Using anthropometric and performance characteristics to predict selection in junior UK Rugby League players.

Research examining the factors influencing selection within talented junior Rugby League players is limited. The aims of this study were firstly to determine whether differences existed for anthropometric and performance characteristics between regional and national selection in high performance UK junior Rugby League players, and secondly to identify variables that discriminated between these selection levels. Regional representative (n=1172) selected junior players (aged 13-16 years) undertook an anthropometric and fitness testing battery with players split according to selection level (i.e., national, regional). MANCOVA analyses, with age and maturation controlled, identified national players as having lower sum of 4 skinfolds scores compared to regional players, and also performed significantly better on all physical tests. Stepwise discriminant analysis identified that estimated maximum oxygen uptake (VO2max), chronological age, body mass, 20 m sprint, height, sum of 4 skinfolds and sitting height discriminated between selection levels, accounting for 28.7% of the variance. This discriminant analysis corresponded to an overall predictive accuracy of 63.3% for all players. These results indicate that performance characteristics differed between selection levels in junior Rugby League players. However, the small magnitude of difference between selection levels suggests that physical qualities only partially explain higher representative selection. The monitoring and evaluation of such variables, alongside game related performance characteristics, provides greater knowledge and understanding about the processes and consequences of selection, training and performance in youth sport

Physiological and Movement Demands of Rugby League Referees: Influence on Penalty Accuracy.

Research into the physiological and movement demands of Rugby League (RL) referees is limited, with only one study in the European Super League (SL). To date, no studies have considered decision-making in RL referees. The purpose of this study was to quantify penalty accuracy scores of RL referees and determine the relationship between penalty accuracy and total distance covered (TD), high-intensity running (HIR) and heart rate per 10-min period of match-play. Time motion analysis was undertaken on 8 referees over 148 European SL games during the 2012 season using 10Hz GPS analysis and heart rate monitors. The number and timing of penalties awarded was quantified using Opta Stats. Referees awarded the correct decision on 74 ± 5% of occasions. Lowest accuracy was observed in the last 10-minute period of the game (67 ± 13%), with a moderate drop (ES= 0.86) in accuracy observed between 60-70 minutes and 70-80 minutes. Despite this, there were only small correlations observed between HRmean, total distance, HIR efforts and penalty accuracy. Although a moderate correlation was observed between maximum velocity and accuracy. Despite only small correlations observed, it would be rash to assume that physiological and movement demands of refereeing have no influence on decision-making. More likely, other confounding variables influence referee decision-making accuracy, requiring further investigation. Findings can be used by referees and coaches to inform training protocols, ensuring training is specific to both cognitive and physical match demands

Precision Error in Dual-Energy X-Ray Absorptiometry Body Composition Measurements in Elite Male Rugby League Players.

Body composition analysis using dual energy X-ray absorptiometry (DXA) is becoming increasingly popular in both clinical and sports science settings. Obesity, characterised by high fat mass (FM), is associated with larger precision errors, however, precision error for athletic groups with high levels of lean mass (LM) are unclear. Total (TB) and regional (limbs and trunk) body composition were determined from two consecutive total body scans (GE Lunar iDXA) with re-positioning in 45 elite male rugby league players (age: 21.8 ±5.4 years BMI: 27.8 ±2.5 kg.m-1). The root mean squared standard deviation (percentage co-efficient of variation) were TB bone mineral content (BMC): 24g (1.7%), TB LM: 321g (1.6%), and TB FM: 280g (2.3%). Regional precision values were superior for measurements of BMC: 4.7-16.3g (1.7-2.1%) and LM: 137-402g (2.0-2.4%), than for FM: 63-299g (3.1-4.1%). Precision error of DXA body composition measurements in elite male rugby players is higher than those reported elsewhere for normal adult populations and similar to those reported in those who are obese. It is advised that caution is applied when interpreting longitudinal DXA-derived body composition measurements in male rugby players and population-specific least significant change should be adopted