The draw rein is an auxiliary rein that only belongs in the hands of an experienced rider, as the rein pressure on the bit is doubled. The Thiedemann rein is a less severe form of the show rein.
The draw reins belong in fine rider hands
The draw rein is one of the most controversial auxiliary reins. In Switzerland, the draw reins are even forbidden in tests and on warm-up areas in show jumping. In Austria it is also prohibited in dressage. Used with great sensitivity, the draw rein in the hand of a sensitive rider can certainly help to limit a horse that is pushing upwards. To do this, however, the rider must react very quickly to the horse's giving in and give in as well. He is also only allowed to use the draw reins in a subtle way, as the pressure doubles in the horse's mouth. In general, he must not force the horse's head into a position and fix it there, as the horse has no way of evading the draw rein.
Question the reason for using draw reins
Ask yourself why you absolutely want to ride with draw reins and in any case get a professional riding instructor before you ride with them. Ask yourself why your horse is doing the way it is doing. Are there physical limitations or is your training not ready yet? Are YOU already able to achieve a correct alignment? The draw rein is by no means an aid to skip points on the training scale and to reach the goal of the horse that is released and swinging loosely over the back more quickly. Even the alleged inventor of the draw reins (William Cavendish, Duke of Newcastle) only used the draw reins in conjunction with a cavesson and did not lead the auxiliary reins through the bit rings. Often Newcastle is even referred to as the spiritual father of the Rollkur and was not known as the most sensitive instructor. So make yourself aware of the force with which you act on the horse's mouth if you use the draw reins incorrectly.
Draw reins inserted correctly
Draw reins should only be used on horses that can already carry themselves and gather, but sometimes break out upwards. The draw reins should hang loosely during work and only limit it when the horse lifts its head up. The draw rein may only limit upwards, but never pull the horse's head down. As with the curb maturity, the rider should first earn the use of draw reins.