Movement and Physiological Demands of Australasian National Rugby League Referees.

PURPOSE: To evaluate the movement and physiological demands of Australasian National Rugby League (NRL) referees, officiating with a 2-referee (ie, lead and pocket) system, and to compare the demands of the lead and pocket referees. METHODS: Global positioning system devices (10 Hz) were used to obtain 86 data sets (lead, n = 41; pocket, n = 45) on 19 NRL referees. Total distance, relative distance covered, and heart rate per half and across match play were examined within and between referees using t tests. Distance, time, and number of movement "efforts" were examined in 6 velocity classifications (ie, standing <0.5, walking 0.51-2.0, jogging 2.01-4.0, running 4.01-5.5, high-speed running 5.51-7.0, and sprinting >7.0 m/s) using analysis of variance. Cohen d effect sizes are reported. RESULTS: There were no significant differences between the lead and pocket referees for any movement or physiological variable. There was an overall significant (large, very large) effect for distance (% distance) and time (% time) (P < .001) between velocity classifications for both the lead and pocket referees. Both roles covered the largest distance and number of efforts at velocities of 0.51-2.0 m/s and 2.01-4.0 m/s, which were interspersed with efforts >5.51 m/s. CONCLUSIONS: Findings highlight the intermittent nature of rugby league refereeing but show that there were no differences in the movement and physiological demands of the 2 refereeing roles. Findings are valuable for those responsible for the preparation, training, and conditioning of NRL referees and to ensure that training prepares for and simulates match demands.

The influence of age, playing position, anthropometry and fitness on career attainment outcomes in rugby league.

This study evaluated the influence of annual-age category, relative age, playing position, anthropometry and fitness on the career attainment outcomes of junior rugby league players originally selected for a talent identification and development (TID) programme. Junior rugby league players (N = 580) were grouped retrospectively according to their career attainment level (i.e., amateur, academy and professional). Anthropometric (height, sitting height, body mass, sum of four skinfolds), maturational (age at peak height velocity; PHV) and fitness (power, speed, change of direction speed, estimated[Formula: see text]) characteristics were assessed at the Under 13s, 14s and 15s annual-age categories. Relative age (Q2 = 8.5% vs. Q4 = 25.5%) and playing position (Pivots = 19.5% vs. Props = 5.8%) influenced the percentage of players attaining professional status. Anthropometry and fitness had a significant effect on career attainment at the Under 14 (P = 0.002, η(2) = 0.16) and 15 (P = 0.01, η(2) = 0.12) annual-age categories. Findings at the Under 14s showed future professional players were significantly later maturing compared to academy and amateur players. Findings suggest that relative age, playing position, anthropometry and fitness can influence the career attainment of junior rugby league players. TID programmes within rugby league, and other related team sports, should be aware and acknowledge the factors influencing long-term career attainment, and not delimit development opportunities during early adolescence.

Retrospective analysis of anthropometric and fitness characteristics associated with long-term career progression in Rugby League.

OBJECTIVES: The current study retrospectively investigated the differences in anthropometric and fitness characteristics of junior rugby league players selected onto a talent identification and development (TID) programme between long-term career progression levels (i.e., amateur, academy, professional). DESIGN: Retrospective design. METHODS: Former junior rugby league players (N=580) selected to a TID programme were grouped according to their career progression level. Anthropometric (height, sitting height, body mass and sum of four skinfolds), maturational and fitness (power, speed, change of direction speed and estimated V̇O2max) assessments were conducted at 13-15 years. Multivariate analysis of covariance (MANCOVA) analyzed differences between career progression levels controlling for chronological age. RESULTS: 57.1% and 12.1% of players selected to the TID programme progressed to academy and professional levels in rugby league, respectively. Sum of four skinfolds (η(2)=0.03), vertical jump (η(2)=0.02), 10 m (η(2)=0.02), 20 m (η(2)=0.02), 30 m (η(2)=0.02), and 60 m (η(2)=0.03) speed, agility 505 left (η(2)=0.06), agility 505 right (η(2)=0.05) and estimated V̇O2max (η(2)=0.03) were superior within junior players who progressed to professional compared to amateur levels. No significant differences were identified between future academy and professional players for any measure. CONCLUSIONS: Findings suggest that lower sum of four skinfolds and advanced fitness characteristics within junior (13-15 years) rugby league players may partially contribute to long-term career progression. Therefore, TID programmes within rugby league should aim to assess and develop body composition and fitness characteristics, especially change of direction speed. However, TID programmes should also consider technical, tactical and psycho-social characteristics of junior rugby league players that may be important for long-term career progression.

An individualized longitudinal approach to monitoring the dynamics of growth and fitness development in adolescent athletes.

This study evaluated the development of anthropometric and fitness characteristics of 3 individual adolescent junior rugby league players and compared their characteristics with a cross-sectional population matched by age and skill level. Cross-sectional anthropometric and fitness assessments were conducted on 1,172 players selected to the Rugby Football League's talent development program (i.e., the Player Performance Pathway) between 2005 and 2008. Three players of differing relative age, maturational status, and playing position were measured and tracked once per year on 3 occasions (Under 13s, 14s, 15s age categories) and compared against the cross-sectional population. Results demonstrated that the later maturing players increased height (player 1 = 9.2%; player 2 = 7.8%) and a number of fitness characteristics (e.g., 60-m speed-player 1 = -14.9%; player 2 = -9.9%) more than the earlier maturing player (player 3-Height = 2.0%, 60-m sprint = -0.7%) over the 2-year period. The variation in the development of anthropometric and fitness characteristics between the 3 players highlights the importance of longitudinally monitoring individual characteristics during adolescence to assess the dynamic changes in growth, maturation, and fitness. Findings showcase the limitations of short-term performance assessments at one-off time points within annual-age categories, instead of advocating individual development and progression tracking without deselection. Coaches should consider using an individual approach, comparing data with population averages, to assist in the prescription of appropriate training and lifestyle interventions to aid the development of junior athletes.

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.