According to the ordinary acceptation of the term, a horse is supposed "to bend well" when he arches his neck, yields to the bit, and uses his knees and hocks freely. This alone by no means conveys an adequate idea, however, of what is meant by bending a horse in the scientific sense. The "Military Aid Book" supplies the following question and answer, which gives in a very concise form a better notion of the matter.
Question: What is the use of the "bending lesson"?—Answer: To make the horse supple in the neck and ribs, to give free action to his shoulder, and teach him to obey the pressure of the leg.
It will be seen, then, that "bending a horse" really means rendering him supple in every portion of his frame, and especially in his ribs and intercostal muscles, as it is suppleness in that part that gives him the lithe, easy motions so pleasant to the rider.
I have before observed that I do not consider an intimate knowledge of the "haut école de manége" indispensable for ordinary riding purposes, either for a lady or gentleman. But, although the "bending lesson" thoroughly carried out may be said to be the very gist of "haut école riding," even in its simple form, unaccompanied by the higher aids, it is of great service in rendering a horse docile and obedient to hand and leg, and for that purpose is always resorted to in our schools of military equitation.
Now, although I do not expect every lady to acquire the art of suppling her own horses, still a knowledge of the "bending lesson" will make her thoroughly acquainted with the reasons why a horse renders ready obedience to her aids of hand and leg; and, on the contrary, why he resists them.
Stiffness (as it is technically termed) has more to do with what is commonly called restiveness than most people imagine. A horse is asked to do something that calls upon him to bend or supple a joint in which, even in early youth, he is still far from supple. He cannot do it. The rider perseveres, and the horse resists. Whereas, when he is thoroughly suppled, he does not know how to disobey his rider (supposing the latter to know what he is about). If a lady, therefore, will pay close attention to the instruction of her master, she will discover that her horse will obey her more readily, and move with more ease to himself and her, when she applies her aids "smoothly" (without which the bending lesson cannot be done), than by the application of sudden or violent indications of her will. For it must be borne in mind that a double bridle is an instrument of great power in a horse's mouth, and that what may seem light handling to the uninitiated rider may be rough to the horse. A fair amount of practice, therefore, in the above-named exercise will have the effect of rendering a lady's hands remarkably true and steady; and, although the lesson may be a little trying to the patience, the pupil will find her reward in increased confidence and proficiency.
For all practical purposes the "bending lesson" proper may be divided into two sections, namely, the "passage" and the "shoulder in," all other movements of the lesson being simply variations from the above named. The "half passage" may be looked upon as an introduction to the "full passage," but admits of being practised with facility at an increased pace at the trot or canter, and at the latter is a very elegant exercise. To begin with the "shoulder in." Let us suppose a horse standing parallel to the boards at the side of the school. To place him in the desired position it is necessary to bring his forehand in, so that his fore and hind legs are placed upon two lines, parallel to each other and to the boards, and then to bend his head inwards at the poll of the neck. No more correct idea, I believe, can be conveyed of the position than that given in the "Aid Book," which furnishes the following answer to the question, How should a horse be placed in "shoulder in"? "Ans.: When a horse is properly bent in 'shoulder in,' the whole body from head to croup is curved; the shoulders leading, fore and hind feet moving on two lines parallel to each other, hind feet one yard from the boards."
Again. "Q. What are the aids for working this lesson?—A. On the word 'right or left shoulder in,' the horse's forehand is brought in by a double feeling of the inward rein, the outward leg closed, so as to bring the horse's hind feet one yard from the boards."
The outward rein leads, the inward preserves the bend; a pressure of the inward leg (of the rider) compels the horse to cross his legs; the outward leg keeps him up to the hand and prevents him from swerving. The horse should be well bent in the pole of the neck, and well kept up to the hand with the outward leg, the shoulders always leading.
It will be seen from the above that the rider compels, or rather coaxes, the horse, by very firm and steady aids, to move with his forehand well up, and his whole figure bent (neck and ribs), with his feet moving on two distinct parallel lines—the effect being to call upon every important joint, and thoroughly to supple the ligaments and tendons, as well as to create muscular development, in a way similar to that of gymnastic or extension exercises in the human being. With young horses in training it is necessary to watch this lesson very carefully, and never to "ask too much" at one time, because any forcing of it would certainly result in restiveness; the strain, even with naturally supple horses, is considerable, and must not be persevered with one moment after it is evidently painful. Of course, in the case of a lady practising the lesson, it must be done upon a horse that has gone through a long course of teaching, and to whom, therefore, the movements cause no inconvenience. But even here the pupil will find that she must use her hand and leg with firmness, steadiness, and decision, without hurry or impatience, or the horse will not answer to her.