A Running Martingale is one of the most popular rider aids. It is used to help prevent the horse from raising his head too high. It consists of a 1/2″(13mm) neck strap and a second strap, 1″(25mm) wide, which is attached to the girth and passes between the horses 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.
When the horse carries its head in the correct position no pressure is felt. However, should the horse raise its head the martingale will restrict the movement of the reins, which in turn causes the bit to bear down on the bars of the horses mouth. The martingale should be fitted so that the rings are in line with the withers to prevent it putting any pressure on the reins when the horses head is held in the correct position.
Generally used with rubber rein stops, which are located on the rein between the bit & the Martingale ring.