Recent misstatements and misquotes in the press and in social media have led to some confusion about what we know about racing surfaces. While the development of an optimal racing surface remains elusive, the last 20 years has seen considerable progress in our understanding. On the topic of racing surfaces we have during this time published 14 studies in refereed journals, advised two PhD dissertations and four Master's theses and, whenever possible, put these ideas into practice. The challenge remains; the inconsistency of racing surfaces in a range of climates and weather must be reduced.
This somewhat eclectic mixture of an engineer and an equine orthopaedic surgeon first got together at Colorado State University (CSU) in 1998. We started with the biological question of cyclic trauma and bone microdamage leading to fracture (characterized by Chris Kawcak in his PhD work at CSU) and then started on the best engineering approach. Our first study examined the possible effects of different dirt racetrack surfaces by using dynamic modeling of the horse and track to quantify the vertical loading of the lower limb, which was published in 2000. With the support of AQHA Racing, we then developed a biomechanical test machine to replicate the loads and speeds of a Thoroughbred forelimb at the gallop, this machine was used to evaluate hoof track interface in racehorses as well as the effects of track maintenance on mechanical properties at Hollywood Park, Santa Anita and Del Mar. Like many studies, this effort raised more questions than it answered. However, we quickly moved from understanding to trying to reduce the inconsistency we observed.
Our first attempt at reducing variation took the form of developing a way to inspect the track base. With support from the Southern California Equine Foundation, we pioneered the use of ground penetrating radar to inspect the base of the racetrack. The next challenge was the inconsistency of the track composition. At that time, different material testing labs were used throughout the industry with inconsistent test methods. The first material testing laboratory in the world focused on racetrack materials was established with leadership from Dan Fick at The Jockey Club. With funding from an industry consortium, we co-founded the non-profit Racing Surfaces Testing Laboratory. Progress continued as a part of The Safety from Start to Finish initiative from Churchill Downs. This support allowed us to develop the first standard test protocol for racing surfaces which combined material testing, base inspection and biomechanical testing of the surfaces. More recently, the New York Governor's Task Force emphasized the need for electronic records and consistency of daily testing. Throughout this work, one theme was repeated; consistency of racing surfaces needs to improve.
From a pragmatic perspective, each source of variation in the surfaces was systematically addressed. Borrowing the language of American manufacturing, we were addressing our process variation to move toward a six-sigma process. It is impossible to eliminate defects; in manufacturing a six sigma process reduces defects to a statistical chance of one defect in 3.4 million parts. In manufacturing, a six-sigma process means that most workers and consumers will never encounter a defective part. We need to make sure the same is true of a catastrophic injury. When lives are at risk on an airplane, or from a horse racing surface, risk minimization must be central.
The death of a race horse from a catastrophic injury is far too common with 1.6 horses per 1,000 starts on all surfaces. Catastrophic injuries are difficult to study because of the uncertainty of their occurrence and multiple causes. Therefore it is critical that every veterinary check and every piece of maintenance equipment is perfect every day. The injury of a horse or rider is a failure of multiple systems, including pre-race exams, the inability to recognize early microdamage, medication rules and preparation of the racing surface. In other words, either the nearly perfect horse on an imperfect surface or an imperfect horse on the nearly perfect surface provides opportunity for catastrophic injury. How do we improve this one part of the multi-factorial equation and obtain a nearly perfect, or six sigma perfect, surface?
With over two decades of work with racing surfaces, the single most significant variable on a dirt or turf racing surface is moisture content. To provide an optimal footing, the moisture content of the surface must be consistent. Like walking on a beach, the wet areas near the water result in deeper footprints as do the drier areas away from the water. Synthetic surfaces dramatically reduce the effect of water. The wax coating not only assists in the movement of water through the surface, but also reduces the role of water in friction between the grain particles. The effect is undeniable. In the annual results from the Equine Injury Database maintained by The Jockey Club, synthetic surfaces reduce overall injury rates from 2.0/1,000 starts on dirt to 1.2/1,000 starts on synthetic. The most comprehensive academic paper on the Equine Injury Database controlled for all other known variables found the same result; synthetic surfaces are safer. For the 380,000 starts over the last decade on synthetic surfaces, that difference in injury rates represents 300 fewer horses lost and 300 riders who were not put at risk.
However, questions remain with synthetic surfaces: synthetic surfaces become difficult to maintain with age, and trainers continue to question if the careers are genuinely longer for horses who race on synthetic surfaces. It has been speculated that a different pattern of injuries is leading to shorter careers from racing on synthetic surfaces. Research by John Bridge at University of Washington Bothell has looked at the mechanisms of wax degradation in racetracks. This approach has the potential to extend the life of these surfaces to ensure a consistently safe surface over time. Concerns by trainers about the length of racing careers must also be addressed. If the biomechanics of these surfaces lead to a different pattern of career ending injuries, a redesigned synthetic may produce better biomechanics. However, the data is clear: synthetic surfaces are safer.
While synthetic surfaces are an obvious solution for a number of locations and racing conditions, unanswered questions and the short life limits their applicability. Turf and dirt racing currently dominate the horse racing industry. Closing the gap in catastrophic injuries from 2.0/1,000 starts on dirt to 1.2/1,000 starts on synthetic or reducing the rate of 1.5/1,000 starts on turf requires a multi-pronged approach. Data from the Equine Injury Database shows a large variation in injury rates between years on both dirt and turf surfaces. In some cases, differences between years results from the small number of starts, but the consistent performance of synthetic surfaces eliminates most explanations. While many risk factors vary between years, the most obvious cause is weather which result in different moisture contents.
Moisture variation is a defect for dirt and turf racing surfaces that causes uncertainty. Too wet, too dry or inconsistent moisture content dominates risk for a natural racing surface. Maintenance can address some of the differences, but timing with changes in moisture content is critical. Moisture content and the reduction of moisture variation in the surface is almost certainly the way in which the safety of dirt and turf tracks can rival that of synthetics. While tens of millions of dollars have been spent on synthetic surfaces, best practices such as overhead watering of turf tracks have not been adopted. For dirt tracks, a complete new approach is needed. Technology to produce consistent moisture content must be developed and deployed. Current use of water trucks and sealed tracks are inadequate to provide an appropriate racing surface under any weather conditions. More information is needed to improve decision making regarding watering and for critical maintenance decisions. Moisture variation in the track due to shadows or wind must be better reduced. For a fraction of the cost of a synthetic track surface, advanced water trucks and sensor networks can provide the tools for safer racetracks. Real-time measurements of the track surface can both protect the athletes and contribute data to our understanding of the sport.
It is to be recognized that there are other causative factors to injury and these can potentially be mitigated against the risk. A good example that we have been working on at CSU for over 20 years is fluid biomarkers that can identify a horse at risk. Drs. Frisbie and McIlwraith at CSU published a study with equine practitioners in Southern California where we looked prospectively at blood biomarkers to predict injury. In a study published in 2010, we demonstrated a 79% predictability six weeks ahead of an injury that something was awry and further imaging evaluation was indicated. Unfortunately, it was difficult to combine the seven assays into a commercial test that was inexpensive enough to be used routinely, but our vision remains that we will ultimately have a blood panel that can identify a horse at risk and then we could go ahead with more sophisticated imaging to define the damage, and hence, risk. We are currently collaborating with other investigators with expertise in metabolomics and our results so far indicate that we can separate the horse with early damage from the horse without damage and hence risk.
Clearly, while surfaces are only a part of a complex equation they must be improved. The idea of six-sigma in manufacturing is the reduction of variation so that we may never see a defective part. The defects in a racing surface must also become so infrequent that fans and owners will be unlikely to experience a track without an optimal surface. Improved certainty in the track surfaces will also reduce the chance that a fan will ever see a catastrophic injury of a horse and the associated risk to a rider. The right technologies should make it possible to reduce, or even eliminate, the gap in safety between synthetic and the other surfaces. Increasing the number of synthetic surfaces and extending the life of current synthetic surfaces will also move racing safety in the right direction. Safe racing must be possible even when the weather is uncertain. No track has been, or will ever be, 100% ready for racing, but uncertainty can be reduced and track defects can be minimized.
Mick Peterson, Ph.D. is Executive Director of the Racing Surfaces Testing Laboratory and a Professor of Biosystems and Agricultural Engineering at the University of Kentucky, Wayne McIlwraith, DVM, Ph.D. is an equine orthopedic surgeon and a University Distinguished Professor and Barbara Cox Anthony University Chair in Orthopaedics at Colorado State University.