Out of the gait

Out of the gait

High-speed film shows limb motion complexity that can't be captured by the naked eye
Sep 01, 2006

A veterinarian (middle) watches a competitor's horse trot 125 feet out and back and then must determine if the horse is lame or is fit enough to continue with the ride. In a typical 50-mile ride, horses are examined four to five times; with upwards of 75 to 100 horses in some rides, this affords the veterinarian many chances to improve the fine art of gait evaluation. Note that the man in overalls is recording the trot out, which the rider will later review and evaluate for possible tips to improve future performance.
Dr. H. was asked to be an event veterinarian for the American Endurance Riding Championships. Out of school for more than 10 years now, Dr. H. considered himself gaining in experience but still learning. When it came time to judge the gaits and motion of the top-10 finishers for the Best Conditioned Award, Dr. H. was excited to hear that all eight veterinarians working the event were going to view the horses in motion and then, as a group, the veterinary staff would pick a consensus winner. There were at least four veterinarians at this ride who were legends in the sport and who had at least 100 years of combined experience evaluating sport horses and analyzing gaits.

"This is my chance to really learn how experienced veterinarians dissect equine gaits and improve my own attempts at lameness diagnosis. I'll make my evaluation and then see how I compare to what my mentors say and what I need to do to improve my eye and evaluation techniques," the young doctor thought.

The top-10 horses were brought out, and they trotted in a figure eight for all the veterinary judges who then went to a separate room to talk about the evaluation.

Dr. H. was not prepared for what happened next. There was no sense of agreement between the vets at all. One veterinarian's best moving horse was another's worst mover. The same horse was judged to have good impulsion by one vet and poor impulsion by another. The more experienced veterinarians were more forceful in their opinions and had better reasoning behind their interpretations of motion but had no better agreement than did any of the less experienced veterinarians. As the sometimes-heated discussion raged on, Dr. H. began wondering how accurate gait evaluation really was if it could be this subjective at this elite level.

And Dr. H. is not the only one. Dr. Kevin Keegan, a veterinarian in the E. Paige Laurie Endowed Program in equine lameness at the University Of Missouri College Of Veterinary Medicine, is one of many researchers who have been looking at this problem. Keegan recently presented papers on the head and pelvic motion patterns of horses with either fore or hind limb lameness. These presentations at the 2005 American Association of Equine Practitioners meeting in Seattle discussed the actual motion of horses with specific lameness issues and called into serious question much of what we think we know about lameness and motion in the horse.

Keegan and other researchers represent the field of kinesiology, or the study of the forces that are involved in movement (kinetics). The development of high-speed film and computer-aided motion analysis has allowed this field of study to expand and subsequently question the efficacy of current standard practices and suggest how veterinary students should be taught to evaluate equine gait and motion.

Out of plain sight

The human eye cannot distinguish events occurring in less than a tenth of a second. At full gallop, a horse takes upwards of 150 steps per minute. At 2.5 steps per second, there are undoubtedly some parts of body, leg, joint and foot motion that humans cannot see. Even at slower speeds in different disciplines many parts of a horse's motion are not observable, and if other factors such as jumping and landing motion or other specific movements dictated by a particular sport are thrown in, then it is no stretch to say that parts of a horse's motion are being, and have always been, missed on evaluation.

New equipment in use at the University of Melbourne Equine Center in Australia and elsewhere now can record a horse's motion at 500 frames per second. Even a standard digital camera will record 30 frames per second. Therefore we now have the ability to simply see things that could not be seen before.