Dr Nessan Costello

The primary aim of this thesis was to evaluate the dietary intake, energy expenditure and energy balance of young professional male rugby league players across the season. Twenty participants from one European Super League U19 academy were recruited. Prior to assessing ‘free-living’ dietary intake, study 1 investigated the validity of a traditional and contemporary dietary assessment tool to measure the total energy intake of young professional rugby league players (n =12). Findings highlighted a small and moderate mean bias for under-reporting by Snap- N-Send a very likely higher (4.96 (0.97) MJ; ES =0.30 (0.07); p =0.0021) total energy expenditure across a five-day microcycle matched for physical activity demands. Findings highlighted the large resting metabolic rates (11.63 (2.46) MJ.day-1), total energy expenditures (18.93 (3.18) MJ.day-1) and moderate physical activity levels (1.6 (0.2)) of players. Players were in a self-reported negative energy balance (-1.63 (1.73) MJ.day-1; p =0.233) and lost body mass (-0.65 (0.78) kg; p =0.076). To support a desired increase in player body mass, case study 1 established the large energy requirements (resting metabolic rate: 14.7 MJ.day-1; total energy expenditure: 22.4 MJ.day-1; physical activity level: 1.5) of one young professional rugby league player across a two-week pre-season microcycle, using the Behaviour Change Wheel to design and implement a behavioural intervention over a twelve week period. Study 4 Findings highlighted the large resting metabolic rates (10.26 (1.49) MJ.day-1), total energy expenditures (16.15 (0.77) MJ.day-1) and moderate physical activity levels (1.6 (0.2)) of players. Players were in a self-reported negative energy balance (-0.70 (1.11) MJ.day-1; p =0.145) and lost body mass (-0.3 (0.6) kg; p =0.222). Sub-analysis within study 4 (n = 5), demonstrated an almost certainly higher total energy expenditure across a pre-season (study 3) vs. in-season microcycle (0.02 MJ.kg.BM- 1; ES =1.14 (0.41); p =0.004). Study 5 and study 6 utilised data collected within study 3 and 4 to investigate the validity of wearable technology or Snap-N-Send to measure the total energy expenditure or total energy intake of young professional rugby league players across ‘true’ free-living conditions (n = 8), respectively. To support appropriate energy intakes following match-play, case study 2 investigated three-day changes in resting metabolic rate following a competitive young professional RL match (n = 5). Findings demonstrated almost certainly, most likely and likely increases in resting metabolic rate at 24 (2.38 (1.02) MJ.day-1; ES =1.06 (0.43); p =0.006), 48 (1.44 (0.93) MJ.day-1; ES =0.62 (0.38); p =0.025) and 72 hours (0.94 (0.78) MJ.day-1;ES =0.40 (0.32); p =0.055) after baseline. In conclusion, studies presented within this thesis establish the large resting and total energy requirements of young professional male rugby league players across the season, which are increased in the days following training-based collisions and competitive match-play. Players require support to consistently achieve desired manipulations of energy balance required for optimal physical development across pivotal youth development periods.

Rugby union exhibits large variations in the idealised player physical profiles across positions. The pursuit of physique ideals with limited professional support can influence eating disorder symptomology, exercise compulsion, and low sexual drive. The primary aims were to (1) explore the prevalence of elite male rugby union players who are at risk for eating disorders, low sex drive, and exercise compulsion, and (2) explore the relationship between risk and players’ professional status, weight, age, and playing position. A secondary aim was to explore the nutritional service support and dietary monitoring practices experienced by the players. Participants were recruited from four elite professional rugby union squads in Ireland. Players (≥tier3) over 18 years of age and training ≥ three times per week were eligible. Participants completed the eating disorder examination questionnaire, exercise addiction inventory, and sex drive section of the low energy availability in males questionnaire. Ninety-seven players participated in the study. The mean age of participants was 22 ± 4 years. Eating disorder risk (9.3%), reported low sex drive (20.6%), and exercise compulsion (16.5%) was indicated. Players in the forwards position, regardless of professional status, reported higher eating concerns ( p  = 0.03). No significant difference was identified between professional status or position when determining sex drive. Access to a nutritionist (99%) and dietary monitoring practices (68%) was reported by players. Awareness of low sex drive and disordered eating in elite rugby should be encouraged, alongside access to professional nutritional support. Further research is needed to understand the contextual risk factors in male players.

Over the last decade, I’ve seen first-hand how body mass and composition monitoring has become routine in elite football. Done well, it supports fuelling, development, and rehabilitation. Done poorly, it fuels anxiety, disordered eating, and a culture where appearance outweighs performance. Recent headlines from Fran Kirby, Alessia Russo, Kalvin Phillips, and Allan Saint-Maximin show body-shaming persists across men’s and women’s football. Similar issues are seen in cycling and cricket, with “fat clubs” still an open secret. Too often, arbitrary percentage targets—without scientific basis—drive harmful behaviours, from extreme low-carb diets to players skipping meals just to “hit green.” As practitioners, we must ask: what does the science actually tell us, and how can we build safer, evidence-based systems?

Purpose To test the hypothesis that training with reduced carbohydrate (CHO) availability increases bone resorption in adolescent soccer players. Methods In a randomised crossover design, ten male players (age: 17.4 ± 0.8 years) from an English Premier League academy completed an acute 90-min field-based training session (occurring between 10:30–12:00) in conditions of high (TRAIN HIGH; 1.5 g.kg−1, 60 g, 1.5 g.kg−1 and 1.5 g.kg−1 consumed at 08:00, during training, 12:30 and 13:30, respectively) or low CHO availability (TRAIN LOW; 0 g.kg−1). Participants also completed a non-exercise trial (REST) under identical dietary conditions to TRAIN LOW. Venous blood samples were obtained at 08:30, 10:30, 12:30 and 14:30 for assessment of bone resorption (βCTX), bone formation (PINP) and calcium metabolism (PTH and ACa). Results External training load did not differ (all P > 0.05) between TRAIN HIGH and TRAIN LOW, as evident for total distance (5.6 ± 0.8; 5.5 ± 0.1 km), average speed (81 ± 9; 85 ± 12 m.min−1) and high-speed running (350 ± 239; 270 ± 89 m). Area under the curve for both βCTX and PINP was significantly greater (P < 0.01 and P = 0.03) in TRAIN LOW versus TRAIN HIGH, whilst no differences in PTH or ACa (P = 0.11 and P = 0.89) were observed between all three trials. Conclusion CHO restriction before, during and after an acute soccer training session increased bone (re)modelling markers in academy players. Despite acute anabolic effects of bone formation, the long-term consequence of bone resorption may impair skeletal development and increase injury risk during growth and maturation.

This study aimed to test the hypothesis that the total daily energy expenditure (TDEE) of male academy soccer players is greater than players not enrolled on a formalised academy programme. English Premier League academy (ACAD: n = 8, 13 years, 50 ± 6 kg, 88 ± 3% predicted adult stature, PAS) and non-academy players (NON-ACAD: n = 6, 13 years, 53 ± 12 kg, 89 ± 3% PAS) were assessed for TDEE (via doubly labelled water) during a 14-day in-season period. External loading was evaluated during training (ACAD: 8 sessions, NON-ACAD: 2 sessions) and games (2 games for both ACAD and NON-ACAD) via GPS, and daily physical activity was evaluated using triaxial accelerometry. Accumulative duration of soccer activity (ACAD: 975 ± 23 min, NON-ACAD: 397 ± 2 min; p < 0.01), distance covered (ACAD: 54.2 ± 8.3 km, NON-ACAD: 21.6 ± 4.7 km; p < 0.05) and time engaged in daily moderate-to-vigorous (ACAD: 124 ± 17 min, NON-ACAD: 79 ± 18 min; p < 0.01) activity was greater in academy players. Academy players displayed greater absolute (ACAD: 3380 ± 517 kcal · d−1, NON-ACAD: 2641 ± 308 kcal · d−1; p < 0.05) and relative TDEE (ACAD: 66 ± 6 kcal · kg · d−1, NON-ACAD: 52 ± 10 kcal · kg · d−1; p < 0.05) versus non-academy players. Given the injury risk associated with high training volumes during growth and maturation, data demonstrate the requirement for academy players to consume sufficient energy (and carbohydrate) intake to support the enhanced energy cost of academy programmes.

Academy soccer players frequently train in the evening (i.e. 1700-2000 h), hence limited time to nutritionally prepare and recover due to schooling, travel and sleep schedules. Accordingly, we assessed timing and quantity of energy intake in the pre-training and post-training period. Over a 3-day in-season training period, male players (n=48; n=8 from under (U) 12, 13, 14, 15/16, 18 and 23 players) from an English Premier League academy self-reported dietary intake and physical activity levels (via the remote food photography method and activity diary, respectively) in the four hours pre- and post-training. Timing of pre-training energy intake ranged from 40 ± 28 mins (U15/U16 players) to 114 ± 71 mins (U18) before training and mean carbohydrate (CHO) intake ranged from 0.8±0.4 g.kg-1 (U23) to 1.5±0.9 g.kg-1 (U12). Timing of post-training energy intake ranged from 39 ± 27 mins (U14) to 70 ± 84 mins (U23) and mean CHO intake ranged from 1.6±0.8 g.kg-1 (U12) to 0.9±0.5 g.kg-1 (U14). In contrast to CHO, all age groups consumed sufficient protein intake in the post-training period (i.e. > 0.3 g.kg-1). We conclude academy soccer players habitually practice sub-optimal fuelling and recovery strategies, the consequence of which could impair growth, maturation and physical performance.

Isotope-based tracer methods allow the determination of total energy expenditure (TEE), water turnover (rH2O), and total body water (TBW) in free-living conditions. These methods have exciting applications in athletes. However, the limited number of available measurements constrains their applicability. The aim was to describe the application of isotope dilution techniques for measuring TEE, rH2O, and TBW in athletic populations. A comprehensive search (https://doi.org/10.17605/OSF.IO/7932T) was performed in three databases: PubMed, EBSCO (CINAHL, MEDLINE, and SPORTDiscus), and Cochrane Library. A total of 1,540 records were identified (564 excluded) and 174 through other sources. After excluding 53 duplicates, 1,097 articles were screened. A total of 121 studies were included, totaling 3,244 measurements from different types of sports, age range, and tier level, with 1,020 from female athletes and 139 measurements where sex was not reported. For TEE, 75 studies were included with values ranging from 1,939 to 10,070 kcal/day. For rH2O, 15 studies were included with values ranging from 2.7 to 13.4 L/day. For TBW, 77 studies were included with values ranging from 29.8 to 76.8 kg. Variability was observed across the studies among the variables of interest. Overall, males showed higher TEE, rH2O, and TBW values than females, with endurance sports showing the greatest variability in energy and water flux, and TBW values varying most in team and mixed sports. Future research should increase representation of females, athletes with disabilities, and Tier 5 “world-class” athletes to establish normative values across sports, age groups, and sex while applying standardized isotope dilution methodologies.

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.

Accurately determining total energy expenditure enables the precise manipulation of energy balance within professional collision-based sports. Therefore, this study investigated the ability of isolated or combined wearable technology to determine the total energy expenditure of professional young rugby league players across a typical pre-season and in-season period. Total energy expenditure was measured via doubly labelled water, the criterion method, across a fourteen-day pre-season (n=6) and seven-day in-season (n=7) period. Practical measures of total energy expenditure included SenseWear Pro3 Armbands in isolation and combined with metabolic power derived from microtechnology units. SenseWear Pro3 Armbands significantly under-reported pre-season (5.00 (2.52) MJ.day-1; p = 0.002) and in-season (2.86 (1.15) MJ.day-1; p < 0.001) total energy expenditure, demonstrating a large and extremely large standardised mean bias, and a very large and large typical error, respectively. Combining metabolic power with SenseWear Pro3 Armbands almost certainly improved pre-season (0.95 (0.15) MJ.day-1; ES = 0.32 ±0.04; p < 0.001) and in-season (1.01 (0.15) MJ.day-1; ES = 0.88 ±1.05; p < 0.001) assessment. However, SenseWear Pro3 Armbands combined with metabolic power continued to significantly under-report pre-season (4.04 (2.38) MJ.day-1; p = 0.004) and in-season (2.18 (0.96) MJ.day-1; p = 0.002) expenditure, demonstrating a large and very large standardised mean bias, and a very large and large typical error, respectively. These findings demonstrate the limitations of utilising isolated or combined wearable technology to accurately determine the total energy expenditure of professional collision-based sport athletes across different stages of the season.

To critically evaluate sport nutrition services available to male and female international rugby unions. Fifteen participants, representing 16 international rugby unions, including nine female and seven male teams (one participant worked with both a female and male union), responded to an online survey. Twelve of the unions recruited were ranked in the top 10 globally by World Rugby. Twelve unions employed accredited nutrition practitioners with significant experience (> 5 years: n = 5; > 10 years: n = 4) and advanced qualifications (master's degrees: n = 8; doctorates: n = 2). Three unions did not employ a qualified nutrition practitioner (female: n = 2; male: n = 1). Full-time employment was more common among nutrition practitioners serving male (n = 4/5) versus female (n = 3/6) unions. Practitioners served male unions for more hours per week (42 ± 28) than female unions (24 ± 20). Practitioners were involved in sport science meetings (n = 14/15), anti-doping education, menu design, strategy development (n = 13/15), body composition assessments, individual consultations (n = 12/15), focusing on fuelling, recovery and injury rehabilitation (n = 14/15). Participants were “moderately confident” (n = 8/15) in using behaviour change techniques. Most participants agreed on the lack of female-specific nutrition guidance (n = 14/15), relying on guidance for male players due to limited evidence (n = 7/9). This study provides the first critical reflection of sport nutrition service delivery within international rugby. The findings highlight gender disparities for female players, with reduced applied support and a lack of female-specific guidelines. Recommendations include enhancing practitioner training in behaviour change, hiring qualified nutritionists, deemphasising body composition assessment, and conducting more research to improve nutrition services, especially for women.

Nutrition guidelines specific to short stature athletes are lacking. Achondroplasia, the most common cause for disproportionate short stature (dwarfism), potentially increases resting energy requirements. Therefore, for the first time, this case study aimed to establish the resting metabolic rate (RMR), physical activity energy expenditure (PAEE), and total energy expenditure (TEE) of a dwarf para-powerlifter across rest and training days. A second aim was to determine the suitability of RMR prediction equations recommended for use in athletic populations. RMR was measured using indirect calorimetry on four occasions (two days post-competition, one day post-training, one- and three-days post-training camps). PAEE was monitored using a wrist-worn accelerometer for two 7-day periods. The thermic effect of feeding was estimated; therefore, TEE was inferred. RMR was greater 1- and 3-days post-training camps (1896 and 1992 kcal∙day−1, respectively) than post-training (1613 kcal∙day−1) and post-competition (1409 kcal∙day−1). PAEE and TEE was similar between rest and training days (PAEE, 957 and 948; TEE, 2715 and 2705 kcal∙day−1, respectively). Accuracy of RMR prediction equations utilised ranged from − 580 to + 189 kcal∙day−1 when compared to measured RMR post competition and training. Underestimation was greater (−412 ± 107 kcal∙day−1) post training camps. Results highlight the importance of establishing the energy requirements of dwarf para-athletes, particularly because prediction equations were not accurate in this case study. Further investigation of energy demands during training camps, particularly the relationship of workload on energy expenditure, are now warranted in a larger population.

Accurate quantification of energy intake is imperative in athletes; however traditional dietary assessment tools are frequently inaccurate. Therefore, this study investigated the validity of a contemporary dietary assessment tool or wearable technology to determine the total energy intake (TEI) of professional young athletes. The TEI of eight professional young male rugby league players was determined by three methods; Snap-N-Send, SenseWear Armbands (SWA) combined with metabolic power and doubly labelled water (DLW; intake-balance method; criterion) across a combined ten-day pre-season and seven-day in-season period. Changes in fasted body mass were recorded, alongside changes in body composition via isotopic dilution and a validated energy density equation. Energy intake was calculated via the intake-balance method. Snap-N-Send non-significantly over-reported pre-season and in-season energy intake by 0.21 (2.37) MJ.day-1 (p = 0.833) and 0.51 (1.73) MJ.day-1 (p = 0.464), respectively. This represented a trivial and small standardised mean bias, and very large and large typical error. SenseWear Armbands and metabolic power significantly under-reported pre-season and in-season TEI by 3.51 (2.42) MJ.day-1 (p = 0.017) and 2.18 (1.85) MJ.day-1 (p = 0.021), respectively. This represents a large and moderate standardised mean bias, and very large and very large typical error. There was a most likely larger daily error reported by SWA and metabolic power than Snap-N-Send across pre-season (3.30 (2.45) MJ.day-1; ES = 1.26 ± 0.68; p = 0.014) and in-season periods (1.67 (2.00) MJ.day-1; ES = 1.27 ± 0.70; p = 0.012). This study demonstrates the enhanced validity of Snap-N-Send for assessing athlete TEI over combined wearable technology, although caution is required when determining the individual TEIs of athletes via Snap-N-Send.

Background Athletes are recognised as being at elevated risk of disordered eating (DE), with particularly high prevalence observed in ‘weight-sensitive’ sports. However, limited research has examined this issue within contact sports such as rugby, where unique physical demands and cultural norms may shape eating behaviours differently. This study aimed to investigate the prevalence, characteristics, and contextual drivers of DE among national-level male and female rugby union and rugby league players in England. A mixed-methods, cross-sectional design was employed utilising an online questionnaire, incorporating the Eating Disorders Examination Questionnaire (EDEQ), the Muscularity Orientated Eating Test (MOET) and open-ended qualitative questions. Participants (n = 182) included current players from Premiership Women’s Rugby, Gallagher Premiership, Women’s Super League, and Men’s Super League. Quantitative data were analysed using descriptive and non-parametric statistics and qualitative responses underwent reflexive content analysis. Results Data from the EDEQ showed 28% of female and 9% of male players exceeded clinical thresholds for DE, with the highest prevalence among front-row forwards and players with a self-reported body mass index of >25 kg/m². Muscularity-oriented DE was similar in both sexes (MOET mean scores: females = 13.8; males = 13.0). Athletes reported DE behaviours including binge eating (40% of participants), compulsive exercise (33%), vomiting (2%), and laxative use (1%). Qualitative findings revealed a perceived link between body composition and performance, with 82% of players attempting to manipulate their bodies in the previous 12 months. 63% of players reported pressure to change their body composition, commonly driven by coaches (17%) or intrinsic motivations (16%). 44% experienced body-related comments in the rugby setting, frequently perceived as insults/jokes (19%), with players reporting emotional distress in response (11%). Conclusion National-level rugby players – particularly females, forwards, and individuals with self-reported high-BMI – are at elevated risk for DE. The findings reveal a high-pressure sporting culture in which physical size is paradoxically required and ridiculed. To address this complex issue, comprehensive and system-wide prevention strategies are urgently needed. These include challenging harmful cultural norms, cultivating psychological safety, and prioritising the holistic health and wellbeing of players across both men’s and women’s national-level rugby.

Background Body mass and composition (fat and fat-free mass) manipulation is a common practice in sport, yet it can pose significant risks to athlete health and wellbeing. Practitioners must continually adapt to the growing body of evidence to implement safe, effective and context-specific practice. Objective This scoping review aimed to summarise dietary recommendations for altering body mass or composition in male and female, adult non-disabled athletes and appraise how these expert-group led recommendations have evolved over time. Methods Electronic databases, including SCOPUS, PubMed, SPORTDiscus, CINAHL Complete and APA PsycINFO were searched (last search 2 August 2024) without date restrictions. Papers were included if they provided dietary recommendations for altering body mass or composition in adult non-disabled athlete populations and were published by an expert organisation. Results From 6068 records screened, 73 documents were included, comprising 45 consensus statements, 27 position stands and 1 practice guideline, endorsed by 14 organisations and developed by 328 experts from 25 countries. Athletics (n = 19), aquatics (n = 7) and team sports (n = 5) were the most represented, leaving many sports underrepresented. A total of 50 documents were standalone rather than part of an updated series. Only 40 papers addressed specific targets, rates or timing of outcome changes. Individualised, realistic and health-focussed targets were recommended, aligned with the athlete’s sport, position, sex, age and competition phase, with gradual changes (e.g. 0.5–1.0 kg/week fat loss) to enhance performance. Common strategies for altering body mass and composition included creating an energy surplus (500–1000 kcal/day) or deficit (250–1000 kcal/day), maintaining energy availability above 30 kcal/kg fat-free mass/day, and periodising carbohydrate intake (3–12 g/kg/day) on the basis of training demands. Protein intake (1.6–2.4 g/kg/day) was recommended across 4–6 feeds from high-quality sources, alongside targeted supplements such as creatine, whey protein and a multi-vitamin and mineral. Recommendations focussed minimal attention on nutrients such as fats, fibre or micronutrients, and the language used was often vague, leaving significant room for interpretation. Conclusions Developing sport-specific, behaviourally anchored and regularly updated dietary recommendations, informed by athlete and multidisciplinary team input, is recommended. This approach would provide actionable, athlete-centred strategies that effectively support body composition goals whilst prioritising health, wellbeing and performance. OSF Registration https://doi.org/10.17605/OSF.IO/B4YJT

Background Despite the increasing presence of chefs in professional football and their influence on nutrition provision, evidence on the specific roles and responsibilities of chefs remains limited. This study aimed to explore the role(s) of chefs and describe the characteristics of catering services within English professional football. Methods Sixty-two chefs (56 males, 6 females) in club supervisory positions within the top four divisions of the English male football pyramid were surveyed during the 2022–2023 season. Results Participants were predominantly male, aged 35–44 years, and employed on full-time permanent contracts. Sixteen participants had the term ‘performance’ in their contracted job title. Participants averaged 24 years of chef work experience, 8 years of football-specific experience, and 45 working hours per week. Twenty-nine participants had responsibility for providing nutrition advice to players, whereas the vast majority used nutritional supplements and produced bespoke nutritional items as part of the catering services provided. Most participants rated their sport nutrition knowledge from ‘good’ to ‘excellent’ although only 18 had undertaken formal sport nutrition training. Fifty-one participants frequently followed a periodised nutrition approach, however 31 lacked defined nutrition targets. Tasks such as travelling to fixtures, hotel menu planning, and hotel food provision were most frequent in the Premier League. Catering services in the Premier League mostly operated year-round, seven days a week, employing 4 or more chefs, and spending £6,000 or more per week, with declining operations, costs, and staffing towards the lower divisions. Forty-nine services covered male academy teams alongside the male senior team. Only 15 covered female senior teams, of which 7 extended coverage to female academy teams. Conclusions Chefs undertake key roles both at and away from the club training ground to implement sport nutrition strategies. Inconsistencies in strategy implementation and catering practices were identified, along with league disparities and gender inequalities in service provision. Our findings underscore the need for a quality-assurance framework for accreditation and increased opportunities for chef-tailored sport nutrition education. We advocate for the title ‘sport chef’, and the establishment of a regulatory body to support the practice of chefs working in professional football.

Background Despite the importance of evidence-based nutrition in elite football, Premier League players often exhibit sub-optimal dietary behaviours, highlighting the need for improved guideline implementation. Purpose This study used the COM-B model and Theoretical Domains Framework (TDF) to explore sport nutritionists’ perceived barriers and enablers to applying the UEFA Consensus Statement on Nutrition. Method Twelve lead sport nutritionists from English Premier League clubs took part in semi-structured interviews (1 hour ± 44 mins). The interviews were structured using the COM-B and TDF and analysed thematically. Results Six key themes were identified, representing six barriers and two enablers, encompassing all three components of the COM-B model and seven TDF domains. Psychological capability barriers included challenges in changing players’ dietary behaviours. Reflective motivation was hindered by doubts regarding the scientific basis of carbohydrate and body composition guidelines, alongside concerns over players’ ability to practically adhere to carbohydrate recommendations. Physical and social opportunity barriers involved restricted time and support for ongoing personal and professional development. Practitioners desired greater autonomy over the nutrition service, which was either enabled or constrained by the club’ social environment. As an enabler, female practitioners’ strong interpersonal skills (psychological capability) supported implementation; however, they also faced gender-related challenges navigating male predominate environments, making the social opportunity for implementation more complex. Conclusion Implementing nutrition guidelines in elite football is challenging. Overcoming barriers-by boosting practitioner confidence, belief in guidelines, professional development support, and autonomy-is key to improving uptake of UEFA recommendations and enhancing player dietary adherence in the English Premier League.

Diet is an ever-changing, poorly characterised and multifaceted phenomenon. Consequently, traditional dietary assessment methods demonstrate considerable random intra- and inter-individual day-to-day variation and systematic over- or under-reporting bias (errors of reliability and validity; Beaton et al. 1997; Freedman et al. 2015) across populations (Pérez-Rodrigo et al. 2015). Expressed practically, true assessments of energy intake are misrepresented by hundreds of calories per day (Archer et al. 2016), erroneously informing medical conclusions (Schoenfeld & Ioannidis 2013), media claims (Archer, Pavela & Lavie 2015) and national dietary guidelines (Chowdhury et al. 2014). Ultimately, the enormous potential of nutrition research to drive national health, patient welfare and public service (Dhurandhar et al. 2015), urgently necessitates, and ethically obligates, the valid assessment of diet within all dietetic output.

Background Adolescent male academy footballers often fail to meet nutritional recommendations, placing them at increased risk of compromised growth, health, and performance. Guided by the Behaviour Change Wheel, this study aimed to select and specify dietary behaviours to underpin a sport nutrition service within an English Football League Championship academy. Two Nominal Group Technique (NGT) workshops (mean duration = 2 h 20 min) were conducted with four experienced sport nutritionists, three of whom were currently employed at the club, and one recently employed. Participants generated, ranked, and refined behaviours through structured group discussion, and a follow-up questionnaire. Audio data were descriptively analysed to provide contextual insight into behaviour selection and prioritisation. Results Twenty-four behaviours were generated, from which a prioritised top 10 were identified. The three highest-ranked behaviours were: (1) consuming ≥ 3 main meals (≥ 900 kcal or 13 kcal·kg⁻¹) and 2 snacks daily (≥ 350 kcal or 5 kcal·kg⁻¹); (2) consuming ≥ 3 carbohydrate portions (40–50 g or 0.5–0.75 g·kg⁻¹) per main meal, and ≥ 1 per snack; and (3) consuming a protein portion (25–30 g or 0.4 g·kg⁻¹) at ≥ 4 eating occasions daily. Collectively, these behaviours formed the “meal frequency and portion size guidance.” Additional behaviours ranked within the top 10 included fruit and vegetable intake, attendance at club-provided meals, hydration practices, and cooking from the club recipe app. Practitioners reported challenges conceptualising behaviours, often defaulting to macronutrient prescriptions, and found prioritisation difficult given the number of valuable behaviours identified. Nonetheless, the iterative NGT process facilitated consensus and provided actionable, evidence-based nutritional guidance. Conclusion This study demonstrates the suitability of the NGT for co-producing and prioritising dietary behaviours in male academy footballers. The approach effectively structured practitioner insights to identify priority areas for sport nutrition service delivery. However, the time-intensive nature of the behavioural analysis highlights the need for greater behavioural science capability within sport nutrition practice. Defining what athletes should do, rather than just focusing solely on nutrient-based prescriptions, is essential for designing effective, theory-informed behavioural interventions. These findings provide a foundation for designing targeted interventions to support the health, wellbeing, and performance of male academy footballers.

To ensure that elite adolescent athletes meet their unique training, growth and maturation demands, it is imperative to have access to valid measures of energy intake. Contemporary methods demand close attention-to-detail, meaning that athletes often do not fully adhere to real-time protocols. This study represents the first investigation of a real-time dietary assessment designed using a comprehensive behaviour change framework (COM-B). In a crossover design, 12 elite adolescent male rugby players recorded their energy intake via an estimated food diary (est-FD) and photography-based mobile assessment ('Snap-n-Send'), combined with a 24-h dietary recall interview. Two 4-day assessment periods were divided into three separate recording environments: 96 h free-living and researcher-observed; 72 h free-living and 10 h researcher-observed. Assessment periods were one month apart. All foods and beverages were provided and weighed by the research team to quantify actual intakes. 'Snap-n-Send' reported a small mean bias for under-reporting across 96 h (-0.75 MJ day(-1); 95% confidence interval [CI] for bias = -5.7% to -2.2%, p < .001), 72 h (-0.76 MJ day(-1); 95% CI for bias = -5.6% to -2.1%, p = .004) and 10 h (-0.72 MJ day(-1); 95% CI for bias = -8.1% to -0.1%; p = .067) environments. The est-FD reported a moderate mean bias for under-reporting across 96 h (-2.89 MJ day(-1); 95% CI for bias = -17.9% to -10.2%; p < .001), 72 h (-2.88 MJ day(-1); 95% CI for bias = -17.9% to -10.1%; p < .001) and 10 h (-2.52 MJ day(-1);-26.1% to -5.3%; p = .023) environments. Results evidence the ability of 'Snap-n-Send' to accurately assess the diet of elite adolescent athletes, signalling the exciting promise of this comprehensive and theoretical behavioural approach within valid dietary assessment.

Limited data exist describing how professional footballers meet their energy requirements during pre-season, a phase characterised by increased training volume and a progressive shift from general conditioning to football-specific preparation. This study quantified total, resting, and activity energy expenditure (AEE), diet-induced thermogenesis, water turnover, and dietary intake in six professional male soccer players (age: 25 ± 1 year; height: 182.5 ± 10.1 cm; body mass: 77.8 ± 8.2 kg). Players were studied across 14 consecutive days, representing training-only and training-plus-match microcycles. Total energy expenditure (TEE) was measured using doubly labelled water, resting energy expenditure (REE) by indirect calorimetry and dietary intake using the remote food photography method. Fourteen-day mean TEE, REE, AEE and water turnover were 13.25 ± 1.31 MJ⋅day−1, 7.96 ± 0.89 MJ⋅day−1, 4.20 ± 1.03 MJ⋅day−1, 5.16 ± 0.66 L⋅day−1, respectively. Physical activity level was 1.67 ± 0.16 AU. Energy, carbohydrate, protein, and fat intakes were 10.95 ± 1.52 MJ⋅day−1, 2.8 ± 0.6 g⋅kg−1⋅day−1, 2.2 ± 0.4 g⋅kg−1⋅day−1, and 1.5 ± 0.4 g⋅kg−1⋅day−1, respectively. Total energy expenditure was not significantly different between training-only and training-plus-match microcycles (+1.89 ± 1.98 MJ⋅day−1; ES = 0.95 ± 1.08; p = 0.100). No significant differences were observed in energy or macronutrient intake across weekly microcycles (p > 0.068) or between days (p > 0.144). Players did not achieve energy balance or align dietary intake with day-to-day training demands, suggesting limited nutrition periodisation during pre-season. These findings highlight the need for practitioners to implement strategies supporting fuelling, recovery and adaptation during this critical phase.

Professional collision-sport athletes report uniquely large energy expenditures across the season (1-4), as determined by gold standard assessment of resting metabolic rate (RMR (5)) and total energy expenditure (TEE (6)). Such expenditures are possibly a consequence of strenuous match demands, which repeatedly expose players to substantial exercise-and collision-induced muscle damage (7). Recovery from such large perturbations of homeostasis (8) are likely to be energetically expensive (9), in part determining the distinct in-season energetic demands of professional collision-sport athletes. Aim. Accurately determining the effect of match play on resting metabolism is essential to optimise acute manipulation of energy balance, player recovery and long-term athlete development. Therefore, for the first time this case report investigated the metabolic cost of a professional young rugby league match.

Due to the unique energetic demands of professional young collision sport athletes, accurate assessment of energy balance is required. Consequently, this is the first study to simultaneously investigate the energy intake, expenditure and balance of professional young rugby league players across a pre-season period. The total energy expenditure of six professional young male rugby league players was measured via doubly labelled water over a fourteen-day assessment period. Resting metabolic rate was measured and physical activity level calculated. Dietary intake was reported via Snap-N-Send over a non-consecutive ten-day assessment period, alongside changes in fasted body mass and hydration status. Accordingly, energy balance was inferred. The mean (standard deviation) difference between total energy intake (16.73 (1.32) MJ.day-1) and total energy expenditure (18.36 (3.05) MJ.day-1) measured over the non-consecutive ten-day period was unclear (-1.63 (1.73) MJ.day-1; ES = 0.91 ±1.28; p = 0.221). This corresponded in a most likely trivial decrease in body mass (-0.65 (0.78) kg; ES = 0.04 ±0.03; p = 0.097). Resting metabolic rate and physical activity level across the fourteen-day pre-season period was 11.20 (2.16) MJ.day-1 and 1.7 (0.2), respectively. For the first time, this study utilises gold standard assessment techniques to elucidate the distinctly large energy expenditures of professional young rugby league players across a pre-season period, emphasising a requirement for equally large energy intakes to achieve targeted body mass and composition adaptations. Accordingly, it is imperative that practitioners regularly assess the energy balance of professional young collision-sport athletes to ensure their unique energetic requirements are achieved.

Designing and implementing successful dietary intervention is integral to the role of sport nutrition professionals as they attempt to positively change the dietary behaviours of athletes. High-performance sport is a time-pressured environment where immediate results can often supersede pursuit of the most effective evidence-based practice. However, efficacious dietary intervention necessitates comprehensive, systematic and theoretical behavioural design and implementation if the habitual dietary behaviours of athletes are to be positively changed. Therefore, this case study demonstrates how the Behaviour Change Wheel was used to design and implement an effective nutritional intervention within professional rugby league. The eight-step intervention targeted athlete consumption of a high quality dietary intake of 25.1 MJ each day, to achieve an overall body mass increase of 5 kg across a twelve-week intervention period. The Capability, Opportunity, Motivation-Behaviour model and APEASE criteria were used to identify population-specific intervention functions, policy categories, behaviour change techniques and modes of intervention delivery. The resulting intervention was successful, increasing the average daily energy intake of the athlete to 24.5 MJ, which corresponded in a 6.2 kg body mass gain. Despite consuming 0.6 MJ less per day than targeted, secondary outcome measures of diet quality, strength, body composition and immune function all substantially improved, supporting a sufficient energy intake and the overall efficacy of a behavioural approach. Ultimately, the Behaviour Change Wheel provides sport nutrition professionals with an effective and practical step-wise method via which to design and implement effective nutritional interventions for use within high-performance sport.

Abstract

Body composition assessments in professional male football often lack sport-specific evidence, risking mismanagement of player health and performance. This study described dual-energy X-ray absorptiometry (DXA)-derived values by playing position, ethnicity, competition level, and seasonal timepoints. A total of 343 players (mean ± SD: age = 22.6 ± 4.6 years; stature = 182.0 ± 6.9 cm; body mass = 79.1 ± 8.6 kg) from the English Premier League (n = 76) and English Football League (n = 267) completed 939 scans over a 10-year period (2014–2024) using DXA (Lunar iDXA, GE Healthcare), with repeat measurements taken across the season. Players were sub-classified as Goalkeepers (n = 32), Central Defenders (n = 55), Wide Defenders (n = 64), Central Midfielders (n = 73), Wide Midfielders (n = 62), and Forwards (n = 57). Body composition ranges specific to position were identified for bone mass (3.5–4.2 kg), lean mass (61.2–69.6 kg), fat mass (9.1–13.5 kg), and percentage body fat (11.6–15.4%). Significant differences in bone, lean, and fat mass were observed between playing positions, ethnicity, and league level ( p  < 0.050). Across a single season, fat-free mass increased significantly, while fat mass decreased (both: p  < 0.001), indicating positive physiological adaptations from moderate body mass increases rather than performance concerns. These findings indicate that body fat values above the commonly cited < 10% threshold are regularly observed in elite male footballers, suggesting the need for more individualised targets over generic team-wide standards. Providing the largest criterion-measured dataset for professional male footballers, this study supports athlete-centred, position-specific decision-making to optimise player health and performance.

The purpose of this study was to quantify the total energy expenditure (TEE) of international female rugby union players. Fifteen players were assessed over 14-days throughout an international multi-game tournament, which represented two consecutive one-match microcycles. Resting metabolic rate (RMR) and TEE were assessed by indirect calorimetry and doubly labelled water, respectively. Physical activity level (PAL) was estimated (TEE:RMR). Mean RMR, TEE, and PAL were 6.60 ± 0.93 MJ.day-1, 13.51 ± 2.28 MJ.day-1 and 2.0 ± 0.3 AU, respectively. There was no difference in TEE (13.74 ± 2.31 vs. 13.92 ± 2.10 MJ.day-1; p = 0.754), or PAL (2.06 ± 0.26 AU vs. 2.09 ± 0.23 AU; p = 0.735) across microcycles, despite substantial decreases in training load (total distance: -8088 m, collisions: -20 n, training duration: -252 min). After correcting for body composition, there was no difference in TEE (13.80 ± 1.74 vs. 13.16 ± 1.97 adj. MJ.day-1, p = 0.190), RMR (6.49 ± 0.81 vs. 6.73 ± 0.83 adj. MJ.day-1, p = 0.633) or PAL (2.15 ± 0.14 vs 1.87 ± 0.26 AU, p = 0.090) between forwards and backs. For an injured participant (n = 1), TEE reduced by 1.7 MJ.day-1 from pre-injury. For participants with illness (n = 3), TEE was similar to pre-illness (+0.49 MJ.day-1). The energy requirements of international female rugby players were consistent across one-match microcycles. Forwards and backs had similar adjusted energy requirements. These findings are critical to inform the dietary guidance provided to female rugby players.

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.

Purpose: Collision sports are characterised by frequent high intensity collisions that induce substantial muscle damage, potentially increasing the energetic cost of recovery. Therefore, this study investigated the energetic cost of collision-based activity for the first time across any sport. Methods: Using a randomised crossover design, six professional young male rugby league players completed two different five-day pre-season training microcycles. Players completed either a collision (COLL; 20 competitive one-on-one collisions) or non-collision (nCOLL; matched for kinematic demands, excluding collisions) training session on the first day of each microcycle, exactly seven days apart. All remaining training sessions were matched and did not involve any collision-based activity. Total energy expenditure was measured using doubly labelled water, the literature gold standard. Results: Collisions resulted in a very likely higher (4.96 ± 0.97 MJ; ES = 0.30 ±0.07; p=0.0021) total energy expenditure across the five-day COLL training microcycle (95.07 ± 16.66 MJ) compared with the nCOLL training microcycle (90.34 ± 16.97 MJ). The COLL training session also resulted in a very likely higher (200 ± 102 AU; ES = 1.43 ±0.74; p=0.007) session rating of perceived exertion and a very likely greater (-14.6 ± 3.3%; ES = -1.60 ±0.51; p=0.002) decrease in wellbeing 24h later. Conclusions: A single collision training session considerably increased total energy expenditure. This may explain the large energy expenditures of collision sport athletes, which appear to exceed kinematic training and match demands. These findings suggest fuelling professional collision-sport athletes appropriately for the "muscle damage caused” alongside the kinematic “work required”. Key words: Nutrition, Recovery, Contact, Rugby

© 2017 Thomas Sawczuk, Ben Jones, Sean Scantlebury, Jonathan Weakley, Dale Read, Nessan Costello, Joshua David Darrall-Jones, Keith Stokes, and Kevin Till This study aimed to evaluate the between-day reliability and usefulness of a fitness testing battery in a group of youth sport athletes. Fifty-nine youth sport athletes (age = 17.3 ± 0.7 years) undertook a fitness testing battery including the isometric mid-thigh pull, counter-movement jump, 5–40 m sprint splits, and the 5–0-5 change of direction test on two occasions separated by 7 days. Usefulness was assessed by comparing the reliability (typical error) to the smallest worthwhile change. The typical error was 5.5% for isometric mid-thigh pull and 3.8% for counter-movement jump. The typical error values were 2.7, 2.5, 2.2, 2.2, and 1.8% for the 5, 10, 20, 30, and 40 m sprint splits, and 4.1% (left) and 5.4% (right) for the 5–0-5 tests. The smallest worthwhile change ranged from 1.1 to 6.1%. All tests were identified as having “good” or “acceptable” reliability. The isometric mid-thigh pull and counter-movement jump had “good” usefulness, all other tests had “marginal” usefulness.

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.