Dr Sarah Whitehead

Seeking to obtain a competitive advantage and manage the risk of injury, team sport organisations are investing in tracking systems that can quantify training and competition characteristics. It is expected that such information can support objective decision-making for the prescription and manipulation of training load. This narrative review aims to summarise, and critically evaluate, different tracking systems and their use within team sports. The selection of systems should be dependent upon the context of the sport and needs careful consideration by practitioners. The selection of metrics requires a critical process to be able to describe, plan, monitor and evaluate training and competition characteristics of each sport. An emerging consideration for tracking systems data is the selection of suitable time analysis, such as temporal durations, peak demands or time series segmentation, whose best use depends on the temporal characteristics of the sport. Finally, examples of characteristics and the application of tracking data across seven popular team sports are presented. Practitioners working in specific team sports are advised to follow a critical thinking process, with a healthy dose of scepticism and awareness of appropriate theoretical frameworks, where possible, when creating new or selecting an existing metric to profile team sport athletes.

The quantification and evaluation of training practices in youth rugby players, including exposure to competition and training loads, is important for supporting long-term athletic development. This chapter discusses the research that focused on training practices and loads of youth rugby players from macrocycle to individual session characteristics. Training loads in youth rugby are highly variable within and between players, and the characteristics of training practices have been shown to differ by age category, playing standard, and region. Inconsistency in the methodologies used to quantify external and internal training loads of youth rugby players is a major limitation of the current research, with limited data available in rugby league. Future research is required to determine the dose-response relationship of training in youth rugby players with regards to long-term athletic development and injury risk. This research should account for all training and match loads, including loads accumulated from other sports and recreational activities, and additional psychological, social, and academic stressors.

This chapter summarises and presents the research quantifying the technical-tactical and physical demands of male youth rugby league and rugby union match-play, and compares between playing positions, standards, and age-grades. In both rugby codes positional differences are apparent, with some differences attributed to the playing standard, indicating the need for position-specific prescription of training practices. Differences in technical-tactical demands between standards of competition are apparent in rugby league match-play, providing potential focus areas for youth rugby league coaches, but further research is required to analyse these differences in rugby union. The physical demands of match-play in both codes vary dependent upon the playing standard and age-grade of competition, influenced primarily by the match length. Further research considering contextual factors and the interaction between the physical and technical-tactical demands that underpin performance across youth rugby are still required.

This book is a comprehensive guide to these protocols and to the key issues relating to physiological testing.

A base of high-quality research is necessary for developing robust literature, and is required before advancing to more complex research. In applied sports settings, practitioners can apply research to practice to support athlete development (e.g., physical preparation). Although netball is among the most popular women’s sports, a limited literature base currently exists in comparison to other team sports. Therefore, this thesis aims to contribute to building the foundation of netball literature, focused on the characteristics of netball match-play. This thesis includes four studies which 1) develop a framework of descriptors and definitions for netball literature and practice, 2/3) assess the reliability and validity of a commonly used microtechnology device in court-sports, and 4) quantify and compare the movement characteristics of elite domestic and international level match-play. Using a Delphi consensus method, study 1 established 25 physical, 29 technical and 41 contextual descriptors and definitions to standardise netball terminology. Studies 2 and 3 identified only inertial movement analysis (IMA) detected jump events and PlayerLoadTM variables are recommended for use in court-sports, following the reliability and validity analysis. The IMA event algorithm for detecting accelerations, decelerations and change-of-direction (COD) events was limited in female court-sport athletes and requires further development. Study 4 observed differences in match-play movement characteristics between competition levels and playing positions. Intensity metrics (e.g., PlayerLoad per minute) were greater at the international level, whereas volume metrics (e.g., PlayerLoadTM) were greater at the domestic level, suggesting that practitioners should focus on match-play intensity when transitioning players from domestic to international competition. Advanced analysis also identified individual variations in movement characteristics for players competing at both levels, supporting more individualised training. In conclusion this thesis develops a framework to support the standardisation of terminology in netball literature and practice, provides guidance on the recommended metrics for quantifying court-sport movement characteristics, and establishes these movement characteristics of elite domestic and international level netball match-play, contributing to the foundation of netball literature.

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.

The aim of this study was to identify between-position (forwards vs. backs) differences in movement variability in cumulative tackle events training during both attacking and defensive roles. Eleven elite adolescent male rugby league players volunteered to participate in this study (mean ± SD, age; 18.5 ± 0.5 years, height; 179.5 ± 5.0 cm, body mass; 88.3 ± 13.0 kg). Participants performed a drill encompassing four blocks of six tackling (i.e. tackling an opponent) and six tackled (i.e. being tackled by an opponent while carrying a ball) events (i.e. 48 total tackles) while wearing a micro-technological inertial measurement unit (WIMU, Realtrack Systems, Spain). The acceleration data were used to calculate sample entropy (SampEn) to analyse the movement variability during tackles performance. In tackling actions SampEn showed significant between-position differences in block 1 (p = 0.0001) and block 2 (p = 0.0003). Significant between-block differences were observed in backs (block 1 vs 3, p = 0,0021; and block 1 vs 4, p = 0,0001) but not in forwards. When being tackled, SampEn showed significant between-position differences in block 1 (p = 0.0007) and block 3 (p = 0.0118). Significant between-block differences were only observed for backs in block 1 vs 4 (p = 0,0025). Movement variability shows a progressive reduction with cumulative tackle events, especially in backs and when in the defensive role (tackling). Forwards present lower movement variability values in all blocks, particularly in the first block, both in the attacking and defensive role. Entropy measures can be used by practitioners as an alternative tool to analyse the temporal structure of variability of tackle actions and quantify the load of these actions according to playing position.

The quantification of the technical, tactical and physical demands of match-play in youth rugby is important for the appropriate prescription of training practices. Differences in the demands of match-play have been identified between positions, playing standards, age grades and phases-of-play. This chapter presents the research that has explored the physical and technical-tactical match demands of youth rugby. The chapter then provides a practical overview of how practitioners can utilise match-demands data to assist in appropriate training prescription through the adaptation, manipulation and evaluation of training drills and practices. The chapter concludes with a range of recommendations and practical implications for the use of match-play data within youth rugby environments.

Using an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1-strongly disagree; 2-somewhat disagree; 3-neither agree nor disagree; 4-somewhat agree; 5-strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.

BACKGROUND: Netball is the one of the most popular women's sports in the world. Since gaining professional status in 2008 there has been a rapid growth in research in the applied sports science and medicine of the sport. A scoping review of the area would provide practitioners and researchers with an overview of the current scientific literature to support on-court performance, player welfare and reduce injury. OBJECTIVE: The primary objective was to identify the current research on the applied sports science and medicine of netball. Additionally, the article provides a brief summary of the research in each topic of sports science and medicine in netball and identifies gaps in the current research. METHODS: Systematic searches of PubMed, SPORTDiscus, MEDLINE and CINAHL were undertaken from earliest record to Dec 2020 and reference lists were manually searched. The PRISMA-ScR protocol was followed. Studies were eligible for inclusion if they investigated netball as a sport or the applied sport science and medicine of netball athletes. RESULTS: 962 studies were identified in the initial search, 150 of which met the inclusion criteria. Injury was the most highly investigated sport science and medicine topic (n = 45), followed by physical qualities (n = 37), match characteristics (n = 24), biomechanics (n = 15), psychology (n = 13), fatigue and recovery (n = 9), training load (n = 4) and nutrition (n = 3). A range of cohorts were used from school to elite and international standards. All cohorts were female netballers, except for one study. A rapid growth in studies over recent years was demonstrated with 65% of studies published in the last decade. There still remains gaps in the literature, with a low evidence base for nutrition, training load and fatigue and recovery. CONCLUSION: This scoping review summarises the current evidence base and key findings that can be used in practice to enhance the applied sport science and medical support to netball athletes across a range of playing standards, and support the growth of the sport. It is evident that netball as a sport is still under-researched.

This study quantified the position-, duration-, and phase-of-play specific peak locomotor characteristics of senior professional rugby league match-play at a multi-club level. Match-play data were collected from 378 male professional rugby league players, from 11 clubs, across two competitive seasons. A total of 9643 match-observations were analysed; 10-Hz instantaneous velocity and acceleration from Catapult S5 microtechnology units were aligned with video footage to determine to the phase-of-play and duration-specific peak locomotor characteristics (average running speed, relative high-speed running [HSR;>5.5 m·s−1], average absolute acceleration). Linear mixed effect models were used to determine positional differences for each dependent variable and differences between phases-of-play. Positional differences for the duration-specific and phase-of-play peak locomotive characteristics were identified. Fullbacks had greater peak HSR during defensive sets (86 ± 70 m·min−1) vs. all other positions (effect size = 0.26 to 0.49, small). Wingers demonstrated the greatest between phase differences with greater peak locomotor characteristics (effect size = 1.23 to 1.65, large) during attacking-defensive set transition vs. defensive sets. The multi-club normative data, and the differences identified, provides practitioners with valuable information for the consideration of training practices; the incorporation of phases-of-play enables greater consideration of technical-tactical factors whilst preparing players for the peak periods of competition.

Several microtechnology devices quantify the external load of team sports using Global Positioning Systems sampling at 5, 10, or 15 Hz. However, for short, explosive actions, such as collisions, these sample rates may be limiting. It is known that very high-frequency sampling is capable of capturing changes in actions over a short period of time. Therefore, the aim of this study was to compare the mean acceleration and entropy values obtained from 100 Hz and 1000 Hz tri-axial accelerometers in tackling actions performed by rugby players. A total of 11 elite adolescent male rugby league players (mean ± SD; age: 18.5 ± 0.5 years; height: 179.5 ± 5.0 cm; body mass: 88.3 ± 13.0 kg) participate in this study. Participants performed tackles (n = 200), which were recorded using two triaxial accelerometers sampling at 100 Hz and 1000 Hz, respectively. The devices were placed together inside the Lycra vests on the players’ backs. The mean acceleration, sample entropy (SampEn), and approximate entropy (ApEn) were analyzed. In mean acceleration, the 1000 Hz accelerometer obtained greater values (p < 0.05). However, SampEn and ApEn were greater with the 100 Hz accelerometer (p < 0.05). A large relationship was observed between the two devices in all the parameters analyzed (R2 > 0.5; p < 0.0001). Sampling frequency can affect the quality of the data collected, and a higher sampling frequency potentially allows for the collection of more accurate motion data. A frequency of 1000 Hz may be suitable for recording short and explosive actions.

INTRODUCTION: Muscle-tendon interaction during movement can be categorised into energy conservation or power amplification/attenuation strategies (1), and the mechanical and morphological properties of male athletes’ tendons adapt to these loading demands (2). Although previous research observed no differences in tendon properties between female endurance runners and inactive controls (3, 4), little is known about these properties in females undergoing habitual power amplification-type loading, such as that experienced by team sport athletes. Therefore, this study investigated Achilles’ tendon (AT) properties in trained female endurance runners and netballers. METHODS: An observational investigation of 7 national level female netballers (16.2 ± 4.5 years netball training experience) and 7 female runners (8.3 ± 2.9 years training) was conducted. AT thickness was assessed at rest using B-mode ultrasound. The AT moment arm was calculated using the tendon excursion method. Participants performed graded isometric ankle plantar flexion contractions on a Cybex dynamometer until a voluntary maximum was reached, whilst dynamic ultrasound recorded displacement of the gastrocnemius medialis myotendinous junction. From each contraction plantar flexion moment, AT force, elongation, and strain were calculated. AT stiffness was defined as the slope of the AT force-elongation relationship (from 20-100% of maximum force). Mean differences (MD) with 95% confidence intervals (CI), Student’s t-tests, and Hedge’s g effect sizes (ES) were used to assess differences in AT properties between groups. RESULTS: Netballers displayed a significantly greater maximal plantar flexion moment (MD 58.1 N.m-1, CI 35.5-80.7 N.m-1, ES 2.81, p<0.001), AT force (MD 822.4 N, CI 294.4-1350.5 N, ES 1.70, p=0.008), AT elongation (MD 5.70 mm, CI 0.40-11.07 mm, ES 1.17, p=0.044), and AT thickness (MD 0.69 mm, CI 0.08-1.30 mm, ES 1.24, p=0.031). No significant differences were found in maximal strain, stiffness, length, or moment arm. CONCLUSION: The greater AT thickness of the netball group suggests that the power amplification-type loading demands inherent to netball training (i.e., jumping, landing) have a hypertrophic effect on the tendon. Additionally, the greater maximal plantar flexion moment, and hence AT force experienced by the netballers may also contribute to this hypertrophic stimulus. This adaptation may be protective in nature, as increased thickness (and presumably cross-sectional area) would reduce peak operating stress and enhance the safety factor of the tendon. Despite differences in AT thickness, no differences in strain or stiffness were found, corroborating earlier findings of uncoupled mechanical and morphological properties (2). These results provide evidence that the AT can adapt to high intensity loading in females. 1. Roberts and Azizi, J Exp Bio, 2011 2. Wiesinger et al., PLOS One, 2016 3. Magnusson et al., Int J Exp Path, 2007 4. Westh et al., Scand J Med Sci Sport 2008

Women's sport has seen substantial growth in recent years, with increased attention to athlete performance and welfare. To support the ongoing professionalisation of women's rugby, performance and wellbeing must be prioritised. This study used a three‐round Delphi‐process to establish performance and wellbeing research priorities for Premiership Women's Rugby (PWR) in England. In Round 1, players and staff provided research priorities, which were grouped into higher‐order categories and themes via content analysis. In Rounds 2 and 3, participants ranked higher‐order categories on a 1–5 Likert scale. Consensus was defined as ≥ 70% agreement. Seventy‐seven participants responded in Round 1 (47 and 43 in Rounds 2 and 3). Player and staff experience of playing or working in PWR was 5.0 (2.0–7.0) and 2.5 (2.0–4.0) years. Following Round 1321 research priorities were provided, 32 higher‐order research priorities and 14 categories were identified, within three themes: performance, wellbeing and injury. Following Round 3, nine research priorities reached consensus within performance ( n  = 1), wellbeing ( n  = 4) and injury ( n  = 4). The highest rated priority was ‘ Investigate the impact of being a dual‐career athlete on wellbeing, and any support mechanisms required ’ (79%). Future research should prioritise studies which are feasible and currently lack a comprehensive evidence‐base. This will enable researchers and governing bodies to address relevant knowledge gaps and inform ongoing performance and player safety initiatives. The research priorities identified in this study, by PWR players and staff, could be investigated to support the development of women's rugby domestically. These findings may also be applicable to other women's sports and leagues globally.

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.

On-field spacing has been linked to successful performance in a number of sportsto date, there is limited research investigating this within rugby league. This study aims to (a) quantify the defensive dispersal during rugby league match-play and (b) identify if contextual factors are associated with the dispersal. Global Positioning System data were analysed from 47 European Super League matches (1598 player files). Defensive dispersal was calculated for 1959 defensive sets of rugby league. Linear mixed models were used to analyse the effects of contextual factors on the average defensive dispersal per set when accounting for team and fixture. On-field position and match half were found to significantly affect defensive dispersal. However, set length, play-the-ball length, and final score difference were found to have minimal impact on defensive dispersal. This study demonstrates that defensive dispersal in rugby league can be measured using GPS data and may be strongly influenced by on-field positioning. As such, it quantifies an important element of tactical preparation for rugby league teams.

INTRODUCTION: For the optimal development of youth rugby league players’, knowledge of the match demands across the different levels is required. The peak demands of game play can be termed the ‘worst case scenario’ (WCS). Quantification of the WCS aids in the prescription of appropriate training drills. This study aimed to quantify, and compare, the absolute and WCS running demands of rugby league match-play between professional club and international youth levels.

BACKGROUND: Quantifying the peak match demands within the football codes is useful for the appropriate prescription of external training load. Wearable microtechnology devices can be used to identify the peak match demands, although various methodologies exist at present. OBJECTIVES: This systematic review aimed to identify the methodologies and microtechnology-derived variables used to determine the peak match demands, and to summarise current data on the peak match demands in the football codes. METHODS: A systematic search of electronic databases was performed from earliest record to May 2018; keywords relating to microtechnology, peak match demands and football codes were used. RESULTS: Twenty-seven studies met the eligibility criteria. Six football codes were reported: rugby league (n = 7), rugby union (n = 5), rugby sevens (n = 4), soccer (n = 6), Australian Football (n = 2) and Gaelic Football (n = 3). Three methodologies were identified: moving averages, segmental and 'ball in play'. The moving averages is the most commonly used (63%) and superior method, identifying higher peak demands than other methods. The most commonly used variables were relative distance covered (63%) and external load in specified speed zones (57%). CONCLUSION: This systematic review has identified moving averages to be the most appropriate method for identifying the peak match demands in the football codes. Practitioners and researchers should choose the most relevant duration-specific period and microtechnology-derived variable for their specific needs. The code specific peak match demands revealed can be used for the prescription of conditioning drills and training intensity.

This study aimed to quantify the duration-specific peak average running speeds of Academy-level rugby league match play, and compare between playing positions. Global positioning system data were collected from 149 players competing across 9 teams during 21 professional Academy (under-19) matches. Players were split into 6 positions: hookers (n = 40), fullbacks (n = 24), halves (n = 47), outside backs (n = 104), middles (n = 118), and backrow forwards (n = 104). Data were extracted and the 10-Hz raw velocity files exported to determine the peak average running speeds, via moving averages of speed (m·min−1), for 10- and 30-second, and 1- to 5- and 10-minute durations. The data were log transformed and analyzed using linear mixed-effect models followed by magnitude-based inferences, to determine differences between positions. Differences in the peak average running speeds are present between positions, indicating the need for position-specific prescription of velocity-based training. Fullbacks perform possibly to most likely greater average running speeds than all other positions, at each duration, except at 10 seconds vs. outside backs. Other differences are duration dependent. For 10 seconds, the average running speed is most likely greater for outside backs vs. the hookers, middles, and backrow forwards, but likely to most likely lower for 10 minutes. Hookers have possibly trivial or lower average speed for 10 seconds vs. middles and backrow forwards, but very likely greater average running speed for 10 minutes. The identified peak average running speeds of Academy-level match play seem similar to previously reported values of senior professional level.

Objectives: To quantify, and compare, the whole- half- and peak-match running demands of professional club and international under-16 rugby league match-play. Methods: Four professional Club (n = 30) and two International (n = 23) under-16 matches were analysed using 10-Hz micro-technology units, with players analysed according to positional groups. Absolute (m) and relative (RD; m.min–1) total, high speed (>5 m·s–1; HSR) and sprint (>7 m·s–1) distance were analysed for whole- and half-match alongside maximum velocity (VMAX; m.s–1). Peak running demands were determined via moving averages of RD for 10, 30, and 60- to 600-seconds. Results: International forwards had most likely higher whole match relative sprint and VMAX, and 1st half RD than club level, and had very likely higher peak running demands at 60-, 180- and 600-second durations. For backs, whole game RD was most likely higher and total and sprint distance was likely higher at club level matches. Peak RD was also very likely higher for club backs at 10- and 60-seconds. Conclusions: The running demand differences between club and international level at the under-16 age group are position dependent, with greater running demands at club level match play for backs, but at the international level of forwards.

The purpose of this study was to investigate the validity of global positioning system (GPS) and micro-electrical-mechanical-system (MEMS) data generated in real-time via a dedicated receiver. Post-session data acted as criterion as it is used to plan the volume and intensity of future training and is downloaded directly from the device. 25 professional rugby league players completed two training sessions wearing a MEMS device (Catapult S5, firmware version: 2.27). During sessions, real-time data was collected via the manufacturer receiver and dedicated software (Openfield v1.14) which was positioned outdoors at the same location for every session. GPS variables included total-, low- (0 to 3 m∙s-1), moderate- (3.1 to 5 m∙s-1), high- (5.1 to 7 m∙s-1) and very-high-speed (> 7.1 m∙s-1) distances. MEMS data included total session PlayerLoad™. When compared to post-session data, mean bias for total-, low-, moderate-, high- and very-high-speed distances were all trivial, with the typical error of the estimate (TEE) small, small, trivial, trivial and small respectively. Pearson correlation coefficients for total-, low-, moderate-, high- and very-high-speed distances were nearly perfect, nearly perfect, perfect, perfect and nearly perfect respectively. For PlayerLoad™, mean bias was trivial whilst TEE was moderate and correlation nearly perfect. Practitioners should be confident that when interpreting real-time speed-derived metrics, the data generated in real-time is comparable to that downloaded directly from the device post-session. However, practitioners should refrain from interpreting accelerometer derived data (i.e. PlayerLoad™) or acknowledge the moderate error associated with this real-time measure.

Youth Rugby provides a summary of the latest and most up-to-date research evidence in relation to developing the youth rugby player. The book provides an overview of the latest scientific research for key topics related to the youth rugby player across the codes of rugby (union, league and 7's; mainly league and union in youth players) whilst also summarising the quality of the evidence available and the limitations of this research and highlighting key future research directions. The book covers a range of fundamental scientific topics relating to paediatric exercise science, human physiology, youth athletic development and high-performance sport. Each author is an experienced researcher within their respective discipline related to the youth rugby player. The book includes chapters on: • Long-term athletic development, growth and maturation, talent identification and the physical demands of youth rugby training and match-play. • Physical characteristics and the current evidence behind training methods to promote desired physical qualities. • Fatigue and recovery, the tackle, psychosocial development, nutrition and injury prevalence and prevention. This text is essential reading for all scientists, students and applied researchers wanting to develop world-class, evidence-based programmes for their youth athletes.

The purpose of this study is to explore how PlayerLoad

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Male academy rugby league players are required to undertake field and resistance training to develop the technical, tactical and physical qualities important for success in the sport. However, limited research is available exploring the training load of academy rugby league players. Therefore, the purpose of this study was to quantify the field and resistance training loads of academy rugby league players during a pre-season period and compare training loads between playing positions (i.e., forwards vs. backs). Field and resistance training load data from 28 adolescent male (age 17 ± 1 years) rugby league players were retrospectively analysed following a 13-week pre-season training period (85 total training observations; 45 field sessions and 40 resistance training sessions). Global positioning system microtechnology, and estimated repetition volume was used to quantify external training load, and session rating of perceived exertion (sRPE) was used to quantify internal training load. Positional differences (forwards n = 13 and backs n = 15) in training load were established using a linear mixed effect model. Mean weekly training frequency was 7 ± 2 with duration totaling 324 ± 137 minutes, and a mean sRPE of 1562 ± 678 arbitrary units (AU). Backs covered more high-speed distance than forwards in weeks two (p = 0.024), and 11 (p = 0.028). Compared to the forwards, backs completed more lower body resistance training volume in week one (p = 0.02), more upper body volume in week three (p< 0.001) and week 12 (p = 0.005). The findings provide novel data on the field and resistance-based training load undertaken by academy rugby league players across a pre-season period, highlighting relative uniformity between playing positions. Quantifying training load can support objective decision making for the prescription and manipulation of future training, ultimately aiming to maximise training within development pathways.

Background: Given the high injury rate of netball, injury prevention is a focus within the sport and for governing bodies. To support the development of appropriate injury mitigation strategies further consideration of the risk factors for injury is needed. Therefore, this study aimed to establish consensus on injury risk factors (RFs) in women’s netball via a combined systematic review and Delphi method approach. 6 Methodology: A systematic search of databases (PubMed, Scopus, MEDLINE, SPORTDiscus, CINAHL) was conducted from inception until June 2023. Twenty-four risk factors (RFs) were extracted from 17 studies and combined with a three-round Delphi approach to achieve consensus. In round-one, experts listed perceived RFs for injury in netball which were combined with the RFs identified via the systematic review. In rounds-two and round-three, experts rated their level of agreement with each risk factor on a 5-point Likert scale (1-strongly disagree to 5-strongly agree). Consensus was defined as >80% agreement (with <10% in disagreement). In round-three, experts also rated the priority for mitigating the risk factor (1- very low to 5-very high). Results: Nineteen experts participated in round-one and round-two, and sixteen participated in round- three (response rate 84%). One-hundred and nine RFs for injury were identified by the systematic review and experts combined. Sixty-one RFs reached consensus, categorised into five groups: ‘individual characteristics’ (n = 22), ‘lifestyle’ (n = 11), ‘training and competition’ (n = 14), ‘sport science and medical provision’ (n = 6) and ‘facilities and equipment’ (n = 8). ‘Poor landing technique/ mechanics’ had a median (interquartile range) mitigation priority rating of 5(1), while all others had median ratings of 3-4.5. Conclusion: This study identifies a range of RFs for injury, provides focus areas for injury prevention and highlights the importance of a multi-disciplinary approach to injury mitigation in netball. Future research is needed to investigate the priority and feasibility of the mitigation of the risk factors in specific environments to support tailored injury prevention strategies.

Fatigue in team sports has been widely researched, with a number of systematic reviews summarising the acute (i.e., within 48-hours) response in outdoor sports. However, the fatigue response to indoor court-based sports is likely to differ to outdoor sports due to smaller playing fields, harder surfaces, and greater match frequencies, thus should be considered separately to outdoor sports. Therefore, this study aimed to conduct a systematic review on acute fatigue in indoor court-based team-sport, identify methods and markers used to measure acute fatigue, and describe acute fatigue responses. A systematic search of the electronic databases (PubMed, SPORTDiscus, MEDLINE and CINHAL) was conducted from earliest record to June 2023. Included studies investigated either a physical, technical, perceptual, or physiological response taken before and after training, match, or tournament play. One-hundred and eight studies were included, measuring 142 markers of fatigue. Large variability in methods, fatigue markers and timeline of measurements were present. Cortisol (n =  43), creatine kinase (n =  28), countermovement jump (n =  26) and testosterone (n =  23) were the most frequently examined fatigue markers. Creatine kinase displayed the most consistent trend, increasing 10–204% at 24-hours across sports. There is large variability across studies in the methods and markers used to determine acute fatigue responses in indoor court-based team sports. Future researchers should focus on markers that display high reliability and transfer to practice. The robustness of studies may be increased by ensuring appropriate methods and timescale of fatigue marker measurement are used. Further research is required to determine which combination of markers best describes a fatigue response.

Muscle-tendon unit (MTU) assessments can be categorised into local (e.g. tendon strain) or global (e.g. jump height) assessments. Although menstrual cycle phase may be a key consideration when implementing these assessments in female athletes, the reliability of many MTU assessments is not well defined within female populations. Therefore, the purpose of this study was to report the test-retest reliability of local and global MTU assessments during the early follicular phase of the menstrual cycle. Seventeen naturally menstruating females (age 28.5 ± 7.3 years) completed local and global MTU assessments during two testing sessions separated over 24-72 hours. Local tests included Achilles’ tendon mechanical testing and isometric strength of ankle plantar flexors and knee extensors, whereas global tests included countermovement, squat, and drop jumps, and the isometric midthigh pull. Based on intraclass correlation coefficient (ICC) statistics, poor to excellent reliability was found for local measures (ICC: 0.096-0.936). Good to excellent reliability was found for all global measures (ICC: 0.788-0.985), excluding the eccentric utilisation ratio (ICC 0.738) and most rate of force development metrics (ICC: 0.635-0.912). Isometric midthigh pull peak force displayed excellent reliability (ICC: 0.966), whereas force-time metrics ranged from moderate to excellent (ICC: 0.635-0.970). Excluding rate of force development (coefficient of variation [CV]: 10.6-35.9%), global measures (CV: 1.6-12.9%) were more reproducible than local measures (CV: 3.6-64.5%). However, local metrics directly measure specific properties of the MTU, and therefore provide valuable information despite lower reproducibility. The novel data reported here provides insight into the natural variability of MTU assessments within female athletes, which can be used to enhance the interpretation of other female athlete data, especially that which aims to investigate other aspects of variability, such as the menstrual cycle.

Muscle-tendon unit (MTU) assessments can be categorised into local (e.g., tendon strain) or global (e.g., jump height) assessments. Although menstrual cycle phase may be a key consideration when implementing these assessments in female athletes, the reliability of many MTU assessments is not well defined within female populations. Therefore, the purpose of this study was to report the test-retest reliability of local and global MTU assessments during the early follicular phase of the menstrual cycle. Seventeen naturally menstruating females (age 28.5 ± 7.3 years) completed local and global MTU assessments during two testing sessions separated over 24–72 hours. Local tests included Achilles’ tendon mechanical testing and isometric strength of ankle plantar flexors and knee extensors, whereas global tests included countermovement, squat, and drop jumps, and the isometric midthigh pull. Based on intraclass correlation coefficient (ICC) statistics, poor to excellent reliability was found for local measures (ICC: 0.096–0.936). Good to excellent reliability was found for all global measures (ICC: 0.788–0.985), excluding the eccentric utilisation ratio (ICC 0.738) and most rate of force development metrics (ICC: 0.635–0.912). Isometric midthigh pull peak force displayed excellent reliability (ICC: 0.966), whereas force-time metrics ranged from moderate to excellent (ICC: 0.635–0.970). Excluding rate of force development (coefficient of variation [CV]: 10.6–35.9%), global measures (CV: 1.6–12.9%) were more reproducible than local measures (CV: 3.6–64.5%). However, local metrics directly measure specific properties of the MTU, and therefore provide valuable information despite lower reproducibility. The novel data reported here provides insight into the natural variability of MTU assessments within female athletes which can be used to enhance the interpretation of other female athlete data, especially that which aims to investigate other aspects of variability, such as the menstrual cycle.

Using a two-phase approach in the form of a rapid literature review and Delphi consensus, this study aimed to reach consensus on the terms, definitions, and potential options to develop a framework that captures the contextual factors that can affect a rugby league ball carrier’s decision making, whilst also determining the perceived importance of these contextual factors. Forty terms, their definitions, and potential options, were extracted from the rapid review. In a two-round Delphi survey, experts rated their level of agreement with each term, definition, and potential options on a 5-point Likert scale. Consensus was defined by ≥80% agreement (with ≤10% in disagreement). The experts then rated the level of importance to a ball carrier’s decision making of each of the terms on a 7-point Likert scale. Eighteen experts participated in round-one and 15 participated in round-two (response rate 83%). Five additional terms were suggested by the experts and reached consensus in the second round of the Delphi survey. In total, consensus was reached on 45 terms, their definitions, and potential options, which were grouped into five themes (match context, offensive context, defensive context, offensive ball carrier skill, and attacking outcomes). Seventeen of the 45 terms were perceived to be important or very important. Nine of these factors were associated with offensive context, and eight were associated with defensive context. The framework can be used by coaches, performance analysts, and researchers to better understand player in-game decisions and to support the design of training interventions.

Objectives To assess the incidence, prevalence and consequences of illness in one professional academy rugby league club during an in-season period. Design Observational prospective cohort study. Method Seventeen male rugby league players (age 17.7 ± 0.7 years, stature 178.8 ± 5.1 cm, body mass 87.2 ± 9.6 kg) completed a weekly self-report illness questionnaire using an amended version of the Oslo Sports Trauma Research Centre (OSTRC) questionnaire on health problems. Results A total of 24 new illnesses were reported over the 25-week study period. 65% of players experienced at least one illness during the study. The incidence of illness in this cohort was 14.3 per 1000-player days, with the respiratory system being most commonly affected (n = 15; 62.5%). The average weekly illness prevalence was 10.3%. Time-loss illness incidence was 1.4 per 1000-player days. Loss of body mass and sleep disruptions were the most commonly reported consequences of illness episodes. Mean body mass loss during a period of illness was 2.2 ± 0.6 kg. Conclusions Academy rugby league players are most commonly affected by respiratory illness with a total of nineteen training and competition days lost to illness. Associated consequences of illness, such as loss of body mass and sleep disruptions may present a challenge and negatively impact a rugby league player’s development. Appropriate medical provisions should be provided for Academy rugby league players to support them during periods of illness to limit the impact of these consequences.

The aim was to use a combination of video analysis and microtechnology (10 Hz global positioning system [GPS]) to quantify and compare the speed and acceleration of ball-carriers and tacklers during the pre-contact phase (contact - 0.5s) of the tackle event during rugby league match-play. Data were collected from 44 professional male rugby league players from two Super League clubs across two competitive matches. Tackle events were coded and subject to three stages of inclusion criteria to identify front-on tackles. 10 Hz GPS data was synchronised with video to extract the speed and acceleration of the ball-carrier and tackler into each front-on tackle (n = 214). Linear mixed effects models (effect size [ES], confidence intervals, p-values) compared differences. Overall, ball-carriers (4.73 ± 1.12 m∙s-1) had greater speed into front-on tackles than tacklers (2.82 ± 1.07 m∙s-1; ES = 1.69). Ball-carriers accelerated (0.67 ± 1.01 m∙s-2) into contact whilst tacklers decelerated (-1.26 ± 1.36 m∙s-2; ES = 1.74). Positional comparisons showed speed was greater during back vs. back (ES = 0.66) and back vs. forward (ES = 0.40) than forward vs. forward tackle events. Findings can be used to inform strategies to improve performance and player welfare.

This systematic review aimed to identify and summarise associations between currently identified contextual factors and match running in senior male professional rugby league. Eligible articles included at least one contextual factor and used GPS to measure at least one displacement variable within competitive senior, male, professional rugby league matches. Of the 15 included studies, the identified contextual factors were grouped into factors related to individual characteristics (n = 3), match result (n = 4), team strength (n = 2), opposition strength (n = 3), match conditions (n = 6), technical and tactical demands (n = 6), spatial and temporal characteristics (n = 7), and nutrition (n = 1). Speed was the most commonly reported measure of match running (100%), followed by distance (47%), and acceleration (20%). Inconsistencies were found between studies for most contextual factors on match running. Higher speeds were generally associated with higher fitness, encountered earlier in the match and whilst defending. All 15 studies utilised a univariate approach to quantify associations of a contextual factor. The inconsistencies found in the associations of given contextual factors highlight the complex and multi-faceted nature of match running. Therefore, practitioners should consider contextual factors when analysing and interpreting GPS data.

This study quantified and compared the movement characteristics of elite domestic and international netball match-play, including fifteen individual players who compete at both levels. Microtechnology data were collected across 75 matches in a league-wide study from players (n = 113) competing in the Netball Superleague (elite domestic) and from international players (n = 23) in 22 international matches. Players were categorised according to the seven playing positions. Accelerometer-derived variables were analysed per whole-match and per quarter, for both absolute (i.e., volume) and relative to duration (i.e., intensity [per minute]) values. The median playing duration ranged across positions from 23.6 to 42.4 minutes at international and 31.6 to 48.1 minutes at domestic level. International matches were greater than elite domestic competition for relative variables across all positions. Moderate to large effect sizes (1.00–1.50) were found between playing levels for PlayerLoadTM per minute (AU·min-1). Significant decreases in both absolute and relative variables were observed across quarters for both competition levels. The movement characteristics are position dependent, with greater absolute characteristics at domestic level across whole-match analysis, but greater relative characteristics at international level. These findings provide practitioners with information to guide training prescription, return-to-play protocols, and transitioning athletes between levels of competition.

This study aimed to identify which physical and technical-tactical performance indicators (PI) can classify between levels of rugby league match-play. Data were collected from 46 European Super League (ESL) and 36 under-19 Academy (Academy) level matches over two seasons. Thirty-one ESL players and 41 Academy players participated. Microtechnology units were used to analyse the physical PI and matches were videoed and coded for individual technical-tactical PI, resulting in 157 predictor variables. Data were split into training and testing datasets. Random forests (RF) were built to reduce the dimensionality of the data, identify variables of importance and build classification models. To aid practical interpretation, conditional inference (CI) trees were built. Nine variables were identified as most important for backs, classifying between levels with 83% (RF) and 78% (CI tree) accuracy. The combination of variables with the highest classification rate was PlayerLoad2D, PlayerLoadSLOW per Kg body mass and high-speed running distance. Four variables were identified as most important for forwards, classifying with 68% (RF) and 64% (CI tree) accuracy. Defensive play-the-ball losses alone had the highest classification rate for forwards. The identified PI and their unique combinations can be developed during training to aid in progression through the rugby league playing pathway.

Objectives: To quantify the incidence of concussion and compare between playing level in male rugby league. Design: Retrospective cohort Methods: Between 2016 and 2022, medically diagnosed concussions in Super League, Championship, and Academy competitions were reported to the Rugby Football League via club medical staff. Anonymised data were analysed using generalized linear mixed-effects models by season, month, and between competitions. Results: Overall, 1,403 concussions were identified from 104,209 player-match hours. Concussion incidence for Super League, Championship, and Academy was 15.5, 10.5, and 14.3 per 1,000 player-match hours, respectively. Championship concussion incidence was significantly lower than the Super League (p<0.001) and Academy (p<0.001). No significant differences were identified between year for Super League (range: 13.3 to 18.8 per 1,000 player-match hours) and Championship (range: 8.4 to 12.1 per 1,000 player-match hours). In Academy (range: 9.6 to 20.5 per 1,000 player-match hours), concussion incidence was significantly greater in 2021 compared to earlier years (2016, p=0.01 and 2017, p=0.03). No significant differences were identified between months for any competition. Conclusions: The incidence of concussion is greater in Super League and Academy compared to the Championship. Academy concussion incidence has increased over time. Different factors between and within competitions, such as changes to medical standards and knowledge, could have influenced the identification and diagnosis of concussion.

Objectives The aim of this study was to describe the incidence and magnitude of head acceleration events (HAEs) during elite men’s and women’s rugby union training for different contact training levels and drill types. Method Data were collected during the 2022–23 and 2023–24 seasons from 203 men and 125 women from 13 clubs using instrumented mouthguards (iMGs) during in-season training. One author reviewed the training videos to identify the contact level and drill type. HAE incidence was calculated per player minute. Results For men’s forwards and backs, only 4.7% and 5.8% of HAEs were ≥ 25 g and ≥ 1.5 Krad/s2, and 3.4% and 4.4% for women’s forwards and backs, respectively. The incidence of ≥ 5 g and ≥ 0.4 Krad/s2 was highest during full-contact training for men’s forwards (0.20/min) and backs (0.16/min) and women’s forwards (0.10/min). HAE incidence was 2–3 times higher during repetition-based compared with game-based training drills for men’s forwards (0.25/min vs 0.09/min) and backs (0.22/min vs 0.09/min) and women’s forwards (0.09/min vs 0.04/min) and backs (0.08/min vs 0.03/min). HAE incidences were halved when repetition-based training drills used pads compared with no pads for men’s forwards (0.21/min vs 0.44/min) and backs (0.17/min vs 0.30/min), and women’s forwards (0.06/min vs 0.14/min) and backs (0.06/min vs 0.10/min). Conclusion The average HAE incidence (~ 13–20% of weekly HAEs) and magnitude during an in-season training week is very low compared with matches. Opportunities to materially reduce HAE exposure in training are likely more limited than previously assumed. Future research on HAE load and injury, and understanding players’ specific weekly training exposure, may inform effective individual player management.

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.

Instrumented mouthguards (iMGs) are a novel technology being used within rugby to quantify head acceleration events. Understanding practitioners' perceptions of the barriers and facilitators to their use is important to support implementation and adoption. This study assessed men's and women's rugby union and league iMG managers' perceptions of staff and player interest in the technology, data and barriers to use. Forty‐six iMG managers (men's rugby union and league n = 20 and n = 9 and women's rugby union and league n = 7 and n = 10) completed an 18‐question survey. Perceived interest in data varied across staff roles with medical staff being reported as having the most interest. The iMG devices were perceived as easy to use but uncomfortable. Several uses of data were identified, including medical applications, player monitoring and player welfare. The comfort, size and fit of the iMG were reported as the major barriers to player use. Time constraints and a lack of understanding of data were barriers to engagement with the data. Continued education on how iMG data can be used is required to increase player and staff buy‐in, alongside improving comfort of the devices. Studies undertaken with iMGs investigating player performance and welfare outcomes will make data more useful and increase engagement.

Abstract

Measurements of muscle-tendon unit (MTU) function can be categorised into local (e.g. tendon strain) or global (e.g. jump height) assessments. Although menstrual cycle phase may be a key consideration when implementing these assessments in female athletes, the reliability of many MTU assessments is not well defined within female populations. Therefore, the purpose of this study was to report the test-retest reliability of local and global MTU function assessments during the early follicular phase of the menstrual cycle. Seventeen naturally menstruating females (age 28.5 ± 7.3 years) completed local and global assessments of MTU function during two testing sessions separated over 24-72 hours. Local tests included Achilles’ tendon mechanical testing and isometric strength of ankle plantar flexors and knee extensors, whereas global tests included countermovement, squat, and drop jumps, and the isometric midthigh pull. Based on intraclass correlation coefficient (ICC) statistics, poor to excellent reliability was found for local measures (ICC: 0.096-0.936). Good to excellent reliability was found for all global measures (ICC: 0.788-0.985), excluding the eccentric utilisation ratio (ICC 0.738) and most rate of force development metrics (ICC: 0.635-0.912). Isometric midthigh pull peak force displayed excellent reliability (ICC: 0.966), whereas force-time metrics ranged from moderate to excellent (ICC: 0.635-0.970). Excluding rate of force development (coefficient of variation [CV]: 10.6-35.9%), global measures (CV: 1.6-12.9%) were more reproducible than local measures (CV: 3.6-64.5%). However, local metrics directly measure specific aspects of MTU function, and therefore provide valuable information despite lower reproducibility. The novel data reported here provides insight into the natural variability of MTU function within female athletes, which can be used to enhance the interpretation of other female athlete data, especially that which aims to investigate other aspects of variability, such as the menstrual cycle.

This study aimed to (1) compare individual player match action characteristics between scholarship, academy, and senior (European Super League, ESL) levels of the rugby league player pathway, and (2) compare match actions between players that have progressed to play ESL and those that did not. Data was collected on 147 players from 95 senior, 69 academy, and 23 scholarship matches over three seasons. Matches were filmed via 2 angles and 26 match action characteristics (e.g., carry, missed tackle) were coded. Linear mixed models identified forty-eight significant differences in match action characteristics when accounting for playing position between playing levels. Over seventy percent of the differences were defensive match actions, indicating there are higher defensive match demands in the ESL when compared to academy and scholarship match play. Seven and eleven match actions characteristics were identified at scholarship and academy levels that differentiated between players who had progressed to play in the ESL and those who had not. All but one of these characteristics were attacking match actions, indicating a player’s attacking qualities are important in their progression to the ESL. These results have implications for both talent identification and long-term athlete development in rugby league.

OBJECTIVES: Full-contact football-code team sports offer a unique environment for illness risk. During training and match-play, players are exposed to high-intensity collisions which may result in skin-on-skin abrasions and transfer of bodily fluids. Understanding the incidence of all illnesses and infections and what impact they cause to time-loss from training and competition is important to improve athlete care within these sports. This review aimed to systematically report, quantify and compare the type, incidence, prevalence and count of illnesses across full-contact football-code team sports. DESIGN/METHODS: A systematic search of Cochrane Library, MEDLINE, SPORTDiscus, PsycINFO and CINAHL electronic databases was performed from inception to October 2019; keywords relating to illness, athletes and epidemiology were used. Studies were excluded if they did not quantify illness or infection, involve elite athletes, investigate full-contact football-code sports or were review articles. RESULTS: Twenty-eight studies met the eligibility criteria. Five different football-codes were reported: American football (n=10), Australian rules football (n=3), rugby league (n=2), rugby sevens (n=3) and rugby union (n=9). One multi-sport study included both American football and rugby union. Full-contact football-code athletes are most commonly affected by respiratory system illnesses. There is a distinct lack of consensus of illness monitoring methodology. CONCLUSIONS: Full-contact football-code team sport athletes are most commonly affected by respiratory system illnesses. Due to various monitoring methodologies, illness incidence could only be compared between studies that used matching incidence exposure measures. High-quality illness surveillance data collection is an essential component to undertake effective and targeted illness prevention in athletes.

This book provides a comprehensive and accessible overview of the research behind the preparation, development and performance of the young rugby player.

To support the understanding, preparation, and long-term development of youth rugby players, the accurate measurement of their physical qualities is vital. This chapter summarises how anthropometry, body composition, strength, power, speed, agility and change-of-direction, aerobic and anaerobic capacity, and athletic movement skills are measured within youth rugby players and discusses the accuracy and reliability of these methods. Furthermore, the implications of using these different testing methods within research are considered. Due to the large discrepancies in testing outcomes between rugby players of similar ages, this chapter will provide recommendations for accurate and reproducible testing of youth rugby players. Additionally, future research directions are provided that will enhance the understanding of youth rugby player development.

Injury risk is a concern for youth rugby, with research since the 1980s reporting the injury incidence within the codes. This chapter aims to review the existing literature on the injury risk (including patterns of injury, risk factors, and concussion) and the injury prevention strategies used within youth rugby union and rugby league. In summary, the chapter shows that injury incidence of children participating is low but does increase during adolescence. Most injuries occur to the knee, shoulder, and head, with the tackle the major cause of injury. Numerous injury prevention strategies have been investigated (e.g., equipment, law modification, integrative neuromuscular training programmes), demonstrating they are effective. Future research should use consistent injury definitions, evaluate injury risk according to other player development factors (e.g., grouping strategies, physical development), and consider wider adoption, implementation, and maintenance of injury prevention strategies to make the codes of rugby as safe as possible.

The quantification and development of physical qualities of youth rugby players is vital to support athlete preparation and long-term development. This chapter summarises and presents the research quantifying the physical qualities and their development of male youth rugby union and rugby league players and compares between age grades and playing positions, whilst considering the effect on career attainment and coaches’ perspectives. A range of research presents the physical qualities of youth rugby players, including stature, body mass, body fat percentage, muscular strength, muscular power, linear speed, change of direction, and aerobic capacity. Differences are apparent by age grade and position. However, the research has several limitations, including the presentation of small sample sizes and lack of consistency in the measures used. Future research should consider the use of national standardised testing batteries due to the inconsistency in testing methods and small samples limiting the reporting of positional differences. Practitioners can use the results from this review to evaluate the physical qualities of youth rugby players to enhance training prescription and goal setting.

In this chapter, the ecological dynamics framework is used to provide an overview of talent identification research in male youth rugby. Specifically, the literature and research implications are reviewed and synthesised using three constraints: (a) the task (i.e., participation history), (b) the performer (i.e., psychological characteristics, technical and tactical skills, physical factors), and (c) the environment (i.e., relative age effects, sociocultural influences). In summary, it is highlighted that talent identification in male youth rugby cannot be based upon any performance characteristic in isolation and that the interaction amongst all constraints should be considered when identifying young talent. Moreover, these constraints appear to be contingent on (a) age group, (b) competition level, (c) nationality, and (d) playing position. Limitations of the current literature and proposed directions for future research are discussed emphasising the need for multidisciplinary and longitudinal research within male and female rugby players.

A variety of kinanthropometric measurements (the study of size, shape, proportion, composition and maturation) have been used to characterise youth rugby-playing cohorts. Herein, differences between age-grades and playing groups (forwards and backs) have been established, whilst maturation appears to influence performance and selection in talent development programmes. Additionally, anthropometric-based grading methods of youth players have been applied as an alternative to traditional age grouping strategies. However, there is a lack of transparency as a consequence of limited detail in the methods for the measures used and limited research examining (1) the differences beyond comparisons of forwards and backs in players of the same age; (2) community age-grade rugby; and (3) youth female rugby. Furthermore, whilst anthropometric-based ‘grouping’ methods appear theoretically sound, there is currently a lack of research to support their proposed benefits.

The concept of training youth athletes is not novel; however, since the turn of the millennium, there has been a significant increase in interest surrounding the efficacy of various training approaches on the holistic development of both children and adolescents. Despite this growing interest, practitioners should remember that youth athletes are a unique population and that their exposure to sports training and strength and conditioning programmes will coincide with normal growth and maturity-related changes in a range of physical, physiological and psychosocial qualities. Understanding key principles of paediatric exercise science and growth and maturation is therefore important to support long-term athletic development of youths. This chapter aims to introduce the key concepts of long-term athletic development related to the youth rugby player, including growth and maturation, physical development, injury risk, training load management and psychosocial development.

This two-part study evaluated the inter- and intra-unit reliability of Catapult Vector S7 microtechnology units in an indoor court-sport setting. In part-one, 27 female netball players completed a controlled movement series on two separate occasions to assess the inter- and intra-unit reliability of inertial movement analysis (IMA) variables (acceleration, deceleration, changes of direction and jumps). In part-two, 13 female netball players participated in 10 netball training sessions to assess the inter-unit reliability of IMA and PlayerLoadTM variables. Participants wore two microtechnology units placed side-by-side. Reliability was assessed using intraclass correlation coefficient (ICC), coefficient of variation (CV) and typical error (TE). Total IMA events showed good inter-unit reliability during the movement series (ICC, 1.00; CV, 3.7%) and training sessions (ICC, 0.99; CV, 4.5%). Inter-unit (ICC, 0.97; CV, 4.7%) and intra-unit (ICC, 0.97; CV, 4.3%) reliability for total IMA jump count was good in the movement series, with moderate CV (7.7%) during training. Reliability decreased when IMA counts were categorised by intensity and movement type. PlayerLoadTM (ICC, 1.00; CV, 1.5%) and associated variables revealed good inter-reliability, except peak PlayerLoadTM (moderate) and PlayerLoadSLOW (moderate). Counts of IMA variables, when considered as total and low-medium counts, and PlayerLoad variables are reliable for monitoring indoor court-sports players.

Objectives Professional sporting organisations invest considerable resources collecting and analysing data in order to better understand the factors that influence performance. Recent advances in non-invasive technologies, such as global positioning systems (GPS), mean that large volumes of data are now readily available to coaches and sport scientists. However analysing such data can be challenging, particularly when sample sizes are small and data sets contain multiple highly correlated variables, as is often the case in a sporting context.

This study aimed to establish consensus on injury risk factors in netball via a combined systematic review and Delphi method approach. A systematic search of databases (PubMed, Scopus, MEDLINE, SPORTDiscus, CINAHL) was conducted from inception until June 2023. Twenty-four risk factors were extracted from 17 studies and combined with a three-round Delphi approach to achieve consensus. In round-one, experts listed perceived risk factors for injury in netball which were combined with the risk factors identified via the systematic review. In round-two and round-three, experts rated their level of agreement with each risk factor on a 5-point Likert scale (1-strongly disagree to 5-strongly agree). Consensus was defined as 80% agreement (with <10% in disagreement). In round-three, experts also rated the priority for mitigating the risk factor (1-very low to 5-very high). Nineteen experts participated in round-one and round-two, and sixteen participated in round-three (response rate 84%). One-hundred and nine risk factors for injury were identified by the systematic review and experts combined. Sixty-one risk factors reached consensus, categorised into five groups: ‘individual characteristics’ (n=22), ‘lifestyle’ (n=11), ‘training and competition’ (n=14), ‘sport science and medical provision’ (n=6) and ‘facilities and equipment’ (n=8). ‘Poor landing technique/mechanics’ had a median (interquartile range) mitigation priority rating of 5(1), while all others had median ratings of 3-4.5. This study identifies a range of risk factors for injury, provides focus areas for injury prevention, and highlights the importance of a multi-disciplinary approach to injury mitigation in netball.

Objectives Report two-years of training injury data in senior and academy professional rugby league. Design Prospective cohort study. Method Match and training time-loss injuries and exposure data were recorded from two-seasons of the European Super League competition. Eleven/12 (2021) and 12/12 (2022) senior and 8/12 (2021) and 12/12 (2022) academy teams participated. Training injuries are described in detail and overall match injuries referred to for comparison only. Results 224,000 training exposure hours were recorded with 293 injuries at the senior (mean [95 % confidence interval]; 3[2–3] per 1000 h) and 268 academy level (2 [2–3] per 1000 h), accounting for 31 % and 40 % of all injuries (i.e., matches and training). The severity of training injuries (senior: 35 [30–39], academy: 36 [30–42] days-lost) was similar to match injuries. Lower-limb injuries had the greatest injury incidence at both levels (senior: 1.85 [1.61–2.12], academy: 1.28 [1.08–1.51] per 1000 h). Head injuries at the academy level had greater severity (35 [25–45] vs. 18 [12–14] days-lost; p < 0.01) and burden (17 [16–18] vs. 4[4–5] days-lost per 1000 h; p = 0.02) than senior level. At the senior level, the incidence of contact injuries was lower than non-contact injuries (risk ratio: 0.29 [0.09–0.88], p = 0.02). Conclusion Training injuries accounted for about a third of injuries, with similar injury severity to match-play. Within training there is a higher rate of non-contact vs. contact injuries. Whilst current injury prevention interventions target matches, these data highlight the importance of collecting high quality training injury data to develop and evaluate injury prevention strategies in training

Objectives To compare match injury incidence, severity and burden in men's and women's elite rugby league. Design A prospective cohort epidemiological study. Methods Time loss match injury data were collected from all men's (11,301 exposure hours) and women's (5,244 exposure hours) Super League clubs. Results Injury incidence and burden were not different between men and women (mean [95 % CI]; 54 [45 to 65] vs. 60 [49 to 74] per 1000 match-hours; p = 0.39, and 2332 [1844 to 2951] vs. 1951 [1560 to 2440] days lost per 1000 match-hours; p = 0.26). However, injury severity was greater for men than women (42 [35–50] vs. 35 [29 to 42]; p = 0.01). Lower limbs accounted for 54 % and 52 % of injuries for men and women, with the head/face the most frequently injured location due to concussion (12 [10 to 15] and 10 [8 to 14] per 1000 match-hours for men and women). Injuries to the knee had the greatest burden for men and women (708 [268–1868] and 863 [320–2328] days lost per 1000 match-hours). Being tackled was the most common injury mechanism for men and women (28 % and 38 %) with greater burden (p < 0.01) than other injury mechanisms. Conclusions Male and female rugby league players have similar injury incidence and burden; however, injury severity was higher in men. Head/face injuries have the highest injury incidence and knee injuries have the highest burden. These injuries should be the focus for prevention initiatives at a league (via laws), player, and coach level, with equal and specific focus for both men's and women's rugby league players.

ABSTRACT

This study aimed to describe the incidence of head acceleration events (HAEs) during pitch‐based in‐season training and matches in professional male rugby league. Data were recorded using instrumented mouthguards from 108 players (70 forwards and 38 backs) at nine Super League teams (2024 season), resulting in 468 player‐training sessions and 665 player‐matches included. Peak linear and angular acceleration were calculated from each HAE and analyzed using generalized linear mixed‐effects models. During the 468 player‐training sessions, 814 HAEs above the lowest magnitude threshold (5  g and 400 rad.s −2 ) were observed and the mean HAE incidence rate per player‐hour was 1.52 (95% confidence intervals; 1.34–1.70). This was substantially lower than matches (25.78 [23.28–28.27] per player‐hour) with HAE incidence being 17 times greater during matches compared to training (incidence rate ratio 16.96 [14.92–19.01]). Higher magnitude HAEs had a lower incidence in both training and matches (e.g., > 25  g 0.04 [0.02–0.06] and 2.01 [1.79–2.24] per player‐hour). Out of 468 player‐training sessions, 307 (~66%) had no HAEs > 10  g and 441 (~94%) had no HAEs > 25  g . Overall, the incidence rates of HAEs during training were low and substantially lower than match‐play. However, a small proportion of relatively high in magnitude HAEs do occur during training, which could be the target of prevention interventions in training. However, given the different HAE rates between training and matches, interventions targeting matches (e.g., law modifications or reduced exposure) would have a larger effect on reducing HAEs for players than training interventions.

Background: Athlete exposure to contact could be a risk factor for injury. Governing bodies should provide guidelines preventing overexposure to contact. Objectives: Describe the current contact load practices and perceptions of contact load requirements within men’s and women’s rugby league to allow the Rugby Football League (RFL) to develop contact load guidelines. Methods: Participants (n=450 players, n=46 coaching staff, n=32 performance staff, n=23 medical staff) completed an online survey of 27 items, assessing the current contact load practices and perceptions within four categories: “current contact load practices” (n=12 items), “perceptions of required contact load” (n = 6 items), “monitoring of contact load” (n=3 items), and “the relationship between contact load and recovery” (n=6 items). Results: During men’s Super League pre-season, full contact and controlled contact training was typically undertaken for 15-30 minutes per week, and wrestling training for 15-45 minutes per week. During the in-season, these three training types were all typically undertaken for 15-30 mins per week. In women’s Super League, all training modalities were undertaken for up to 30 minutes per week in the pre- and in-season periods. Both men’s and women’s Super League players and staff perceived 15-30 minutes of full contact training per week was enough to prepare players for the physical demands of rugby league, but a higher duration may be required to prepare for the technical contact demands. Conclusion: Men’s and women’s Super League clubs currently undertake more contact training during pre-season than in-season, which was planned by coaches and is deemed adequate to prepare players for the demands of rugby league. This study provides data to develop contact load guidelines to improve player welfare whilst not impacting performance.

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 text is essential reading for all scientists, students and applied researchers wanting to develop world-class, evidence-based programmes for their youth athletes.

The importance of contributors that can result in negative player outcomes in sport and the feasibility and barriers to modifying these to optimise player health and well-being have yet to be established. Within rugby codes (rugby league, rugby union and rugby sevens), within male and female cohorts across playing levels (full-time senior, part-time senior, age grade), this project aims to develop a consensus on contributors to negative biopsychosocial outcomes in rugby players (known as the CoNBO study) and establish stakeholder perceived importance of the identified contributors and barriers to their management. This project will consist of three parts; part 1: a systematic review, part 2: a three-round expert Delphi study and part 3: stakeholder rating of feasibility and barriers to management. Within part 1, systematic searches of electronic databases (PubMed, Scopus, MEDLINE, SPORTDiscus, CINAHL) will be performed. The systematic review protocol is registered with PROSPERO. Studies will be searched to identify physical, psychological and/or social factors resulting in negative player outcomes in rugby. Part 2 will consist of a three-round expert Delphi consensus study to establish additional physical, psychological and/or social factors that result in negative player outcomes in rugby and their importance. In part 3, stakeholders (eg, coaches, chief executive officers and players) will provide perceptions of the feasibility and barriers to modifying the identified factors within their setting. On completion, several manuscripts will be submitted for publication in peer-reviewed journals. The findings of this project have worldwide relevance for stakeholders in the rugby codes. PROSPERO registration number CRD42022346751.

The authors contributing to this book are world leading in their respective fields, ranging from academics researching rugby performance to practitioners delivering this information within the professional game.

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.

Determining key performance indicators and classifying players accurately between competitive levels is one of the classification challenges in sports analytics. A recent study applied Random Forest algorithm to identify important variables to classify rugby league players into academy and senior levels and achieved 82.0% and 67.5% accuracy for backs and forwards. However, the classification accuracy could be improved due to limitations in the existing method. Therefore, this study aimed to introduce and implement feature selection technique to identify key performance indicators in rugby league positional groups and assess the performances of six classification algorithms. Fifteen and fourteen of 157 performance indicators for backs and forwards were identified respectively as key performance indicators by the correlation-based feature selection method, with seven common indicators between the positional groups. Classification results show that models developed using the key performance indicators had improved performance for both positional groups than models developed using all performance indicators. 5-Nearest Neighbour produced the best classification accuracy for backs and forwards (accuracy = 85% and 77%) which is higher than the previous method’s accuracies. When analysing classification questions in sport science, researchers are encouraged to evaluate multiple classification algorithms and a feature selection method should be considered for identifying key variables.