What are draw reins and side reins, and what are the risks of using them incorrectly?

Draw reins and side reins are auxiliary training aids that create an additional rein contact from the girth or surcingle to the bit, applying rein pressure that encourages the horse to carry its head and neck in a more collected or lower position than it offers naturally. They are used in specific training contexts by experienced riders and trainers, and they are misused far more often than they are used correctly, producing horses with false outlines, restricted movement, and behind-the-vertical head positions that reflect compression rather than training. Draw reins run from the girth, through the bit rings, and back to the rider's hands, where they are held alongside the regular reins. In practice, inexperienced riders tend to hold constant draw rein contact, which compresses the horse behind the vertical and teaches the horse to evade into that position rather than developing genuine collection. Side reins are used during lunge work rather than under saddle, attaching from the surcingle or saddle girth rings to the bit to provide a fixed contact point that encourages the horse to seek contact as it moves. The critical fitting principle is that side reins should be adjusted to allow the horse to carry its head at or slightly in front of the vertical in a natural working position — not to pull the head behind the vertical or to create any sustained backward pressure on the mouth. Both tools should be used only by riders with sufficient training and experience to recognize correct and incorrect head carriage, and only in specific training contexts where they serve a defined purpose rather than as routine equipment for every ride.