Traditionally, bitted bridles have provided the main means of controlling ridden horses. The metal bit applies focused pressure on areas of sensitive tissue within the horse's mouth.
According to Dr Robert Cook, Surgery Professor Emeritus at Tuft's University in Massachusetts, the bit is to blame for numerous problems in the horse, including headshaking and upper respiratory obstruction.
For the past ten years Dr Cook has been researching the adverse effects of the bit and the advantages of communicating without using a bit. He developed a new type of bitless bridle that differs from hackamores and other traditional bitless bridles in being painless and incorporating a crossunder principle.
Is the bitless bridle as effective as Dr Cook would have us believe? Two small-scale studies have looked at how horses behave and perform in bitless or bitted bridles.