Racehorse speed is an interesting topic. Many believe that, as a racehorse cannot train itself to get quicker, the speed of a racehorse purely comes down to breeding, and that their speed has plateaued in the modern day. There are, however, studies that have been conducted and found that racehorses have, and are still getting quicker. Like athletes, horses are timed during their races, and naturally, some run faster than others. Several variables influence the speed at which the horses run, such as going, weight, and equipment. Whether the apparent improvement in time is through genetics, improved training, jockey tactics, or other environmental factors, though, is still heavily debated.
Dependent on the race distance (sprint vs. long-distance), racehorses have a base cruising speed/top speed. The only significant factor that separates horses is their ability to get to that speed and their ability to maintain it. The class of horse also impacts speed, with class 7 horses being significantly slower than a group horse. When considering this proposal, it is important to acknowledge horses such as Frankel, who had a higher cruising burst and stamina retention than the average racehorse. Comparing the likes of Frankel and other top-class horses against their counterparts from the past helps to further analyse the changes that have taken place.
Now, let’s look at some arguments for and against this statement:
Arguments for racehorses evolving and becoming quicker themselves:
· Improved breeding methods and an increase in quality in the gene pool have had a significant impact on the ability and quality of horses.
· Increased importing of well-bred American horses since the '90s has made breeding more commercialised.
· The average weight of horses has increased between 1997-2012, where better runners carry a higher weight. Winning times/speeds continue to improve despite this, thus outlining an overall improvement.
· The previous datasets used for studies were considerably smaller, so less accurate, and gave a false sense of stagnation.
Arguments against racehorses evolving and becoming quicker themselves:
· The modern riding style which sees jockeys crouched over the horses reduces energy demand, whilst a change in jockey tactics also influences how horses are ridden.
· In the early 1900s, jockeys opted to use shorter stirrups which can be attributed to rapid improvement around that time, again in the 70s/80s when they were shortened further.
· Modern thoroughbreds are descendants of a small number of horses through ancestry, so the narrow genetic diversity has caused them to plateau.
· Athlete's competing in track and field events mostly have gotten bigger and developed slightly longer legs, whereas racehorses are mostly the same in size, shape, etc.
Despite the above, some factors have remained constant which could have impacted how quickly horses improved:
· The equipment used by racehorses hasn't altered as it has with humans. For example, wearing lighter shoes or swimsuits that cause less friction have all contributed to improved race times for athletes, but no such evolution for racehorses.
· Despite improvements in synthetic surfaces, they are still very much similar to the old dirt tracks from the 18th century. Running tracks for athletes are now more shock absorbent and bouncier, contributing to improved race times. The racecourse, though, is still very similar to how it has always been.
· Horses do not have the motivation to go faster. The jockey encourages them and they enjoy what they are doing, but they do not have the mental capacity to push themselves to break a record, for example. They are running simply to beat the others around them and are likely already running to capacity.
Here are some examples of timings from the Kentucky Derby across the past 100 years:
1913: Donerail – 2:04 4/5
1937: War Admiral – 2:03 1/5
1949: Ponder – 2:04 1/5
1974: Cannonade – 2:04
2014: California Chrome – 2:03:66
So what do the studies say?
A study conducted by Patrick Sharman at the University of Exeter has found that thoroughbred performance has improved, after analysing a dataset of some 616,084 races since the 1850s. Previous studies failed to consider variables such as ground softness and also focussed solely on a small dataset taken from middle/long-distance elite races.
This study found that the greatest increases in speed were in sprint races, whilst there was a slower rate of improvement in the middle/long-distance races. The reason for this is unknown, however, it suggests that breeding favours speed over endurance, and so improvements in thoroughbred horses might not be done yet! This data further emphasised that improvement is still ongoing, particularly at the top level. Horses are defying heavier weights and soft ground to improve on previous best-race times. For example, there has been an improvement in predicted winning times in sprint races from 1997 to 2012 of around 1.18 seconds (the equivalent of around 7 horse lengths).
Sharman said: “There has been a consensus over the last 30 years that horse speeds appeared to be stagnating. Our study shows that this is not the case and, by using a much larger dataset than previously analysed, we have revealed that horses have been getting faster. Interestingly, both the historical and current rate of improvement is greatest over sprint distances. The challenge now is to find out whether this pattern of improvement has a genetic basis".
Co-author of the study Alistair Wilson said: “Jockey style could influence why horses are getting faster, though many factors could be at play, including breeding. There is no hard physical limit to how fast horses can get, though there will be a gradual process of diminishing returns.”
Another reason for a more prominent increase in speed in sprint races could be attributed to a heavier focus on breeding sprint horses since breeding commercialisation. The increased commercialisation of racehorse breeding that has occurred since the 1970s has had a serious impact on the gene pool. The quality of the horses available has risen, as has the population. This would give further variety to the gene pool for horses aimed at these distances, although care should be taken as to not link these changes purely to breeding alone. The study did note that they did not factor in handicap weight as the better runners tend to be the top weight and this would impact the speed they run at, masking any underlying genetic improvement.
Whilst the above study provides significant data outlining that racehorses are indeed still getting quicker, there is no concrete answer to why that is. Next, let's look at a study conducted by Mark Denny from Stanford University in 2008. This study suggests that racehorses have "hit their limits" in terms of speed, whilst humans, mostly, have not. Could it be that despite selective breeding giving you desired traits; it also narrows the gene pool? Let’s see…
The Kentucky Derby winning times from 1950 to 2010 seem to have hit a rough average of between 120-125 seconds, with no real improvement as there was beforehand (1900-1950). The three major Triple Crown horse races were analysed in the study against varying distances in elite men's and women's athletics. Significantly, whilst winning times in the Kentucky Derby seemed to have hit a dead-end, race times in the men’s 100 metres seem to still be improving. This gives the impression that speed has its limits, but not what accounts for those limits.
First, the genetic diversity of racehorses is limited. Modern thoroughbreds are, in fact, descendants of a few horses, with around 95% being able to trace their ancestry back to a single horse. This means that almost all racehorses worldwide have a very similar genetic make-up, limiting the extreme potential that they could reach. Also, the population of racehorses is much smaller than that of humans (7 billion), limiting the number of racehorses that may possess extreme speed.
Judging by the consistency of the times run in the Kentucky Derby, it seems safe to assume that based on breeding practices and other factors; it is almost impossible to produce a faster horse than the current record holder Secretariat, at 1:59:40. This, though, is just an assumption. There is the possibility that, in the future, breeding practices could change, as could training methods and other environmental factors. This makes it impossible to rule out that horses will become faster still as genetic diversity may be increased.
Second, it’s also interesting to consider what could happen if humans didn’t engage in any other athletic pursuit. Many fail to reach their full athletic potential as runners as they are lost to other sports such as football. The sole purpose of a racehorse is to run, so it would be interesting to see the difference if this was the case with humans. David Epstein wrote in his book “The Sports Gene”: “While it's unclear whether speed is innate or nurtured, one important reason for Jamaican athletes' success in short-distance races is that in their country, every child is made to try sprinting at some point." This offers the idea that Jamaica's success in sprinting might not be down to speed being innate, but in fact, more towards nurturing those who look to possess ability. This can help further one's development in a particular field rather than believing it is solely down to genetic make-up.
So, as previously mentioned, the improvement in the early 1900s and again in the '70s had been attributed to the use of shortened stirrups, and also an alteration in jockey riding style. These shortened stirrups improved race times by up to 7%, and the winning speed on average has increased by around 0.11% per year since 1997 in elite sprint races. This increase wasn’t linear either, thus giving credibility to the idea that these alterations had the biggest impact, as improvements stagnated between these changes being made.
It is never safe to assume, particularly when breaking records. Records are being broken all the time, often age-old records that are never expected to be beaten. These improvements being down to genetic changes is less likely than it is being linked to changes in environmental factors. With racehorses at least, although there is the potential for changes in the gene pool in the future, it appears they are already running at capacity. Breeding is a genetic lottery, and some horses are naturally faster than others, so it is impossible to pinpoint any purely genetic improvements. Changes in environmental factors are far more likely to bring about improvement as people constantly find new ways to do things. There is also the likelihood of changes to equipment and other factors in the future.
Patrick Sharman and Alistair Wilson - Racehorses are getting faster (June 2015)
Mark Denny - Limits to running speeds in dogs, horses and humans (October 2008)