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A century of invention paves the way for new information on gait analysis
You're probably thoroughly fed up reading about the millennium and the ensuing Y2K meltdown. At risk of pushing you over the millennial edge, this column will reflect on the history of equine gait analysis and take a look at what the future may bring. Throughout our long association with the horse, we have been fascinated by the horse in motion. Because the artist's eye could not perceive the different stages of the stride in fast-moving horses, from prehistoric cave paintings until the 1870s, horses were depicted by artists in various unlikely poses. Typically, galloping horses were shown in an airborne phase with the hind limbs stretched out behind and the forelimbs extended in front. It was not until the advent of photography and the work of Eadweard Muybridge in the 1870s that artists and scientists could really begin to understand the movement of the horse. Eadweard Muybridge was one of the great inventors of the late 19th century. Although British by birth, Muybridge established himself as a landscape photographer in California. He was employed by Leland Stanford (railroad magnate and founder of Stanford University) to settle a bet. Stanford wanted Muybridge to prove that there was an airborne, period of suspension during the trot. Stanford owned a famous trotting horse called Occident who served as the test horse. Camera shutter speeds were too slow to capture moving subjects without blurring, so Muybridge developed a method of reducing the exposure time. Then he devised an ingenious system of still cameras triggered in sequence to record sequential photographs. Muybridge captured Occident's feet in the suspension phase, and Stanford won his bet. Later, working at the University of Pennsylvania, Muybridge did many other motion studies, taking 30,000 photographs of animals and people. In 1887, he published these in an 11 volume work titled Animal Locomotion. (Dover Publications, Inc. in New York reprinted some of these in a 1979 edition Muybridge's Complete Human and Animal Locomotion.) To study human movement, Muybridge often photographed his subjects without clothing, as in the sequence of a horse jumping with a nude rider. Other pictures in the book show naked farriers working at the forge; a hazardous occupation indeed. (Riders at the McPhail Center are encouraged to wear clothing during data collection, especially during the Michigan winters.) These studies in motion were to revolutionize thinking in many disciplines. Dr. Oliver Wendell Holmes attributed his design of artificial limbs to the Muybridge studies. Other doctors used them to understand and treat patients suffering from abnormal gaits such as lateral sclerosis. American realist painter Thomas Eakins owned a set of Muybridge's prints. Muybridge continued his studies of motion and experimented with equipment. He is credited with being a critical link in the development of motion pictures. However, more sophisticated equipment evolved during the next century allowing the study of locomotion in ways Muybridge never dreamed of. The advent of moving pictures and, later, the development of video cameras, greatly enhances our ability to visualize and analyze movements today. We are all familiar with the value of video for critiquing our own performance. In research studies, detailed analysis of videotape provides accurate information about the way the horse moves. This ultimately will help us to understand and prevent injuries like pulled suspensory ligaments, bone spavins, and pastern- joint arthritis. Other new equipment includes force plates that measure the forces between the hoof and the ground. Electromyography shows which muscles are active at certain times and various transducers indicate how different body tissues are being loaded. One application of this information could be the development of better footing which could reduces stress injuries. Computerization has revolutionized gait analysis by automating many of the tedious and repetitive tasks. For example, our studies often involve putting reflective markers on a horse and making a video of the horse in motion. During the analysis the markers on the horse are digitized on a frame by frame basis. This takes several hours, if we do it manually, but the computer can be programmed to perform this task in a fraction of the time. The resulting data then go through several stages of analysis that involve mathematical calculations. Again, the computer can be programmed to perform all necessary calculations automatically. No doubt about it, life in the lab is much easier than it used to be. Many trainers have come to appreciate the benefits of the scientific approach as a means of improving performance and enhancing soundness of athletic horses. The fact that you, the end users, are excited about the work we're doing in the McPhail Center is very gratifying and your feedback is useful in indicating which problems are most important to address in the future. The 21st century will be one of enlightenment not only for scientists, but also for you, the riders, trainers and judges of dressage horses who will apply the new knowledge. And herein lies my optimism for the future. We still have much to learn, but at least now we have the equipment and facilities needed to make real progress. The future looks bright! |