The science of equine performance with Dr. Hilary Clayton

Dr. Hilary Clayton

 

Hilary Clayton here. I’m going to be writing a series of blogs with Sleip that will cover a range of topical subjects in the world of sport horses. For this first blog, though, it’s been suggested that I introduce myself. So here goes.

My journey

I was born in Matlock, a small town in the middle of England, a long time ago. I grew up in the English countryside where I developed a love of animals and nature. I discovered horses when I was about 10 years old and was hooked for life. Looking back, it’s amazing how something as simple as taking a few lessons at the local riding school set in motion a chain of events that brought me to where I am today.

Throughout my teenage years I was active in equestrian pursuits. The Pony Club provided a broad foundation not just in equitation but also in stable management and general horse care. It brought opportunities to participate in many types of competitions from gymkhana games to eventing.

In high school I studied the sciences and worked hard to get good grades in order to pursue my chosen career as a veterinarian.  At that time, veterinary medicine was very much a male-dominated profession with only a few women being admitted to veterinary colleges each year. In spite of the long odds against being accepted, this was my ambition and through hard work and determination I was accepted to the Glasgow University Veterinary College in 1968. 

Five years later, I emerged as a fully qualified veterinarian. My first job was in a six-person, mixed animal practice. It was a period of intense learning and skill development. Although I worked with all types of animals, I found myself gravitating towards small animal practice, especially surgery.

After two years in practice, I was keen to try my hand at doing research and entered a PhD programme at Glasgow University in the Department of Veterinary Parasitology. Parascaris equorum, the equine roundworm, became my worm and for almost 3 years I was immersed in its life history, pathogenesis, and treatment. I have to tell you about my first experiment because it’s the stuff that research dreams are made of.

Little was known about P. equorum when I started my PhD, so my first experiment was a very simple one that would pave the way for more elaborate studies later. It involved oral infection of worm-free pony foals with different numbers of P. equorum eggs. Four months after infection, foals that received 100 eggs were thin and pot-bellied and they had about 100 huge roundworms in their small intestine. Foals that received 10,000 P. equorum eggs appeared normal in size and weight in spite of having 10,000 small worms in their intestine. I was hooked on research - but not on worms.

Equestrian sports had always been my passion, and I was drawn to research on sport horses but this wasn’t a “thing” yet. In the 1970s, Swedish veterinarians were applying high-speed cinematography and aerospace technology to study the gaits of trotters. I found this type of research fascinating and started to explore opportunities to do research in equine gait analysis. The search led to a position at the Western College of Veterinary Medicine in Saskatoon, Canada, where Dr. Doug Leach had an equine gait lab equipped with high-speed cine cameras and a Vanguard Motion Analyzer. Although this was state-of-the-art equipment in the early 1980s, it was unbelievably tedious and time-consuming to use. It would take weeks to get results of a simple two-dimensional study. Having been there and done that, I am truly appreciative of the current gait analysis systems. 

The last two decades of the twentieth century were a time of tremendous advancement, not only in equine gait analysis, but also in the developing area of equine sports science. This was where I wanted to be. I became involved with the Association for Equine Sports Medicine (AESM), which had been started by a group of veterinarians in the Western USA who were interested in endurance racing. Soon afterwards, the first International Conference on Equine Exercise Physiology (ICEEP) was held in the UK. At that time, most of the equine sports science research involved physiological studies of the cardiovascular, respiratory and muscular systems. Biomechanics was only a small part of sport science in the beginning - but how times have changed! At the last ICEEP, biomechanics was the topic area with the largest number of presentations. The rapid rise in biomechanical productivity was largely due to computerization and software development that can now deliver almost instantaneous results.

In 1997 I moved to Michigan State University to become the first incumbent of the Mary Anne McPhail Chair in Equine Sports Medicine – the opportunity of a lifetime! Three years later, the university opened the McPhail Equine Performance Centre. It was one of the first of a new generation of buildings that incorporated research and clinical activities under the same roof. Over the years, I acquired equipment for 3D analysis of kinematics and ground reaction forces as well as a saddle pressure mapping system. Often, though, we would have to cobble together our own equipment – what would we have done without duct tape and baling twine!

Over the years, my own research has covered a wide range of topics related to equestrian biomechanics. I’m going to take you on a quick tour here and you can look forward to revisiting these topics and learning more about what we learned in future blogs.

Bit studies using fluoroscopy

At Glasgow University I initiated a series of fluoroscopic studies investigating the position and action of various bits in the horse’s mouth. The results were published and received a lot of attention over the years. About 20 years later these studies were revived and continued in Michigan.

Cervical kinematics

The neck is a highly mobile part of the spine and this study was the first to measure the maximal range of motion in flexion-extension, lateral bending and axial (twisting) rotation in cadaver specimens of foals and adult horses. 

Hoof trimming and shoeing 

As the interface between the horse and the ground, the hoof is of fundamental importance in generating the forces that drive locomotion and in determining how those forces are transmitted through the limbs to the horse’s body. My studies in this area have looked at how the hoof adapts to barefoot trimming, the effect of shoes on the flight arc of the hoof and the effects of shoe design on breakover.

Olympic studies of sporting performance in dressage and show jumping horses

My research team was chosen to collect biomechanical data during the dressage and show jumping competitions at the Olympic Games in Barcelona in 1992 and Atlanta in 1996. In the dressage arena we analyzed data for the basic gaits and for the’ 3 Ps’ – passage, piaffe and pirouettes. In the show jumping competitions our focus was on how jumping characteristics change over different fence types (vertical, spread, water) and on the factors that determine success in clearing a water jump.

Time motion analysis and conditioning programs

In addition to studying gait analysis, I have always been interested in conditioning programs for equine athletes and how to customize these for different sports. The first book I wrote was called Conditioning Sport Horses and I have continued to develop conditioning techniques and programs both to improve athletic performance and for rehabilitation.  

Rein tension 

Rein tension was a mystery until the early years of the 21st century. As a rider I knew it was important but there was no information on this topic and no commercially available systems to measure it. So the first challenge was to put together the components to make lightweight sensors and transmit the data to a storage system. Thank goodness for duct tape and baler twine! The results turned out to be quite surprising as you’ll learn in a future blog.

Pressure on the horse’s back

The majority of equestrian sports are based on the suitability of the horse’s back to carry a rider but the mechanical effects of the rider’s weight can have implications for the horse’s soundness. The rider’s ability to coordinate with the horse’s movements is a major component of the harmony between rider and horse. Additionally, communications between rider and horse are key to a good performance. 

Physiotherapy research

One of the skills of managing a research program is recognizing emerging areas that will benefit from evidence-based information. Veterinary physiotherapy is an area in which my lab was at the forefront of investigating the outcomes of different types of therapy and providing evidence-based research on the techniques used by equine therapists. The rehabilitation field has grown enormously over the last 10-15 years and it’s gratifying to see many more studies being performed in this area.

Dynamic balance of the horse

A series of studies of high-level dressage horses, both warmbloods and Iberians, has studied how horses control their balance to achieve collection and self-carriage.  We identified changes in limb positioning and coordination of the limb movements as well as the ground reaction forces. This line of research has proved to be crucial in understanding the mechanics of piaffe and passage.

This is a sampling of the research I’ve done and that I will enthusiastically share with you in future blogs. Before signing off, I have to stress that my research would not have been possible without the help of colleagues, grad students, students and volunteer riders with their horses. There are too many to list everyone by name but you know who you are and I am grateful to you all!