• 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.