Author(s): OREILLY, J., POON, E.T.C., SHERIDAN, S., Institution: THE CHINESE UNIVERSITY OF HONG KONG, Country: HONG KONG, Abstract-ID: 833

INTRODUCTION:
Weight-restricted jockeys commonly report low bone density and elevated injury risk. Since 2021, Hong Kong-based professional jockeys have received integrated sports science support (nutrition, strength and conditioning, therapy services and on-site training facilities). The aim of this study was to describe longitudinal changes in whole-body DXA bone and body composition metrics under free-living conditions

METHODS:
Annual whole-body DXA scans were collected from 2021-2025 in professional jockeys (33 unique riders; 32 male, 1 female; 111 observations). Rider turnover occurred; n per year ranged 21-24. Outcomes were whole-body bone mineral density (BMD, g/cm2) and T-score, plus body mass, lean and fat mass. (i) In riders with paired data at 2021 and 2025 (n=13), changes were tested using paired t-tests (two-tailed) with Wilcoxon sensitivity analyses. (ii) To use all available data, linear mixed models with Year (categorical) and random intercepts for rider assessed year effects (Holm-adjusted pairwise tests vs 2021).
RESULTS:
In the paired cohort, BMD increased from 1.037 +/- 0.063 to 1.070 +/- 0.064 g/cm2 (mean change +0.033, 95% CI 0.025-0.042; p < 0.001; Wilcoxon p < 0.001), corresponding to a mean individual increase of +3.24% (95% CI 2.41-4.07). T-score improved from -1.74 +/- 0.75 to -1.34 +/- 0.72 (change +0.40, 95% CI 0.28-0.52; p < 0.001; Wilcoxon p < 0.001). Lean mass increased modestly (+0.95 kg, p = 0.015) with no clear change in fat mass (p = 0.058). Mixed models showed higher BMD in 2023-2025 vs 2021 (differences +0.026 to +0.033 g/cm2; all Holm p < 0.001) and improved T-scores in 2023-2025 vs 2021 (+0.29 to +0.38; Holm p <= 0.001), while 2022 did not differ from 2021.
CONCLUSION:
Clinically meaningful improvements in whole-body BMD and T-score were observed over 2021-2025 in a free-living, sports science-supported jockey cohort, despite roster turnover. Improved skeletal health may enhance injury resilience and support quicker return to ride following musculoskeletal injury, highlighting the value of integrated athlete care and DXA monitoring in weight-restricted sports.

References:
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