Stride analysis
![TRIDE analysis technology has now given trainers the option of employing an accurate, scientific aid to bolster their understanding. Simple to use, automated stride analysis technology is still in its infancy and is now available on the market. Only time will tell how much value it will add, or whether it can supersede jockey feedback and the observation of the naked eye, but the early signs are encouraging. The extent of man’s fascination with the Thoroughbred stride is best emphasized by the fact that the first motion picture displaying device in history, the zoopraxiscope invented by Edweard Muybridge, was developed in order to settle an argument on whether all four of a horse’s hooves were ever off the ground at the same time during a gallop. On the other hand, the importance of stride analysis might be best emphasized by expensive two-year-old The Green Monkey, who was sold for $16 million on the basis of his 9.8-second breeze at the 2006 Fasig-Tipton Calder sale. EQB, a bloodstock agent and consultant company that offers gait analysis as part of their package, would have advised against buying the colt. EQB said of The Green Monkey’s breeze: “…high-speed film revealed that the entire work was done at a rotary gallop, a very quick gait that can produce fast times but costs more The stride of the Thoroughbred has been a subject of fascination for horsemen since the early days of racehorse breeding. Furthermore, trainers of the racehorse have for a long time recognized the importance of stride patterns as a factor in ascertaining an individual’s ability, fitness, and soundness as well as predicting what distance it will be suited to and on what going it is most likely to act. WORDS: DaviD ThiSelTOn PhOTOS: GeORGe SelWYn, Si BaRBeR S RACING energy and is unlikely to be maintained over longer distances.” The Green Monkey ran three times, running third once and fourth twice, before being sent to stud for a covering fee of $5,000. EQB were pioneers in “gait analysis” 25 years ago and also invented the world’s first heart rate monitor. Today they consult some of the top racing stables in the U.S. They use digital highspeed video equipment in order to analyze a horse’s stride in ultra-slow motion, digitized to hundreds of pictures per second. Their extensive research revealed a positive correlation between the efficiency of the stride and subsequent racing success. They divulged, “Once a horse attains racing speed, the motion of the limbs consumes the most energy, and efficiency in this area is worth noting. Extraneous limb motion can also have soundness consequences.” The “extraneous” movement is often impossible to spot with the naked eye, or even with regular video, and EQB also pointed out that “inefficiencies seen at racing speed are often unpredictable from the conformation and walk seen back at the barn, which may seem perfect.” EQB also provides data with which to study stride length, stride frequency, extension and other parameters of a horses’ gait, and the company measures horses’ cardiovascular systems with ultrasound in addition to offering a variety of traditional bloodstock services. Equitronics, an Australian company, recently achieved a world first when adding a stride length function to its automated system, which is called E-Trakka. E-Trakka’s electronic horse blanket collects the raw stride length data, in addition to speed, heart rate, GPS, and sectional timing data, and the system’s software processes it into meaningful displays. Andrew Stuart, who developed the E-Trakka system, is a former jockey and trainer who has dedicated most of his career to improving the professionalism of the racehorse training industry. His methodology marries science, art, and what he calls “good old fashioned horse sense.” The stride length function of the E-Trakka system has added immeasurably to the chances of identifying a horse’s inherent ability, as well as his chances of picking up soundness issues and his capacity to monitor fitness. It could also contribute to a “best guess” of the horse’s optimum racing distance. Stuart and his team noticed, after a lot of raw data collection, that there was a very close relationship between stride length and speed in the zone between 28 and 60 km/hour, or roughly 17 and 37 mph. He said, “In the average workout there is a lot of data in this zone and 50 km/hour (approximately 31 mph) was identified as the most relevant point.” The resulting “SL50” (Stride Length 50) number is the captured stride length at the time the horse travels at 50 km/hour. With the use of “high end maths,” the SL50 is computed after the analysis of hundreds of individual strides. To date the SL50 range has been between five, six, and seven meters (about 16.4, 19.7, and 23 feet) with an average of 6.1, or 20 feet. Graded horses tend to have an SL50 larger than 6.5 (21.3 feet). The E-Trakka Profiler software also provides all other stride length readings during a workout, including stride length at peak speed. The stride length of a Graded horse at peak speed could get close to eight meters, or some 26.2 feet. For a 1200 meter (about 6-furlong) race, a horse travelling at 61 kph (38 mph) with an average stride of 6.6 meters would take 182 strides compared to 166 strides for a horse with an average stride of 7.2 meters. That’s an extra 16 strides, or 10% more, for the horse with the smaller stride length. A chart that couples stride length and speed versus time shows the stride shortening at the end of a workout. This could obviously be useful in monitoring a horse’s fitness, for the stride length shortens as a horse tires. The stride length function on the E-Trakka system was fine-tuned before market release with the help of feedback from trainers who used it during its second stage of development. Stuart said, “With E-Trakka having already collected over 20,000 benchmark readings of GPS and heart rate in the field, the new stride length [feature] fills a few important gaps that were missing. Stride length on its own, or GPS and heart on their own, does not supply as complete a picture as we now have.” Stuart views the equine athlete as being made up of “ten key factors.” These fall under the categories of “Cardiovascular system” (heart size, heart rate, and lung function/venous system); “Conformation” (stride length, efficiency of stride, and peak speed); Muscular system (anaerobic capacity and aerobic capacity); “Structural” (leg and body soundness); and “General” (controllable factors like training methods, nutrition, general health, and mental health). He said, “There are a few important points of basic knowledge in the determination of stride relevance. One is that an equine athlete is made up of what we would call ten key factors. One factor is the actual stride length and the others determine the horse’s ability to use this asset. That is why sometimes trainers can be confused as to why the best moving horse does not win a race. They may have a small heart and poor muscular development, which doesn’t allow them to use their asset of a long stride. In the opposite example we have horses with a shorter stride but great energy systems which allow them to cover their weakness. But as a general rule of thumb a longer stride is a good asset. Other weakness can be picked up in the GPS and heart rate profiles. For example, a poor recovering horse with a low peak speed does not have the natural talent to use its asset.” Stuart continued, “Longer striders are more suitable to distance and in fact no short striders have been successful over distance unless it is an extremely weak race where their other assets (heart size and fitness) are better than the others. All our successful Group horses or stayers have had a long stride and a lot of the Group 1 winners have had a stride of between 6.7 - 6.9 SL50.” A key note, according to Stuart’s research, is that at peak speeds, every time a horse lands on its front feet it slows down by an average of 3 kph (1.86 mph). It will make up this deficit when it pushes with its back legs, provided it has sufficient energy to do so. However, this means more energy is required to maintain motion and quite often in track work the peak speed a horse can reach is only maintained for 3-4 seconds, which means more energy is required to maintain motion. Stuart added, “Shorter striders tend to run over shorter distances. However, a Group 1 1200-1600 meter (6-8 furlong) horse who had earned $1.7 million in stakes had a 6.8 meter, or 22.3 feet, SL50. The short strider with a fast leg turnover can be successful as long as they have a high peak speed and high anaerobic power. Where it gets very interesting is that 90% of the longer striders are winning and 90% of the short striders are losing across the board.” Stuart also spoke about soundness issues. “The general statement from trainers are that their short striders are experiencing issues! A horse that dropped from 6.4 meter (21 feet) SL50 to 6.1 was found to be shin sore. A beautiful big horse I expected to be 6.4-plus was found to be 5.85 and the trainer said that the horse was ‘rough going.’ The horse had won a trial but then bled. Did he bleed because of the extra stress of a trial, and is breathing related to stride? I’m not sure but I suspect so. A Group horse who carried issue was reading 6.3, but after he had his joints treated was reading 6.65 and won a Group 1. A Group 1 horse who was reading 6.5 dropped to 6.1 and was found to have bowed a tendon. All observations that you would expect, but have never seen before.” Stuart said that the surface and weight of the rider affected the mean average, but added that most trainers work their horses in the same environment, so general trends can be recognized. He said that “laziness” also affected stride length and cited one example of a horse that read 6.3 on its own, but 6.6 when working upsides another horse, and this subject went on to win a Group 3. Although he has not yet attempted to correlate a horse’s structural measurements with stride length, Stuart did mention the example of an 18-hand mammoth that read only 6.1 and “could not get out of his own way.” Stuart believes that the most important first phase of a horse’s training regimen is to identify its athletic ability and capacity to race. The importance of this belief is connected to two key statements he makes in his philosophy of training: 1) One of the greatest challenges a Thoroughbred horse trainer faces is the application of stress to a talented horse, as the stress applied may never be great enough to create the advance in the horse’s fitness. 2) Stress must never be applied greater than the limbs or body can tolerate. Considering the stride length research to date, the SL50 measurement looks likely to become an invaluable aid in ascertaining a horse’s capacity to race. In making another point in his training philosophy, Stuart says, “The percentage of fast twitch muscle compared to slow twitch muscle will determine a horse’s ideal distance. The ability of a trainer to recognize the horse’s muscle fiber assets and train the combination of slow and fast twitch muscles correctly will produce better performances than those that do not.” Testing the horse’s anaerobic capacity by means of peak speed and recovery time is the methods he advises in “best guessing” a horse’s optimum distance. However, the SL50 measurement might also make a contribution to determining this, for as he says short striders are usually suited to shorter races. E-Trakka is easy to use and requires no user input. The EquinITy system, developed by Fine Equinity in the U.K., is an intelligent training system designed to assist racehorse trainers in the assessment of the health and fitness of their horses. They are now in the process of developing a stride length function. EquinITy also uses trainer feedback during their development phases. As a consequence, their current software is comprehensive and includes such facilities as stable management as well as a function called “racefinder” that can successfully place a fit horse in races for which it is eligible. At present the lightweight girth they use collects heart rate and GPS data. The EquinITy “second generation of hardware and software” will have the capacity to monitor stride length and a rollout is expected in about six months’ time. It is planned that the second generation product will also include a “realtime simcard” so that live data will be available to a person standing on the side of the gallop. EquinITy puts an emphasis on simplicity of use and affordability. No input is required from the trainer and each girth only requires one download per training period as it can be equated to the software’s “training schedule” function. Tim Jones, the commercial director of Fine Equinity, said, “A trainer can retrospectively gather what a horse had done on any given day. For example, if a horse is running in the King George in 2013, the trainer will be able to establish what they did right, or wrong, in the horse’s preparation for that race in 2012.” The EquinITy system records data four times a second. In their stride length function, the number of strides will be able to be monitored at any stage of the workout and for any distance chosen. However, their research has used number of strides per furlong as a base measurement. Jones emphasized that the data gathered would be useful in combination with other data (sectional timing, heart rate, and GPS altitude) rather than on its own. EquinITy’s research has shown that in a race over a mile there is not much difference between the number of strides of different horses in the middle part of the race and that it is the “business end” that separates the men from the boys. They found that the average stride per furlong was 30, while the very best horses achieved a reading of 23 or 24. Jones said that the data gathered would allow a trainer to build up a stride pattern associated with each horse and it would be left to the trainer to interpret how best this could be used. In summary Jones said, “The stride pattern might be an indicator of how good a horse is or what distance it is best suited to as well as its fitness and wellbeing. The system is not diagnostic but can provide a pointer to a problem. An increased heart rate might indicate a breathing issue or that the horse is a bleeder. “The stride pattern might be an indicator of how good a horse is or what distance it is best suited to as well as its fitness and wellbeing” Tim Jones The Gmax girth features a heart-rate monitor, stride sensors and temperature sensors STRIDE NA ISSUE 30_Jerkins feature.qxd 24/10/2013 23:23 Page 7 that have a larger stride length but that will also be able to increase their frequency as they accelerate. “There are other measures to be found. Different horses can suit different ground conditions and this may become clearer in time as we are still working on this. Having a controlled piece of work on a track with a rider is much harder to replicate than on a treadmill, but alas we cannot change the going on the treadmill. When horses get tired the stride length certainly decreases, although the frequency may or may not change. Interestingly, the size of the horse doesn’t always match up to stride length, although it is obviously a factor.” He added, “I have a couple of horses who have very long strides but don’t seem to have STRIDE AN that have a larger stride length but that will also be able to increase their frequency as they accelerate. “There are other measures to be found. Different horses can suit different ground conditions and this may become clearer in time as we are still working on this. Having a controlled piece of work on a track with a rider is much harder to replicate than on a treadmill, but alas we cannot change the going on the treadmill. When horses get tired the stride length certainly decreases, although the frequency may or may not change. Interestingly, the size of the horse doesn’t always match up to stride length, although it is obviously a factor.” He added, “I have a couple of horses who have very long strides but don’t seem to have STRIDE ANALYSIS “The ability of a trainer to recognise the horse’s muscle fibre assets and train the combination of slow and fast twitch muscles correctly will produce better performances than those that do not” Furthermore, alarm bells will ring if a horse has a pattern of 30 strides per furlong and all of a sudden there are 32 or 34 strides.” Horses First Racing is a British stable in Wiltshire that uses advanced scientific tools as an aid in the training of horses. Horses First’s trainer Jeremy Gask has been researching stride length for a few reasons, one of the main ones being as an early indication of lameness or discomfort. He does all of his research on a treadmill as this “allows for a controlled environment and surface,” and factors like “wind speed, distraction or a rider moving about unnecessarily” are eliminated. The speed of the horse can also be controlled on a treadmill. Gask said that although stride length decreases “as a rule” in a lame horse, this was not always the case, as “it appears the odd horse can ‘climb’ or even try and get off its front legs,” and he uses “stride frequency” as a measure on the treadmill as it will produce a more accurate reading and is easier to record. He said that for any given speed there is a ‘decrease’ in stride length, but in compensation there is a consequent increase in frequency. Gask added, “Stride length is going to be more and more interesting over time as the technology and understanding increases. The better horses certainly appear to have a greater stride length and lower frequency at a given speed. However, in time it is going to be interesting to measure the higher-class horses the ability to increase frequency when the busy part of the work or race comes. I am working on trying to increase this through training but time will tell as to the success.” Gask hasn’t yet worked on the possible relationship between stride length and a horse’s distance preference. He uses a system called Gmax, a fully integrated girth with GPS tracking, to collect speed and sectional timing data. It has a heart Rate monitor, stride sensors, and temperature sensors for both ambient and skin temperatures. The data can be collected in real time with 3G or through a Wi-Fi connection Gask also has a dedicated Treadmill Display Unit (TDU) designed by Gmax that records ECG trace, heart rate, speed, and elevation. Mike de Kock, who is known for his dynamic approach, is another trainer who has experimented with stride length technology. He used it as an aid in Shea Shea’s preparation for the Grade 1 Al Quoz Sprint, which he won. De Kock admitted he was still “learning,” but he and his team have revealed that what they were most interested in, after the horses’ stride patterns had been built up, was to use the data as an indicator of soundness issues and to also monitor the stride length at the end of a workout as an indicator of peak fitness. In conclusion, it is still early days, but there seems little doubt that stride analysis technology is going to add a new dimension to the methods of racehorse trainers worldwide.n](https://static1.squarespace.com/static/517636f8e4b0cb4f8c8697ba/t/57232ece5559869e244c9cfb/1461923937695/)
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THIS ARTICLE FIRST APPEARED IN - NORTH AMERICAN TRAINER - ISSUE 30
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THIS ARTICLE FIRST APPEARED IN - NORTH AMERICAN TRAINER - ISSUE 30