New Relations for Three-Dimensional Supersymmetric Scattering Amplitudes

We provide evidence for a duality between color and kinematics in three-dimensional supersymmetric Chern-Simons matter theories. We show that the six-point amplitude in the maximally supersymmetric, N=8, theory can be arranged so that the kinematic factors satisfy the fundamental identity of three-algebras. We further show that the four- and six-point N=8 amplitudes can be "squared" into the amplitudes of N=16 three-dimensional supergravity, thus providing evidence for a hidden three-algebra structure in the dynamics of the supergravity.Comment: 8 pages, 2 figure

Monitoring anthropometry and fitness using maturity groups within youth rugby league.

The purpose of the present study was to evaluate the anthropometry and fitness, and change in these characteristics over time, of youth rugby league players by using maturity status to determine annual categories instead of traditional chronological annual-age grouping. One hundred and twenty one male rugby league players were assessed using anthropometric (i.e., height, sitting height, body mass and sum of four skinfolds) and fitness (i.e., vertical jump, medicine ball chest throw, 10m and 20m sprint and multi stage fitness test; MSFT) measures over a 5 year period. Each player was classified into one of six maturity groups based on their maturity offset (Years from Peak Height Velocity; i.e., 1.5 YPHV). MANOVA analyses identified significant (p<0.001) main effects for maturity group for cross-sectional characteristics and longitudinal change in performance over time. Analyses demonstrated that more mature groups had greater anthropometric and fitness characteristics, except for endurance performance (MSFT -2.5 YPHV = 1872 ± 18 m vs 2.5 YPHV = 1675 ± 275m). For longitudinal changes in characteristics over time, a significant effect was only identified for height and sitting height (p<0.05). These findings provide comparative data for anthropometric and fitness characteristics and change in performance over time in accordance to maturity status within youth rugby league players. Classifying players into annual maturity groups may be an additional or alternative assessment method for evaluating anthropometry and fitness performance in adolescent populations. Further, tracking performance changes over time, especially in relation to maturation, may reduce the limitations associated with chronological annual-age grouping

Monitoring workloads in collision sports: External load measures alone may not provide the full picture

PURPOSE: To compare the external loads and external:internal load ratios (EL:IL) during match-play of adolescent collision sport athletes playing at both elite (i.e., academy) and sub-elite (i.e., school) standards. METHODS: Following ethics approval, seventeen elite adolescent male rugby union players (mean ± SD age = 17 ± 1 years) were recruited for this study. Global positioning system (GPS) locomotor (i.e., relative distance [RD; m·min-1], low speed activity [LSA; relative distance <61% maximum velocity [Vmax]], high speed running [HSR; relative distance ≥61% Vmax]), and accelerometer (relative PlayerLoadTM [RPL; AU·min-1], PLSLOW [relative accelerations <2 m·s-1], PLFAST [relative accelerations ≥2 m·s-1]) external loads, and session rating of perceived exertion (sRPE) internal load measures were obtained from 22 matches resulting in 86 match files (39 sub-elite and 47 elite match files; 5 ± 2 match files per subject). Perceptual wellbeing measures (i.e., fatigue, sleep quality, upper-body and lower-body soreness, stress, and mood) were also recorded using a 5-point Likert scale on the mornings pre- and post-match. Data were analysed using Cohen’s d effect sizes (d) and magnitude-based inferences. RESULTS: Differences in external loads were unclear between playing standards for RD (d = -0.2) and RPL (d = 0.0). However, subjects’ EL:IL were very likely lower during elite compared to sub-elite matches for both RD:sRPE (d = -1.0) and RPL:sRPE (d = -0.8), due to the very likely greater sRPE during elite matches (d = -1.1). There were unclear differences between sub-elite and elite matches for distribution of GPS and accelerometer variables (i.e., LSA, HSR, PLSLOW, and PLFAST; Table 1). Changes in total perceptual wellbeing were possibly greater following elite compared to sub-elite matches, with unclear differences for changes in sleep quality, lower-body soreness, stress and mood. However, changes in perceptual fatigue and upper-body soreness were both likely greater following elite matches. CONCLUSIONS: Adolescent rugby union players had similar locomotor and accelerometer external loads (i.e., RD, LSA, HSR, RPL, PLSLOW and PLFAST) during both elite and sub-elite standard matches. However, EL:IL was substantially reduced in higher standard matches, indicating a higher perception of effort for a given external load. Greater changes in perceptual fatigue and upper-body soreness following elite match-play may be related to greater magnitude of collision-based activity at higher playing standards. This may be due to the increased body mass and running velocities of opponents at higher playing standards, which may not be fully accounted for using external load measures alone. PRACTICAL APPLICATION: As collision sports require more than just movement and acceleration demands, the inclusion of subjective load measures (i.e., sRPE) or EL:IL may provide a further insight to the true demands of training or match-play than GPS and accelerometer data alone

Do physical qualities influence the attainment of professional status within elite 16-19 year old rugby league players?

OBJECTIVES The current study retrospectively compared the physical qualities of elite academy rugby league players (aged 16-19 years) by career attainment level (i.e., academy or professional). DESIGN: Retrospective cross-sectional and longitudinal design. METHODS: Eighty-one academy rugby league players were assessed for physical qualities (height, body mass, skinfolds, speed, momentum, vertical jump, Yo-Yo Level 1 and 1-RM squat, bench press and prone row) at the Under 17-19 age categories between 2007 and 2012. Player's career attainment level was determined in 2014. Longitudinal changes in physical qualities between Under 17 and 19s were compared by career attainment level. RESULTS: Professional players demonstrated moderate significant advantages for height (d=0.98) and 1-RM squat (d=0.66) at the Under 17s, 1-RM bench press (d=0.76) at the Under 18s and 1-RM prone row (d=0.73) at the Under 19s age categories when compared to academy players. When assessed longitudinally (Under 17s-19s), professional players significantly outperformed academy players for 1-RM squat (η2=0.20). Professional players also demonstrated greater increases in body mass (8.2 vs. 2.9kg) and 10m momentum (47 vs. 17kgs-1) than academy players between the Under 17s and 19s. CONCLUSIONS: Advanced physical qualities, particularly height and absolute strength, within 16-19 year old players may contribute to attaining professional status in rugby league. Further, the development of body mass and momentum for players within an academy is an important consideration in the progress towards professional rugby league. Therefore, practitioners should aim to identify and develop the physical qualities, especially size and strength, within academy rugby league players

A sex difference in the response of the rodent postsynaptic density to synGAP haploinsufficiency

SynGAP is a postsynaptic density (PSD) protein that binds to PDZ domains of the scaffold protein PSD-95. We previously reported that heterozygous deletion of Syngap1 in mice is correlated with increased steady-state levels of other key PSD proteins that bind PSD-95, although the level of PSD-95 remains constant (Walkup et al., 2016). For example, the ratio to PSD-95 of Transmembrane AMPA-Receptor-associated Proteins (TARPs), which mediate binding of AMPA-type glutamate receptors to PSD-95, was increased in young Syngap1+/- mice. Here we show that only females and not males show a highly significant correlation between an increase in TARP and a decrease in synGAP in the PSDs of Syngap1+/- rodents. The data reveal a sex difference in the adaptation of the PSD scaffold to synGAP haploinsufficiency

Differences in the Movement Skills and Physical Qualities of Elite Senior & Academy Rugby League Players.

The aim of the present study was to investigate (a) the differences in the movement skills and physical qualities between academy and senior rugby league players, and (b) the relationships between movement skills and physical qualities. Fifty-five male rugby league players (Senior, n=18; Under 19 n=23; Under 16, n=14) undertook a physical testing battery including anthropometric (stature & body mass), strength (isometric mid-thigh pull; IMTP) and power (countermovement jump; CMJ) qualities, alongside the athletic ability assessment (AAA; comprised of overhead squat, double lunge, single-leg Romanian deadlift, press-up and pull-up exercises). Univariate analysis of variance demonstrated significant (p<0.001) differences in body mass, IMTP peak force, CMJ mean power, and AAA movement skills between groups. The greatest observed differences for total movement skills, peak force and mean power were identified between Under 16 and 19 academy age groups. Spearman's rank correlation coefficients demonstrated a significant moderate (r=0.31) relationship between peak force and total movement skill. Furthermore, trivial (r=0.01) and small (r=0.13; r=0.22) relationships were observed between power qualities and total movement skill. These findings highlight that both movement skills and physical qualities differentiate between academy age groups, and provides comparative data for English senior and academy rugby league players

Injury incidence and characteristics in South African school first team rugby: A case study

Background: Despite its apparent popularity, participation in the sport of rugby union is accompanied by a significant risk of injury. Concerned parties have recently questioned whether this risk is acceptable within school populations. This is difficult to assess within the South African schools’ population as no recent longitudinal injury studies exist. Objectives: To determine the training habits, rugby-related exposure and injury risk within a population of South African high school first team rugby players. Methods: Training and match exposure in both school and provincial competition examined and the resultant injuries were longitudinally observed for the duration of a South African high school rugby season. Results: Match (79, 95%CI 52-105 injuries/1 000 h) and training (7, 95%CI 3-11 injuries /1000h) injury incidences were demonstrated to be greater than previously reported incidences in similar populations in England and Ireland. Weeks where players were exposed to both school and provincial competition (34, 95%CI 19-49 injuries /1 000 h) had significantly (p<0.05) greater injury incidences than during school competition alone (19, 95%CI 12-26 injuries /1 000 h). Conclusions: The injury risk demonstrated was greater than expected and represents reasons for concern. Possible reasons for the high injury incidence recorded may be the frequency of games played within the season, and the overlap of school and provincial competitions. It should be noted that these results were taken from one school over one season and might not be representative of the incidence of school rugby injuries overall. However, this research demonstrates the need for a multischool longitudinal study within South African schools rugby to determine the overall risk

Effects of an intensifed competition period on neuromuscular function in youth rugby union players

Playing rugby union matches causes a number of fatigue responses, including reduced lower body neuromuscular function (NMF) (commonly measured by counter movement jump (CMJ))(1). The time course of this response following match play is well established in professional (2) and academy (3) level rugby union players, who take at least 60 hours for NMF to recover. No data exist for high school level rugby union players, but these players are often exposed to multiple game tournaments and festivals (2 games in 3 days, or 3 games in 5 days) within their competition structures. Aim. The aim of this case study is to document the NMF response to playing three rugby union matches within five days. This will provide useful information to practitioners who must manage fatigue and recovery of youth rugby union players who play multiple games within short time periods

The Use of Microtechnology to Quantify the Peak Match Demands of the Football Codes: A Systematic Review.

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

Reliability and Usefulness of Linear Sprint Testing in Adolescent Rugby Union and League Players.

The purpose of the present study was to evaluate; 1) whether there were differences in sprint times at 5, 10, 20, 30 and 40 m between rugby union and rugby league players; 2) determine the reliability and usefulness of linear sprint testing in adolescent rugby players. Data were collected on 28 rugby union and league academy players over two testing sessions, with three day's rest between sessions. Rugby league players were faster at 5 m than rugby union players, with further difference unclear. Sprint time at 10, 20, 30 and 40 m were all reliable (CV = 3.1%, 1.8%, 2.0% and 1.3%) but greater than the smallest worthwhile change (SWC (0.2 x between-subject SD)), rating the test as marginal for usefulness. While the test was incapable of detecting the SWC we recommend that practitioners and researchers use Hopkins' proposed method (22); whereby plotting the change score of the individual at each split (± TE expressed as a CV) against the SWC, and visually inspecting whether the TE crosses into the SWC is capable of identifying whether a change is both real (greater than the noise of the test, i.e., >TE) and of practical significance (>SWC). Researchers and practitioners can use the TE and SWC from the present study to assess changes in performance of adolescent rugby players when using single beam timing gates