Influence of playing standard and physical fitness on activity profiles and post-match fatigue during intensified junior rugby league competition

Background: The aim of this study was to determine whether the fatigue responses to the same intensified rugby league competition differed depending on playing standard and physical fitness. Methods: Players from a high-standard (n = 15) and a low-standard (n = 16) junior rugby league team had lower body neuromuscular fatigue, perceptual wellbeing, and blood creatine kinase (CK) assessed over an intensified competition. Global positioning system units measured match activity profiles and rating of perceived exertion-assessed internal loads. Players were divided into high- and low-fitness groups across the two standards based on Yo-Yo intermittent recovery test performance. Results: Playing intensity increased with playing standard and fitness levels (high-standard = 92 ± 6 m·min−1 vs. 88 ± 6 m·min−1; low-standard = 88 ± 2 m·min−1 vs. 83 ± 6 m·min−1). Despite greater internal and external loads, high-fitness players showed smaller reductions in lower body power (high-standard effect size [ES] = −0.74; low-standard ES = −0.41). High-standard players had smaller increases in blood CK (77% ± 94% vs. 113% ± 81%; ES = −0.41), primarily due to very small increases in the high-fitness group (50% ± 45%). Conclusions: Increased fitness leads to greater internal and external workloads during intensified competition, smaller increases in blood CK, and less neuromuscular fatigue. Maximising player fitness should be a primary goal of coaches in order to increase match workloads and reduce post-match fatigue during intensified competition.