Running martingales help give the rider extra control by discouraging the horse from raising its head beyond the point that the bit works correctly in the horse’s mouth. It works by stabilising the reins and applying downward pressure on the mouth via the bit and reins when the horse raises its head too high. Many riders like to use a martingale when jumping, especially on a young or strong horse.
The running martingale is made up of two straps: one strap attaches to the girth after passing through the horse’s front legs, then branches into two straps, with a ring at the end of each through which the reins pass. The reins should have rein stops added to prevent the rings from getting snagged on the buckle or billet where the rein attaches to the bit. This split strap is held in place by a second strap that sits around the horse’s neck.
The running martingale is popular with most riders because it has little or no influence on the horse when it is going correctly and also provides a useful neckstrap for those awkward moments. It also allows the rider to open the rein to the side, unlike the bib martingale.
The running martingale is most commonly used for jumping and is accepted under British Showjumping and British Eventing rules (in the show jumping and cross-country phases). It is also allowed in working hunter classes, although not in any other showing or dressage classes.
A pilot study has found a link between martingales and rein tension on horses ridden by novice riders
Some horses try to grab the straps of a running martingales in their mouths, in which case a bib martingale (where the area between the two straps leading to the reins is filled in with leather) would be a better choice. The straps of a running martingale can quite easily get caught when opening and shutting gates, so this is worth keeping an eye out for.
The running martingale’s straps can be elasticated, providing the horse with a less rigid feeling when raising their heads. This may be a good choice for horses that fight when feeling the restriction of the martingale.
The sliding martingale has a similar action to the running martingale. It has a single strap or cord with a ring at each end rather than two separate straps. The cord passes through a ring where the two straps would join on a running martingale.