title: Physiological responses to an intensified period of rugby league competition.
abstract: This study investigated the physiological responses to an intensified period of rugby league competition and the subsequent impact on match performance. The participants were 7 rugby league players competing in an international student tournament. The tournament involved three 80-minute games over a 5-day period, with 48 hours between each match. Baseline measures of upper and lower body neuromuscular functions via a plyometric press-up (PP) and countermovement jump (CMJ), respectively (peak power and peak force were measured), blood creatine kinase (CK), and perceptions of well-being were assessed with a questionnaire. These measures were repeated every morning of the competition; neuromuscular fatigue and CK were additionally assessed within 2 hours after the cessation of each game. During each match, player movements were recorded via global positioning system units. There were meaningful reductions in upper (effect size [ES] = -0.55) and lower body (ES = -0.73) neuromuscular functions, and perceptual well-being (ES = -1.56) and increases in blood CK (ES = 2.32) after game 1. These changes increased in magnitude as the competition progressed. There were large reductions in the relative distance covered in high-speed running (ES = -1.49) and maximal accelerations (ES = -0.85) during game 3. Additionally, moderate reductions in the percentage of successful tackles completed were observed during game 3 (ES = -0.59). Collectively, these results demonstrate that during an intensified period of rugby league competition, characterized by only 48 hours between matches, fatigue will accumulate. This cumulative fatigue may compromise high-intensity match activities such as high-speed running, accelerations, and tackling. Furthermore, CMJs and PPs appear to be sensitive measures for monitoring neuromuscular function in rugby league players.
authors.affiliation: School of Exercise Science, Australian Catholic University, Brisbane, Australia. r.johnston88@hotmail.co.uk
authors.forename: Rich D
authors.initials: RD
authors.lastname: Johnston
authors.forename: Neil V
authors.initials: NV
authors.lastname: Gibson
authors.forename: Craig
authors.initials: C
authors.lastname: Twist
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Gabbett
authors.forename: Sophie A
authors.initials: SA
authors.lastname: MacNay
authors.forename: Niall G
authors.initials: NG
authors.lastname: MacFarlane
mesh_terms: D054874:Athletic Performance / Q000502:physiology; D003402:Creatine Kinase / Q000097:blood; D005221:Fatigue / Q000503:physiopathology*; D005538:Football / Q000502:physiology*; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D034941:Upper Extremity / Q000502:physiology; D055815:Young Adult
chemical_list: D003402:Creatine Kinase