Running Martingale - Traditional Range
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. Sanctioning organizations require a running martingale to be used in conjunction with rein stops if the reins are buckled to the bit.