• Energy expenditure, metabolic power and high speed activity during linear and multi-directional running

      Oxendale, Chelsea; Highton, Jamie M.; Twist, Craig; University of Chester (Elsevier, 2017-03-21)
      Objectives: The purpose of the study was to compare measures of energy expenditure derived from indirect calorimetry and micro-technology, as well as high power and high speed activity during linear and multi-directional running. Design: Repeated measures Methods: Twelve university standard team sport players completed a linear and multi-directional running condition. Estimated energy expenditure, as well as time at high speed (> 14.4 km.h-1) and high power (> 20 W.kg-1) were quantified using a 10 Hz micro-technology device and compared with energy expenditure derived from indirect calorimetry. Results: Measured energy expenditure was higher during the multi-directional condition (9.0 ± 2.0 cf. 5.9 ± 1.4 kcal.min-1), whereas estimated energy expenditure was higher during the linear condition (8.7 ± 2.1 cf. 6.5 ± 1.5 kcal.min-1). Whilst measures of energy expenditure were strongly related (r > 0.89, p < 0.001), metabolic power underestimated energy expenditure by 52% (95% LoA: 20-93%) and 34% (95% LoA: 12-59%) during the multi-directional and linear condition, respectively. Time at high power was 41% (95% LoA: 4-92%) greater than time at high speed during the multi-directional condition, whereas time at high power was 5% (95% LoA: -17-9%) lower than time at high speed during the linear condition. Conclusions: Estimated energy expenditure and time at high metabolic power can reflect changes in internal load. However, micro-technology cannot be used to determine the energy cost of intermittent running.
    • 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.
    • The Unsuitability of Energy Expenditure Derived From Microtechnology for Assessing Internal Load in Collision-Based Activities

      Highton, Jamie M.; Mullen, Thomas; Norris, Jonathan; Oxendale, Chelsea; Twist, Craig (Human Kinetics, 2016-05-25)
      This aim of this study was to examine the validity of energy expenditure derived from micro-technology when measured during a repeated effort rugby protocol. Sixteen male rugby players completed a repeated effort protocol comprising 3 sets of 6 collisions during which movement activity and energy expenditure (EEGPS) were measured using micro-technology. In addition, energy expenditure was also estimated from open circuit spirometry (EEVO2). Whilst related (r = 0.63, 90%CI 0.08-0.89), there was a systematic underestimation of energy expenditure during the protocol (-5.94 ± 0.67 kcalmin-1) for EEGPS (7.2 ± 1.0 kcalmin-1) compared to EEVO2 (13.2 ± 2.3 kcalmin-1). High-speed running distance (r = 0.50, 95%CI -0.66-0.84) was related to EEVO2, while Player Load was not (r = 0.37, 95%CI -0.81-0.68). Whilst metabolic power might provide a different measure of external load than other typically used micro-technology metrics (e.g. high-speed running, Player Load), it underestimates energy expenditure during intermittent team sports that involve collisions.