Researchers Examine Effects of Rider Stability

Austrian researchers have reported that the stability of a rider’s seat affects the forces acting on a horse’s back. Using an electronic pressure mat placed under a dressage saddle, scientists with the University of Veterinary Medicine Vienna’s Movement Science Group measured the forces created when an experienced rider rode 10 different sound horses at the sitting trot, rising trot, and in the two-point (jumping) position. The rider held each position for 20 seconds.

"In this study we wanted to see which seat position is the most stable for the rider, and which position least stressful for the horse," said Christian Peham, PhD, head of the Movement Science Group.

In each riding position, the researchers measured rider stability by determining the movement of the center of pressure (COP) along the transverse (X, or side-to-side) and longitudinal (Y, or up and down) axis. The researchers used a statistical calculation to determine the highest and lowest points of stability in the three different positions.

The sitting trot created the highest load, followed by the rising trot and the two-point seat. In the two-point position, the rider’s back is most stable, placing the least amount of load on the horse’s back. In all positions movement on the Y-axis accounted for the differences in load. The rider’s transverse movement had no effect.

According to Hilary M. Clayton, BVMS, PhD, McPhail Dressage Chair in Equine Sports Medicine at Michigan State University, the two-point seat puts less load on the horse's back because the joints in the rider's legs, especially the knee and, to a lesser extent the hip and ankle, act as shock absorbers.

"As the horse's body bounces up and down, the rider's joints flex and extend to maintain the rider's back in a consistent position with the horse, moving up and down beneath him/her," Clayton explained.

The cushioning effect of the rider's joints avoids large fluctuations in force on the horse's back as compared with the sitting trot, in which the rider's body oscillates with the horse.

For young horses, or horses recovering from back problems, a combination of the rising trot and two-point positions provides optimal training conditions without overloading the horse’s back. According to Peham, "These positions are the most stable for the rider, and least stressful for the horse."

The study, "A comparison of forces acting on the horse's back and the stability of the rider's seat in different positions at the trot," was published in the May 2009 Veterinary Journal. The abstract is available online.  

About the Author

Nancy Zacks, MS

Nancy Zacks holds an M.S. in Science Journalism from the Boston University College of Communication. She grew up in suburban Philadelphia where she learned to ride over fields and fences in nearby Malvern, Pa. When not writing, she enjoys riding at an eventing barn, drawing and painting horses, volunteering at a therapeutic riding program, and walking with Lilly, her black Labrador Retriever.

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