sport in the US, Indian Relay is the ultimate horse race. The athletes, Native American only, jump off the horse and onto the next riding three laps on a flat track - bareback. Kemmer is a mugger. The one, who stops the horse after the rider jumped off. Who gets run over and dragged behind when the horse does not stop. If your horse gets loose your team is disqualified, so you better hold on to it.
When a guy named Henry Skunkcap brought it first to the Blackfeet, Kemmer was one of his apprentices. As you have to stop a 1000 pounds horse, muggers are usually big guys. But Kemmer figured a small guy might work as well, if he is quick enough and got the balls to do it.