This thesis presents the use of a new sigmoid activation function in backpropagation artificial neural networks (ANNs). ANNs using conventional activation functions may generalize poorly when trained on a set which includes quirky, mislabeled, unbalanced, or otherwise complicated data. This new activation function is an attempt to improve generalization and reduce overtraining on mislabeled or irrelevant data by restricting training when inputs to the hidden neurons are sufficiently small. This activation function includes a flattened, low-training region which grows or shrinks during back-propagation to ensure a desired proportion of inputs inside the low-training region. With a desired low-training proportion of 0, this activation function reduces to a standard sigmoidal curve. A network with the new activation function implemented in the hidden layer is trained on benchmark data sets and compared with the standard activation function in an attempt to improve area under the curve for the receiver operating characteristic in biological and other classification tasks.

Background: The number of women participating in sports has increased dramatically, though research in sports are often performed on men. Physical exercise is known to increase physical performance and improve well-being. Although exercise has beneficial health effects for most of the women, it is known that strenuous exercise may also have negative health consequences. Common are menstrual dysfunctions and the medical effects of a long-standing amenorrhea are serious. Moreover, strenuous exercise without adequate recovery may lead to overreaching (OR) /overtraining syndrome (OTS). An improved muscle strength are of great importance in many sports, hence an increased understanding on how to generate optimal strength training programs in women without negative side effects are essential. The aims of this thesis were to investigate the effects on strength and power of high frequency periodised leg resistance training to evaluate a training regime and moreover to investigate if the training was well accepted and without potential exercise-related negative consequences. Moreover, to provide normative data on oxytocin and cortisol to elucidate if these hormones could be one diagnostic marker in combination with others to monitor and diagnose female athletes that may be at risk to develop OR/OTS. Methods: Fifty-nine women, participated in the four month intervention study. Two groups performed high frequency leg resistance training for two weeks of each menstrual/oral contraceptive (OC) cycle. The remaining part of the cycle they performed the leg training once a week. Group 1, trained with high frequency (5 times·w-1) during the first two weeks of each cycle, and group 2, during the last two weeks of each cycle. A control group performed regular (3 times·w-1) leg resistance training. Another 33 women participated in the observational study. The OC users and non-users, were followed over a nine-month period with monthly blood sampling of oxytocin and cortisol, and the Profile of Mood State (POMS) as a subjective measure of OR/OTS. Results: The women who performed high frequency leg resistance training, 5 times·w-1, during the first two weeks of each cycle showed significant increase in jump height, peak torque values in hamstrings, increased lean body mass of the legs, and their experiences of the training were positive. These results were not found when the periodised training was performed during the last two weeks of each cycle. In the control group an increase in jump height, and peak torque (left hamstring) was observed. There were no evident differences in the training effects between women with or without OC use. Moreover, no exercise-related negative consequences were detected in any of the three groups. The women in the observational study showed seasonal variations in oxytocin and cortisol, with different pattern in OC users to non-users. No convincing relationships to POMS were found.  Conclusions: The high frequency periodised leg resistance training during the first two weeks of the cycle is more beneficial to optimize resistance training, than the last two weeks. The high frequency periodised leg resistance training was not associated with exercise-related negative consequences and was well accepted when performed during the first two weeks of each cycle. Due to seasonality and impact of OC use, oxytocin and cortisol are not suggested to be optimal, diagnostic markers alone/in combination with others, to detect OR/OTS in physically active women.

Cette étude vise à estimer l’apport en glutamine (Gln) alimentaire chez des athlètes soumis à un protocole de supplémentation en glutamine ainsi qu’à clarifier les informations diffusées au grand public en ce qui concerne les sources alimentaires de glutamine. Des études cliniques ont démontré que la supplémentation en glutamine pouvait réduire la morbidité et la mortalité chez des sujets en phase critique (grands brulés, chirurgie…). Le mécanisme en cause semble impliquer le système immunitaire. Cependant, les études chez les sportifs, dont le système immunitaire a de fortes chances d’être affaibli lors de périodes d’entraînement prolongées impliquant des efforts longs et intenses, n’ont pas été concluantes. Or, ces études négligent systématiquement l’apport alimentaire en glutamine, si bien qu’il est probable que les résultats contradictoires observés puissent en partie être expliqués par les choix alimentaires des sujets. Puisque la méthode conventionnelle de dosage des acides aminés dans les protéines alimentaires transforme la glutamine en glutamate, les tables de composition des aliments présentent la glutamine et le glutamate ensemble sous la dénomination « glutamate » ou « Glu », ce qui a comme conséquence de créer de l’ambiguïté. La dénomination « Glx » devrait être utilisée. Partant de la probabilité qu’un apport en Glx élevé soit un bon indicateur de l’apport en glutamine, nous avons créé un calculateur de Glx et avons évalué l’alimentation de 12 athlètes faisant partie d’une étude de supplémentation en glutamine. Nous avons alors constaté que l’apport en Glx était directement proportionnel à l’apport en protéines, avec 20,64 % ± 1,13 % de l’apport protéique sous forme de Glx. Grâce à quelques données sur la séquence primaire des acides aminés, nous avons pu constater que le rapport Gln/Glx pouvait être très variable d’un type de protéine à l’autre. Alors que le ratio molaire Gln/Glx est de ~95 % pour les α et β-gliadines, il n’est que de ~43 % pour la caséine, de ~36 % pour la β-lactoglobuline, de ~31 % pour l’ovalbumine et de ~28 % pour l’actine. Il est donc possible que certaines protéines puissent présenter des avantages par rapport à d’autres, à quantité égale de Glx. / The purpose of this study is to estimate the dietary glutamine (Gln) intake of subjects undertaking a glutamine supplementation protocol and to clarify the information about the glutamine content of food products. Clinical studies have demonstrated that glutamine supplementation can reduce mortality and morbidity associated with critical illness and that the mechanism underneath may imply the immune system. Studies undertaken on elite athletes, who may experience a drop in immune defence subsequent to long and strenuous training, have not been conclusive at this time. Yet, these studies systematically do not take glutamine intake from food into consideration in such a way that the conflicting results observed could have something to do with the food choices of the subjects. Since the conventional method used for the analysis of the amino acids content in food converts glutamine into glutamate, the food databases present glutamine and glutamate under the denomination “glutamate” or “Glu”. However, the term “Glx” should be used. Based on the probability that a high Glx intake could be a good indicator of glutamine intake, we have created a Glx calculator and have used it to analyse the food diaries of 12 athletes who participated in a study on glutamine supplementation. We observed that Glx intake was directly proportional to protein intake with 20,64 % ± 1,13 % of protein intake being Glx. Using data from the primary structure of amino acids, we observed that different types of protein showed a wide range of Gln/Glx ratios. While α and β-gliadins present a molar ratio of Gln/Glx of ~95 %, this ratio drops to 43 % for casein, 36 % for β-lactoglobulin, 31 % for ovalbumin and 28 % for actins. It is thus possible that certain types of protein can present advantages with regard to others, Glx remaining constant.

Ce travail a été réalisé en cotutelle. / Le syndrome du surentraînement survient généralement suite à un haut degré de stress, associé ou non, au stress de l’entraînement et à un manque certain de repos et de récupération. La manifestation d’un tel syndrome peut être lourd de conséquences tant sur le plan médical que sur le plan social et économique. Il est donc important à ce jour, de valider des outils de prévention pertinents. Plusieurs théories ont donc tenté de déterminer l’avènement du surentraînement et d’en extraire des outils de prévention valides. Néanmoins, nos connaissances à ce sujet restent encore parcellaires. Malgré tout, deux axes de recherches nous permettraient d’accéder à des outils non-invasifs et accessibles. Les mesures de la régulation autonome du myocarde semblent être, depuis les résultats très encourageants de Bosquet et al (2008), des outils très prometteurs. De même, l’utilisation des performances cognitives pourraient être des outils très intéressants dans la prévention du surentraînement (Nederhof et al. 2006, Dupuy et al. 2010). Dans une perspective holistique, le modèle de Thayer et al (2009), nous permettrait d’intégrer l’utilisation combinée des performances cognitives aux indices de la variabilité de la fréquence cardiaque. Dans une démarche de validation il est également nécessaire de connaitre la sensibilité de ces techniques. Or à ce jour la reproductibilité des indices de la réactivation parasympathique ; technique relativement récente, ne sont pas connues. De même, il est important de faire la distinction entre la fatigue aiguë induite par une séance d’entraînement et une fatigue plus chronique. Si les relations entre fatigue aiguë et régulation autonome du myocarde sont bien connues, les relations avec la cognition, sont relativement moins claires. Les deux premières études de cette thèse, vont donc s’intéresser à connaitre la reproductibilité de indices de la réactivation parasympathique et les effets de la fatigue aiguë induite par un exercice sur la cognition associée au contrôle autonome du cœur. Les résultats nous montrent que les indices de la réactivation parasympathique sont moyennement reproductibles, nécessitant une attention toute particulière sur la standardisation de leurs mesures. Par ailleurs, bien que la fatigue induite par l’exercice, produise des désordres d’ordre physiologique, les performances cognitives semblent relativement stables. Apres avoir vérifié ces points d’ordre technologique et méthodologique, il était intéressant de vérifier l’effet d’une surcharge d’entraînement sur les outils retenus, afin d’apprécier leur sensibilité aux effets d’une fatigue chronique. Les résultats nous montrent à la fois l’intérêt d’utiliser les mesures de la variabilité de la fréquence cardiaque ainsi que les mesures de la réactivation parasympathique. Ces deux mesures semblent sensibles aux variations de la charge d’entraînement ainsi qu’à l’état de fatigue des sportifs. Tout aussi intéressant, les performances cognitives semblent également nous permettre de prévenir un état d’intolérance à l’entraînement. Ce travail de thèse trouve toute sa légitimité car il s’inscrit dans une logique d’amélioration de la santé et de prévention du dépassement voire du surentraînement chez le sportif. Les résultats issus de ce travail de thèse, nous permettent d’apporter de nouveaux outils de prévention ainsi que des recommandations quant à leur utilisation. / Overtraining syndrome usually occurs due to a high degree of stress, associated or not, the stress of training and a certain lack of rest and recovery. The demonstration of such a syndrome can have serious consequences both medically and socially and economically.It is therefore important to date to validate relevant prevention tools. Several theories have attempted to determine the advent of overtraining and extract valid prevention tools.Nevertheless, our knowledge on this subject are still patchy. Nevertheless, two lines of research would allow us to access non-invasive tools and accessible. Measures of autonomic regulation of the myocardium seem to be, from the very encouraging results of Grove et al (2008), tools very promising. Similarly, the use of cognitive performance could be very interesting tools in the prevention of overtraining (Nederhof et al. 2006, Dupuy et al. 2010). From a holistic perspective, the model of Thayer et al (2009), we would integrate the combined use of cognitive performance indices of heart rate variability. In a process of validation is also necessary to know the sensitivity of these techniques. Yet to date the reliability of the indices of parasympathetic reactivation; relatively new technique, are not known. Similarly, it is important to distinguish between acute fatigue induced by a workout and more chronic fatigue. If the relationship between acute fatigue and autonomic regulation of the myocardium are well known, the relationship with cognition, are relatively less clear. The first two studies in this thesis are therefore interested to know the reproducibility of indices of parasympathetic reactivation and effects of acute fatigue induced by exercise on cognition associated with the autonomous control of the heart. The results show that the indices of parasympathetic reactivation are moderately reproducible, requiring special attention on the standardization of measurements. Moreover, although fatigue induced by exercise, produce physiological disorders, cognitive performance appear relatively stable. After checking these points technological and methodological, it was interesting to test the effect of overload training on the tools used in order to assess their sensitivity to the effects of chronic fatigue. The results show both the value of using measures of heart rate variability and measures of parasympathetic reactivation. These two measures appear sensitive to changes in training load and to the fatigue of athletes. Equally interesting, cognitive performance also appear to us to prevent a state of intolerance in training. This thesis finds its legitimacy because it is a logical improvement of health and prevention of overtraining or even exceeded in athletes. The results of this thesis, we can provide new tools for prevention and recommendations for their use.

Cette étude vise à estimer l’apport en glutamine (Gln) alimentaire chez des athlètes soumis à un protocole de supplémentation en glutamine ainsi qu’à clarifier les informations diffusées au grand public en ce qui concerne les sources alimentaires de glutamine. Des études cliniques ont démontré que la supplémentation en glutamine pouvait réduire la morbidité et la mortalité chez des sujets en phase critique (grands brulés, chirurgie…). Le mécanisme en cause semble impliquer le système immunitaire. Cependant, les études chez les sportifs, dont le système immunitaire a de fortes chances d’être affaibli lors de périodes d’entraînement prolongées impliquant des efforts longs et intenses, n’ont pas été concluantes. Or, ces études négligent systématiquement l’apport alimentaire en glutamine, si bien qu’il est probable que les résultats contradictoires observés puissent en partie être expliqués par les choix alimentaires des sujets. Puisque la méthode conventionnelle de dosage des acides aminés dans les protéines alimentaires transforme la glutamine en glutamate, les tables de composition des aliments présentent la glutamine et le glutamate ensemble sous la dénomination « glutamate » ou « Glu », ce qui a comme conséquence de créer de l’ambiguïté. La dénomination « Glx » devrait être utilisée. Partant de la probabilité qu’un apport en Glx élevé soit un bon indicateur de l’apport en glutamine, nous avons créé un calculateur de Glx et avons évalué l’alimentation de 12 athlètes faisant partie d’une étude de supplémentation en glutamine. Nous avons alors constaté que l’apport en Glx était directement proportionnel à l’apport en protéines, avec 20,64 % ± 1,13 % de l’apport protéique sous forme de Glx. Grâce à quelques données sur la séquence primaire des acides aminés, nous avons pu constater que le rapport Gln/Glx pouvait être très variable d’un type de protéine à l’autre. Alors que le ratio molaire Gln/Glx est de ~95 % pour les α et β-gliadines, il n’est que de ~43 % pour la caséine, de ~36 % pour la β-lactoglobuline, de ~31 % pour l’ovalbumine et de ~28 % pour l’actine. Il est donc possible que certaines protéines puissent présenter des avantages par rapport à d’autres, à quantité égale de Glx. / The purpose of this study is to estimate the dietary glutamine (Gln) intake of subjects undertaking a glutamine supplementation protocol and to clarify the information about the glutamine content of food products. Clinical studies have demonstrated that glutamine supplementation can reduce mortality and morbidity associated with critical illness and that the mechanism underneath may imply the immune system. Studies undertaken on elite athletes, who may experience a drop in immune defence subsequent to long and strenuous training, have not been conclusive at this time. Yet, these studies systematically do not take glutamine intake from food into consideration in such a way that the conflicting results observed could have something to do with the food choices of the subjects. Since the conventional method used for the analysis of the amino acids content in food converts glutamine into glutamate, the food databases present glutamine and glutamate under the denomination “glutamate” or “Glu”. However, the term “Glx” should be used. Based on the probability that a high Glx intake could be a good indicator of glutamine intake, we have created a Glx calculator and have used it to analyse the food diaries of 12 athletes who participated in a study on glutamine supplementation. We observed that Glx intake was directly proportional to protein intake with 20,64 % ± 1,13 % of protein intake being Glx. Using data from the primary structure of amino acids, we observed that different types of protein showed a wide range of Gln/Glx ratios. While α and β-gliadins present a molar ratio of Gln/Glx of ~95 %, this ratio drops to 43 % for casein, 36 % for β-lactoglobulin, 31 % for ovalbumin and 28 % for actins. It is thus possible that certain types of protein can present advantages with regard to others, Glx remaining constant.

Le syndrome du surentraînement survient généralement suite à un haut degré de stress, associé ou non, au stress de l’entraînement et à un manque certain de repos et de récupération. La manifestation d’un tel syndrome peut être lourd de conséquences tant sur le plan médical que sur le plan social et économique. Il est donc important à ce jour, de valider des outils de prévention pertinents. Plusieurs théories ont donc tenté de déterminer l’avènement du surentraînement et d’en extraire des outils de prévention valides. Néanmoins, nos connaissances à ce sujet restent encore parcellaires. Malgré tout, deux axes de recherches nous permettraient d’accéder à des outils non-invasifs et accessibles. Les mesures de la régulation autonome du myocarde semblent être, depuis les résultats très encourageants de Bosquet et al (2008), des outils très prometteurs. De même, l’utilisation des performances cognitives pourraient être des outils très intéressants dans la prévention du surentraînement (Nederhof et al. 2006, Dupuy et al. 2010). Dans une perspective holistique, le modèle de Thayer et al (2009), nous permettrait d’intégrer l’utilisation combinée des performances cognitives aux indices de la variabilité de la fréquence cardiaque. Dans une démarche de validation il est également nécessaire de connaitre la sensibilité de ces techniques. Or à ce jour la reproductibilité des indices de la réactivation parasympathique ; technique relativement récente, ne sont pas connues. De même, il est important de faire la distinction entre la fatigue aiguë induite par une séance d’entraînement et une fatigue plus chronique. Si les relations entre fatigue aiguë et régulation autonome du myocarde sont bien connues, les relations avec la cognition, sont relativement moins claires. Les deux premières études de cette thèse, vont donc s’intéresser à connaitre la reproductibilité de indices de la réactivation parasympathique et les effets de la fatigue aiguë induite par un exercice sur la cognition associée au contrôle autonome du cœur. Les résultats nous montrent que les indices de la réactivation parasympathique sont moyennement reproductibles, nécessitant une attention toute particulière sur la standardisation de leurs mesures. Par ailleurs, bien que la fatigue induite par l’exercice, produise des désordres d’ordre physiologique, les performances cognitives semblent relativement stables. Apres avoir vérifié ces points d’ordre technologique et méthodologique, il était intéressant de vérifier l’effet d’une surcharge d’entraînement sur les outils retenus, afin d’apprécier leur sensibilité aux effets d’une fatigue chronique. Les résultats nous montrent à la fois l’intérêt d’utiliser les mesures de la variabilité de la fréquence cardiaque ainsi que les mesures de la réactivation parasympathique. Ces deux mesures semblent sensibles aux variations de la charge d’entraînement ainsi qu’à l’état de fatigue des sportifs. Tout aussi intéressant, les performances cognitives semblent également nous permettre de prévenir un état d’intolérance à l’entraînement. Ce travail de thèse trouve toute sa légitimité car il s’inscrit dans une logique d’amélioration de la santé et de prévention du dépassement voire du surentraînement chez le sportif. Les résultats issus de ce travail de thèse, nous permettent d’apporter de nouveaux outils de prévention ainsi que des recommandations quant à leur utilisation. / Overtraining syndrome usually occurs due to a high degree of stress, associated or not, the stress of training and a certain lack of rest and recovery. The demonstration of such a syndrome can have serious consequences both medically and socially and economically.It is therefore important to date to validate relevant prevention tools. Several theories have attempted to determine the advent of overtraining and extract valid prevention tools.Nevertheless, our knowledge on this subject are still patchy. Nevertheless, two lines of research would allow us to access non-invasive tools and accessible. Measures of autonomic regulation of the myocardium seem to be, from the very encouraging results of Grove et al (2008), tools very promising. Similarly, the use of cognitive performance could be very interesting tools in the prevention of overtraining (Nederhof et al. 2006, Dupuy et al. 2010). From a holistic perspective, the model of Thayer et al (2009), we would integrate the combined use of cognitive performance indices of heart rate variability. In a process of validation is also necessary to know the sensitivity of these techniques. Yet to date the reliability of the indices of parasympathetic reactivation; relatively new technique, are not known. Similarly, it is important to distinguish between acute fatigue induced by a workout and more chronic fatigue. If the relationship between acute fatigue and autonomic regulation of the myocardium are well known, the relationship with cognition, are relatively less clear. The first two studies in this thesis are therefore interested to know the reproducibility of indices of parasympathetic reactivation and effects of acute fatigue induced by exercise on cognition associated with the autonomous control of the heart. The results show that the indices of parasympathetic reactivation are moderately reproducible, requiring special attention on the standardization of measurements. Moreover, although fatigue induced by exercise, produce physiological disorders, cognitive performance appear relatively stable. After checking these points technological and methodological, it was interesting to test the effect of overload training on the tools used in order to assess their sensitivity to the effects of chronic fatigue. The results show both the value of using measures of heart rate variability and measures of parasympathetic reactivation. These two measures appear sensitive to changes in training load and to the fatigue of athletes. Equally interesting, cognitive performance also appear to us to prevent a state of intolerance in training. This thesis finds its legitimacy because it is a logical improvement of health and prevention of overtraining or even exceeded in athletes. The results of this thesis, we can provide new tools for prevention and recommendations for their use. / Ce travail a été réalisé en cotutelle.

Introduction: College soccer begins in August and ends in November, allowing athletes less than 4 months to condition and play all regular season matches. A consistent consequence of this condensed season structure is an elevated risk of training distress. In turn, training distress can lead to impaired performance and an increased likelihood of injury. Thus, it is important to identify signs of symptoms of distress early so that appropriate adjustments to training volume can be made. Simple, noninvasive techniques, which can be implemented by coaching staff, are ideal. This study investigated whether heart rate recovery was effective as an indicator of training distress in collegiate soccer players. Methods: 26 women and 17 men were enrolled in the study. Data were collected at 4 time points, measuring shuttle run time, heart rate recovery time, resting heart rate values, and MTDS questionnaire score. Heart rate recovery time was defined as the duration it took an athlete to reach 60% heart rate maximum from peak heart rate following the shuttle run. Results: Shuttle run times were prolonged in the beginning and end of season compared to the two mid-season tests (p < 0.001); heart rate recovery times differed at each time period (p=0.003); freshmen deviation from baseline was greater compared to all other grades (p=0.001). Although not statistically significant, resting heart rate values trended up at the end of the season for both genders. Conclusions: Heart rate recovery did not detect training distress in athletes; shuttle run times and resting heart rate appeared to be possible variables that should be taken in to consideration for further research and possibly assist in tailoring training session for optimal performance.

Many athletes incorporate high training volumes and limited recovery periods into their training regimes. This may disrupt the fragile balance and the accumulation of exercise stress may exceed an athlete's finite capacity of resistance. A state of elevated fatigue, increased mood disturbance and decreased exercise performance can result. This is commonly known as overreaching and if increased training and limited recovery is continued, it is believed that the more serious state of overtraining may develop. This is relatively commonly experienced in athletes, however little scientific investigation has been conducted to determine the characteristics and underlying mechanisms. The overall aim of this thesis was to gain a greater understanding of the state of overreaching and to specifically provide new information on potential markers of this state as well as possible mechanisms. To study the cumulative effects of exercise stress and subsequent recovery on performance changes, fatigue indicators and possible mechanisms, the training of endurance cyclists was systematically controlled and monitored in two separate investigations. A number of variables were assessed including performance, physiological, biochemical, psychological, immunological and hormonal variables. In addition heart rate variability and serotonergic responsiveness were also assessed. Some of the more pertinent effects of overreaching included an increase in heart rate variability, a reduction in carbohydrate oxidation, an increase in serotonergic responsiveness and a reduction in stress hormone concentrations. These results suggest that autonomic imbalance in combination with decreased hormonal release appears to be related to the decline in performance and elevated fatigue apparent in overreached athletes. Additionally it also appears that alterations in the hypothalamic-pituitary adrenal axis may occur in overreached athletes.

Intense exercise is known to cause alterations in the psychophysiological status of an athlete. Monitoring the health and recovery of an athlete is imperative for the maintenance of performance and reduced fatigue and injury incidence. The physicality associated with select sports results in significant elevations and suppression of psychophysiological biomarkers that are often modulated by game-related impacts, intense training regimes and psychosocial aspects associated with the professional era. The aim of the studies outlined in this thesis were to determine the effectiveness of selected “stress” markers in several sports that result in significant “stress”, and quantify the level of acute and chronic “stress” following individual games and competitions to improve athlete management and recovery. Study one aimed at developing a new strong-cation exchange high performance liquid chromatography (SCX-HPLC) method for the detection and quantification of urinary pterins and creatinine in a body-building cohort completing high intensity resistance training. The method had an intra- and inter-assay variability of 3.04 % and 5.42 % respectively, with visibly clear peaks and no tailing. Urinary neopterin (NP) and 7,8-dihydroneopterin during a week of competitive natural body-building did not significantly change indicating no alteration in immune system function and oxidative stress. It did provide evidence for the use of specific gravity as a similarly reliable method for urine volume correction following exercise. Study two focused on a playoff game of elite amateur rugby. The time course changes of NP, cortisol, salivary immunoglobulin A (sIgA) and myoglobin in 11 elite amateur rugby players were measured up to 86 hours post-game. Cortisol increased 4-fold, myoglobin 2.85-fold, NP 1.75-fold and total NP 2.3-fold, all significant, whilst sIgA did not change. All markers returned to baseline within 17 hours providing valuable information for sample collection schedule optimization. Respiratory elastance was also measured by ventilation for the assessment of exercise induced lung inflammation/injury following the game (Chapter three). There was an increase in elastance in selected individuals that did not correlate with either global positioning system (GPS) or impact data. It was shown however, that a ventilator is capable of measuring respiratory changes in a conscious and healthy individual. Study three focused on the final three games of professional rugby in the 2013 ITM Cup. The acute and cumulative changes in the same four markers were analysed following three home games. There were significant increases in NP, total NP, cortisol and myoglobin along with significant suppression of sIgA (p < 0.05). Large intra- and inter-individual variation existed between players with changes associated with total impacts. Moreover, impact induced muscle damage may account for changes in oxidative status. Specific gravity (SG) was shown to be a more reliable marker for urine volume correction in comparison to creatinine; while some players showed signs of cumulative stress. Study four examined stress in a professional team throughout the 22 week 2014 Super 15 competition. Part one investigated changes in oxidative stress and muscle damage markers to solidify the muscle damage/oxidative status theory postulated in the previous study. Experimental evidence showed iron and myoglobin are separately capable of oxidizing 7,8-dihydroneopterin to NP in vitro. It was then identified that players who suffered the greatest muscle damage as a result of impacts also had the greatest change in oxidative status (NP). This evidence suggests rugby union induces significant alterations in oxidative status that may be exacerbated by the impact induced release of myoglobin. Part two measured urinary NT-proBNP during the last two consecutive home games to identify whether rugby union causes significant cardiovascular stress and if the pre to post-game change can be explained by GPS technology. Significant individualized elevations were observed in games one and two which did not correlate with any GPS measurements or impacts. Concentrations returned to normal ~ 36 hours post-game suggesting no permanent damage to cardiac muscle had occurred. The lack of correlation suggests GPS technology is not an accurate measure of cardiovascular stress in professional rugby union. Part three involved the measurement of cortisol, total NP and sIgA throughout the season to assess the degree of cumulative stress. Samples were taken at regular intervals ~ 36 hours post-game for 22 weeks. Extreme inter-individual variation was present. Select individuals showed continual elevation in immune system activation and psychophysiological stress, whilst others presented with a continual decline in immune system function. Collectively however, minor deviations from baseline in all markers were observed and participation in long distance travel did not significantly affect the psychophysiological status of the group. Together this suggests a season does not cause an accumulation in psychophysiological stress, although careful individual player analysis is warranted. Understanding rugby union positional demands is essential for training program specification and position specific development of players. Part four used GPS, video-analysis and biochemical analysis to identify positional demands in five regular season games. Forwards tended to be involved in more impacts and covered less distance, while backs covered more distance and carried the ball into contact more regularly. There was no difference in the psychophysiological status between positions indicating both aspects of stress (impacts and distance covered) may induce a similar response. Alternatively, individual biological variation may be solely responsible for this change suggesting careful consideration should be given when using traditional work-load measures such as GPS when quantifying “stress”. Part five assessed the effectiveness of varied recovery interventions. Total NP, cortisol, myoglobin and sIgA were measured pre- post- and ~ 36 hours post game to identify which intervention was most effective at returning players to a psychophysiological state that allowed for the resumption of normal training. Findings concluded the immediate post-game strategy employed by the team (cold bath, consumption of protein and carbohydrates, compression garments and eight hours sleep) seemed to provide the greatest psychophysiological improvement regardless of the “next-day” intervention. There was large inter-individual variation and players were still in a state of recovery ~ 36 hours post-game as indicated by the elevated total NP and sIgA concentrations. Study five had four aspects. Develop a new, cost-effective and simple reverse phase HPLC (RP-HPLC) method for the quantification of urinary myoglobin in a clinically relevant range, quantify the level of structural stress following a simulated mixed martial arts (MMA) contest, determine whether cold water immersion attenuates the level of inflammation and muscle damage following a contest, and whether this hypothesized attenuation may be explained by cryotherapy induced mononuclear cell activation suppression in vitro. The RP-HPLC method had an intra- and inter-assay variations from 0.32 - 2.94 %. Linearity was in the range of 5 – 1000 µg/mL which detected significant increases in urinary myoglobin following the MMA contest. Total NP was found to significantly increase following the contest and return to approximately pre-contest levels 24 hours later for the passive group only. Cold water immersion was further found to attenuate the total NP increase in the first two hours post-contest solidifying its use as a recovery technique following intense exercise, while cryotherapy significantly suppressed T-cell activation. This study provides a reliable and repeatable assay for muscle damage quantification in a clinically relevant range, evidence of the physicality associated with MMA, and indicates cold water immersion is a reliable recovery intervention that may impart its positive benefits through T-cell suppression. The data generated by these investigations highlights the necessity for individual physiological analysis. Group data often masks the extreme variation that exists in clinical and exercise trials where treatment and management of athletes is conducted for recovery and performance. Biochemical analysis provides an added sophistication of work-load and psychophysiological assessment that common technological methods cannot emulate. With a lack of correlation between the quantitative changes in specific non-overlapping biomarkers and GPS, video-analysis and questionnaires, it would seem pertinent to develop a non-invasive quantitative approach in elite sport to understand the level of exercise-induced psychophysiological stress for the precise management of athletes.