Weight loss practice, nutritional status, bone health, and injury history: A profile of professional jockeys in Korea

The impact of weight loss diet programs on anemia, nutrient deficiencies, and organ dysfunction markers among university female students: A cross-sectional study

Practicing restricted weight loss diet programs (WLDPs) without proper supervision can result in nutritional deficiency, which can lead to the development of several nutritional disorders. The current cross-sectional study aimed to investigate the impact of WLDPs practiced by university female students on the prevalence of micronutrient deficiencies, anemia, and organs dysfunction, and to assess the association of identified anomalies with dieting practices and dietary habits of university female students. A total of 185 (105 dieting and 80 non-dieting) volunteers’ female students at Al-Hussein Bin Talal University participated in this study. After the participants answered a questionnaire, blood samples were collected for hematological and biochemical analysis, and the body mass index (BMI) was determined. The results show that there were no significant differences between dieting and non-dieting groups in biochemical markers of kidney and liver functions as well as serum levels of copper, zinc, and folate. On the other hand, dieting participants exhibited significantly lower level of hemoglobin, serum ferritin, iron, and vitamin B12 than encounter group (p<0.05). Attempting WLDPs significantly increased the prevalence of anemia (46.7%), iron deficiency (57.1%), and iron deficiency anemia (IDA) (41.9%), comparing to non-dieting students (28.7%, 33.8%, and 15.0%, respectively) (p<0.005). Chi-square test showed that the development of anemia among dieting girls was significantly dependence of several factors including BMI category, source and duration of the diet programs, and skipping breakfast (p<0.05). In conclusion, young girls attempting WLDPs without professional guidance are more prone to the risk of nutrients deficiencies and the development nutritional disorders like IDA. An educational program should be employed to teach young females on when and how to adopt healthy WLDPs.

Relationships Between Sports Club Participation and Health Determinants in Adolescents and Young Adults

Physical fitness is a powerful marker of health in adolescents and young adults. The purpose of this study was to measure the relationships between age, sex, body mass index, and sports club participation on physical fitness. The population included 49,988 participants (23,721 girls and 26,267 boys) who were divided into five age groups (11–12, 13–14, 15–16, 17–18, and 19–21 years). Body mass index was calculated. Physical fitness was assessed with the Diagnoform^® Tonic battery. Sports club participation was also documented. The practiced sport was collected. The effects of age, sex, body mass index class, and sports club participation were tested. Boys' PF increased with age at a faster rate and was better than that of girls, except for flexibility (p < 0.001). For girls, a decrease was observed in endurance, speed and flexibility at 17-18 years. Sports club participation was greater for boys at every age. Obese participants had the lowest physical fitness and sports club participation. Sports club participation increased physical fitness. Team sports seemed best for improving physical fitness, except flexibility. The study shows that sports club participation may be a key element for building health in adolescents. Preventive healthcare projects that promote sports club are needed to target sports club dropouts (obese adolescents and girls). Bridges should be built between physical education classes and sports clubs in adolescence to improve the health status of young people.

Body Composition and Bone Health Status of Jockeys: Current Findings, Assessment Methods and Classification Criteria

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.

Weight-Making Practices Among Jockeys: An Update and Review of the Emergent Scientific Literature

Numerous publications have described the behaviors employed by professional jockeys on a daily basis to achieve and maintain a minimum racing weight. This narrative review provides an update of recent publications that report on the impact of such practices. Although rapid weight-loss techniques such as calorie restriction and dehydration are commonly thought to be deleterious to jockeys, little evidence exists of enduring health consequences. There is evidence to suggest that jockey training behaviors and dietary choices are not aligned with optimum preparation for the physiological demands of the sport. Further research is necessary to better measure the health impact of jockey weight-making behaviors; such data might guide reforms of athlete behavior and regulatory practices within the global sport of horse racing.

Review of physical fitness, physiological demands and performance characteristics of jockeys

This narrative review collates data from different equestrian disciplines, both amateur and professional, to describe the physiological demands, muscle activity and synchronicity of movement involved in jockeys riding in a race and to identify limitations within our current knowledge. A literature search was conducted in Web of Science, Google Scholar, PubMed and Scopus using search terms related to jockeys, equestrian riders and their physiological demands, muscle use, movement dynamics and experience. Abstracts, theses and non-peer reviewed articles were excluded from the analysis. Jockeys work at close to their physiological capacity during a race. The quasi-isometric maintenance of the jockey position requires muscular strength and endurance, specifically from the legs and the core, both to maintain their position and adapt to the movement of the horse. Synchronous movement between horse and rider requires a coordinated activation pattern of the rider’s core muscles, resulting in less work done by the horse to carry the rider, possibly leading to a competitive advantage in race riding. Reports of chronic fatigue in jockeys demonstrate poor quantification of workload and recovery. The lack of quantitative workload metrics for jockeys’ limits calculation of a threshold required to reach race riding competency and development of sport-specific training programmes. Until the sport-specific demands of race riding are quantified, the development of evidence-based sport specific and potentially performance enhancing jockey strength and conditioning programmes cannot be realised.

Medicine in the Sport of Horse Racing

Horseracing is among the most popular and increasingly lucrative industry sports in the nation. The average jockey must control a thoroughbred horse 10 times their weight that may act unpredictably whether at rest or full gallop resulting in falls, kicks, or even biting injuries. Despite the risks, jockeys do not have access to the same quality of medical care that is standard in similarly profitable sports organizations. Beyond the mental and physical demands of training and performance endured by any professional athlete, jockeys are confronted with health challenges unique to their sport. In this review of the literature, we aim to educate sports medicine physicians regarding the underlying causes of injuries, describe injury management, and make recommendations for appropriate preventive strategies. Overall, there is a void of literature, and so our authors offer expert opinion and encourage others to get involved in making this a safer sport.

Jockey Career Length and Risk Factors for Loss from Thoroughbred Race Riding

Professional thoroughbred racing jockeys repeatedly work close to physiological capacity during races, whilst maintaining low body weights, on a daily basis with no off-season. The effects of this on their career length is unknown. The aim of this study was to examine the career lengths and reasons for loss from the industry of 674 jockeys and apprentices who rode over 14 racing seasons and 421,596 race day starts in New Zealand. Descriptors were compared between jockeys in short (1–2 years), middle (3–9 years) and long (>10 years) career cohorts with descriptive statistics and Kaplan–Meier survival curves. The median career length for jockeys was 2 years (IQR 1–6). Long career cohort jockeys (11%) had lower carried weights (IQR 56–57 kg, p = 0.03), 40 times the median number of rides per season (248, IQR 61–434, p < 0.001), half the rate per 1000 rides of falling (1.1, 95% CI 1.0–1.2, p = 0.009) and 1.3 times the rate of winning (100, 95% CI 99–101, p < 0.01) than jockeys in the short career cohort. Jockeys who rode over 200 races per season had careers three times longer than jockeys with fewer races per season (p < 0.001). Half of the 40% of jockeys who failed to complete their apprenticeship were lost from the industry in their first year of race riding. In conclusion, most jockeys had short careers where the workload of a jockey and their ability to obtain rides had greater impact on career longevity than their performance.

Vitamin D, genetics, and bone mineral density during weight loss

PURPOSE OF REVIEW

The current review is to summarize the recent progress in the research of the relation between vitamin D and bone mineral density (BMD) during weight-loss interventions, and describe how genetic factors interact with weight-loss interventions on changes in bone health.

RECENT FINDINGS

Obesity has shown to be a protective factor for bone health, whereas the relation between weight loss and BMD has yet to be well established. Although beneficial on a variety of metabolic outcomes, weight-loss interventions, such as dietary modifications and surgical treatment, showed adverse effects on bone health in some studies. Despite the biological plausibility for a role of vitamin D in promoting bone health, current evidence does not consistently support the connection between changes in circulating vitamin D levels and BMD during weight loss, partly because of insufficient vitamin D levels during weight loss. Genome-wide association studies have identified genetic variants related to the blood levels of vitamin D; and emerging evidence suggests that dietary intakes may modify the relationship between genetically determined circulating vitamin D levels and change in BMD in response to weight-loss diets.

SUMMARY

The relations of changes in circulating vitamin D levels with bone health during weight-loss interventions remain to be established, and the role of genetic factors would be considered in future investigations.