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Research Features - High Stakes

University of Maine Professor of Mechanical Engineering Michael Peterson invented a biomechanical hoof device for testing racetracks. Designed to duplicate the force produced by a running horse, the mechanism measures the impact and horizontal movement of the hoof hitting the surface. With it, Peterson can test the response of the track to the impact of a horse hoof during a race and measure the forces placed on a horse's leg. Data generated by the robotic device can help horse owners and trainers, jockeys and track managers make more informed decisions about racing on certain surfaces and in particular conditions. In addition, it could lead to standardization of tracks, ensuring uniformity between racing surfaces.

University of Maine Professor of Mechanical Engineering Michael Peterson invented a biomechanical hoof device for testing racetracks. Designed to duplicate the force produced by a running horse, the mechanism measures the impact and horizontal movement of the hoof hitting the surface. With it, Peterson can test the response of the track to the impact of a horse hoof during a race and measure the forces placed on a horse's leg. Data generated by the robotic device can help horse owners and trainers, jockeys and track managers make more informed decisions about racing on certain surfaces and in particular conditions. In addition, it could lead to standardization of tracks, ensuring uniformity between racing surfaces.

Just over a year ago, the sight of Barbaro shattering his right hind leg at the start of the 131st running of the Preakness sent up a collective gasp heard coast to coast. The national vigil during the colt’s eight-month struggle to recover from his catastrophic injury drew millions of fans, including many who knew little about horse racing, but were captivated by his story.

However, for those who know horses and racing, the now unforgettable image of Barbaro’s catastrophic injury that ultimately ended his life this past January was eerily familiar.

Those in the racing industry remember Ruffian, the equally promising 3-year-old filly who similarly captured the hearts and minds of Americans in 1975, only to break down at Belmont Park and be euthanized. In the 1990 Breeder’s Cup, another 3-year-old, Go for the Wand, broke her front right foreleg and was put down.

Through the years, other catastrophic injuries only ended the racing careers — not the lives -— of high-profile horses, as in the case of Charismatic, who recovered in 1999 after breaking his left foreleg.

Then there are the untold numbers of local racers like Miss Pretty Promises, a 2-year-old quarter horse who crossed the finish line in seventh place at Retama Park, Texas, in April 2006, only to crumple to the ground with both front legs broken, as detailed by the San Antonio Express-News.

No nationwide statistics are kept on the number of racehorses each year that sustain catastrophic injuries, but most industry officials and veterinarians agree that the rate is low. The number often cited: fewer than two fatal injuries in 1,000 race starts.

But all agree that’s two horses too many.

“Since World War II, there’s been a consistent decline in the number of starts per horse and the lengths of race horses’ careers,” says biomechanics expert Michael Peterson, who uses engineering principles to understand the dynamics of animal motion. “The horses are facing multifactorial risk — from genetics and training protocols to an emphasis on racing younger and the priorities of the racing business. Tracks have improved, but not enough. But if we can take tracks out of the equation, we can then focus on other concerns. The goal is to keep horses and jockeys safe.”
In 1994, an industry panel called for a quantitative evaluation of racetracks. The panel, which included noted horse trainer Richard Mandela, and track superintendents Dennis Moore of Hollywood Park and Steve Wood of Del Mar and Santa Anita parks in California, turned for answers to veterinarian and equine orthopedic surgeon C. Wayne McIlwraith, who directs the Orthopedic Research Center at Colorado State University, and Peterson, a researcher at Colorado State before joining the University of Maine mechanical engineering faculty in 1999.

Peterson and Colorado State graduate students conducted preliminary investigations of the effects of track surfaces on joint loading or stress in racehorses. As a horse runs, the pressure on the legs depends on how fast the hoof stops, how hard the landing is and how much resistance is present as the animal pushes off.

Traditionally, it’s believed that a track that is too soft causes bowed tendons, while an extremely hard track results in broken legs. Today, Peterson and others are saying disease and injury risks are more complicated.

“When the leg on a horse breaks, it is not usually just because of a bad step but because of accumulated damage to joints and bone,” he says. “That suggests that any solution to joint disease has to start from the beginning of the horse’s life.”

Peterson began focusing on a track’s shear strength — the pressure of the surface on the front and back of the hoof as the horse stops and pushes off. If the shear strength is low on a “cuppy” track, the hoof slips as the horse propels itself forward, risking tendon and soft tissue injury. If the shear force is high, the pressure on the hoof causes increased horizontal stress on the bones in the hind legs producing the huge forces needed to propel the racehorse at a gallop.

Both the hardness and shear strength of the track directly affect the forces exerted on the horse as it runs, says Peterson. Understanding these forces and keeping them in an acceptable range are essential to injury prevention.

The more Peterson talked to veterinarians and track superintendents, the more he recognized the need for a device to measure variations between tracks, including deviations beneath the well-groomed surfaces. Peterson was particularly concerned about deep compaction — hard spots related to that “proverbial bad step.”
Peterson invented a biomechanical hoof device for impact testing on racetracks. Designed to duplicate the force produced by a running horse, the mechanism measures the vertical and horizontal accelerations, and vertical force on the hoof hitting the soil. With it, Peterson can test the response of the track to the impact of a horse hoof during a race and measure the forces placed on a horse’s leg.

With data generated by the robotic device, horse owners and trainers, jockeys and track managers can make more informed decisions about racing on certain surfaces and in particular conditions.

In 2004 at tracks in California, Peterson used the device to find inconsistencies among surfaces at different tracks, as well as something no one expected — deviations in individual tracks. Along one backstretch, the vertical stiffness of the track “dropped off the map.”

“It was so much softer,” Peterson says. “It would be like the difference between running on grass and then on a street. In no way can that be good for a horse.”

Soil samples confirmed uniform surface composition, but ground-penetrating radar revealed that 8 inches down, an underground stream or poor drainage had caused a washout. After the track bed was reconstructed, the backstretch was retested and found consistent.

“What I like about that is we found the problem before trainers and veterinarians found bowed tendons in the horses. That’s the goal. We don’t want to be waiting to have a backlog of injuries for the track veterinarian before determining if it’s a track-related problem,” says Peterson, who has had inquires about his testing system from as far away as Australia, where there is interest in standardizing tracks.

Last October, Peterson was among the national experts and prominent members of the thoroughbred breeding and racing industry who gathered in Lexington, Ky., for a Welfare and Safety of the Racehorse Summit, sponsored by Grayson-Jockey Club Research Foundation and the Jockey Club. The goal was to identify critical issues affecting horse health and longevity of racing careers, and to develop a strategic plan to address those problems.

Participants focused on issues related to the decline in the racing careers of thoroughbreds in the last 50 years in terms of fewer years raced and annual starts. Two of the resulting six recommendations from the summit deal with injury monitoring, including development of a national injury reporting and surveillance system. Another recommendation calls for safer racing surfaces throughout the country, gathering data to ultimately implement a certification and standardization process for racing surfaces.

Implementation of the recommendations by industry stakeholders or regulatory agencies is purely voluntary.
The Welfare and Safety of the Racehorse Summit was held at Keeneland, a horse racing complex that was among the first in North America to install a Polytrack surface made of silica sand, fibers, recycled rubber and wax. Keeneland’s fall race meet last October was the first conducted on the new track.

This past March, Del Mar Park in California also announced the debut of its new Polytrack racing surface for this season, making it the fourth horse racing facility in the country to replace dirt or turf with engineered material. The California Horse Racing Board has mandated that all major tracks in that state have synthetic tracks installed by the end of this year.

Installation of the new surfaces, costing upward of $10 million per track, has led to improvements in base layers, reducing variations around a track from 24 percent to 7 percent, Peterson says. And at least initially, that has translated into fewer catastrophic injuries.

Nevertheless, Peterson worries about the “synthetic movement,” which has its roots in Europe and England. In particular, he is concerned how this surface is going to hold up under different environmental conditions and uses. Like traditional dirt horse tracks used for generations yet largely untested, the new synthetic surfaces leave engineers like Peterson with more questions than answers.

“In England, these tracks are used for racing only,” Peterson says. “But you take Del Mar, where between 5 and 10 a.m., there can be as many as 2,000 horses that have worked out down the straightaway.”

In addition, says Peterson, the synthetic track movement has divided the horse racing industry into the “haves and have nots.”

“I’m worried about those facilities that can’t afford $10 million tracks to keep horses sound,” he says. “That’s a huge challenge for fairgrounds and other smaller tracks without the big stakes appeal.”

Research on how to test and maintain the synthetic tracks in the United States for the optimum safety of horses and jockeys could be the next set of questions Peterson tackles. He also is now looking for a dirt horse track where he can spend a season collecting data.

“I’d like to see standard maintenance protocols according to the compositions of the tracks,” he says, “including responses to changes in temperature and moisture content.”

 


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