Teaching your horse to flex, rein back, hindquarter yield, forehand yield and side pass can greatly improve their suppleness, rideability and relaxation. It is something that I now teach to all my young horses to help give them more tools as they progress into more advanced movements.
NOTE: Although Rio has show jumped to 1.25m, I didn't have any focus on body control at the time, so these videos show case his learning process after I started building more of an appreciation for body control work.