A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California thoroughbred racehorses.
Abstract: The objective of this study was to investigate the relationship between intensive racing and training schedules and risk of either catastrophic musculoskeletal injury (CMI) or lay-up from racing in California Thoroughbreds. Thoroughbred racehorses that sustained a CMI during racing or training and either were subsequently euthanized or died on a California racetrack during 1991 and 1992 were studied using a case-crossover study design. Each study subject (case) provided its own self-matched control information in the form of 'typical' exposure frequency, determined or estimated from historic information. Periods of rapid average daily accumulation of high-speed exercise distance were identified for each horse from official race and training histories with a sliding 60-day window. Those window frames containing an average daily rate of distance accumulation exceeding 75th percentile cutoff values were classified as exposed frames followed by 30 days of increased risk, or hazard periods. All remaining days (excluding periods of layoff from racing) were considered non-hazard time at risk. The relative risk (RR) of CMI within 30 days following a period of rapid accumulation of high-speed exercise distance (during a hazard period) was 4.2 (95% confidence interval [CI] = 3.0, 5.8). Of these 214 cases, 84 (39%) were injured during a hazard period whereas on average only 22% of total career time at risk was hazard time for these horses. A second analysis was performed for horses with at least 1 lay-up period from racing of > or = 60 days. RR for a lay-up beginning during a hazard period was estimated for the last lay-up experienced by each horse. The RR for lay-up beginning during a hazard period was 4.8 (95% CI = 2.9, 8.1). Of these 98 cases, 32 (33%) of the lay-ups began during a hazard period whereas on average, only 22% of at-risk time up to last lay-up was hazard time for these horses.
Publication Date: 1998-03-21 PubMed ID: 9500171DOI: 10.1016/s0167-5877(97)00047-0Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigated the correlation between high-frequency racing and training routines and the risk of severe muscle-skeletal injuries or lay-up periods in thoroughbred racehorses in California. Using historical information as a control, the study found that periods of intense high-speed exercise increased the risk of catastrophic injury or lay-up.
Study Methodology
- The research incorporated a case-crossover study design, focusing on thoroughbred racehorses that experienced catastrophic musculoskeletal injuries (CMI) during racing or training in California in 1991 and 1992. The sample also included horses that were euthanized or died on the racetrack.
- The study used historical data to determine ‘typical’ exposure frequency which acted as a self-matched control for each subject.
- A sliding 60-day window was used to identify periods of rapid daily accumulation of high-speed exercise.
- Any window frames where the average daily rate of distance accumulation exceeded the 75th percentile were classified as exposed frames followed by 30 days of increased risk, or hazard periods.
- Any days outside of the hazard periods were considered non-hazard time at risk unless the horses were on layoff from racing.
Findings and Conclusion
- The study found that the relative risk (RR) of CMI within 30 days after high-speed exercise during a hazard period was 4.2, meaning horses were four times more likely to sustain a CMI following intense training or racing.
- Out of 214 cases, 39% were injured during a hazard period, whereas on average, only 22% of total career time at risk was hazard time.
- The study also analysed the risk of lay-up periods, or extended breaks from racing due to injury or overtraining. The RR for a lay-up starting during a hazard period was 4.8, nearly five times the normal risk.
- Out of 98 cases of lay-ups, 33% started during a hazard period, again significantly higher than the average 22% of at-risk time.
- The study therefore concludes that intensive racing and training schedules significantly increase the risk of severe injury and lay-up in thoroughbred racehorses.
Cite This Article
APA
Estberg L, Gardner IA, Stover SM, Johnson BJ.
(1998).
A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California thoroughbred racehorses.
Prev Vet Med, 33(1-4), 159-170.
https://doi.org/10.1016/s0167-5877(97)00047-0 Publication
Researcher Affiliations
- California Veterinary Diagnostic Laboratory System, School of Veterinary Medicine, University of California, Davis 95617, USA.
MeSH Terms
- Age Distribution
- Animals
- California
- Case-Control Studies
- Cross-Over Studies
- Data Interpretation, Statistical
- Databases, Factual
- Female
- Horses / injuries
- Horses / physiology
- Male
- Morbidity
- Mortality
- Musculoskeletal Physiological Phenomena
- Musculoskeletal System / injuries
- Physical Conditioning, Animal / physiology
- Risk Factors
- Running / injuries
- Running / physiology
Citations
This article has been cited 16 times.- Darbandi H, Munsters C, Parmentier J, Havinga P. Detecting fatigue of sport horses with biomechanical gait features using inertial sensors.. PLoS One 2023;18(4):e0284554.
- Legg KA, Gee EK, Breheny M, Gibson MJ, Rogers CW. A Bioeconomic Model for the Thoroughbred Racing Industry-Optimisation of the Production Cycle with a Horse Centric Welfare Perspective.. Animals (Basel) 2023 Jan 30;13(3).
- Shaffer SK, Stover SM, Fyhrie DP. Training drives turnover rates in racehorse proximal sesamoid bones.. Sci Rep 2023 Jan 27;13(1):205.
- Morrice-West AV, Hitchens PL, Walmsley EA, Tasker K, Lim SL, Smith AD, Whitton RC. Relationship between Thoroughbred workloads in racing and the fatigue life of equine subchondral bone.. Sci Rep 2022 Jul 7;12(1):11528.
- Hellings IR, Skjerve E, Karlstam E, Valheim M, Ihler CF, Fintl C. Racing-associated fatalities in Norwegian and Swedish harness racehorses: Incidence rates, risk factors, and principal postmortem findings.. J Vet Intern Med 2022 Mar;36(2):778-786.
- Palmer AL, Rogers CW, Stafford KJ, Gal A, Bolwell CF. Risk-Factors for Soft-Tissue Injuries, Lacerations and Fractures During Racing in Greyhounds in New Zealand.. Front Vet Sci 2021;8:737146.
- Crawford KL, Finnane A, Greer RM, Barnes TS, Phillips CJC, Woldeyohannes SM, Bishop EL, Perkins NR, Ahern BJ. Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia.. Front Vet Sci 2021;8:698298.
- Physick-Sheard P, Avison A, Sears W. Factors Associated with Fatality in Ontario Thoroughbred Racehorses: 2003-2015.. Animals (Basel) 2021 Oct 13;11(10).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Bishop EL, Woldeyohannes SM, Perkins NR, Ahern BJ. A Prospective Study of Training Methods for Two-Year-Old Thoroughbred Racehorses in Queensland, Australia, and Analysis of the Differences in Training Methods between Trainers of Varying Stable Sizes.. Animals (Basel) 2021 Mar 25;11(4).
- Crawford KL, Finnane A, Phillips CJC, Greer RM, Woldeyohannes SM, Perkins NR, Kidd LJ, Ahern BJ. The Risk Factors for Musculoskeletal Injuries in Thoroughbred Racehorses in Queensland, Australia: How These Vary for Two-Year-Old and Older Horses and with Type of Injury.. Animals (Basel) 2021 Jan 21;11(2).
- Crawford KL, Ahern BJ, Perkins NR, Phillips CJC, Finnane A. The Effect of Combined Training and Racing High-Speed Exercise History on Musculoskeletal Injuries in Thoroughbred Racehorses: A Systematic Review and Meta-Analysis of the Current Literature.. Animals (Basel) 2020 Nov 11;10(11).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses.. Animals (Basel) 2020 Nov 5;10(11).
- Hitchens PL, Hill AE, Stover SM. Relationship Between Historical Lameness, Medication Usage, Surgery, and Exercise With Catastrophic Musculoskeletal Injury in Racehorses.. Front Vet Sci 2018;5:217.
- Maeda Y, Hanada M, Oikawa MA. Epidemiology of racing injuries in Thoroughbred racehorses with special reference to bone fractures: Japanese experience from the 1980s to 2000s.. J Equine Sci 2016;27(3):81-97.
- Dubois MS, Morello S, Rayment K, Markel MD, Vanderby R Jr, Kalscheur VL, Hao Z, McCabe RP, Marquis P, Muir P. Computed tomographic imaging of subchondral fatigue cracks in the distal end of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex-vivo model.. PLoS One 2014;9(7):e101230.
- Leblond A, Villard I, Leblond L, Sabatier P, Sasco AJ. A retrospective evaluation of the causes of death of 448 insured French horses in 1995.. Vet Res Commun 2000 Mar;24(2):85-102.
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