Daily Changes of Resting Metabolic Rate in Elite Rugby Union Players

Introduction Preparation for competitive contact sport has been extensively researched. There are, however, limited data to guide players as to how the demands of their sport affect the energy requirements of recovery. We aimed to provide novel data on changes in resting metabolic rate (RMR) in contact sport athletes and relate these to the physical demands of training and competition. Methods Twenty-two elite professional Premiership Rugby Union players were recruited to the study. Indirect calorimetry (Vyntus CPX canopy; CareFusion) was used to measure RMR each morning of the competitive game week, in a fasted, rested state. External loads for training and game play were monitored and recorded using global positioning systems (Catapult Innovations, Australia), whereas internal loads were tracked using rate of perceived exertion scales. Collisions were reviewed and recorded by expert video analysts for contacts in general play (breakdown and tackle area) or the set piece (scrum or maul). Results There were significant (P = 0.005) mean increases in RMR of approximately 231 kcal the morning after (game day [GD] + 1) and 3 d after the game (GD + 3), compared with the day before the game (GD - 1). The players were exposed to internal and external loads during the training week comparable to that of a match day; however, despite the equivocal loads between training and game play, there were no significant increases in RMR after training. Conclusion The collisions experienced in rugby match play are likely to be responsible for the significant increases in RMR at GD + 1 and GD + 3. Consequently, the measurement of RMR via indirect calorimetry may provide a novel noninvasive measure of the effects of collisions. This study provides a novel insight to the energy requirements of recovering from contact sport.