Racing Surfaces Testing Laboratory director Christie Mahaffey, left, and undergraduate Molly Segee prepare a machine that simulates the loading of a horse’s hoof to test surface stiffness, which varies with temperature. That information is being compiled in a database correlating racetrack surface conditions with horse injuries in North America.
The antique Cape Cod-style house on a quiet corner in Orono, Maine, belies its latest occupant. Computers, laboratory benches, and hefty equipment and machinery dominate the furnishings. Lining the walls are stacks of plastic buckets containing labeled soil samples from horse racing tracks all across the United States and Canada. While the Racing Surfaces Testing Laboratory may keep an outwardly low profile, the horse racing world is beating a path to its door, hoping to tap into research to improve what have been increasingly long odds in recent decades against keeping equines and their jockeys safe.
Racing Surfaces Testing Laboratory founder Michael “Mick” Peterson, the University of Maine Libra Professor of Engineering, has been contracting with track owners and racing industry leaders since 2004 to test the strength, stability and water-retaining qualities of track surfaces, both natural and synthetic. Groups include Churchill Downs Inc., which launched a Safety from Start to Finish program three years ago and has had Peterson evaluating its racing surfaces.
Interest in Peterson’s work has surged in response to recent high-profile racing injuries that have captured public attention. In 2008, the 3-year-old filly Eight Belles was euthanized on the track after breaking both front ankles immediately following a second-place finish in the Kentucky Derby. In 2006, the colt Barbaro, a favorite for that year’s Triple Crown, shattered 20 bones in his right hind leg while running the Preakness. Barbaro was put down eight months later after efforts to rehabilitate him failed.
Such devastating injuries raise important questions about track conditions and other factors, says Christie Mahaffey, who received her Ph.D. in mechanical engineering in May and serves as director of the laboratory.
“If a track can say, ‘We’ve done all this testing and we have the numbers to back up the integrity of our track,’ then it forces officials to look at other issues like drug use, training and genetics,” she says.
Mahaffey is examining the interface between a horse’s galloping hoof and the track surface it strikes. She earned her undergraduate degree in biology from Pennsylvania State University and her master’s from College of the Atlantic in Bar Harbor, where she studied the use of spatial modeling to predict the risk of whale strikes — collisions between whales and ships — in the Gulf of Maine.
In the Racing Surfaces Testing Laboratory, UMaine undergraduate Julia Bradson, left, prepares samples from racetrack surfaces for the drying ovens. In preparation for triaxial shear testing, Molly Segee then mixes the dried material with a measured amount of water and compacts it.
Using the biomechanical hoof Peterson invented to study racetrack injuries, Mahaffey focuses on “the first impact” — the split-second of the hoof’s initial contact with the track and its small but crucial slide before the horse shifts its weight onto the extended leg. The degree, angle and depth of that slide, and the track conditions that affect it, are critical factors in injuries sustained by racehorses, she says.
The robotic hoof is aligned to hit the ground flat while simultaneously sliding at an 82-degree angle. It slams the track surface with the equivalent energy of a horse’s impact at full gallop and generates readings on dozens of points representing the hoof and leg.
Mahaffey has used the robotic device to collect data at tracks and arenas in New York, Florida, Kentucky, California and other states.
Racetrack composition in the U.S. varies regionally. West Coast tracks often are built with more clay than those in the East in order to preserve moisture due to lower precipitation and humidity. The clay helps maintain the desired shear strength, but may reduce cushioning and make the track surface too hard. Eastern tracks often employ more sand to promote drainage, but may lose shear strength.
Variations in composition within one track are also dangerous.
By improving the understanding of how specific track materials and moisture conditions affect the way a horse’s hoof lands, Mahaffey says her research can help track owners create optimal race surfaces for horses.
Peterson’s lab also involves undergraduates from a variety of disciplines in the research. Julia Bradson, a second-year student, is majoring in international affairs with a minor in soil sciences. She and Molly Segee, a fourth-year mechanical engineering major with a minor in robotics, analyze track samples for moisture capacity and shear strength.
Nick Hartley, a senior in civil engineering, spent a couple summers as a soils tester and inspector for the Maine Department of Transportation (MDOT). At the MDOT central testing lab in Bangor, he encountered the Microal test, a mechanical process for measuring the rate of degradation in a soil sample. MDOT uses the test to evaluate road construction materials. In Peterson’s lab, Hartley quickly saw how the test could be used for analyzing racing surfaces.
“With my information and a single phone call, the Santa Anita racetrack in California committed to purchasing the machine for the lab and sponsoring a project on wear in racing surface materials,” Hartley says. “It shows me that different disciplines have to work together in real-world applications.”
