The present research examined the neuromuscular, biochemical, endocrine and physiological responses of elite Rugby League players to competitive match-play. To achieve this aim, five experimental research studies were undertaken and are presented as chapters three, four, five, six and seven of the thesis. Each experimental study within the present thesis was designed to build upon the preceeding chapter to enhance our understanding of the demands of Rugby League match-play and develop the primary aim of the thesis. Muscular force and power have been determined to be
important characteristics of elite Rugby League players, therefore the rational for Experimental Study 1 was to establish the primary force and power measures associated with CMJ and SJ performance using a functional measure of SSC exercise that could be implemented with a large group of players in an efficient manner. The relative contribution of the primary force and power measures associated with CMJ and SJ performance, namely PF, PP and PRFD were established and identified as the most appropriate variables of VJ performance for future studies to identify neuromuscular fatigue and the time course of neuromuscular recovery post-match.
Following the establishment of PF, PP and PRFD as the primary contributors to VJ performance in Experimental Study 1, an analysis of playing position-specific movement patterns during NRL competition was undertaken to establish the demands of elite Rugby League match-play using GPS
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and accelerometer technology. Recent studies have examined the time-motion characteristics of semi- professional Rugby League match-play using video-based tracking methods, however no studies have examined the position specific movement and match-play specific physiological demands of NRL match-play using contemporary GPS / accelerometry. The rational for Experimental Study 2 therefore was to undertake the first multiple match position-specific analysis of elite NRL match-play in almost 10 yrs using GPS / accelerometer technology under 2009 match-play defensive and interchange rule structures.
Experimental Study 3 increased the scope of our understanding of the biochemical and endocrine responses of elite Rugby League players to competitive match-play. The rational for this novel study was to incorporate GPS / acceleromerty techniques utilised in experimental study two while
undertaking a simultaneous investigation of the pre- and post-match sTest, sCort, sT:C and plasma [CK] to quantify the demands of NRL match-play and examine the rate of recovery for a period of six days post-match. Further insight into the demands of elite Rugby League match-play was provided via an examination of pre- and post-match markers of neuromuscular fatigue in experiemental study four. Experimental Study 4 examined PF, PP and PRFD during CMJ and SJ that were determined to be the primary determinants of VJ performance in experimental study two to establish the change in SSC performance and the magnitude of change in these force-power variables to determine neuromuscular fatigue following elite Rugby League match-play. The PF, PP and PRFD measured during the CMJ and SJ were compared to the degree of change in plasma [CK] and endocrine measures to ascertain the correlation between dependent and independent variables associated with elite Rugby League match- play and the post-match recovery period. An additional rational for the Experimental Studies 3 and 4 was to determine whether plasma [CK], salivary endocrine and force-power measures during the CMJ and SJ could be used as objective markers of muscle damage, stress and neuromuscular fatigue experienced by elite Rugby League players pre, during and post-match.
One of the fundamental characteristics of elite Rugby League match-play that differentiates the sport from other football codes and contact sports is the degree of blunt force trauma and incidence of high velocity collisions during competition. The rational for Experimental Study 5 therefore was to further develop our knowledge regarding the demands of elite Rugby League match-play via examination of the relationship between pre- and post-match plasma [CK] and endocrine responses and the intensity, number and distribution of impacts associated with collisions during NRL competition. The collective results of Experimental Studies 2, 3, 4 and 5 may also be used to monitor individual player tolerance to training and competitive loads and should be considered when developing recovery and training plans over the course of an extended season of weekly elite Rugby League competition.
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The research undertaken in the present thesis aimed to comprehensively investigate the
neuromuscular, biochemical, endocrine and physiological responses of elite Rugby League players to competitive match-play. There are a number of novel aspects to each of the experimental studies presented as five individual chapters, including the determination of PF, PP and PRFD as the primary contributors to VJD during the CMJ, quantification of the position specific physiological demands of NRL match-play using GPS / accelerometer technology, examination of plasma [CK], sCort, sTest, sT:C and markers of neuromuscular fatigue pre- and post- elite Rugby League match-play and an examination of the biochemical and endocrine response associated with repeated blunt force trauma during match-play in the NRL. Independently and collectively, each of the five experimental studies presented in the present thesis represent a more robust investigation of NRL match-play than reported previously and contribute to the current understanding of the demands of elite Rugby League
competition.
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