Rugby Sevens Running Performance: Managing Fatigue During Tournament Play

Abstract

<p>The overall objective of this thesis was to examine performance, physiological and perceptual changes during repeated Rugby Sevens matches and to assess the efficacy of repeated cold water immersion (CWI) as a recovery strategy. The outcomes of this thesis improve the current understanding of fatigue development and provide evidence of the effects of CWI during a congested day of Rugby Sevens, with the potential to inform athletes’ preparation and tournament management. These outcomes were achieved through five original experimental chapters. This thesis includes a General Introduction, a Literature Review, five experimental Chapters and a General Discussion with concluding remarks that address the thesis aims.</p> <p>The aim of the Literature Review (Chapter 1) was to establish methodological guidelines for the design and implementation of Football simulation protocols. Within the Sport Sciences domain, researchers have developed protocols that aim to replicate the external and internal loads imposed by competitive events, to facilitate the study of performance or to assess recovery and nutritional strategies in a controlled environment. The Literature Review presents a critical appraisal of current Football simulation protocols, with particular interest in ecological validity and reliability, as well as the relevant limitations reported by previous researchers. The systematic search extended across all Football codes, due to the limited amount of protocols specific to Rugby Union. </p> <p>Chapter 2 describes the mean and peak demands of elite-level Rugby Sevens by incorporating a model based on the current knowledge of the energy costs associated with different running patterns, in order to provide a comprehensive measurement of running work rate. A secondary aim was to evaluate the agreement between velocity- and metabolic-based indices of work rate to identify fluctuations in running intensity. During the conception of the present thesis, the body of literature on Rugby Sevens was small and only a limited amount of studies focussed on the match demands of international Rugby Sevens. Moreover, the match analysis techniques previously employed overlooked the physiological load imposed by demanding movements such as acceleration and decelerations.</p> <p>Chapter 3 investigates the appropriateness of the specific Rugby Sevens Simulation Protocol (R7SP), a match simulation based on the findings of Chapter 2, as a valid and reliable experimental protocol for use in applied Rugby Sevens research. The impracticalities of manipulating individual’s preparatory and recovery routines during competitions, measuring players’ physiological responses during competitions, the high match-to-match variability in work rate and the lack of control over the experimental conditions during competitions, provide a strong rationale for the use of simulation match simulation within the thesis’ experimental design. Chapter 3 described the development process of the R7SP, according to the guidelines provided in the Literature Review. Variables representing the external and internal loads were measured during the R7SP and compared with the literature available. The reliability of the measured variables was then assessed by calculating the typical error of measurement and the smallest worthwhile changes.</p> <p>Chapter 4 investigated changes in sprint performance and assessed the effects of repeated cold water immersions (CWI) on physiological, perceptual and performance measurements during a congested day of simulated Rugby Sevens. Despite the established evidence of reductions in running work rate between halves of Rugby Sevens, previous research could not identify changes in mean or peak running intensity during repeated matches. Similarly, it is unclear if the early symptoms of fatigue observed during the second half (decreased work rate and increased physiological responses) are transient in nature or are worsened by playing repeated matches. Anecdotally, CWI are widely used in Rugby Sevens tournaments to improve recovery and players’ perception of wellbeing. In attempt to identify the presence of fatigue symptomatology and to observe the effects of CWI, Chapter 4 simulated a worst case scenario, characterised by a congested schedule of three intense matches of the Rugby Sevens protocol validated in Study Two.</p> <p>Chapter 5 investigated changes in isokinetic (IK) strength, jumping performance, flexibility and muscle damage during the simulated day of Rugby Sevens and assessed the efficacy of CWI to support muscle recovery. Previous research observed reductions in male players’ neuromuscular performance (jumping) between two successive tournament days and increased levels of markers of muscle damage following three repeated matches. Conversely, jumping performance did not change in female Rugby Sevens players during a single tournament day. In light of the lack of consensus of the acute (~3 h) effects of CWI on strength and neuromuscular performance, it is currently unclear whether this commonly used strategy is beneficial during a typical tournament schedule.</p> <p>Chapter 6 observed the effects of CWI on autonomic and inflammatory responses during the simulated day of Rugby Sevens. Autonomic balance is largely used to monitor athletes’ physiological stress, due to its prominent role in homeostatic regulation. Study Three identified how symptoms of fatigue and muscle soreness caused by repeated Rugby Sevens matches can be ameliorated through repeated administration of CWI. Study Four observed biochemical and functional evidence of muscle damage after a day of simulated Rugby Sevens, which were mitigated by repeated CWI. Among other responses arising from damaging events to muscle fibers, inflammation is heavily involved in the regenerative processes. Within the literature, several studies suggest a positive role of CWI to successfully attenuate inflammation, reduce muscle soreness and hasten parasympathetic reactivation following exercise. Therefore, measurements of autonomic imbalance and inflammation were conducted to help in the interpretation of the observed decrements in perceived wellbeing during a congested day of Rugby Sevens.</p> <p>Chapter 4, 5 and 6 present experimental data collected as part of a comprehensive original study. Due to the amount of variables analysed, data have been presented in three different chapters in attempt to focus on each different feature of fatigue and recovery in Rugby Sevens. Chapter 7 incorporates a summary of the experimental findings and offers practical applications based on the relationship on the variables monitored within the thesis.</p>