Title: Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers Objectives: The aim of this study was to determine the effect of cold water immersion on intermittent isometric forearm flexor contraction to failure in rock climbers. Methods: Thirty-two climbers (15 male and 17 female) completed three intermittent trials to failure, on a climbing-specific handgrip dynamometer, on three separate visits to the laboratory. For each visit a different recovery strategy was employed: passive recovery (PAS), cold water immersion at 8 řC (CWI 8) or 15 řC (CWI 15). The force time integral (FTI - time of contraction multiplied by the force of contraction) was determined to assess intermittent performance. The tissue saturation index (TSI) and total haemoglobin (tHb) during isometric contractions from near-infrared spectroscopy (NIRS) were determined to assess hemodynamic changes. Differences between repeated trials and three recovery protocols, derived parameters NIRS, were assessed using repeated measures ANOVA with Bonferroni corrections. Results: There was no significant difference between conditions after trial one. In response to the PAS recovery condition there was a 10% and 22% decrease in FTI in the second and third trials, respectively. The PAS...

The hand has the highest surface area-to-volume ratio of any body part. This property offers the potential for the hand to serve an important function in thermoregulation through radiative heat loss. Theoretically, the capacity for heat loss may be influenced by hand and digit proportions, but the extent to which these proportions influence the hand's radiative properties remains under-investigated. Although hand morphology is highly constrained by both integration and functional dexterity, phenotypic variation in hand and digit proportions across human populations shows broad ecogeographic patterns. These patterns have been associated with climate adaptation. However, the theory linking climate adaptation to such ecogeographic patterns is based on underlying assumptions relating to thermodynamic principles, which have not been tested in vivo. This study sought to determine the influence of hand and digit proportions on heat loss from the hands directly, the additional anthropometric factors that may affect this relationship, and the impact of variation in hand proportions on dexterity in the cold. The relationship between hand proportions and thermoregulation was tested through both laboratory-based investigation and a field study. The laboratory investigation assessed the relationship between hand proportions and heat loss, the influence of body size and composition on this relationship, and the effect of morphological variation on manual dexterity. Participants (N=114; 18-50 years of age), underwent a 3-minute ice-water hand-immersion. Thermal imaging analysis was used to quantify heat loss. Hand and digit proportions were quantified using 2D and 3D scanning techniques; body size and composition were measured using established anthropometric methods and bio-impedance analysis. After accounting for body size, hand width, digit-to-palm length ratio, and skeletal muscle mass were significant predictors of heat loss from the hand, whilsthand length and fat mass were not. A separate set of participants (N=40) performed a Purdue pegboard dexterity test before and after the immersion test, which demonstrated that digit width alone negatively correlated with dexterity. The field study tested whether phenotypic variation in upper limb proportions could be attributed to cold adaptation or selection for dexterity in living populations exposed to significant energetic stress. Upper limb segment lengths were obtained from participants (N=254; 18-59 years of age), from highland and lowland regions of the Nepalese Himalayas using established anthropometric methods, and relative hand proportions were assessed in relation to severe energetic stress associated with life at high altitude. Relative to height, hand length and hand width were not reduced with altitude stress, whilst ulna length was. This indicates that cold adaptation is not shaping hand proportions in this case, although phenotypic variation in other limb segments may be attributed to cold adaptation or a thrifty phenotype mechanism. The current study provides empirical evidence to support the link between surface area-to-volume ratio, thermodynamic principles and ecogeographical patterns in human hand morphology. However, this research also demonstrates the complexity of the hand's role in thermoregulation; not only do other factors such as muscularity affect heat loss from the hand, but hand morphology is also highly constrained by integration and dexterity.

La contribution relative des différentes entrées sensorielles dans le contrôle postural a souvent été étudiée dans le cadre de la posture érigée fondamentale. L’objectif de nos travaux a été de déterminer cette contribution dans deux postures relativement proches dans leur configuration : l’appui tendu renversé (ATR) et la verticale inversée (VI) en milieu aquatique. Si la vision est souvent considérée comme information principale dans le contrôle postural de la station érigée, la configuration structurelle (champ visuel restreint en ATR, immersion de l’œil en VI) de ces deux postures laisse imaginer un fonctionnement différent. La perturbation des différents capteurs sensoriels impliqués dans le contrôle postural a permis d’observer la réorganisation mise en place par le système nerveux central (SNC) pour y remédier. De plus la prise en compte d’un facteur perceptif comme la dépendance au champ visuel nous a paru être un élément pertinent pour tenter d’observer d’éventuelles différences interindividuelles dans les comportements des sujets. La perturbation du contrôle postural a été évaluée au travers d’une analyse cinématique et d’une analyse stabilométrique de l’ATR (analyse classique et non-linéaire). Les résultats de ces analyses laissent entrevoir des différences de stratégie entre les sujets dépendants et indépendants au champ visuel dans le contrôle de l’appui tendu renversé, ce qui ne semble pas être le cas en verticale inversée / The relative contribution of the different sensory inputs in erect postural control has often been studied. The aim of this work is to determine this contribution in two positions relatively close in their configuration: the handstand and the upside-down posture in water. If vision is often considered as the main information in postural control, the structural configuration (restricted visual field in handstand, eye’s immersion in upside-down posture) of these two postures lets imagine a different operation. Disruption of sensory receptors involved in postural control has allowed observing the reorganization implemented by the central nervous system (CNS). In addition, the visual field dependence appeared to be a relevant factor to observe interindividual behavioral differences. Disturbance of postural control was assessed through a kinematic analysis and a stabilometric analysis of the handstand (classical analysis and non-linear analysis). Results of these analyzes suggest different strategy according to visual field dependence in the control of the handstand, which does not seem to be the case in upside-down posture

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.

(Cf. corpus p. 25-26) Ce travail de thèse s'est articulé autour de deux problématiques : les réponses cardiovasculaires consécutives à l/ différents protocoles d'exercice et 2/ différents protocoles de récupération. Concernant la première, 3 protocoles de recherches ont été menés. L'un avait pour objectif de déterminer les effets aigus d'exercices de même durée proposant une quantité de travail totale équivalente distribuée de façon constante (CC) ou intermittente (IT), sur la rigidité artérielle multi-segmentaire et ses déterminants. Les deux autres se proposaient d'explorer les dysfonctions cardiaques induites par des exercices de durées plus longues (2 à 4 heures) et leurs mécanismes sous-jacents. La seconde problématique de ce travail de doctorat a conduit à la réalisation de 5 protocoles de recherche. L'immersion contrastée (alternance d'immersions d'une à deux minutes jusqu'à l'aine à ~ 12°C et à ~ 36°C), l'immersion en eau froide (~ 12°C) et la compression élastique ont été tout particulièrement étudiées. Les points suivants ont été abordés : la comparaison des effets de la compression élastique et de l'immersion contrastée sur la performance subséquente ; la connaissance des facteurs concourant aux bénéfices de ces dernières entre des efforts intenses et brefs (c.-à-d. étude du débit sanguin musculaire, de la saturation tissulaire en oxygène, de la clairance des métabolites, etc.) ; l'étude des effets de la pression hydrostatique seule (immersion à neutralité thermique ), et ceux de celle-ci associée au froid (immersion en eau froide ) ou à l'alternance de température (immersion contrastée) sur le débit sanguin musculaire; et enfin l'étude des effets sur certains paramètres de la récupération du port d'une compression élastique au cours et au décours d'un trail. Dans ce contexte, les résultats de nos études mettent en évidence qu'un exercice de type IT diminue davantage la rigidité artérielle multi-segmentaire qu'un exercice de type CC. Cette diminution plus prononcée est associée à un relargage plus important de substances vasodilatatrices (NO,ANP, lactates, etc.). Nous avons également montré qu'un exercice prolongé de durée modérée engendre des dysfonctions cardiaques transitoires. Plus particulièrement, certains indices de contractilité évalués par une technique échocardiographique de dernière génération (c.-à-d. le « Speckle Tracking Echocardiography ») nous ont permis de mettre en évidence que la baisse de la fonction systolique du ventricule gauche (VG) était associée à une atteinte contractile du myocarde dans des conditions standardisées de fréquence et de charge cardiaques. Nos résultats soulignent également le rôle clé de la torsion ventriculaire dans la diminution du remplissage du VG et par conséquent de la fonction diastolique à l'arrêt de l'effort. Les études expérimentales s'intéressant aux techniques de récupération post-exercice indiquent que l'immersion contrastée et la compression élastique par rapport à une récupération passive, lorsqu'elles sont appliquées immédiatement après un premier exercice fatiguant, améliorent la performance subséquente (exercice de pédalage de 5 min) lorsque celle-ci est répétée dans un laps de temps court (15 min). De plus, l'immersion contrastée est plus efficace que la compression élastique pour améliorer la performance subséquente. Ces techniques de récupération accélèrent la clairance du lactate, cette dernière étant accélérée davantage après l'immersion contractée. La compression élastique augmente le débit sanguin musculaire mais également la saturation tissulaire en oxygène, que ce soit avant et après l'effort. Par rapport à une récupération passive, l'immersion contrastée augmente également le débit sanguin musculaire après l'effort, et davantage que la compression élastique. (...) / (Cf. corpus p. 27-28) This thesis work focuses on the cardiovascular responses consecutive to l/ various exercice modalities and 2/ various post-exercise recovery interventions. With regard to the exercise modalities, 3 experimental protocols were led. The first one aimed to compare the acute effects of constant and interval exercises on regional arterial stiffness and these determinants. Two others studies focused on the cardiac dysfunctions induced by exercises of longer durations (2-3h) and the underlying mechanisms. The second problematic of this thesis work led to 5 studies. The following questions were approached: the comparison of the effects of contrast water therapy and compression stockings on the subsequent performance; the knowledge of the factors at the origin of the benefits of these recovery interventions between repeated brief and exhaustive bouts of physical exercise (i.e. muscle blood flow, muscle oxygenation, removal of metabolic waste, etc.) ; the changes in leg muscle blood flow, caused by hydrostatic pressure alone [thermoneutral water immersion), and in addition to cooling (cold water immersion) or alternating of temperature (contrast water therapy); and finally the effects of elastic compression worn during and after a trail running race on the participants' recovery. Our results show that interval exercise decreases more regional arterial stiffness [central and peripheral) than constant exercise. This more pronounced decrease is associated with a higher concentration of vasodilator factors (NO, ANP, lactates, etc.). We also show that a prolonged exercise (2-3h) induce transient cardiac dysfunctions. Specifically, parameters of systolic function evaluated using 2D-speckle tracking echocardiography not only at rest, but also during incremental tests to adjust heart rate demonstrate that the 3h-period of prolonged and strenuous exercise induces left ventricular systolic dysfunction. Our results also demonstrate that depressed diastolic function is associated with delayed untwisting velocity. The studies focusing on post-exercise recovery interventions indicate that compared with passive recovery, contrast water therapy and compression stockings improve the subsequent 5-min maximal performance in cycling when this one is repeated during a brief elapsed time (i.e. 15 min). Moreover, contrast water therapy is more efficient than compression stockings to improve the subsequent performance. Theses recovery interventions accelerate the removal of lactates, and contrast water therapy more than compression stockings. The elastic compression increases muscle blood flow but also tissue oxygen saturation, before and after a physical exercise. Contrast water therapy also increases muscle blood flow after an exercise compared with a passive recovery, and more than elastic compression. (...)

As the prevalence of cardiovascular diseases continues to exponentially grow in populations across the globe, the necessity of determining underlying factors, effective methods of diagnoses, and universally available preventive measures also grows. Early detection of endothelial dysfunction, a proven precursor of cardiovascular diseases, can be extremely impactful in encouraging preventative measures and early intervention before medical conditions become chronic. In recent years, ice plunging, a form of cryotherapy involving full body immersion in cold water, has gained popularity within circles of fitness and health practitioners, gaining the interest of people of all backgrounds. Certain parallels observed between the human physiological response to cold exposure and endothelial function encourage further study of the effects of ice plunging on cardiovascular health. Calibrated cuff plethysmography is a promising method of reflecting on endothelial function by measuring arterial compliance of select blood vessels. In this study, a calibrated cuff plethysmography device was built and tested for efficiency as it was used to measure compliance and cross-sectional area of the brachial artery of 14 participants 30 minutes before, immediately after, and 30 minutes after a 5-minute cold plunge in a temperature of 10°C - 15°C. Results found some significant differences between baseline measurements recorded immediately after the ice plunge and measurements recorded during reactive hyperemia conditions at normal body temperature but did not conclude that 5-minute cold-water immersion intervention had a significant impact on arterial compliance or area overall since this was a short term experiment with only acute intervention methods. The device used was concluded to effectively measure arterial compliance and area.