In military riding, which demands special control over the animal’s movements, the horse’s head is drawn in, and the rider’s hand raised, much more than they would be in ordinary work.
_The running martingale._--The legitimate uses of this gear are to aid in keeping the horse straight, and to prevent the reins going over his head; but not to keep the head down. If this martingale be so short as to exert a downward pull on the reins, too much weight will be thrown on the forehand. If the horse raises his head even when this martingale is lengthened out, so as to bring its rings on a level with the withers, when it is pulled up, the downward direction of the reins, from the mouth-piece to the rings of the martingale, will produce the same ill effect. Hence, it is a maxim among all good jockeys, that the head of the race-horse, with whom a level style of galloping is one of the chief essentials to success, should be kept down by the rider’s hands, and not by the running martingale. It is the custom, therefore, among jockeys, when they use this gear, to lengthen it out, so that, when it is drawn up, to test its length, its rings will come up to the angle of the lower jaw, when the head is held in a natural position--a length which will obviate any chance of there being a downward pull on the reins.
In the training of a race-horse that “star-gazes,” the use of a running martingale, in order to keep his head down, besides interfering with his action, is detrimental to the soundness of his legs and feet, by reason of the extra weight thrown, thereby, on his forehand.
Respecting the injurious effects of hampering the action of the neck muscles, and of putting a severe downward pressure on the mouth, especially during rapid motion, I may quote the following interesting extract from ‘White’s Veterinary Art,’ which was written many years ago: “There is a great danger, however, of attempting to make the mouth at the time of riding, by means of a running rein; for if he is a stubborn or runaway horse, there is great danger of throwing him down, and in the most dangerous manner that can be. For, if he is determined to run away, and the rider endeavours to prevent him by a running rein, in drawing the nose down to his chest, the muscles of the shoulder are so restrained that he must of necessity pull him down topsy-turvy. Since the body being propelled by the muscles of the hind parts, the restraint thus imposed upon the extensor muscles of the fore-leg, prevents their being thrown out to the extent required, and he comes down with the most dangerous violence. I have known this accident happen with horses that have had upright shoulders and very well-formed hind parts; and I have also known very safe horses, that have contracted a habit of going with their noses poked out, become very unsafe, and soon get broken knees by the endeavour to improve their carriage by a martingale or running rein.”