Saddle Science: Tree Width’s Effect on Horses’ Thoracic Spines

Saddles with trees that are too narrow or too wide can reduce range of motion in horses’ backs, a study found.

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Saddle Science: Tree Width
Riding in saddles that are too narrow or too wide likely affect thoracolumbar kinematics due to the instability and positioning of the saddle and rider, MacKechnie-Guire said. | Photo: iStock
Saddle fit has historically been an art rather than a science, with little research to support what constitutes good fit. One area lacking objective evidence is the effect of saddle width on horses’ backs. Russell MacKechnie-Guire, of Centaur Biomechanics and The Royal Veterinary College, in Hatfield, U.K., recently conducted a study to evaluate just this. He presented his findings at the 2019 British Equine Veterinary Association Congress, held Sept. 11-14 in Birmingham, U.K.

“There is a notion in the industry that fitting saddles too wide will allow the thoracolumbar region (the part of the spine that runs from the horse’s withers to his pelvis) to increase its range of motion and improve muscular function, but none of this is supported by scientific evidence,” he began.

In his current study, he aimed to evaluate the effect of three different saddle widths (correct, narrow, and wide) on thoracolumbar kinematics (movement) in horses ridden at the canter, a gait at which this part of the spine has increased range of motion.

His team fitted 13 sound horses housed at the same facility with a validated sensor system and glued inertial measuring units along each horse’s poll; withers; 13th (T13) and 18th (T18) thoracic vertebrae; third lumbar (L3); sacrum; and left and right tuber coxae (LTC, RTC). They collected data as two similar-sized, right-handed female riders rode each horse in a properly fitted, general-purpose Kent & Masters English saddle. MacKechnie-Guire said they chose this type of saddle because of the adjustability of the tree width

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Alexandra Beckstett, a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as assistant editor of its book division, Eclipse Press, before joining The Horse. She was the managing editor of The Horse for nearly 14 years and is now editorial director of EquiManagement and My New Horse, sister publications of The Horse.

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