CHANGES IN LOWER-BODY STRENGTH AND POWER ACROSS A PROFESSIONAL RUGBY LEAGUE SEASON AND THE ABILITY OF COUNTERMOVEMENT JUMP VARIABLES TO PREDICT CHANGES IN MAXIMUM SQUAT STRENGTH.

Data showing strength and power capabilities is required to assess the effectiveness of training, adaptations to training and to prescribe accurate training loads. Given the weekly turnaround structure of the Australian national rugby league (NRL) competitive season, it is essential to establish a test that can quickly, easily and accurately provide feedback on maximal lower body strength, without being detrimental or disruptive to athletes training and performance. Onerepetition maximum (1RM) squat strength and countermovement (CMJ) were assessed at the end of the 2019 and 2020 preseason in a group of nineteen professional rugby league players to assess the change in strength and power between seasons. A correlation analysis was conducted to assess the CMJ variables with the strongest correlation to 1RM squat strength. Results showed these professional rugby league athletes exhibited large and significant mean increases of 7.39kg (±15.22) in 1RM squat strength, 0.10 kg·kg-1 (±0.17) in relative 1RM squat strength and 145.57W (±273.44) in CMJ peak power from 2019 to the 2020 season. CMJ average concentric power had a large and significant correlation with 1RM strength (r = 0.73 in 2019 and 0.71 in 2020). This was the largest correlation to 1RM squat strength of all the CMJ variables recorded. Significant and large increases in lower-body strength and average power were evident between professional rugby league seasons. CMJ may be able to be used to understand changes to 1RM squat strength throughout a professional rugby league season. However, this requires further research. ABSTRACT FROM AUTHOR