RESUMEN
Jockeys are unlike other weight-making athletes as the sport of horse racing requires strict weight management to meet the racing stipulations, protracted working hours and an extended racing season with limited downtime. Several studies have reported on the body composition and bone status of male and female professional and retired jockeys, yet the variety of assessment techniques, lack of standardised testing protocols and classification inconsistency make interpretation and comparison between studies problematic. This review aimed to appraise the existing body composition and bone health evidence in jockeys and evaluate the assessment methods and classification criteria used. Dual-energy X-ray absorptiometry (DXA) has been used most frequently in jockey research to assess body composition and bone status, while various generic skinfold equations have been used to predict body fat percentage. Evidence indicates flat jockeys are now taller and heavier than the data reported in earlier studies. Absolute fat mass has steadily increased in male jockeys in the last decade. The bone status of male jockeys remains a concern as constant low bone density (BMD) is evident in a large percentage of young and experienced professional jockeys. Due to limited studies and variations in assessment methods, further research is required to investigate bone turnover markers in male and female jockeys. A standardised testing protocol using internationally recognised assessment guidelines is critical for the accurate interpretation and evaluation of body composition and bone health measurements. Furthermore, establishing jockey-specific BMD and bone turnover reference ranges should be considered using existing and future data.
RESUMEN
Compromised bone density in jockeys has previously been identified as an important health and safety concern in horseracing. Despite this, no update on the bone density status in Irish jockeys has been provided in the past decade. The study aimed to conduct a comprehensive update of the current bone density status in professional Irish jockeys and identify possible contributory physical and lifestyle factors. Eighty-five professional male jockeys (flat n = 39; national hunt (NH) n = 46) completed a dual-energy X-ray absorptiometry (DXA) scan for the assessment of body composition and bone mineral density (BMD) at the lumbar spine (LS), femoral neck (FN) and hip, 24-hour food recall, bone-specific physical activity questionnaire (BPAQ) and lifestyle questionnaire on weight making practices and injury history. Z-scores were interpreted to assess current bone density status. Correlation analysis was used to identify physical and lifestyle factors associated with bone mineral apparent density (BMAD). Results revealed a high prevalence of low BMD (Z-score < - 1.0) at the LS (44%), FN (15%) and hip (29%) in Irish jockeys. Analysis of jockeys physical characteristics found a positive relationship with the LS but not FN BMAD. Riding experience and timing of weight cut in NH and the practice of cutting weight in flat jockeys negatively influenced BMAD sites, while supplement use in flat jockeys displayed a positive effect on LS BMAD. Findings indicate the need for targeted individualised support strategies. Further investigation is required into jockey-specific intervention strategies that promote the development of optimal bone health in professional jockeys.
RESUMEN
The assessment of body composition in horse racing, a unique weight-restricted sport, provides an important health and performance indicator. The accuracy of skinfold prediction equations at estimating % body fat (% BF) was compared with dual-energy X-ray absorptiometry (DXA) data in a group of professional Irish jockeys (age 27.5 ± 7.7 years). Body composition was assessed in seventy-two male professional jockeys (flat n=35 and national hunt n=37) using standardised guidelines for skinfold thickness at 8 sites and DXA body fat assessment. Hydration status was assessed using urine specific gravity (Usg) to determine if participants were euhydrated and male specific prediction equations (Durnin and Womersley, Evans, Lohman, Reilly, Withers and Zemski) were selected to estimate % BF. Jockey-group specific equations were developed using the collected dataset. The selected equations underestimated % BF with variability between equations ranging from 7% to 10% compared to the DXA % BF of 15%. Flat jockeys were significantly lighter and shorter (p < 0.05) compared to national hunt jockeys resulting in the need for individual jockey-specific equations. The Flat and National Hunt Jockey specific equations demonstrated overall agreement accounting for 84% and 83% variance, respectively. Caution must be taken when using existing prediction equations due to the variability of % BF relative to DXA. Jockey-specific equations offer an alternative method for interpreting estimated body fat %.