Ever since the 1880s, when Edweard Muybridge set up a series of cameras to capture the character of footfalls of a racehorse, we’ve been fascinated by how horses move. No doubt you’ve seen that early sequence of photos, which demonstrated that the artists who produced hunting prints and racing scenes were wrong: horses didn’t trot or gallop in great leaps like a rabbit, with all four feet off the ground, but instead performed a complex pattern of footfalls which propelled them forward too fast for the human eye to catch every detail.

Muybridge’s work not only changed the face of equestrian art (the transition is particularly obvious in the work of the great impressionist Degas, who incorporated realistic galloping poses in his paintings of European racecourses after the photos were published), it launched an entire field of study which continues to fascinate us today. For horses don’t just walk, trot, and canter. They pace, they fox-trot, they tolt, they rack, they perform paso largos and running walks and a vast array of other gaits. They take ordinary gaits and transform them, with training, into elegant maneuvers like piaffe, passage, and pirouettes. They move differently when carrying a rider than when they’re performing on their own. They move differently, too, when they’re sound than when they’re sore or diseased. And how their various joints and limbs behave as they move—and the forces they exert, and receive—provide us with an endless series of questions to answer, and avenues to explore, in the study of equine locomotion.

Hilary M. Clayton, BVMS, PhD, has made the gait analysis of sport horses her life’s work. After 15 years at the University of Saskatchewan, she relocated in 1997 to Michigan State University in Lansing, Michigan. There, under the auspices of the McPhail Endowed Dressage Chair (a permanent position created by MSU alumnus and dressage enthusiast Mary Anne McPhail and her husband Walter), she established the McPhail Gait Analysis lab, with the objective of creating a center for the scientific study of the sport of dressage, with a special emphasis on soundness problems.

At MSU, Clayton is continuing to explore the many ways in which horses move, using a number of sophisticated techniques including high-speed video analysis, force plates which measure the impact of the equine foot on the ground, and computer analysis. Her work combines veterinary science with the nuts and bolts of biomechanics, and, indeed, the staff and graduate students who populate Clayton’s lab are as likely to come from a background in mechanical engineering as from vet school. With an amazing number of projects on the go at any given time, her lab must be not only one of the busiest in North America, but also one of the most productive