2005 Global Dressage Forum

Better Bitting for Happier Horses

Dr Hilary Clayton, professor in equine biomechanics at the Mary Anne McPhail equine research center of Michigan State University, was one of the keynote speakers at this year's GDF and delivered some academic wisdom on the anatomy of the horse in two different sessions.

Her first session was on her fluoroscopic research on bits in a horse's mouth. Clayton researched the position of the bit in the mouth and which behaviour it evokes. She discovered that a horse is constantly moving is tongue and that horses dislike the bit touching the palate. Because the tongue fills up the entire mouth space, horses prefer to have thinner bits that lie not too low on the tongue and that are double jointed, providing more comfort.

Two bit company representatives from Hermes Sprenger in Germany and Mylers in England backed up Clayton's research. Sprenger stressed the fact that horse like a bit partly made of copper as it stimulates the production of saliva. Rubber or nylon bits work like razors in the mouth because they dry out the mouth more than stainless steel or aurigan bits.

An interesting question was raised whether we were harming the horse by riding in a compulsory double bridle. Clayton replied that "there is awfully a lot of metal in their mouth. Horses do not always have the oral conformation to house such a bit." Christina Stuckelberger added that a severe tightening of the noseband and curb chain also hurt the horse. Balkenhol mentioned that a tightening of the noseband is a typical reaction to hide training problems.

Clayton's second session had extremely scientific explanations of the locomotion of horses, using technical graphics and physics that were hard to digest. Ground reaction force, force plate, breaking and propulsion components, vertical, longitudinal and transverse forces were terminology that Clayton explained and used throughout her exposé. Clayton's locomotion research focused on the horse's usage of its hindquarters.

She talked about "diagonal association" which could be 'positive' if the horse moves with an uphill balance touching the ground first with the hind quarters and then with the front legs. 'Negative' dissociation is when the front legs hit the ground before the hind quarters. This is all a matter of milliseconds. Some of the top horses at the 1992 and 2004 Olympic Games move with negative dissociation, while others move with positive dissociation. Clayton showed video clips of Rembrandt who has a clear positive dissociation movement mechanism, while Ignacio Rambla's Evento moved with negative dissociation.

The most striking point that Clayton made in her long exposé was that the canter becomes four-beat in the canter pirouette due to diagonal dissociation. Christine Stuckelberger commented that "twenty years ago, Eric Lette and Georg Wahl said that the pirouette was four-beat but everybody protested. I am glad that today it has been scientifically proven."

Text copyrighted Astrid Appels/Eurodressage.com, Images copyrighted Dirk Caremans -
No Reproduction allowed without explicit permission

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