Sarah Chantler

In an invited editorial, Tucker et al. [1] addressed the eligibility controversy regarding the Paris 2024 Olympic boxing competition. They cited Lundberg et al. [2] concerning the in/eligibility of transgender women for the female sports category and identified performance differences between males and females alongside studies involving testosterone suppression. Several authors of the present letter also co-authored Lundberg et al. [2] and stand by that paper, but declined co-authorship of Tucker et al.'s editorial [1] and present here, with additional collaborators, challenges to that editorial.

Background: Low levels of physical activity, poor cardiorespiratory fitness, and a sedentary lifestyle have been associated with increased risk for cardiovascular disease (CVD) and type 2 diabetes (T2D). Few studies have examined their independent associations in an urban black sub-Saharan African population. Objectives: To examine the independent associations of physical activity, cardiorespiratory fitness, and sedentary time on body composition and cardiometabolic risk factors for CVD and T2D in black South African women. Materials and Methods: A subsample (n = 76; 18-45 years) was recruited, as part of a cross-sectional study. Accelerometry, cardiorespiratory fitness, body composition, insulin sensitivity, serum lipids, and blood pressure were measured. Results: Light- but not moderate- to vigorous intensity physical activity was inversely associated with trunk fat mass (r = -0.25, P = 0.03). Sedentary time was associated with triglyceride (TG) (r = 0.36, P = 0.01) and TG/HDL-C (r = 0.34, P = 0.04), and these relationships were independent of body fat. Cardiorespiratory fitness was inversely associated with body fat % (r = -0.34, P = 0.02), central fat mass (r = -0.31, P = 0.03), visceral adipose tissue (VAT, r = -0.47, P < 0.01), and insulin resistance (HOMA-IR; r = -0.41, P = 0.01). The association between cardiorespiratory fitness and HOMA-IR was independent of body fat and physical activity, but not VAT. Cardiorespiratory fitness was inversely associated with sedentary time (r = -0.31, P = 0.03), but not with any of the physical activity variables (P > 0.05). Conclusion: Both physical activity and cardiorespiratory fitness were associated with reduced total and central fat mass, VAT, and reduced cardiometabolic risk for CVD and T2D. Longitudinal studies are required to confirm whether the promotion of increasing light physical activity, while reducing sedentary time and increasing cardiorespiratory fitness, reduces the risk for obesity, CVD and T2D.

South Africa (SA) is undergoing a rapid epidemiological transition and has the highest prevalence of obesity in sub- Saharan Africa (SSA), with black women being the most affected (obesity prevalence 31.8%). Although genetic factors are important, socio-cultural, environmental and behavioural factors, as well as the influence of socio-economic status, more likely explain the high prevalence of obesity in black SA women. This review examines these determinants in black SA women, and compares them to their white counterparts, black SA men, and where appropriate, to women from SSA. Specifically this review focuses on environmental factors influencing obesity, the influence of urbanisation, as well as the interaction with socio-cultural and socio-economic factors. In addition, the role of maternal and early life factors and cultural aspects relating to body image are discussed. This information can be used to guide public health interventions aimed at reducing obesity in black SA women.

Summary: We examined ethnic differences in bone mineral density (BMD) and the contribution of body composition, lifestyle and socioeconomic factors in South African women. Femoral neck and total hip BMD were higher, but lumbar spine BMD was lower in black women, with body composition, lifestyle and socioeconomic status (SES) factors contributing differently in ethnic groups. Introduction: There is a paucity of data on the relative contribution of body composition, lifestyle factors and SES, unique to different ethnic groups in South Africa, to BMD. We examined differences in femoral neck (FN), total hip (TH) and lumbar spine (LS) BMD between black and white premenopausal South African women and the associations between BMD and body composition, lifestyle factors and SES in these two ethnic groups. Methods: BMD and body composition were measured in 240 black (27 ± 7; 18-45 years) and 187 white (31 ± 8; 18-45 years) women using dual-energy X-ray absorptiometry. Questionnaires were administered to examine SES, physical activity and dietary intake. Results: After co-varying for age, FN and TH were higher in black than white women (FN 0.882 ± 0.128 vs. 0.827 ± 0.116 g/cm

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Exercise appears to elicit damage to the gut endothelial cell lining as demonstrated through increases in concentration of plasma intestinal fatty acid binding protein (i-FABP). The majority of previous research has focussed on endurance exercise, with limited data on high intensity contact sports. The high intensity nature of rugby exercise, combined with trauma from collisions, suggests that this may cause considerable increases in gastrointestinal damage and permeability Therefore, the purpose of the study was to investigate the effects of a standardised rugby conditioning session on plasma i-FABP concentrations as a marker of gut endothelial damage.

Background: Low levels of physical activity (PA) have been associated with increased risk for cardiovascular disease (CVD) and type 2 diabetes (T2D), but few studies have examined whether meeting international PA guidelines is associated with reduced risk in a black South African (SA) population. The aims of this study were to compare body composition and cardio-metabolic risk factors for CVD and T2D between active and inactive groups (part 1, cross-sectional analysis) and, to determine whether PA level predicts changes in body composition and cardio-metabolic risk factors for CVD and T2D at follow-up after 5.5-years (part 2, longitudinal analysis). Methods. Part 1 included a sample of 240 apparently healthy black SA women (26 ± 7 years) who underwent the following measurements at baseline: PA (Global Physical Activity Questionnaire (GPAQ)), body composition and regional fat distribution (dual-energy x-ray absorptiometry and computerised tomography), blood pressure, fasting glucose, insulin and lipid concentrations. For part 2, a sub-sample of women (n = 57) underwent the same measurements after a 5.5-year period. Results: At baseline, 61% of women were classified as meeting the guidelines for moderate- to vigorous-intensity physical activity (MVPA) according to GPAQ. Women who were active had significantly lower body weight (p < 0.001), body fat (BMI, fat mass, % body fat, waist circumference, central and appendicular fat mass, all p < 0.001), and measures of insulin resistance (fasting serum insulin and HOMA-IR, both p = 0.01), and higher high-density lipoprotein cholesterol (p = 0.041), compared to the inactive group. At follow-up, all body fat measures increased significantly in both groups and diastolic blood pressure decreased significantly in those who were active at baseline, but did not change in those who were inactive. Conclusions: Meeting PA guidelines was associated with decreased risk for CVD and T2D in black SA women, but did not prevent the increase in body fat over time. Interventions promoting physical activity to specifically address obesity in this high-risk group are recommended. © 2014 Dickie et al.; licensee BioMed Central Ltd.

Background: Ethnic differences in body composition and cardiometabolic risk have been reported in cross-sectional studies. This study aimed to investigate changes in body composition over 5.5 years, and its association with cardiometabolic risk in premenopausal black South African (SA) women. Methods: Changes in body composition and body fat distribution (dual-energy x-ray absorptiometry and computerized tomography), fasting glucose, insulin, and lipid concentrations, were measured in 63 black SA women at baseline (age: 27 ± 8 years), and 5.5 years later. Results: Body weight and fat mass (FM) increased by 6.9 ± 9.9 kg and 4.3 ± 6.9 kg, respectively, over the 5.5 years with a relative (%FM) increase in central and decrease in peripheral FM (all P < 0.05). Fasting glucose and lipid concentrations (except HDL-cholesterol) increased over the follow-up period (all P < 0.05). Both baseline and changes in body fat distribution were associated with cardiometabolic risk. Independent of baseline age, FM and insulin sensitivity, baseline trunk:leg was associated with reduced insulin sensitivity at follow-up (Matsuda index; β = -0.41, P = 0.002). Increasing trunk:gynoid ratio was associated with higher plasma insulin levels (β = 0.31, P = 0.023) and reduced insulin sensitivity (Matsuda index; β = -0.52, P < 0.001) at follow-up. Conclusions: Weight gain in free-living black SA women over 5.5 years was associated with a centralization of fat mass, which predicted an increase in cardiometabolic risk.

Background. Internationally young athletes are reported to have a poor understanding of the principles of sports nutrition and supplement use; hence their diet may be unhealthy and inappropriate for  participation in sport. There is limited research on current nutritional knowledge and attitudes of under-16  (U16) age-group level rugby players in South Africa (SA).Objectives. To assess dietary- and supplement-related knowledge and attitudes of 198 U16  national-level rugby players in SA.Methods. Over a period of four consecutive years a total of 198 players attending nutrition workshops at the annual selection camp received and completed an anonymous structured questionnaire.   Anthropometric measures (weight, height and skinfolds) were gathered by registered biokineticists.Results. Of players 87% (168/193) indicated that they wanted to increase lean muscle mass, with 42% (82/194) feeling pressurised to do so by their coach and/or parents. Almost half (85/196) believed their diets to be poor. Players had better knowledge about nutrition recovery strategies than pre-game meals. Seventy per cent (136/195) identified optimal timing and 56% (109/196) knew the ideal macronutrient composition of recovery meals. Over 60% of players believed  supplements were safe (115/192) and necessary (132/193) for increasing muscle mass, and almost half (106/195) believed they could take creatine. Over a third (68/170) also believed that the protein quality of supplements was higher than that of food. Supplements were primarily recommended by coaches and non-dietetic medical practitioners. Eight of the players self-prescribed supplements and four were taking supplements on the advice of a store salesperson or representative.Conclusion. The elite U16 rugby players in this study lacked comprehensive sports nutritional  knowledge, yet had an overly positive attitude toward  supplementation and used supplements  haphazardly to achieve body composition goals. Tailor-made nutrition interventions with a strong education component are recommended to improve players’ nutritional knowledge, as well as access to registered dietitians working in sport to advise on supplements.

Objective: To identify socio-demographic and lifestyle determinants of weight gain in a sample of premenopasual black South African (SA) women. Methods: Changes in body composition (dual-energy X-ray absorptiometry, computerised tomography), socio-economic status (SES) and behavioural/lifestyle factors were measured in 64 black SA women at baseline (27 ± 8 years) and after 5.5 years. Results: A lower body mass index (BMI) and nulliparity, together with access to sanitation, were significant determinants of weight gain and change in body fat distribution over 5.5 years. In addition, younger women increased their body weight more than their older counterparts, but this association was not independent of other determinants. Conclusion: Further research is required to examine the effect of changing SES, as well as the full impact of childbearing on weight gain over time in younger women with lower BMIs. This information will suggest areas for possible intervention to prevent long-term weight gain in these women.

The International Olympic Committee (IOC) recently published a framework on fairness, inclusion, and nondiscrimination on the basis of gender identity and sex variations. Although we appreciate the IOC's recognition of the role of sports science and medicine in policy development, we disagree with the assertion that the IOC framework is consistent with existing scientific and medical evidence and question its recommendations for implementation. Testosterone exposure during male development results in physical differences between male and female bodies; this process underpins male athletic advantage in muscle mass, strength and power, and endurance and aerobic capacity. The IOC's “no presumption of advantage” principle disregards this reality. Studies show that transgender women (male‐born individuals who identify as women) with suppressed testosterone retain muscle mass, strength, and other physical advantages compared to females; male performance advantage cannot be eliminated with testosterone suppression. The IOC's concept of “meaningful competition” is flawed because fairness of category does not hinge on closely matched performances. The female category ensures fair competition for female athletes by excluding male advantages. Case‐by‐case testing for transgender women may lead to stigmatization and cannot be robustly managed in practice. We argue that eligibility criteria for female competition must consider male development rather than relying on current testosterone levels. Female athletes should be recognized as the key stakeholders in the consultation and decision‐making processes. We urge the IOC to reevaluate the recommendations of their Framework to include a comprehensive understanding of the biological advantages of male development to ensure fairness and safety in female sports.

This study aimed to assess the self-reported frequency and severity of gastrointestinal symptoms (GIS) at rest and around rugby training and match play in male and female rugby union players. An online questionnaire was sent to registered rugby union players (sevens or fifteens). Thirteen GIS were assessed alongside perceptions of appetite around rugby and rest using Likert and visual analog scales. Questions investigating a range of medical and dietary factors were included. Three hundred and twenty-five players (male n=271, female n=54) participated in the study. More frequent GIS (at least one GIS experienced weekly/more often) was reported by players at rest (n=203; 62%) compared to around rugby (n=154; 47%). The overall severity of GIS was low (mild discomfort), but a portion of players (33%) did report symptoms of moderate severity around rugby. Female players reported more frequent and severe symptoms compared to male counterparts (p<0.001). Self-reported appetite was significantly lower after matches compared to training. There were no dietary or medical factors associated with GIS severity scores. This study describes GIS characteristics in male and female rugby union players. Half of the players assessed experienced some form of GIS that may affect nutrition, training, or performance, and should thus be a consideration for practitioners supporting this cohort.

The nutritional requirements of a youth rugby player are influenced by biological growth and maturation and the demands of training and competition, alongside a requirement to significantly increase fat-free and overall body mass towards those of senior players. Therefore, it is inappropriate to simply apply the nutrition guidelines and dietary practices of senior rugby players within youth populations. Current evidence outlines the large resting and total energy requirements of youth male rugby players, necessitating equally large energy intakes, especially in the days following competitive match-play and training-based collisions. A consistently positive energy and protein balance is required to ensure targeted physical developments are achieved. Sufficient intakes of dietary carbohydrate, fat and fluid are essential to meet the demands of training and match-play, alongside overall health and wellbeing. A varied and balanced diet that meets these requirements should provide sufficient intakes of essential micronutrients. Supplement intakes should be overseen by a nutrition professional and only prioritised in periods of clinical necessity (i.e., iron, vitamin D). Care is required around the assessment of anthropometric and body composition variables, emphasising appropriate fuelling for fat-free mass development. This chapter reviews the nutritional requirements of young rugby players, while also discussing the safe assessment of anthropometrics and body composition. The nutritional requirements of a youth rugby player are influenced by biological growth and maturation and the demands of training and competition, alongside a requirement to significantly increase fat-free and overall body mass towards those of senior players. This chapter reviews the nutritional requirements of young rugby players, while also discussing the safe assessment of anthropometrics and body composition. Before evaluating the energy requirements of a youth rugby player, it is essential to first understand energy expenditure. Carbohydrate is the primary fuel for high-intensity activities; it is therefore a key macronutrient when preparing youth rugby players for both training and match-play. Youth rugby players are advised to achieve the protein target through real foods rather than through supplementation. Youth players are more likely to achieve a body composition that is more representative of professional adult players, and therefore potentially cope with the increased physical demands of senior match-play.

The nutritional requirements of a youth rugby player are influenced by their biological growth and maturation, physical development and the demands of training and competition. This chapter reviews the current literature on nutrition of youth rugby players, including energy requirements, dietary intakes, hydration, micronutrients and supplements. In summary, the energy and macronutrient requirements of youth rugby players are dictated by their total energy expenditures which increase with age and body size. Whilst youth rugby players appear to meet their daily fat and protein intakes, many players fail to achieve optimal carbohydrate intakes. Furthermore, diet quality does not meet current recommendations, although it does appear to improve with age. The hydration requirements of youth players do not appear to differ from those of their adult counterparts; however, adolescent players may have a greater need for calcium and iron. Finally, although many players regularly consume dietary supplements, there is limited evidence to support their use within this population. Future research is required, particularly in youth female players, to establish nutritional requirements and enhance nutritional practices.

Modern-day nutritional approaches for rugby players require careful application of research findings to practice, underpinned by a sound understanding of the physical and physiological demands of the professional game. Leanness for players is considered important for their power-to-weight ratios. However, data has shown that strength, as a reflection of muscle mass, is still more important for success, not body fat levels. Significant injuries or reduced training loads will force change on a professional player’s nutritional profile. The goals for most players during an injury are to mobilise as soon as possible, prevent unnecessary weight gain and maintain muscle mass, which shifts the energy and macronutrient requirements. Recently, the women’s game has gained popularity with the first group of professional contracts being offered to English players in 2018. Using websites, webinars, infographics and other communication strategies, both the promotion of nutrition education and access to what the professionals are eating has become more available.

Establishing normative ranges for Bone Mineral Density in female team sport athletes Purpose: It is common that female athlete cohorts generally have higher bone density compared to non-athletic controls or typical reference populations. However, activity specific reference databases are required to identify athletes who have comparatively low BMD within their sport, as this may highlight increased risk of stress fractures or occurrences of low energy availability. Method: A secondary data analysis of three female team sport cohorts (cricket, rugby league, netball, n=103) will be completed from previous dual x-ray absorptiometry scans (Lunar iDXA, GE Medical Systems). Bone mineral density (total, lumbar spine [L1-L4], total hip and neck of femur) will be analysed alongside age, mass, stature, and fat free lean mass. Results: Data is yet to be analysed. Conclusion: Sport specific ranges will inform improved practice to enable early identification of athletes at present risk or stress fracture or low energy availability outcomes as well as future risk of osteoporosis or fracture with ageing.

Objective This systematic review and meta-analysis aimed to determine differences in body composition between playing standard and age in male rugby union and rugby league athletes. Eligibility criteria The MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines for design, implementation, and reporting were followed. Studies were required to be in male rugby union or league and have body composition as the primary or secondary outcome. Data was required to be presented separately for positional groups and body composition presented as whole-body. Data sources PubMed, Cochrane Library, MEDLINE, SPORTDiscus, and CINHAHL via EBSCOhost. Risk of bias The methodological quality of the included studies was evaluated using a modified assessment scale Results 58 studies were included for meta-analysis. Results highlighted significantly higher fat-free mass in senior elite than senior sub-elite or junior elite athletes for all RU and RL forwards. Small and non-significant differences were found in fat mass between rugby union playing standards and age categories. Rugby league senior elite forwards had less fat mass than junior elite forwards. Conclusions Practitioners should prioritise training and nutritional strategies that maximise fat-free mass development, especially in junior elite cohorts.

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Nutrition strategies and supplements may have a role to play in diminishing exercise associated gastrointestinal cell damage and permeability. The aim of this systematic review was to determine the influence of dietary supplements on markers of exercise-induced gut endothelial cell damage and/or permeability. Five databases were searched through to February 2021. Studies were selected that evaluated indirect markers of gut endothelial cell damage and permeability in response to exercise with and without a specified supplement, including with and without water. Acute and chronic supplementation protocols were included. Twenty-seven studies were included. The studies investigated a wide range of supplements including bovine colostrum, glutamine, probiotics, supplemental carbohydrate and protein, nitrate or nitrate precursors and water across a variety of endurance exercise protocols. The majority of studies using bovine colostrum and glutamine demonstrated a reduction in selected markers of gut cell damage and permeability compared to placebo conditions. Carbohydrate intake before and during exercise and maintaining euhydration may partially mitigate gut damage and permeability but coincide with other performance nutrition strategies. Single strain probiotic strains showed some positive findings, but the results are likely strain, dosage and duration specific. Bovine colostrum, glutamine, carbohydrate supplementation and maintaining euhydration may reduce exercise-associated endothelial damage and improve gut permeability. In spite of a large heterogeneity across the selected studies, appropriate inclusion of different nutrition strategies could mitigate the initial phases of gastrointestinal cell disturbances in athletes associated with exercise. However, research is needed to clarify if this will contribute to improved athlete gastrointestinal and performance outcomes.

Aim Exercise appears to cause damage to the endothelial lining of the human gastrointestinal tract and elicit a significant increase in gut permeability. Objective The aim of this review was to determine the effect of an acute bout of exercise on gut damage and permeability outcomes in healthy populations using a meta-analysis. Methods PubMed, The Cochrane Library as well as MEDLINE, SPORTDiscus and CINHAL, via EBSCOhost were searched through February 2019. Studies were selected that evaluated urinary (ratio of disaccharide/monosaccharide excretion) or plasma markers [intestinal Fatty Acid Binding Protein (i-FABP)] of gut permeability and gut cell damage in response to a single bout of exercise. Results A total of 34 studies were included. A random-effects meta-analysis was performed, and showed a large and moderate effect size for markers of gut damage (i-FABP) (ES 0.81; 95% CI 0.63–0.98; n = 26; p < 0.001) and gut permeability (Disaccharide Sugar/Monosaccharide Sugar) (ES 0.70; 95% CI 0.29–1.11; n = 17; p < 0.001), respectively. Exercise performed in hot conditions (> 23 °C) further increased markers of gut damage compared with thermoneutral conditions [ES 1.06 (95% CI 0.88–1.23) vs. 0.66 (95% CI 0.43–0.89); p < 0.001]. Exercise duration did not have any significant effect on gut damage or permeability outcomes. Conclusions These findings demonstrate that a single bout of exercise increases gut damage and gut permeability in healthy participants, with gut damage being exacerbated in hot environments. Further investigation into nutritional strategies to minimise gut damage and permeability after exercise is required. PROSPERO database number (CRD42018086339).

PURPOSE: To assess indirect markers of intestinal endothelial cell damage and permeability in academy rugby players in response to rugby training at the beginning and end of preseason. METHODS: Blood and urinary measures (intestinal fatty acid binding protein and lactulose:rhamnose) as measures of gastrointestinal cell damage and permeability were taken at rest and after a standardised collision-based rugby training session in 19 elite male academy rugby players (age: 20 ± 1 years, backs: 89.3 ± 8.4 kg; forwards: 111.8 ± 7.6 kg) at the start of preseason. A subsample (n = 5) repeated the protocol after six weeks of preseason training. Gastrointestinal symptoms (GIS; range of thirteen standard symptoms), aerobic capacity (30-15 intermittent fitness test), and strength (1 repetition maximum) were also measured. RESULTS: Following the rugby training session at the start of preseason, there was an increase (median; interquartile range) in intestinal fatty acid binding protein (2140; 1260-2730 to 3245; 1985-5143 pg/ml, p = 0.003) and lactulose:rhamnose (0.31; 0.26-0.34 to 0.97; 0.82-1.07, p < 0.001). After six weeks of preseason training players physical qualities improved, and the same trends in blood and urinary measures were observed within the subsample. Overall, the frequency and severity of GIS were low and not correlated to markers of endothelial damage. CONCLUSIONS: Rugby training resulted in increased intestinal endothelial cell damage and permeability compared to rest. A similar magnitude of effect was observed after six weeks of pre-season training. This was not related to the experience of GIS.

BACKGROUND: Elite rugby players experience poor sleep quality and quantity. This lack of sleep could compromise post-exercise recovery. Therefore, it appears central to encourage sleep in order to improve recovery kinetics. However, the effectiveness of an acute ergogenic strategy such as sleep extension on recovery has yet to be investigated among athletes. AIM: To compare the effects of a single night of sleep extension to an active recovery session (CON) on post-exercise recovery kinetics. METHODS: In a randomised cross-over design, 10 male rugby union players participated in two evening training sessions (19:30) involving collision activity, 7-days apart. After each session, participants either extended their sleep to 10 hours or attended an early morning recovery session (07:30). Prior to (PRE), immediately after (POST 0 hour [h]), 14h (POST 14) and 36h (POST 36) post training, neuromuscular, perceptual and cognitive measures of fatigue were assessed. Objective sleep parameters were monitored two days before the training session and over the two-day recovery period. RESULTS: The training session induced substantial decreases in countermovement jump mean power and wellness across all time points, while heart rate recovery decreased at POST 0 in both conditions. Sleep extension resulted in greater total sleep time (effect size [90% confidence interval]: 5.35 [4.56 to 6.14]) but greater sleep fragmentation than CON (2.85 [2.00 to 3.70]). Between group differences highlight a faster recovery of cognitive performance following sleep extension (-1.53 [-2.33 to -0.74]) at POST 14, while autonomic function (-1.00 [-1.85 to -0.16]) and upper-body neuromuscular function (-0.78 [-1.65 to 0.08]) were better in CON. However, no difference in recovery status between groups was observed at POST 36. CONCLUSION: The main finding of this study suggests that sleep extension could affect cognitive function positively but did not improve neuromuscular function the day after a late exercise bout.

Abstract

This is the first study to assess longitudinal changes in anthropometric, physiological, and physical qualities of international women’s rugby league players. Thirteen forwards and 11 backs were tested three times over a 10-month period. Assessments included: standing height and body mass, body composition measured by dual x-ray absorptiometry (DXA), a blood panel, resting metabolic rate (RMR) assessed by indirect calorimetry, aerobic capacity (i.e., VLO 2 max) evaluated by an incremental treadmill test, and isometric force production measured by a force plate. During the pre-season phase, lean mass increased significantly by ∼2% for backs (testing point 1: 47 kg; testing point 2: 48 kg) and forwards (testing point 1: 50 kg; testing point 2: 51 kg) (p = ≤ 0.05). Backs significantly increased their VLO 2 max by 22% from testing point 1 (40 ml·kg −1 ·min −1 ) to testing point 3 (49 ml·kg −1 ·min −1 ) (p = ≤ 0.04). The VLO 2 max of forwards increased by 10% from testing point 1 (41 ml·kg −1 ·min −1 ) to testing point 3 (45 ml·kg −1 ·min −1 ), however this change was not significant (p = ≥ 0.05). Body mass (values represent the range of means across the three testing points) (backs: 68 kg; forwards: 77-78 kg), fat mass percentage (backs: 25-26%; forwards: 30-31%), resting metabolic rate (backs: 7 MJ·day −1 ; forwards: 7 MJ·day −1 ), isometric mid-thigh pull (backs: 2106-2180 N; forwards: 2155-2241 N), isometric bench press (backs: 799-822 N; forwards: 999-1024 N), isometric prone row (backs: 625-628 N; forwards: 667-678 N) and bloods (backs: ferritin 21-29 ug/L, haemoglobin 137-140 g/L, iron 17-21 umol/L, transferrin 3 g/L, transferring saturation 23-28%; forwards: ferritin 31-33 ug/L, haemoglobin 141-145 g/L, iron 20-23 umol/L, transferrin 3 g/L, transferrin saturation 26-31%) did not change (p = ≥ 0.05). This study provides novel longitudinal data which can be used to better prepare women rugby league players for the unique demands of their sport, underpinning female athlete health.

Rugby union (RU) is a skill-collision team sport played at junior and senior levels worldwide. Within England, age-grade rugby governs the participation and talent development of youth players. The RU player development pathway has recently been questioned, regarding player performance and wellbeing, which sport science research can address. The purpose of this review was to summarise and critically appraise the literature in relation to the applied sport science of male age-grade RU players in England focusing upon 1) match-play characteristics, 2) training exposures, 3) physical qualities, 4) fatigue and recovery, 5) nutrition, 6) psychological challenges and development, and 7) injury. Current research evidence suggests that age, playing level and position influence the match-play characteristics of age-grade RU. Training exposures of players are described as ‘organised chaos’ due to the multiple environments and stakeholders involved in coordinating training schedules. Fatigue is apparent up to 72 hours post match-play. Well developed physical qualities are important for player development and injury risk reduction. The nutritional requirements are high due to the energetic costs of collisions. Concerns around the psychological characteristics have also been identified (e.g., perfectionism). Injury risk is an important consideration with prevention strategies available. This review highlights the important multi-disciplinary aspects of sport science for developing age-grade RU players for continued participation and player development. The review describes where some current practices may not be optimal, provides a framework to assist practitioners to effectively prepare age-grade players for the holistic demands of youth RU and considers areas for future research.

Background: Body composition and bone health are important for netball from a performance and health perspective (e.g., bone stress injury), given the typical characteristics of players and demands of the game. Objectives: The objectives of this study are to quantify and compare the positional group-specific body composition and site-specific bone health outcomes of netball players and to establish within-season changes in these variables. Methods: Forty-seven female netball players (senior: n=23, under-21: n=24) from one Netball Super League (NSL) franchise participated across three seasons (2021-2023). Dual-energy X-ray absorptiometry (DEXA) scans were conducted four times per season. Total body, anteroposterior lumbar spine and total hip scans were performed. General and generalised linear mixed models were used to compare positional groups and age groups, and to investigate within-season changes. Results: Goal circle netball players had greater total mass and bone mass than midcourt netball players at both levels (p<0.05, effect size: moderate to very large), but not when scaled for height. Senior players had greater lean mass, bone mass, total bone mineral density and bone mineral content than under-21 players (p<0.05, effect size: moderate to very large). No group-level significant changes were observed across a playing season, but individual trends varied. Conclusion: These findings highlight the importance of continued physical development in the under-21 squad before progressing to a senior squad, as well as the need for individualised approaches to nutritional and training interventions that support physical development, addressing positional requirements and developmental stages. Future research should explore longitudinal body composition trajectories across career phases and multiple teams to refine normative benchmarks.

This is the first study to assess longitudinal changes in anthropometric, physiological, and physical qualities of international women’s rugby league players. Thirteen forwards and 11 backs were tested three times over a 10-month period. Assessments included: standing height and body mass, body composition measured by dual x-ray absorptiometry (DXA), a blood panel, resting metabolic rate (RMR) assessed by indirect calorimetry, aerobic capacity (i.e.,V˙O2max) evaluated by an incremental treadmill test, and isometric force production measured by a force plate. During the pre-season phase, lean mass increased significantly by ~2% for backs (testing point 1: 47 kg; testing point 2: 48 kg) and forwards (testing point 1: 50 kg; testing point 2: 51 kg) (p = ≤ 0.05). Backs significantly increased their V˙O2max by 22% from testing point 1 (40 ml kg-1 min-1) to testing point 3 (49 ml kg-1 min-1) (p = ≤ 0.04). The V˙O2max of forwards increased by 10% from testing point 1 (41 ml kg-1 min-1) to testing point 3 (45 ml kg-1 min-1), however this change was not significant (p = ≥ 0.05). Body mass (values represent the range of means across the three testing points) (backs: 68 kg; forwards: 77–78 kg), fat mass percentage (backs: 25–26%; forwards: 30–31%), resting metabolic rate (backs: 7 MJ day-1; forwards: 7 MJ day-1), isometric mid-thigh pull (backs: 2106–2180 N; forwards: 2155–2241 N), isometric bench press (backs: 799–822 N; forwards: 999–1024 N), isometric prone row (backs: 625–628 N; forwards: 667–678 N) and bloods (backs: ferritin 21–29 ug/L, haemoglobin 137–140 g/L, iron 17–21 umol/L, transferrin 3 g/L, transferring saturation 23–28%; forwards: ferritin 31–33 ug/L, haemoglobin 141–145 g/L, iron 20–23 umol/L, transferrin 3 g/L, transferrin saturation 26–31%) did not change (p = ≥ 0.05). This study provides novel longitudinal data which can be used to better prepare women rugby league players for the unique demands of their sport, underpinning female athlete health.

To establish the criterion-assessed energy and fluid requirements of female netball players, 13 adult players from a senior Netball Super League squad were assessed over 14 days in a cross-sectional design, representing a two- and one-match microcycle, respectively. Total energy expenditure (TEE) and water turnover (WT) were measured by doubly labeled water. Resting and activity energy expenditure were measured by indirect calorimetry and Actiheart, respectively. Mean 14-day TEE was 13.46 ± 1.20 MJ day−1 (95% CI, 12.63–14.39 MJ day−1). Resting energy expenditure was 6.53 ± 0.60 MJ day−1 (95% CI, 6.17–6.89 MJ day−1). Physical activity level was 2.07 ± 0.19 arbitrary units (AU) (95% CI, 1.95–2.18 AU). Mean WT was 4.1 ± 0.9 L day−1 (95% CI, 3.6–4.7 L day−1). Match days led to significantly greater TEE than training (+2.85 ± 0.70 MJ day−1; 95% CI, +1.00– +4.70 MJ day−1; p = 0.002) and rest (+4.85 ± 0.70 MJ day−1; 95% CI, +3.13–+6.56 MJ day−1; p < 0.001) days. Matches led to significantly greater energy expenditure (+1.85 ± 1.27 MJ; 95% CI, +0.95–+2.76 MJ day−1; p = 0.001) than court-based training sessions. There was no significant difference in TEE (+0.03 ± 0.35 MJ day−1; 95% CI, −0.74–+0.80 MJ day−1; p = 0.936) across weeks. Calibrated Actiheart 5 monitors underestimated TEE (−1.92 ± 1.21 MJ day−1). Energy and fluid turnover were greatest on match days, followed by training and rest days, with no difference across weeks. This study provides criterion-assessed energy and fluid requirements to inform dietary guidance for female netball players.