STRENGTH AND POWER CHARACTERISTICS OF ELITE JUNIOR AND SENIOR RUGBY LEAGUE ATHLETES.

INTRODUCTION: Strength and conditioning coaches play an important role in developing the physical attributes required for sport while athletes are progressing through the developmental years. Strength and power are important characteristics for performance in rugby league. The purpose of this study was to provide a lower body strength and power profile of elite junior (aged 17-20 years) and elite senior (open-aged professional) rugby league athletes within their respective player positions groups. In doing this, the research will provide practitioners with improved understanding of what physical attributes should be targeted in an appropriate athletic development program for 17-20 year old elite rugby league athletes. METHODS: Twenty junior aged elite RL players currently competing in the elite junior National Youth Competition and 25 senior aged rugby league players currently competing in the elite professional National Rugby League competition were recruited. Participants were split into 3 player groups; Adjustables (ADJ), Hit-Up Forwards (HUF) and Outside Backs (OB), as determined by their dominant playing position during matches. The testing protocol was conducted during preseason consisting of counter-movement jump, repeated jump, broad jump, and isometric mid-thigh pull. The effects of player group (senior vs junior) and position (ADJ vs HUF vs OB) on lower body strength, power, and jump results were investigated using a two-way analysis of variance. Statistical significance was set at an alpha level of 0.05. Where significant interactions or main effects were found, post hoc pairwise comparisons were made using the least significant difference method. Cohen's d effect sizes (ES) were calculated for pairwise comparisons. RESULTS: OB (5781N ± 615N, ES=1.26) and HUF (5862N ± 747N, ES=1.26) players showed greater absolute lower body power during the counter-movement jump than ADJ (4985N ± 642N, p < 0.05). Junior HUF (6271N ± 932N) showed greater absolute lower body power than senior HUF (5590N ± 456N, p < 0.05, ES=0.92). Senior OB (6184N ± 571N) showed greater absolute lower body power than junior OB (5429N ± 417N, p < 0.05, ES=1.51). There were no significant interactions for reactive strength index in the repeat effort jump test. HUF players (288cm ± 17cm, ES=1.03) and OB players (288cm ± 16cm, ES=1.01) showed greater distance in the broad jump test than ADJ (272cm ± 16cm, p < 0.05). Senior players (3883N ± 675N) showed greater absolute lower body peak force in the IMTP than junior players (3329N ± 410N, p < 0.05, ES=0.90). HUF (3913N ± 656N) players showed greater absolute lower body peak force than ADJ (3159N ± 369N, p < 0.05, ES=1.39). Senior HUF (4127N ± 759N, ES=0.95) and senior OB (3801N ± 400N, ES=1.36) showed greater absolute lower body peak force than junior HUF (3591N ± 25N, p < 0.05) and junior OB (3244N ± 419N, p < 0.05) respectively. DISCUSSION: In the current research, senior players showed significantly greater maximum force production during the isometric midthigh pull test than junior players across all playing positions. Senior OB demonstrated greater lower body power than junior OB in the counter-movement jump. These findings are consistent with elite rugby league match data, which indicate maximal power production an important part of the game for OB players, due to the sprint running demands. In contrast to the OB position, junior age HUF showed greater lower body power than senior HUF during the countermovement jump test. The increased wrestling demands require HUF to have greater upper body strength and body mass to enhance this technical element of the game. In summary, this research has shown differences in the strength and power profile of rugby league athletes across senior and junior players and different playing positions. These results provide important guidelines for practitioners involved in developing training programs for elite junior aged athletes preparing for elite senior rugby league. PRACTICAL APPLICATION: • Improving lower body strength should be the main priority for any athletic development program aimed at developing junior rugby league athletes into senior elite rugby league athletes. • Consideration must be given to the requirements of different playing positions when focusing on other physical qualities within a development program • When focusing on upper body strength and mass for improved tackling and wrestling in rugby league in hit-up forwards, ensure lower body power production is also being addressed. [ABSTRACT FROM AUTHOR]