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Wednesday, January 26, 2011

Video: Equine Biomechanics Integrated with an Icelandic Horse's Disco-Rhythm Hoofbeats by Swiss Researchers



Are you awake now?

This video is your wake-up call. It's a fast-cut peek inside the high-tech equine performance testing laboratory at the University of Zurich in Switzerland, where kinematic- and kinetic-research are undergoing an exciting fusion under the direction of biomechanics research professor Michael Weishaupt PhD DMV. Where the disco beat came from is anyone's guess!

Are the researchers trying to turn this Icelandic into an Olympian or a racehorse? No, there are no Frankenhorses in biomechanics labs. "The application of knowledge pertaining to sports medicine does not aim to increase the speed of the horse or allow it to jump higher, but to keep the athlete sound, prepare it optimally for a specific event, and to recognize detrimental influences early in order to avoid an untimely end to an athletic career," wrote Dr Weishaupt along with Zurich's esteemed professor of equine surgery, Dr Jorg Auer, in an explanation of the research at Zurich.

To do that, Weishaupt and his colleagues are combining kinetic and kinematic research in the same evaluation system. Two formerly exclusive branches of biomechanics research are now under the hood of the same laboratory testing matrix.

Kinematics is nothing new to Hoofcare + Lameness readers. Kinematics is simply the study of motion. A student of dressage could be said to be an equine kinematics scholar, on some level.  But in the world of clinical evaluation of horses, we have typically talked about kinematics as the two-dimensional recording of a horse's movement in order to gain insight into a horse's stride's length or velocity or frequency, or to determine lameness. It works very nicely to prove or enhance what we think we see with our naked eyes or what the rider thinks he or she feels from the saddle.

For the past five years or so, kinematics in the laboratory has been moving ahead. Three-dimensional gait analysis has been used in research to delve deeper into the horse's movement so that joints can be analyzed for the complex structures that many of them are. A hinge joint like the fetlock might be analyzed in two dimensions, but what about the hock or the spine? And what about the coffin joint, a complex structure with three types of motion patterns--flexion-extension, abduction-adduction and axial rotation?

And what if a specific location in the limb could be isolated, such as the distal end of the cannon bone, where so many racing injuries occur? If the forces there can be measured over different track surfaces, aren't we light years ahead in preventing breakdowns?

When studying the motion of the horse, it's not just about the legs. The neck and head and back are critical components so gait analysis has expanded to putting markers all over the horse. The angular motion patterns (flexion-extension, lateral bending and lateral excursion) of six vertebrae (T10, T13, T17, L1, L3 and L5) and the axial rotation of the pelvis are calculated by the software used in the research--in the case of our friends in Zurich, that would be the Qualisys system.

In this video, provided by Qualisys, researchers used a similar system at the University of Agricultural Science in Uppsala, Sweden; 12 cameras recorded the horse in three dimensions on a sensitized treadmill so that the movement of the head and neck could be studied with each footfall and with the movement of the rider. Notice that the horse's center of gravity is always clearly marked on the screen.

So now the leading research labs may use three or many more cameras and create almost realistic moving horses on computer screens. Wireless technology has also improved the operations in the equine research laboratory.

If kinematics is the study of motion, kinetics is its alter ego, the study of force. Kinematics might not care if you were a ballerina or a gorilla crossing a Broadway stage--you'd just be a pattern of dots for it to interpret. And kinetics wouldn't care how synchronous or straight your limbs worked as you crossed; kinetics would worry instead about what happened when your feet hit the stage. Did you slide? Did you hit with enough force to break through a board? How long did each foot stay on the floor?

Researchers explore kinetics with force plates and, more recently, the alternative of pressure-sensitive materials such as mats and walkways embedded with sensors. In Zurich's case, it is an instrumented (sensor-embedded) treadmill (photo, above), or "TiF": a "Treadmill-integrated Force" measuring system able to record the vertical ground reaction forces of all four limbs simultaneously and report it instantly.

The buzzwords of kinetics are ground reaction force and center of gravity. A foot in water finds little resistance, but a foot usually lands on somewhat solid ground, depending on the nature of the footing. If the surface was rigid and foot was a wine glass, it would shatter, but it's designed to deform and store energy when it meets the ground. How to measure what happens during that meeting is the goal of kinetic research.

So the scientists at the University of Zurich wanted to analyze how the Icelandic horse on the treadmill in the video is moving (kinematics) while intermittently impacting the ground (kinetics) with his hooves. One of the new advantages of hoof-related research is the integration of the kinetic and kinematic tools. As the video screen draws the dotted horse that the cameras see, the pressure sensors simultaneously are recording the data of the impact of each footfall. The integration of these systems is relatively recent.

But there is a third entity going on here. The addition of a saddle and rider will affect the kinematics of the horse and no doubt the kinetics as well. So the researchers are measuring the pressure and movement of the saddle. Last year the same lab studied dressage horses at the collected walk--a deceptively simple gait that is a challenge to many upper level horses--and measured how much and in what direction at what phase of the stride the saddle moved.

Believe it or not, little research on the walk had been done before, and in particular, no one had tested how the rider and saddle might affect the horse's score at the walk. Since racehorses tend to trot, pace or gallop for a living, you will find a deep history of studies on those gaits over the course of equine biomechanics history. Sport horse kinetics and kinematics is a far less investigated field of study.

In the Zurich tests, all the dressage horses' saddles moved in the same directions at the same phases of the strides, and the rider's movement was the same as well.

And what about the hooves? Labs like Zurich have conducted comparative studies of how a horse moves while unshod, shod normally, and shod with rolled toe or "four point" shoes to study the effects of shoeing changes on kinematics and kinetics--in particular, the timing of the phases of the stride. Does a particular shoe cause a horse to keep its foot on the ground longer than another, and might this be associated with an increased potential for injury? 

So now the dressage horses have gone home and the Icelandic horses are being tested. A research project in progress is Kinetics, kinematics and energetics of the tölt: Effects of rider interaction and shoeing manipulations. The tölt is the amazing fast gait of the Icelandic horse; it is their signature show gait, and possibly unique to the breed. Will changing the shoes on an Icelandic horse change its ability to perform the tölt?

Since no one has studied an Icelandic horse with the resources that are available today, no one really knows.

But someone will. And, by extension, the world will know soon after that.

Thanks to BartMedia Designs for this video.


Here's a little video about using similar but more simplified equipment for testing humans. I hope this helps you understand biomechanics research a little better! The concepts mentioned in this blog post are vastly over-simplified but once you understand the basic concepts, it will all start to make sense.


To learn more: BYSTRÖM, A., RHODIN, M., Von PEINEN, K., WEISHAUPT, M. A. and ROEPSTORFF, L. (2010), Kinematics of saddle and rider in high-level dressage horses performing collected walk on a treadmill. Equine Veterinary Journal, 42: 340–345. doi: 10.1111/j.2042-3306.2010.00063.x

Anyone interested in learning more about equine biomechanics would be well-served by attending the Equinology biomechanics course with Dr. Hilary Clayton at the McPhail Equine Performance Center at Michigan State University's College of Veterinary Medicine in the fall of 2012. A combined course in biomechanics and lameness evaluation with Dr. Clayton will be offered in England in March 2011 at Writtle College.

 © Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.
 
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2 comments:

bundle#1 said...

I really enjoy all the information you put on your blog. I have given you an award on mine. :)

beth said...

Fran, thank you for this wonderful post! This shows research in such a colorful and complete way. These gait analysis systems can be used by computational neuroscientists to apply rehabilitation research for both animals and humans. What makes horses sound versus unsound may have something to do with gait patterns. Standardizing values for the gaited horses provides valuable information for comparison. Awesome videos too!