Allan Melvill Pope, Horse Training by Modern Methods
“ When a horse is collected, the rider, by having omitted bending the neck near the shoulders during training, has the neck firm on the shoulders and not flexible or “rubber-necked.” Hence the rider acts on the neck through the mouth and on the shoulders through the neck. The hind quarters by being under the horse bind themselves to the forehand. The rider then by acting on the forehand acts likewise upon the hind quarters. ”
