They used to hold " Ride and Tie" races around Rutland Water - a few years ago now. 2 runners, 1 horse. Runner 1 would set out, runner 2 would ride the horse to check point 1, overtaking the runner, tie the horse, run to check point 2, where runner 1 would have already collected the horse, overtaken them and left horse at next check point etc. Thats how I got started running, and then doing running to keep me fit for horse endurance rides, where the more you ran alongside the horse, the better the time would be. Then the horse got too old, so I had to run by myself !