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Use of statistical models to evaluate racing performance in Thoroughbreds
Abstract
To develop a statistical model to evaluate the influence of specific parameters on racing performance in Thoroughbreds.
Survey.
Racing records of Thoroughbreds performing in Louisiana from 1981 to 1985.
Race results for 20 randomly selected days from 5 racetracks during 5 years were analyzed, using regression analysis.
The most influential parameter was distance raced. There were significant differences in racing performance among horses at different tracks. At the tracks examined, fast racing surfaces resulted in significantly faster finish times than good racing surfaces, and good racing surfaces resulted in significantly faster finish times than muddy racing surfaces. Finish times also were significantly faster as a function of increasing purse amount and age of horse. Finish times were significantly faster during quarter 4 (summer) and significantly slower during quarter 1 (fall). Races were run at significantly faster times as the number of the race progressed during the day. The finish times were significantly slower as the number of horses competing in the race increased, as the weight carried by the horse increased, and as the starting position away from the rail increased.
The coefficients used in the statistical model of this report may be used by researchers to compare before injury and after treatment finish times. The coefficients can be used to standardize past racing performances to uniform conditions, thus permitting comparison from 1 race to another to determine success of treatments and to inform owners of prognosis.
... Older racehorses tend to have higher stride frequencies which is consistent with higher speed if stride length is unchanged 30,38,39 . Average race speed has also been reported to increase with age until 4.5 years followed by a plateau period [40][41][42] . According to our previous investigation, the effect of finishing position on strides is variable depending on the stage of the race, but overall horses with better finishing positions take similar or slightly fewer strides than the rest of the field and average higher speed over race starts 30,43 . ...
... The relationship of weight carried on fatigue accrual was dependent on the class of race, where greater weight carried did not necessarily result in greater fatigue damage. Our previous investigation showed that overall the number of strides per race tended to decrease with increasing weight carried, and greater weight carried is reported to be associated with slower racing times 30,42 . For the lower classed races, the estimated fatigue damage did not increase with greater weight carried due to a slight increase in speed compensating for fewer strides. ...
Fatigue life (FL) is the number of cycles of load sustained by a material before failure, and is dependent on the load magnitude. For athletes, ‘cycles’ translates to number of strides, with load proportional to speed. To improve previous investigations estimating workload from distance, we used speed (m/s, x) per stride collected using 5 Hz GPS/800 Hz accelerometer sensors as a proxy for limb load to investigate factors associated with FL in a Thoroughbred race start model over 25,234 race starts, using a combination of mathematical and regression modelling. Fore-limb vertical force (NKg-1) was estimated using a published equation: Vertical force = 2.778 + 2.1376x − 0.0535x2. Joint load (σ) was estimated based on the vertical force, scaled according to the maximum speed and defined experimental loads for the expected variation in load distribution across a joint surface (54-90 MPa). Percentage FL (%FL) was estimated using a published equation for cycles to failure (Nf) summed across each race start: Nf = 10(σ-134.2)/−14.1. Multivariable mixed-effects linear regression models were generated on %FL, adjusting for horse-level clustering, presented as coefficients; 95%CI. Scaled to the highest joint load, individual starts accrued a mean of 9.34%FL (sd. 1.64). Older age (coef. 0.03; 0.002–0.04), longer race-distances (non-linear power transformed), and firmer track surfaces (ref. Heavy 10: Good 3 coef. 2.37; 2.26–2.48) were associated with greater %FL, and males accrued less than females (p < 0.01). Most variables associated with %FL are reported risk factors for injury. Monitoring strides in racehorses may therefore allow identification of horses at risk, enabling early detection of injury.
... Due to their relatively high value within the equine industry, racehorses are often subjected to diagnostic and therapeutic interventions and provide a unique population for which objective performance measurements are available for each participating individual in the form of racing outcome. 'Success' is often considered in terms of an animal's ability to remain competitive within its intended use, which can be interpreted as restoration[2]or improvement of athletic ability[3]. However, there remains no consensus on what objective measures quantify racehorse performance appropriately[3; 4], and debate continues as to what measures may represent 'success' more meaningfully; a measure of 'longevity', such as ability to continue racing over an extended time frame, or a measure of 'quality', such as the ability to win a top rated race or accrue earnings[5]. ...
... Three studies have previously performed comparative work to assess the ability of outcome measures to represent racing success[2; 4; 20]. In 1996, Martin et al.[2]aimed to develop a statistical model to evaluate the influence of variables on racing performance measured as finish time in TBs in the USA, suggesting race times require adjustment by eleven different variables in multivariable regression modelling. Cheetham et al.[20]investigated whether both race earnings and number of race starts were associated with horse signalment (age, sex, ...
Background:
Racing performance is often used as a measurable outcome variable in research studies investigating clinical diagnoses or interventions. However, the use of many different performance measures largely precludes conduct of meaningful comparative studies and, to date, those being used have not been collated.
Objectives:
To systematically review the veterinary scientific literature for the use of racing performance as a measurable outcome variable in clinical studies of racehorses, collate and identify those most popular, and identify their advantages and disadvantages.
Study design:
Systematic literature review.
Methods:
The search criteria "((racing AND performance) AND ("horses" OR "equidae"))" were adapted for both MEDLINE and CAB Abstracts databases. Data were collected in standardised recording forms for binary, categorical and quantitative measures, and the use of performance indices.
Results:
In total 217 studies that described racing performance were identified, contributing 117 different performance measures. No one performance measure was used in all studies, despite 90.3% using more than one variable. Data regarding race starts and earnings were used most commonly, with 88.0% and 54.4% of studies including at least one measure of starts and earnings, respectively. Seventeen variables were used 10 times or more, with the top five comprising: 'return to racing', 'number of starts', 'days to first start', 'earnings per period of time' and 'earnings per start'.
Main limitations:
The search strategies may not have identified all relevant papers, introducing bias to the review.
Conclusions:
Performance indices have been developed to improve assessment of interventions; however, they are not widely adopted in the scientific literature. Use of the two most commonly identified measures, whether the horse returned to racing and number of starts over a defined period of time, would best facilitate future systematic reviews and meta-analyses in advance of the development of a gold-standard measure of race performance outcome. This article is protected by copyright. All rights reserved.
... Increase in the running distance raised the running time as supported by several researchers (15,19,20,22,24), it also can be said that effect of the distance on the racing performance was significant. The decline of the running time in the horses in the group A and the increase of the running time in the group C are expected outcomes when the criteria of group forming were considered. ...
... Naturally, total amount of the prize won was high on the turf track as well. Martin et al. (19), Langolish (18) and Moritsu et al. (20) similarly expressed the rise in the prize won on the turf track compared to the dirt track. ...
The aim of this study was to investigate the factors affecting racing performance and to estimate the heritability of racing performance in Arabian horses. In this study the records were obtained from 6203 races of 616 male foals of 37 stallions racing at open races in different race tracks in Turkey during the years of 1991-2000. The least squares mean of racing time was found to be 176.29±0.95 seconds and there were significant differences (p<0.001) in racing years, racing distances, racing groups and race tracks. The estimated mean value for the amount of earning was 15660.6±556.7 $ (USA). The effect of mare age, year, distance, racing group, race tracks and foal age on the earning were significant (p<0.05; p<0.001). There were statistically significant differences among mean value of speed (m/second) for all of the investigated factors and the variance among stallions was found to be significant. The heritability of mean speed was estimated as 0.170±0.001 according to paternal half sib correlation method, the heritability according to the mean amount of earnings was 0.46±0.15. In this study heritability for racing performance was found to be moderate and therefore it is concluded that this character was improved by selection.
... Total race time decreases (ie horses run faster) for 3-year-olds compared with 2-year-olds. 39 Higher weight carried was associated with reduced number of strides of greater duration in the early and mid-race stages. Across all 200 m race sectionals, this effect was more prominent in lower class races, with horses in high class races maintaining their stride characteristics as weight carried increased. ...
Background
With each stride, galloping horses generate large skeletal loads which influence bone physiology, and may contribute to musculoskeletal injury. Horse speed and stride characteristics are related, but the usefulness of using horse speed and distance travelled as a proxy for stride characteristics is unknown.
Objectives
We aimed to determine stride characteristics, their variance and their relationship with speed in horses performing maximally.
Study design
Retrospective cross‐sectional analysis of archived data.
Methods
Stride characteristics obtained using GPS and inertial sensors in Thoroughbred horses were retrieved. Data per 200 m race segment (‘sectionals’) for horses competing in races (N = 25,259 race starts) were analysed to determine if speed predicted stride parameters. Multivariable mixed‐effects linear regression models were fitted.
Results
Mean (±SD) stride length, stride count (number of strides per 200 m), duration and speed were 7.08 ± 0.39 m, 28.32 ± 1.56 strides/200 m, 0.43 ± 0.02 s/stride and 16.63 ± 1.04 m/s across all sectionals and starts. Speed and stride length decreased, and stride count increased with race progression (P < 0.001). Male sex, greater race distance, better finishing position and firmer track surfaces were associated with less strides per 200 m and longer stride durations.
Main limitations
Lack of an independent party validation of the measurement system used in this study.
Conclusions
There was a substantial inter‐horse variation in stride parameters, with speed predicting half or less of this variation. Speed alone does not fully explain stride characteristics in horses. Future studies aimed at investigating the impact of gait on bone biology and pathology would benefit from accounting for stride characteristics (eg length and duration).
... Some researchers have studied the age of the racehorse and dam, the year of the race, race distance, racing categories and surface of the race track in order to evaluate possible correlations between these factors and the race performances of horses (Köseman and Özbeyaz 2009). Others have reported that the age of the horse, race distance, structure of the track, amount of the jackpot, running season, number of running horses, handicap weight of the horse and the horse's position on the track were significant factors in race performance (Martin et al. 1996). ...
... 1A, 1B, 2A and 2B). One of the reasons why the average speed increase during this period was slower than in subsequent periods might be that increases in carried weight inhibited the average speed increases associated with growth [4]. In the JRA races, the weight carried increased with growth in the males & geldings group (Table 3). ...
The running performance of Thoroughbred racehorses has been reported to peak when they are between 4 and 5 years old. However, changes in their racing speed by month or season have not been reported. The purposes of this study were to reveal the average racing speed of Thoroughbreds, and observe changes in their average speed with age. The surveyed races were flat races on turf and dirt tracks with firm or standard track conditions held by the Japan Racing Association from January 1st, 2002 to December 31st, 2010. The racing speed of each horse was calculated by dividing the race distance (m) by the horse’s final time (sec). Average speeds per month for each age and distance condition were calculated for each gender group when there were 30 or more starters per month for each age and distance condition for each gender group. The common characteristic change for all conditions was an average speed increase up until the first half of the age of 4 years old. The effect of
increased carry weight on average speed was small, and average speed increased with the growth of the horse. After the latter half of the age of 4 years old, the horses’ average speed remained almost constant, with little variation. It is speculated that decreases in the weight carried; and the retirement of less well performing horses; are responsible for the maintenance of average speed.
Objective:
To identify prognostic factors for return to racing after lag screw repair of condylar fractures and develop a predictive model for return to racing.
Study design:
Retrospective cohort study.
Animals:
A total of 356 horses referred to a single referral hospital in the UK with a third metacarpal/metatarsal condylar fracture between January 1999 and December 2018.
Methods:
Age, sex, fracture site, fracture characteristics, surgery related variables and complications were retrieved from case records. Data were divided into two sets for model training and model validation. Univariable analyses were performed, and predictors were selected in a stepwise fashion for inclusion in the multivariable logistic regression model. Sensitivity and specificity were evaluated using the second dataset.
Results:
Older horses, fillies, fractures of forelimbs, complex, complete, displaced or propagating fractures and concurrent proximal sesamoid bone fracture were negatively associated with return to racing. Colts and geldings were 3 and 4 times more likely to race than fillies, respectively. Horses with hindlimb, incomplete or nonpropagating fractures were 4, 5 and 4 times more likely to race than those with a forelimb, complete or propagating fracture, respectively. Using a predicted probability cut-off threshold of 0.5, a predictive model was created within one dataset (sensitivity = 84%, specificity = 50.5%) and applied to another (sensitivity = 83.1%, specificity = 24.0%).
Conclusion:
Negative prognostic factors were identified and led to a predictive model with acceptable sensitivity and specificity in the tested population.
Clinical significance:
The results provide proof of concept for the model in the reported population and justify further validation in different populations of horses.
Kantitatif bir karakter olan atların yarış ve yarışma performansı genetik ve çevresel faktörlerin etkisinde şekillenmektedir. Bu nedenle bireyler ve populasyonlar arasında varyasyon bulunmaktadır. Genetik etki, tayın anasından ve babasından aldığı genlerden dolayı sahip olduğu genotip kapasitesini ifade etmektedir. Performansı etkileyen çevresel faktörler arasında; cinsiyet, yaş, doğum ağırlığı, mesafe, handikap ağırlığı, pist tipi ve parkur yapısı, ana yaşı, konulan ikramiye, koşan at sayısı, atın pistteki koştuğu yer, binici deneyimi gibi faktörler yer almaktadır. Bu derlemenin amacı, atların yarış ve yarışma performanslarını etkileyen genetik ve çevresel faktörler hakkında bilgi sunmaktır.
The aim of this study was to investigate the factors affecting racing performance and to estimate the heritability of racing performance in Arabian horses. In this study the records were obtained from 6203 races of 616 male foals of 37 stallions racing at open races in different race tracks in Turkey during the years of 1991-2000. The least squares mean of racing time was found to be 176.29±0.95 seconds and there were significant differences (p<0.001) in racing years, racing distances, racing groups and race tracks. The estimated mean value for the amount of earning was 15660.6±556.7 $ (USA). The effect of mare age, year, distance, racing group, race tracks and foal age on the earning were significant (p<0.05; p<0.001). There were statistically significant differences among mean value of speed (m/second) for all of the investigated factors and the variance among stallions was found to be significant. The heritability of mean speed was estimated as 0.170±0.001 according to paternal half sib correlation method, the heritability according to the mean amount of earnings was 0.46±0.15. In this study heritability for racing performance was found to be moderate and therefore it is concluded that this character was improved by selection.
More than 1 million racing records of American Quarter Horses were used to provide a description of Quarter Horse racing data. The data presented five racing distances (201,320, 366, 402 and 796 m). Finish time was used to measure racing performance. Means and variances for finish time increased with length of the race, but the distributions were similar for the five distances. Each distribution was skewed to the right and more peaked than a normal distribution. Repeated records were an important source of information and their use should improve the accuracy of genetic evaluations when comparing horses and sires across races and tracks. There was a tendency for more older horses and geldings to be found in the longer races. Two-year-old horses raced almost exclusively against other 2-yr-olds, and most 3-yr-olds raced with horses their own age. An interaction was detected between sex and age that was interpreted to be the result of differential selection rates among the sexes. Further study of age and sex effects is needed to develop factors for adjusting Quarter Horse racing data for use in genetic evaluation.
In 3 groups of horses with exercise-induced pulmonary hemorrhage (EIPH), comparisons of racing times and finishing positions were made between the 5 races before the horses were given furosemide and 5 races after furosemide administration. The horses were grouped according to 3 methods used to diagnose EIPH: group 1, observation of hemorrhage at the nostrils within 1 hour after a workout or race; group 2, observation of pulmonary hemorrhage only by endoscopic examination after a race or workout; and group 3, observation of hemorrhage at the nostrils during a race or immediately after a race. Group 4 horses were randomly selected horses running during the study period and were not given furosemide. The statistical method was analysis of covariance and the dependent variable was horses' time per distance. The study compared the 4 groups of horses, using the estimated value of the horses (less than or equal to +10,000 or greater than +10,000), and the horses' interaction in races 1 through 5 before and races 6 through 10 after furosemide treatment. The horses' times were adjusted by the relevant covariates, distance, track variant, and winning time per distance. Significant changes in horses' time per distance were not noticed when comparing values from races 1 through 5 with those in races 6 through 10 in group 1 horses.(ABSTRACT TRUNCATED AT 250 WORDS)