The Hormonal Profile of Elite Super League Players During and After Competition
mesheuropmc: human activities
It has been suggested that steroid hormones, particularly testosterone and cortisol, may play an important role in skeletal muscle growth, repair and even motivation to train, which have obvious implications for elite rugby. However, the hormonal profile of elite Super League players during and after competition is currently poorly understood. To gain insight into hormonal physiology in this athletic population, eighteen professional Super League Rugby League players were recruited for this project to profile the diurnal variation in salivary testosterone and cortisol levels (at rest and across matches). All players were familiarised with the saliva collection techniques, and samples were collected over 4 separate fixtures during the 2012-13 season. Salivary testosterone and cortisol levels were monitored on the nearest rest day to the game at 3 key time points corresponding to game day, just after waking (09.30), pre-game (14.00) and post-game (17.30). In order to examine the effects of elite rugby league match play, a second set of samples were collected at the same time points on game day during 4 fixtures and then analysed using a competitive ELISA.Initial findings confirmed excellent reliability for the repeated assessment of salivary testosterone and cortisol levels in the study population (CV’s = 1.1 – 3.3%). Diurnal variation in salivary testosterone and cortisol was also identified at rest, with both hormones decreasing across the day at each time point cortisol 09.30 (0.275 ± 0.050μG/DL), 14.00 (0.087 ± 0.014μG/DL) and 17.30 (0.079 ± 0.027μG/DL) and testosterone 09.30 (141.9 ± 18.6pg.dl), 14.00 (110.3± 17.4pg.dl) and 17.30 (101.3± 9.5pg.dl), except the testosterone measurement between 14.00 and 17.30 (P > 0.05). As a pooled dataset, salivary testosterone was elevated on game day, compared to resting data, 09.30 (162.4 ± 18.0pg.dl), 14.00 (134.5± 13.0pg.dl) and 17.30 (169.1± 12.8pg.dl). There was also a significant decrease between the game-day salivary testosterone from AM to pre (-16%), before increasing from pre to post game (28%). Salivary cortisol levels increased to 09.30 (0.337 ± 0.105μG/DL), 14.00 (0.362 ± 0.042μG/DL) and 17.30 (1.101 ± 0.219μG/DL) compared to resting data. There was also a significant game-day increase in cortisol between AM and pre game (249%) and from pre to post game (219%). Individual match analysis further revealed some different hormonal patterns, possibly due to the nature of the individual games played and the opposition.In summary, this thesis has provided novel findings on professional rugby league players with circadian variation in salivary testosterone and cortisol levels identified on a resting day (decreasing from morning to afternoon), as well as match-day changes (increases) that can be attributed to the playing of professional rugby league matches. As a further benefit, this project has validated the utility of saliva-based measurements within the elite sporting environment. Research has suggested that steroid hormones such as testosterone can influence athlete motivation to perform; therefore, future research could investigate factors that affect game-to-game variations in these hormones and assess if such factors may affect game-day performance.
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