The two most common types of martingale, the standing and the running, are used to control the horse's head height, and to prevent the horse from throwing its head so high that the rider gets hit in the face by the horse's poll or upper neck. When a horse's head gets above a desired height, the martingale places pressure on the head so that it becomes more difficult or impossible to raise it higher.
The standing martingale has a single strap which is attached to the girth, passes between the horse's front legs and is fixed to the back of the noseband. To prevent it from catching on other objects, it also has a neck strap. A variation is attached to a breastplate in lieu of a neck strap. When correctly fitted it should be possible to push the martingale strap up to touch the horse's throatlatch.
A variation of the standing martingale, called a tiedown, is seen almost exclusively in the western riding disciplines. A tiedown is adjusted much shorter than a standing martingale and is intended primarily to prevent the horse from flipping its head up when asked to abruptly stop or turn in speed events. It consists of an adjustable strap, one end which attaches to the horse's breastplate and the other which attaches to a noseband on the bridle. The noseband can be of leather, but may also be of lariat rope, or even plastic-covered cable, which can make the western tiedown considerably harsher than the English-style standing martingale.
With both pieces of equipment, the slack is taken up out of the strap when the horse raises its head above the desired point, and pressure is placed on the horse's nose.
The standing martingale is competition legal for show hunter and hunt seat equitation riders over fences, and is popular in fox hunting, polocrosse and in polo. It is also seen on some military and police horses, partly for style and tradition, but also in the event of an emergency situation that may require the rider to handle the horse in an abrupt manner. It is not legal for flat classes. The tiedown is commonly seen in rodeo and speed events such as O-Mok-See games, but is not show legal in any other western-style horse show competition.
Due to the risk of injury to the cartilage of the nose, the martingale strap should never be attached to a drop noseband. Because of the danger of both nose and jaw injuries, it also should also not be attached to a figure-eight noseband. A standing martingale can be attached to the cavesson (the upper, heavier strap) of a flash noseband, but not to the lower, "flash" strap.
A standing martingale may cause great pain to a horse if misused in combination with certain other equipment. If used in conjunction with a gag bit, a standing martingale can trap the head of the horse, simultaneously asking the horse to raise and lower its head and providing no source of relief in either direction. This combination is sometimes seen in polo, in some rodeo events, and occasionally in the lower levels of jumping.
Overuse or misuse of a standing martingale or tiedown, particularly as a means to prevent a horse from tossing its head, can lead to the overdevelopment of the muscles on the underside of the neck, creating an undesirable "upside down" neck that makes it more difficult for the horse to relax and flex properly. It may also lead to a horse tensing its back muscles and moving "flat," especially over fences, all of which put undue pressure on the horse's spine, reduce the shock-absorbing capacity of the leg anatomy, and can over time lead to lameness. There is also a risk of accidents: If a horse is sufficiently "trapped" by a combination of a too-short martingale and too-harsh bit, the horse may rear or fall down in an attempt to free itself from the source of pain.
The running martingale consists of a strap which is attached to the girth and passes between the horse's front legs before dividing into two pieces. At the end of each of these straps is a small metal ring through which the reins pass. It is held in the correct position by a neck strap or breastplate.
A running martingale is adjusted so that each of the "forks" has about an inch of slack when the horse holds its head in the normal position The reins make a straight line from the rider's hand to the bit ring when the horse's head in at the correct height and the running martingale is not in effect.
When the horse raises its head above the desired point, the running martingale adds leverage through the reins to the bit on the bars of the horse's mouth. The leverage created by this pressure strongly encourages the horse to lower its head. A running martingale provides more freedom for the horse than a standing martingale. If a horse happens to trip on landing after a fence, the rider can slide the reins and the horse will have full use of its head and neck.
Because of this safety factor, the running martingale is the only style of martingale permitted for use in eventing competitions and horse racing. Show jumpers also prefer the running martingale due to the extra freedom it provides. Running martingales are also used outside of the competition arena on young horses being trained in the Saddle seat, western riding, and many other disciplines.
A running martingale should be used with rein stops, which are rubber or leather stops slipped onto the rein between the bit and the ring of the martingale. They stop the martingale from sliding too far forward and getting caught on the bit or on the buckles or studs that attach the reins to the bit. Some sanctioning organizations will disqualify a rider if rein stops are not used with a running martingale.
The German Martingale, also called a Market Harborough, consists of a split fork that comes up from the chest, runs through the rings of the bit and attaches to rings on the reins of the bridle between the bit and the rider's hand. It acts in a manner similar to a running martingale, but with greater leverage. It is not show legal and is used primarily as a training aid.