Sometimes when speaking of collection we refer to a horse being “on the bit.” This is meant to describe a horse who accepts good contact with the bit, making an elastic contact from his jaw through the reins to the rider’s hands. This is good if one other element is in place. That would be the impulsive force. That force comes from a combination of a horse’s natural desire to move forward enhanced by forward urging of the seat bones and legs. Once our friend Baucher described this as being “behind the bit and, and in front of the legs.” later authors described the condition as being “on the aids.” This situation puts the horse in the arched position with the connected tension of a strung bow, able to respond instantly and in balance to the rider’s wish.
The mechanics of this dance is to teach a horse to go forward from light seat and leg cues, not kicking, but a “whisper of the boot,” then receiving the surge with soft rein hands, and spongeing the reins for a half second, then releasing. This suggests to the horse rather than forcing him, to reach up under his body with his hind legs, and elevate the withers rather than the neck. By repeating this procedure we reward the horse with short periods of “liberty on parole.” This strategy prevents resistance and stiffening of the horse;s body, if you’re careful, and rhythmical. Perhaps a better way to express collection, is “awakened and put together,” which in French is “Rassemblé”