• Influence of contextual factors, technical performance and movement demands on the subjective task load associated with professional rugby league match-play

      Mullen, Thomas; Twist, Craig; Daniels, Matthew; Dobbin, Nick; Highton, Jamie; University of Chester
      Purpose: The aim of the study was to identify the association between several contextual match factors, technical performance and external movement demands on the subjective task load of elite rugby league players. Methods: Individual subjective task load, quantified using the National Aeronautics and Space Administration Task Load Index (NASA-TLX), was collected from 29 professional rugby league players from one club competing in the European Super League throughout the 2017 season. The sample consisted of 26 matches, culminating in 441 individual data points. Linear mixed-modelling was adopted to analyze the data for relationships and revealed that various combinations of contextual factors, technical performance and movement demands were associated with subjective task load. Results: Greater number of tackles (effect size correlation ± 90% CI; η2= 0.18 ±0.11), errors (η2= 0.15 ±0.08) decelerations (η2= 0.12 ±0.08), increased sprint distance (η2= 0.13 ±0.08), losing matches (η2= 0.36 ±0.08) and increased perception of effort (η2= 0.27 ±0.08) led to most likely – very likely increases in subjective total task load. The independent variables included in the final model for subjective mental demand (match outcome, time played and number of accelerations) were unclear, excluding a likely small correlation with the number of technical errors (η2= 0.10 ±0.08). Conclusions: These data provide a greater understanding of the subjective task load and their association with several contextual factors, technical performance and external movement demands during rugby league competition. Practitioners could use this detailed quantification of internal loads to inform the prescription of recovery sessions and current training practices.
    • Influence of Playing Standard on Upper- and Lower-Body Strength, Power, and Velocity Characteristics of Elite Rugby League Players

      Fernandes, John; Daniels, Matthew; Myler, Liam; Twist, Craig (MDPI, 2019-04-17)
      Background: To compare load–velocity and load–power relationships among first grade (n = 26, age 22.9 ± 4.3 years), academy (n = 23, age 17.1 ± 1.0 years), and scholarship (n = 16, age 15.4 ± 0.5 years) Super League rugby league players. Methods: Participants completed assessments of maximal upper- and lower-body strength (1RM) and peak velocity and power at 20, 40, 60, and 80 kg during bench press and squat exercises, in a randomised order. Results: Bench press and squat 1RM were highest for first grade players compared with other standards (effect size (ES) = −0.43 to −3.18). Peak velocities during bench and squat were greater in the higher playing standards (ES = −0.39 to −3.72 range), except for the squat at 20 and 40 kg. Peak power was higher in the better playing standards for all loads and exercises. For all three groups, velocity was correlated to optimal bench press power (r = 0.514 to 0.766), but only 1RM was related to optimal power (r = 0.635) in the scholarship players. Only squat 1RM in the academy was related to optimal squat power (r = 0.505). Conclusions: Peak velocity and power are key physical qualities to be developed that enable progression from junior elite rugby league to first grade level. Resistance training should emphasise both maximal strength and velocity components, in order to optimise upper- and lower-body power in professional rugby league players.
    • The influence of preseason training phase and training load on body composition and its relationship with physical qualities in professional junior rugby league players

      Dobbin, Nick; Gardner, Adrian; Daniels, Matthew; Twist, Craig; University of Chester (Taylor & Francis, 2018-05-08)
      This study investigated changes in body composition in relation to training load determined using RPE and duration (sRPE), and its relationship with physical qualities over a preseason period. Sixteen professional academy players (age = 17.2 ± 0.7 years; stature = 179.9 ± 4.9 cm; body mass = 88.5 ± 10.1 kg) participated in the study. Body composition was assessed before and after each training phase and physical qualities assessed at the start and end of preseason. Across the whole preseason period, skinfold thickness, body fat percentage and fat mass were most likely lower (ES = -0.73 to -1.00), and fat free mass and lean mass were likely to most likely higher (ES = 0.31 to 0.40). Results indicated that the magnitude of change appeared phase-dependent (ES = -0.05 to -0.85) and demonstrated large individual variability. Changes in physical qualities ranged from unclear to most likely (ES = -0.50 to 0.64). Small to moderate correlations were observed between changes in body composition, and TL with changes in physical qualities. This study suggests training phase and TL can influence a player’s body composition; that large inter-participant variability exists; and that body composition and TL are related to the change in physical qualities.
    • Player responses to match and training demands during an intensified fixture schedule in professional rugby league: A case study.

      Twist, Craig; Highton, Jamie M.; Daniels, Matthew; Mill, Nathan; Close, Graeme L.; University of Chester; St Helens RFC; Liverpool John Moores (Human Kinetics, 2017-09-30)
      Player loads and fatigue responses are reported in 15 professional rugby league players (24.3 ± 3.8 y) during a period of intensified fixtures. Repeated measures of internal and external loads, perceived well-being, and jump flight time were recorded across 22 d, comprising 9 training sessions and matches on days 5, 12, 15, and 21 (player exposure: 3.6 ± 0.6 matches). Mean training loads (session rating of perceived exertion × duration) between matches were 1177, 1083, 103, and 650 AU. Relative distance in match 1 (82 m/min) and match 4 (79 m/min) was very likely lower in match 2 (76 m/min) and likely higher in match 3 (86 m/min). High-intensity running (≥5.5 m/s) was likely to very likely lower than match 1 (5 m/min) in matches 2–4 (2, 4, and 3 m/min, respectively). Low-intensity activity was likely to very likely lower than match 1 (78 m/min) in match 2 (74 m/min) and match 4 (73 m/min) but likely higher in match 3 (81 m/min). Accumulated accelerometer loads for matches 1–4 were 384, 473, 373, and 391 AU, respectively. Perceived well-being returned to baseline values (~21 AU) before all matches but was very likely to most likely lower the day after each match (~17 AU). Prematch jump flight times were likely to most likely lower across the period, with mean values of 0.66, 0.65, 0.62, and 0.64 s before matches 1–4, respectively. Across a 22-d cycle with fixture congestion, professional rugby league players experience cumulative neuromuscular fatigue and impaired match running performance.
    • Pre-season training responses and their associations with training load in elite rugby league players

      Daniels, Matthew; Highton, Jamie M.; Twist, Craig; St Helens RFC; University of Chester (Taylor and Francis, 2019-05-07)
      Strength, power and endurance characteristics and their association with training load during a 7-week preseason training phase was assessed in elite rugby league players. Twenty-two players (age 23.3 ± 4.4 years) performed bench throw, one repetition maximum (1RM) bench press, squat jumps, three repetition maximum (3RM) squats, prone pull ups and prone Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) before and after the 7-week preseason period. Training was classified into Gym, Field and Wrestle, with training load of each monitored using session rating of perceived exertion (sRPE) multiplied by training duration (sRPE-TL). There were most likely improvements in 3RM back squat, prone pull-ups and Yo-Yo IR1 and likely improvements in bench press, bench throw and squat jump after the 7-week training programme (ES = 0.3 to 1.2). Accumulated sRPE-TL for Gym, Field and Wrestle sessions was 9176 ± 1187, 10906 ± 2162, and 1072 ± 315 AU, respectively. Relationships between mean weekly sRPE-TL and changes in physical qualities was trivial to large (r = -0.67 to 0.34). This study suggests sRPE-TL is unsuitable to detect dose-response relationships between training load and the changes in physical qualities of elite rugby league players during the pre-season period.
    • The Relationship Between Match-Play Characteristics of Elite Rugby League and Indirect Markers of Muscle Damage

      Oxendale, Chelsea; Twist, Craig; Daniels, Matthew; Highton, Jamie M.; University of Chester; St Helens Rugby League Club (Human Kinetics, 2016)
      Purpose: Whilst exercise-induced muscle damage (EIMD) after a rugby league match has been well documented, the specific match actions that contribute to EIMD are unclear. Accordingly, the purpose of this study was to examine the relationship between the physical demands of elite rugby league matches and subsequent EIMD. Methods: Twenty-eight performances were captured using 10 Hz global positioning systems. Upper and lower body neuromuscular fatigue, creatine kinase (CK) and perceived muscle soreness were assessed 24 h before and at 12, 36 and 60 h after a competitive match. Results: High-intensity running was moderately higher in backs (6.6 ± 2.6 m•min-1) compared to forwards (5.1 ± 1.6 m•min-1), whereas total collisions were moderately lower (31.1 ± 13.1 cf. 54.1 ± 37.0). Duration (r = 0.9, CI: 0.77 to 0.96), total distance covered (r = 0.86, CI: 0.7 to 0.95) and distance covered over 18 km•h-1 (r = 0.76, CI: 0.51 to 0.91) were associated with increased CK concentration post-match. Total collisions and repeated high-intensity efforts (RHIE) were associated with large decrements in upper body neuromuscular performance (r = -0.48, CI: -0.74 to 0.02 and r = -0.49, CI: -0.77 to 0.05, respectively), muscle soreness (r = -0.68, CI: -0.87 to -0.1 and r = -0.66, CI: -0.89 to 0.21, respectively), and CK concentration (r = 0.67, CI: 0.42 to 0.85 and r = 0.73, CI: 0.51 to 0.87, respectively). Conclusion: Match duration, high-intensity running and collisions were associated with variations in EIMD markers, suggesting recovery is dependent on individual match demands.