Researchers Study the Biomechanics of Collection

In passage, the researchers noted decreased phase-shifts between horse and rider movements—in other words the rider was more “in sync” with the horse—probably indicating the rider used the seat actively.

Photo: Hippo Foto/Dirk Caremans/FEI

We talk a lot about collection in riding, but what is collection, exactly? And how do our horses achieve it?

This almost mystical concept conjures different ideas from different riders and trainers across the globe, but new biomechanical research in Sweden is shedding light on this mystery. By studying the precise, detailed movements (the kinematics) of both horse and rider in three trotting gaits on a treadmill, researchers have gained a better understanding of exactly what’s going on during collection, and how horses and riders physically interact with each other.

Such a study could show whether riders are actually doing what they (and their instructors) think they’re doing, and could also help trainers be more precise in their explanations, said Anna Byström, a PhD candidate at the Swedish University of Agricultural Sciences’ Institute for Anatomy, Physiology, and Biochemistry, in Uppsala. It can also help define what collection actually is, she added.

Byström and colleagues analyzed the three-dimensional movements of seven high-level dressage horse/rider teams in three gaits: collected trot (in three speeds), free trot (performed on a loose-rein), and passage. The horses and riders, equipped with reflective markers, performed on a high-speed treadmill in a laboratory.

In passage, the rider’s pelvis tilted forward (“tucked in” towards the front of the saddle) and the rider’s back was more rounded than in collected trot, Byström said. In passage the researchers also noted decreased phase-shifts between horse and rider movements—in other words the rider was more “in sync” with the horse—probably indicating that the rider “used the seat more actively,” she said. On loose reins the rider leaned more forward, and the rider’s pelvis was tilted back more, compared to collected trot, and revealed the greatest back arch among all the gaits tested.

While it could be that the rider is reacting to the horse’s movements, changes in the rider’s position do not seem to correlate with the horse, Byström said. These are probably intentional movements meant to communicate with the horse or even encourage him, through biomechanics, to adjust his balance under the rider’s shifting weight, she said.

“Since horses, just as humans and other animals, have a natural strive to remain in balance, I believe that horses are innately responsive to weight aids,” she said. “But since collection is a ‘schooled’ form of slow movement, there is of course also an aspect of trained response.”

The horses and riders in Byström's study were equipped with reflective markers and performed on a high-speed treadmill.

Photo: Courtesy Dr. Anna Byström

Byström’s work has also helped clarify what definitions should be seen as physical and which ones as “metaphorical,” she said—meaning the movement is not real but only an impression. “For example, the FEI (Fédération Equestre Internationale) rules states that the passage is characterized by a more accentuated flexion of the knees and hocks and a prolonged suspension,” she said. “But our kinematic study could only confirm the first statement; suspension duration was unchanged compared to collected trot. Thus, ‘a prolonged suspension’ must be interpreted as the impression the horse should give to an observer, rather than a factual kinematic description.”

The results can also give riders a better understanding of the timing of their seat cues, she added. “When we measured the rider’s movements at the trot, we could conclude that if the increased muscle tension (to ask for a half-halt) is to have the right effect, then it must be applied during the first half of stance, to counteract the lumbar back extension and cranial rotation of the pelvis that occurs as the rider moves downwards relative to the horse,” she said. “If the same muscle action is applied during the second half of the stance, when the rider is moving out of the saddle, it’s unlikely to affect the pressure under the seat bones.”

Overall, her work showed that while horses and riders often appear to move in harmony, riders purposefully create differences in synchronicity with the horse’s gait to achieve certain outcomes.

“I believe, though, that the synchronicity is influenced as a consequence of the rider being more or less active,” she added. “It’s not an aim that the rider has in mind, or at least the rider wouldn’t use that word to describe it.”

The detailed results give insight into how high-level riders get their horses to take up certain movements, and also how they maintain those actions, said Byström.

“I hope that our studies, and future research in the same field, will be of value for riders and trainers in making riding instructions more detailed and understandable, to complement (but not replace) the traditional, experience-based teaching approaches,” she said.

The study, “Differences in rider movement pattern between different degrees of collection at the trot in high-level dressage horses ridden on a treadmill,” was published in Human Movement Science

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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