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Sports medicine - open2024; 10(1); 119; doi: 10.1186/s40798-024-00783-9

Cardiac Structure and Function of Elite Australian Jockeys Compared to the General Population: An Observational Cross-Sectional Study.

Abstract: Research highlights the intense physiological demands of thoroughbred racing on jockeys, with elevated heart rates and substantial oxygen uptake, confirming the rigorous physical nature of the sport, however, the cardiovascular changes resulting from the physical demands of thoroughbred racing remain unexplored in Australian jockeys. Therefore, the objective of this study was to compare measures of cardiac structure and function of professional Australian jockeys to that of the general population and to determine if there are differences in heart structure and function detected using echocardiography. Methods: Forty-six jockeys and thirty-three participants from the general population underwent two-dimensional echocardiography, which included all standard views and measurements. Each measurement was compared between groups using a Mann-Whitney U test. Results: Groups were matched for age (jockeys (35 ± 12 years) and controls (36 ± 13 years)). Jockeys were shorter (1.64 ± 0.07 m vs. 1.75 ± 0.09 m, p < 0.001), lighter (56.5 ± 6.0 kg vs. 74.2 ± 12.9 kg, p < 0.001) and had a lower body surface area (BSA) (1.55 ± 0.17 m vs.1.9 ± 0.2 m, p < 0.001). Jockeys had a larger absolute left ventricular (LV) end diastolic volume than the control group (120 ± 18.2 ml vs. 109.3 ± 29.0 ml, p = 0.05) which had a larger variation when indexed for BSA (78.0 ± 12.2 ml/m vs. 57.5 ± 13.3 ml/m, p < 0.001). Jockeys demonstrated a higher LV mass index (79.4 ± 18.1 g/m vs. 64.2 ± 15.4 g/m, p < 0.001). Left atrial volume index was larger in jockeys (33.4 ± 6.5 mL/m vs. 26.3 ± 7.0 mL/m, p < 0.001). There were no differences in global longitudinal strain (GLS) for either group overall (-19.3 ± 3.0% vs. -19.8 ± 1.6%, p = 0.52), but 17% of the jockey group demonstrated an abnormal GLS. Conclusions: Jockeys have adaptations to their cardiac structure and function compared to the general population. Differences could be attributed to chronic physiological demands of racing and should be considered in future research involving jockeys.
© 2024. The Author(s).
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Publication Date: 2024-11-05 PubMed ID: 39499420PubMed Central: PMC11538223DOI: 10.1186/s40798-024-00783-9Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study compares the heart structure and function of elite Australian jockeys with that of the general population.
  • It investigates if the intense physical demands of thoroughbred racing result in measurable differences in cardiac features using echocardiography.

Introduction

  • Thoroughbred racing places intense physiological demands on jockeys, including elevated heart rates and significant oxygen consumption.
  • While these physical stresses are known, the specific cardiac structural and functional changes in Australian jockeys have not been studied before.
  • The research aimed to fill this knowledge gap by comparing jockeys’ cardiac parameters with those from a control group representing the general population.

Methods

  • Participants included 46 professional Australian jockeys and 33 individuals from the general population.
  • All participants underwent two-dimensional echocardiography, capturing standard heart views and measurements.
  • Measurements compared included left ventricular volume, mass, atrial volume, and functional parameters like global longitudinal strain (GLS).
  • Statistical analysis employed the Mann-Whitney U test to detect differences between groups.

Participant Characteristics

  • Groups were age-matched: jockeys averaged 35 years, controls 36 years.
  • Jockeys were significantly shorter (1.64 m vs. 1.75 m) and lighter (56.5 kg vs. 74.2 kg) than controls.
  • Body surface area (BSA) was also lower in jockeys (1.55 m²) compared to the control group (1.9 m²).

Key Findings in Cardiac Structure

  • Jockeys had a larger absolute left ventricular (LV) end-diastolic volume than controls (120 ml vs. 109.3 ml), borderline statistically significant (p=0.05).
  • When LV volume was indexed to body size (BSA), jockeys had substantially larger volumes (78.0 ml/m² vs. 57.5 ml/m²), indicating greater heart chamber size relative to body size (p<0.001).
  • The LV mass index, reflecting left ventricular muscle mass adjusted for body size, was significantly higher in jockeys (79.4 g/m² vs. 64.2 g/m²), suggesting thicker or more muscular heart walls (p<0.001).
  • Left atrial volume index, a measure of the size of the left atrium in relation to body size, was also larger in jockeys (33.4 mL/m² vs. 26.3 mL/m²), indicating possible adaptations of the atrial chamber (p<0.001).

Key Findings in Cardiac Function

  • No significant differences were found in global longitudinal strain (GLS) between jockeys and controls overall, a key echocardiographic measure of heart muscle deformation and function (-19.3% vs. -19.8%, p=0.52).
  • However, 17% of jockeys showed abnormal GLS values, which may indicate subclinical or early functional changes in a subset of the jockey group.

Interpretation and Conclusions

  • Elite Australian jockeys show distinct cardiac adaptations in structure, including larger and more muscular left ventricles and larger left atria relative to body size, likely due to the chronic physical demands of thoroughbred racing.
  • The absence of overall functional impairment (GLS) suggests that despite structural changes, heart function is largely preserved in jockeys.
  • The presence of abnormal GLS values in some jockeys warrants further investigation to understand potential clinical implications.
  • These findings emphasize the need to consider such physiological cardiac remodeling in future research and health monitoring of jockeys.

Cite This Article

APA
Farley A, Bennett H, Eston R, Perry R. (2024). Cardiac Structure and Function of Elite Australian Jockeys Compared to the General Population: An Observational Cross-Sectional Study. Sports Med Open, 10(1), 119. https://doi.org/10.1186/s40798-024-00783-9

Publication

Sports medicine - open
ISSN: 2199-1170
NlmUniqueID: 101662568
Country: Switzerland
Language: English
Volume: 10
Issue: 1
Pages: 119
PII: 119

Researcher Affiliations

Farley, Angela
  • Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, City East Campus, Frome Road, Adelaide, South Australia, 5001, Australia. angela.farley@unisa.edu.au.
Bennett, Hunter
  • Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, City East Campus, Frome Road, Adelaide, South Australia, 5001, Australia.
Eston, Roger
  • Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, City East Campus, Frome Road, Adelaide, South Australia, 5001, Australia.
Perry, Rebecca
  • Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, City East Campus, Frome Road, Adelaide, South Australia, 5001, Australia.

Conflict of Interest Statement

AF, HB, RE, and RP have no declarations of interest or conflicts of interest that are directly relevant to the content of this article and declare that they have no competing interests.

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Citations

This article has been cited 2 times.
  1. Legg KA, Cochrane DJ, Gee EK, Chin YY, Rogers CW. Relationship between experience and head kinematics in race riding jockeys. Sci Rep 2025 Apr 26;15(1):14686.
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  2. Özkan Ö, Yakut İ, Dönmez G, Korkusuz F. Vitamin D Deficiency Does Not Impair Diastolic Function in Elite Athletes. Medicina (Kaunas) 2025 Feb 26;61(3).
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