Game-play characteristics differ between the European Super League and National Rugby League: Implications for coaching and talent recruitment

Objectives: To compare the game-play characteristics between the European Super League (ESL) and the National Rugby League (NRL) competitions. Methods: Eleven team performance indicators were extracted from each match played by every ESL and NRL team over their respective 2016 season. Data was averaged, classified according to competition (Two levels: ESL and NRL), and modelled using univariate and multivariate techniques. Specifically, effect size statistics enabled between group comparisons, while non-metric multidimensional scaling enabled multivariate insights into competition dissimilarity. Results: Seven of the 11 performance indicators showed ‘large’ to ‘very large’ effects. Notably, NRL game-play generated fewer ‘line breaks’, ‘errors’, ‘tackles’ and ‘dummy half runs’ relative to ESL game-play (d >1.2). Despite the NRL generating fewer ‘all runs’ (d = 1.27 [0.57-1.95]), game-play in this competition generated greater ‘all run distances’ relative to the ESL (d = 1.78 [1.02-2.51]). Non-metric multidimensional scaling revealed clear multivariate competition dissimilarity, with ESL and NRL teams orienting distinctive positions on the ordination surface. Further, there was a greater spread in the relative positioning of NRL teams compared to ESL teams, indicating greater team dissimilarity within the NRL. Conclusions: Our observations may be explained by differing competition rule interpretations, in addition to differing game strategies and player skill capabilities. Both coaches and talent recruitment managers associated with these competitions may consider our data to assist with the identification and recruitment of suitable players from these respective competitions

Influences of gender and socioeconomic status on motor Proficiency of Primary School Children in the UK

As the development of movement skills are so crucial to a child's involvement in lifelong physical activity and sport, the purpose of this study was to assess the motor proficiency of children aged 4-7years (range=4.3-7.2years), whilst considering gender and socioeconomic status. 369 children (176 females, 193 males, aged=5.96±0.57years) were assessed for fine motor precision, fine motor integration, manual dexterity, bilateral co-ordination, balance, speed and agility, upper-limb co-ordination and strength. The average standard score for all participants was 44.4±8.9, classifying the participants towards the lower end of the average score. Multivariate analysis of covariance identified significant effects for gender (p<0.001) and socioeconomic status (p<0.001). Females outperformed males for fine motor skills and boys outperformed girls for catch and dribble gross motor skills. High socioeconomic status significantly outperformed middle and/or low socioeconomic status for total, fine and gross motor proficiency. Current motor proficiency of primary children aged 4-7years in the UK is just below average with differences evident between gender and socioeconomic status. Teachers and sport coaches working with primary aged children should concentrate on the development of movement skills, whilst considering differences between genders and socioeconomic status

Anthropometric, speed and endurance characteristics of English academy soccer players: Do they influence obtaining a professional contract at 18 years of age

This study evaluated the anthropometric, speed and endurance characteristics of English academy soccer players, comparing players who obtained a ‘professional’ contract at 18 years old with those that did not (‘academy’); 443 male academy soccer players from an English professional club undertook anthropometric (height and body mass), speed (10 and 20 m sprint) and endurance (Yo-Yo intermittent endurance test level 2 [Yo-Yo]) assessments between 2005 and 2012. Significant improvements with age were found for speed and endurance at each annual age group up until U18 age category. Significant differences were only observed between ‘professional’ and ‘academy’ players for 10 m (p = 0.003, η2 = 0.01) and 20 m (p = 0.001, η2 = 0.01) speed at U16 and U18 and Yo-Yo performance (p = 0.001, η2 = 0.12) at U18 age category. Practitioners should use speed and endurance assessments for monitoring physical development of players rather than for talent identification purposes

The origin of galaxy scaling laws in LCDM

It has long been recognized that tight relations link the mass, size, and characteristic velocity of galaxies. These scaling laws reflect the way in which baryons populate, cool, and settle at the center of their host dark matter halos; the angular momentum they retain in the assembly process; as well as the radial distribution and mass scalings of the dark matter halos. There has been steady progress in our understanding of these processes in recent years, mainly as sophisticated N-body and hydrodynamical simulation techniques have enabled the numerical realization of galaxy models of ever increasing complexity, realism, and appeal. These simulations have now clarified the origin of these galaxy scaling laws in a universe dominated by cold dark matter: these relations arise from the tight (but highly non-linear) relations between (i) galaxy mass and halo mass, (ii) galaxy size and halo characteristic radius; and (iii) from the self-similar mass nature of cold dark matter halo mass profiles. The excellent agreement between simulated and observed galaxy scaling laws is a resounding success for the LCDM cosmogony on the highly non-linear scales of individual galaxies.Comment: Contribution to the Proceedings of the Simons Conference "Illuminating Dark Matter", held in Kruen, Germany, in May 2018, eds. R. Essig, K. Zurek, J. Fen

The Relative Age Effect in Selection to International Team Matches in Norwegian Handball

Many elite sport organisations have introduced structured talent identification and development (TID) initiatives in youth sports to better facilitate elite sport performance. However, selection mechanisms for TID programmes (e.g., junior international team) are biased towards relatively older athletes and limited studies exist with Scandinavian contexts. Therefore, the aim of this study was to explore the relative age effect (RAE) in youth, junior and senior male and female international team selections among Norwegian handball players (n = 657). A Chi-square goodness-of-fit test assessed whether a skewed birthdate distribution occurred at the youth, junior and senior international team levels and odds-ratios were calculated for RAE distribution. Moreover, a Kruskal-Wallis test was used to assess differences between the number of international youth, junior and senior level appearances by birth quartiles. Significant uneven birth date distributions were shown for youth (χ2(7) = female 40.383 and male 105.716, p <0.001) and junior (χ2(7) = female 27.427 and male 30.948, p <0.001) international players, favouring the relatively older player (odds-ratio of 1.9–8.3). At the senior level, no uneven distribution was identified. The comparison of the number of matches in each age category and the quartile of birth showed a difference in the women’s youth category, where players in quartile 8 had a significantly lower number of appearances compared to quartile 1. The results form part of a growing body of knowledge about selection mechanisms in sport, which favours relatively older athletes within Norwegian Handball. Such findings are important for policy and practice for informing TID programmes for inclusive selection opportunities for all players

Enhancing the Evaluation and Interpretation of Fitness Testing Data within Youth Athletes

Fitness testing is common practice within youth athletes. However, the interpretation of fitness data often occurs within chronological annual-age categories, resulting in athletes being (dis)advantaged due to age or maturity discrepancies. Instead, evaluating fitness performance against rolling averages may be more appropriate. This article presents a novel method for analyzing fitness testing data in youth athletes using Z-scores according to rolling averages for both chronological age and maturity status. This analysis technique allows the dual ability to interpret youth fitness performance according to age and maturation, enhancing accuracy of data interpretation for talent identification, development and strength and conditioning programming

Relative Age Effects Across and Within Female Sport Contexts: A Systematic Review and Meta-Analysis

Subtle differences in chronological age within sport (bi-) annual-age groupings can contribute to immediate participation and long-term attainment discrepancies; known as the relative age effect. Voluminous studies have examined relative age effects in male sport; however, their prevalence and context-specific magnitude in female sport remain undetermined. The objective of this study was to determine the prevalence and magnitude of relative age effects in female sport via examination of published data spanning 1984–2016. Registered with PROSPERO (No. 42016053497) and using Preferred Reporting Items for Systematic Reviews and Meta-analysis systematic search guidelines, 57 studies were identified, containing 308 independent samples across 25 sports. Distribution data were synthesised using odds ratio meta-analyses, applying an invariance random-effects model. Follow-up subgroup category analyses examined whether relative age effect magnitudes were moderated by age group, competition level, sport type, sport context and study quality. When comparing the relatively oldest (quartile 1) vs. youngest (quartile 4) individuals across all female sport contexts, the overall pooled estimate identified a significant but small relative age effect (odds ratio=1.25; 95% confidence interval 1.21–1.30; p=0.01; odds ratio adjusted=1.21). Subgroup analyses revealed the relative age effect magnitude was higher in pre-adolescent (≤ 11 years) and adolescent (12–14 years) age groups and at higher competition levels. Relative age effect magnitudes were higher in team-based and individual sport contexts associated with high physiological demands. The findings highlight relative age effects are prevalent across the female sport contexts examined. Relative age effect magnitude is moderated by interactions between developmental stages, competition level and sport context demands. Modifications to sport policy, organisational and athlete development system structure, as well as practitioner intervention are recommended to prevent relative age effect-related participation and longer term attainment inequalities

A comparison of game-play characteristics between elite youth and senior Australian National Rugby League competitions

Objectives: To compare game-play characteristics between elite youth and senior Australian National Rugby League (NRL) competitions. Design: Longitudinal observational. Methods: The dataset consisted of 12 team performance indicators (e.g., ‘all runs’, ‘offloads’ and ‘tackles’) extracted from all 2016 national under 20 (U20) competition (elite youth; n = 372 observations) and National Rugby League (NRL) (elite senior; n = 378 observations) matches. Data was classified according to competition (Two levels: U20 and NRL) and modelled using two techniques. Firstly, non-metric multidimensional scaling resolved multivariate competition (dis)similarity, visualised using a two-dimensional ordination. Secondly, a conditional interference (CI) classification tree was grown to reveal the performance indicators most capable of explaining competition level. Results: Non-metric multidimensional scaling revealed high competition dissimilarity, with U20 and NRL teams orienting distinctive positions on the first dimension of the ordination surface. Five team performance indicators were retained within the CI tree (‘all runs’, ‘tackle breaks’, ‘tackles’, ‘missed tackles’, and ‘kicks’), which correctly classified 79% of the U20 observations and 93% of the NRL observations. Conclusions: Multivariate differences between elite youth and senior rugby league competitions were identified. Specifically, NRL game-play was classified by a greater number of ‘all runs’, and ‘tackles’ and a lower number of ‘missed tackles’ relative to the U20 competition. Given the national U20 competition is purported to assist with the development of prospective NRL players, junior coaches may consider training interventions that primarily aid the tackling capacities of players. This may subsequently assist with talent development and player progression in Australian rugby league