A sensor worn in the saddle cloth may help reduce the risk of catastrophic injury in racehorses.
Researchers, led by Warwick Bailey at Washington State University, have been working with the biometric sensor, developed by the company Stride Safe, to monitor Thoroughbred racehorses during racing and training.
By analysing the collected data, the team identified subtle stride changes linked to a increased risk of injury, enabling interventions before catastrophic breakdowns occurred. The researchers highlighted three horses flagged in 2023 at Churchill Downs in a report published in the Journal of the American Veterinary Association.
The sensor tracks changes in the rate and direction of a horse's leg and body movements, generating graphs of its stride pattern. An algorithm processes this data and compares it to an "ideal stride" derived from high-performing, sound racehorses. Using data from over 6,500 starts, the algorithm also identifies similarities with strides from horses that suffered catastrophic injuries. The horse is then assigned an injury risk factor from 1 to 5, based on how much its stride deviates from the ideal and how similar it is to an injury-associated stride.
Risk status was categorized from 1 to 5. Horses with a risk factor of 1 had a stride pattern within 2 standard deviations (SDs) of the ideal stride, while those with a risk factor of 5 had a stride pattern more than 5 SDs from the ideal stride. Horses with a risk factor of 5 were 950 times more likely to suffer a catastrophic injury than those with a risk factor of 1.
In a database of 6,618 starts, 70% were categorized as risk factor 1, 16.5% as risk factor 2, 7% as risk factor 3, 3% as risk factor 4, and 3.5% as risk factor 5.
“These racehorses get extensive examinations before races, but catastrophic injuries still happen, and not because they stepped in a hole or took a bad step. A large percentage have a pre-existing pathology not readily apparent on clinical examination,” said Dr. Denise Mc Sweeney, an equine surgery resident at WSU who was the first author on the study. “From our sensor data, we know most catastrophic injuries have a distinct stride pattern. Now we can see when there's something wrong with their strides and step in before a major injury occurs.”
“We know there are about 1.25 catastrophic injuries per 1,000 starts, but identifying those horses before such an event occurs is like finding a needle in a haystack, as they are often subjectively sound during a pre-race examination, and many don’t show any decrease in performance,” Mc Sweeney said. “But if you can narrow it down, like the 3.5% we had out of that group, it is a lot easier to intervene and hopefully prevent injuries.”
To test and refine the algorithm, a sensor was placed on horses starting at Churchill Downs and Ellis Park in Kentucky from April 29 to July 2, 2023. Mc Sweeney was responsible for collecting clinical data on the high-risk horses.
In their report, the team focused on a pair of 3-year-old colts and a 4-year-old stallion flagged as category 5.
In each instance, the sensors alerted veterinarians and trainers to potential injury risks. The abnormal stride pattern was detected either during racing (cases 1 and 2) or while breezing (case 3) (a training run where the horse is allowed to run at a swift pace, often close to its maximum speed)
Subsequent veterinary examinations and 18F-sodium fluoride (18F-NaF) positron emission tomography were conducted in each case. The research team discovered significant 18F-NaF uptake in the condyles of the third metacarpal bone in cases 1 and 2, identifying these horses as being at increased risk for condylar fractures. In the third case, the 18F-NaF uptake pattern indicated that the third carpal bone was likely causing the horse’s lameness. Radiography confirmed an impending slab fracture.
The researchers report that “following periods of convalescence, cases 1 and 2 returned to racing and were identified by the sensor system as no longer being at high risk of catastrophic musculoskeletal injury. Case 3 returned to training but has yet to return to racing.”
“These are prime examples of how this technology can prevent horses from breaking,” Mc Sweeney said. “With this information, the trainers and their vets were able to put the brakes on, and now these horses are going on to have longer careers and, hopefully, avoid a catastrophic injury.”
Mc Sweeney is hopeful the sensors will become standard for all thoroughbred racing and training. “I believe this is going to make a huge impact,” she said. “The sensors can save the lives of horses and jockeys – they already have.”
For more details, see:
Using accelerometers to identify a high risk of catastrophic musculoskeletal injury in three racing Thoroughbreds
Denise Mc Sweeney DVM, MS, Mikael Holmström DVM, PhD, Kevin D. Donohue PhD , David H. Lambert BVSc, and Warwick M. Bayly BVSc, PhD, DACVIM
https://doi.org/10.2460/javma.24.02.0114
See also: https://www.stridesafeusa.com
