Dissertations / Theses on the topic 'Exercise Physiology'
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1
Voutselas, Vasileios. "The influence of exercise parameters on post-exercise metabolic rate." Thesis, University of Essex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268743.
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Niedre, Peter Cameron. "Exercise intensity and the post-exercise elevation in esophageal temperature." Thesis, University of Ottawa (Canada), 2000. http://hdl.handle.net/10393/9226.
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In order to examine the effects of exercise intensity on the post exercise elevation in esophageal temperature (DeltaTes), 8 male subjects performed 15 minutes of treadmill running exercise at 3 different exercise intensities, subthreshold (70% VO2max), threshold (84% VO 2max, and suprathreshold (93% VO2max), followed by an upright 45 minute recovery period. In addition, the effects of exercise intensity on the internal temperature threshold for cutaneous vasodilation (Tdil ), as well as post exercise blood pressure, cutaneous blood flow (SkBF) and cardiovascular conductance (DeltaCVC), were examined. Significant differences (p < 0.05) in DeltaTes were found between the 3 exercise intensities during exercise, as well as between suprathreshold (0.91°C), and threshold (0.56°C)/subthreshold (0.44°C) intensities during the recovery period. The elevated DeltaTes remained significantly above pre-exercise values for the entire recovery period for all 3 exercise intensities. Exercise intensity also demonstrated an effect on Tdil during exercise where significant differences were found between the 3 exercise intensities (0.26°C, 0.47°C, 0.84°C for subthreshold, threshold, and suprathreshold intensities respectively). However, no significant correlation was found between Tdil, and post exercise DeltaTes. Finally, a state of hypotension with respect to pre-exercise was observed during recovery from suprathreshold exercise. This could explain the significantly higher post exercise elevation in DeltaTes from subthreshold and threshold exercise.
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Qayyum, Mohammed Shahzad. "The physiology of potassium during exercise and recovery." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386644.
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Shirreffs, Susan Margaret. "Post-exercise rehydration in man." Thesis, University of Aberdeen, 1996. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU550461.
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The experiments of this thesis have confirmed and widened much of the previous knowledge concerning recovery from moderate levels of exercise-induced dehydration. A protocol for inducing sweat loss and monitoring recovery has been established and verified, and a reliable methodology for the collection and analysis of whole body sweat developed. In general, intermittent exercise at an intensity corresponding to 60% 2max was undertaken in a warm (approximately 34°C), humid (60-70% rh) environment. Subjects were dehydrated by approximately 2% of their body mass and rehydrated with a fluid volume equivalent to 3% of their body mass. The composition of the rehydration fluid was determined by the aims of each particular study. By systematically varying the sodium concentration of rehydration fluids, the importance of sodium consumption for the retention of the ingested water was confirmed. However, when the sodium intake was extremely high (206 mmol from consumption of a 100 mmol l-1Na+ drink), fluid balance restoration was achieved at the expense of an excess of sodium retention and an increased potassium excretion. This effect on potassium levels must be considered to be undesirable for anything other than the short term situation. Alcohol consumption in the form of beer is the beverage of choice of many individuals following exercise but is frequently advised against because of the diuretic actions of the alcohol. However, this thesis demonstrates that the diuretic effect of alcohol is substantially blunted when alcohol is consumed following a moderate level of hypohydration induced by exercising in the heat; there appears to be no difference in recovery, in terms of fluid balance, from dehydration whether the rehydration beverage is alcohol-free or contains up to 2% alcohol and sufficient volume is consumed.
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Soucie, Luc. "Exercise hypotension: A retrospective analysis." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/9829.
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This retrospective study assessed the usefulness of a drop and a blunted systolic blood pressure (SBP) response to exercise testing as predictors of multiple or left main coronary artery disease (CAD) as defined by a 'Coronary Score' (CS). Three types of systolic BP response to exercise were used: (1) an increase by more than 20 mmHg (Group I, n = 107), (2) an increase by 20 mmHg or less (Group II, n = 84), and (3) a decrease of at least 10 mmHg (Group III, n = 45). The extent of CAD was significantly greater in groups II and III than in group I (group I, $6.7\pm6.9;$ group II, $9.3\pm7.1;$ group III, $11.7\pm8.5,$ p 0.05). However, the difference was not statistically different between groups II and III which reinforces the value of a blunted SBP response. Treatment outcome also differed between SBP groups. Seventy percent of patients in group I received medical therapy. Over 70% of those in groups II and III underwent coronary angioplasty (PTCA) or coronary bypass surgery (CABG). It was concluded that similarly to a drop in SBP, a blunted SBP response to treadmill exercise testing in patients with known or suspected CAD is a potential indicator of multiple or left main coronary artery disease.
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Kenny, Glen. "Thermal homeostasis following dynamic exercise." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6486.
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Recent published work showed post-exercise (PostEx) esophageal temperature (Tes) recovered rapidly to a persistent plateau that was significantly elevated (0.5$\sp\circ$C or more) above pre-exercise (PreEx) values. Non-acral skin temperatures, except over exercised muscle, returned rapidly to PreEx levels. Rectal temperatures (Tre) fell gradually during recovery reaching a plateau late in recovery (45 min) equal in magnitude of difference from Tes to PreEx values. Surface temperatures over the quadriceps remained high, indicating that heat was trapped in muscle. A similarity between the exercise Tes at which skin surface dilation occurred (Tdil) and the PostEx Tes was identified. These observations contradict the widely accepted "load-error" prinicple of thermoregulation which predicts that displacement of core temperature (Tco) from a hypothalamic set point (SPhy) will induce defense reflexes until the displacement is reversed. These data lead to the hypothesis that there was some residual influence related to exercise that retained the modulation of thermal reflex thresholds during recovery. Testing of the hypothesis was conducted with experiments to establish if: (1) the PostEx Tes was related to PreEx temperature; (2) exogenous thermal loading would produce the same post treatment elevation; (3) PostEx Tes elevation followed by exogenous thermal loading would result in an increase in the Tes elevation and (4) a 5 min exercise generating Tes below Tdil would result in a PostEx elevation of Tes. It was demonstrated that repeated running-recovery cycles produced patterns of rise and then fall of Tes to an elevated PostEx plateau that was equal to Tdil. This was similar to previous results except that the second exercise was begun at an elevated Tes and produced further elevation of Tdil with a comparable effect on PostEx Tes. Similarly, the third exercise further increased Tes following which it recovered to an even higher plateau equal in magnitude to Tdil. We observed that exogenous heat loading, by immersion of subjects in a bath of water at 44$\sp\circ$C to produce a rate of increase and peak elevation of Tes equal to exercise, did not result in a post-treatment elevation in Tes. Similarly, the PostEx Tes elevated plateau, equal to Tdil, remained unchanged following water immersion at 44$\sp\circ$C despite a larger total heat gain during the immersion. These observations eliminate whole body heat content changes as the primary cause of the Tes elevation and support the hypothesis that the homeothermic defense mechanisms become inoperative during recovery at a temperature above resting values as defined by Tdil. The physiological importance of Tdil in defining upper limits of resting temperature cannot be determined at this point. However, the physiological relationship of Tdil with PostEx Tes suggests that neuro-muscular activity significantly influences thermolytic controls which persist in recovery. That Tdil may represent the upper limit of a range of "normal temperatures" is supported by data from a 5 min exercise performed to a Tes elevation below Tdil. Within minutes of exercise termination Tes achieved a stable elevated PostEx Tes (0.3$\sp\circ$C or greater) which was maintained with no change over 65 min of recovery. The data suggest the possibility of: (1) a metabolically induced change in SPhy thermosensitivity, (2) a decreased sensitivity to an increase LE, or (3) a range of temperature regulation defined by an upper threshold control for thermolytic temperature defense reflexes.
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Ramsey, Michael W. "Physiology of Sprint and Road Cycling." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/4106.
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Shaw, Aaron P. "The Effect of a Pre-Exercise Nutritional Supplement on Muscle Fatigue During Handgrip Exercise." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1373030510.
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Axelrod, Christopher L. "Menopausal Status Impairs Resistance Exercise-Induced Inflammatory Recovery." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu1463070138.
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Vanderluit, Jacqueline L. "The effect of dynamic exercise on the blood pressure response to isometric exercise in normotensive males." Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7527.
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The purpose of this study was to determine whether the pressor response to a static handgrip exercise would be blunted if performed during or immediately following dynamic exercise. Male subjects performed one minute handgrip (HG) contractions under three conditions (1) standing at rest, (2) during the 4th to 5th min of treadmill walking exercise and (3) during recovery one min following the combined exercise. The handgrip exercises were performed at 30% and 40% of maximum voluntary contraction (MVC). The results indicated that there was a main effect of intensity, such that HG exercises performed at 40% MVC produced a significantly greater blood pressure response than HG at 30% MVC for all three conditions. The systolic response to static exercise is blunted when a HG at 30% MVC is performed during moderate dynamic exercise but not with HG contractions at 40% MVC. In addition, the systolic response to static exercise is also blunted when HG contractions at both 30% and 40% MVC are performed following dynamic exercise. Also, dynamic exercise augments the diastolic response to static contractions (30% & 40% MVC) performed following dynamic effort. (Abstract shortened by UMI.)
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Cathcart, Andrew James. "The control of the exercise hyperpnoea." Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/6540/.
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A relatively recent proposal suggests that a plastic element to the ventilatory control system might be held accountable for the experimentally observed matching of VE to VCO2. That is, Martin and Mitchell (1993) reported that goats consistently over-breathed during treadmill exercise, following conditioning to treadmill exercise while breathing through an external dead space. This has been taken as evidence that the steady-state ventilatory response can be modulated. Therefore, the existence of a similar mechanism in the human exercise hyperpnoea was investigated; replicating as closely as possible the study of Martin and Mitchell (1993). Furthermore, the requirement for such a mechanism was investigated by studying the control of the exercise hyperpnoea in the absence of such a 'learned-response'. The results show no evidence of plasticity during phase II or phase III of the exercise ventilatory response under normal conditions. Furthermore, subjects devoid of any exercise experience were able to generate an appropriate, in terms of PaCO2 regulation, ventilatory response during sub-lactate threshold cycle ergometer exercise. Therefore, under the conditions of the study, no requirement for an 'exercise-memory' in the genesis of a 'normal' exercise hyperpnoea could be found. In conclusion, there appears to be no primary role for respiratory plasticity in the control of the exercise hyperpnoea.
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Cacija, Gordana. "Expertise and training effects on co-ordination dynamics in a whole body rhythmical task." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2003. https://ro.ecu.edu.au/theses/1330.
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This research consists of two studies. The purpose was to investigate the effects of slow and fast music tempo on interjoint co-ordination variability in an aerobic stepping task. The 'step knee-up' task is a cyclical whole body movement performed on the step platform. The exercise consisted of a few repetitive cycles. A cycle was defined by eight counts, four counts for the left leg pattern and four for the right leg as follows: The first half of the cycle was counted: I. Step up with the left foot onto the 20-cm step platform, 2. Flex the right hip to bring the right knee up; 3. Step down to the floor with the right foot and, 4.Tap once with the left foot on the floor near the right foot. The second half of the cycle consisted of the following four counts: I. Step up onto the platform with the right foot; 2. Flex the left hip to bring the left knee up. 3. Step down to the floor with the left foot and, 4. Tap once with the right foot on the floor near the right foot. The participants were instructed to move both arms simultaneously forward and backward so that the limbs would perform in-phase movement, which is opposite to the natural anti-phase arm movements that accompanies walking and stepping activities. This pattern of the arm movements has been defined as a proposed pattern or the 'to-be-learned' pattern. In particular, the research examined to what extent unskilled and skilled participants would adjust their movement co-ordination to cope with changes in performance conditions in attempting to achieve the criterion task. In the first study, these effects were observed in novices and experts, while the effects of the fast tempo training on intrinsic dynamics (self-paced condition) were considered in the second study. Both studies were based on the Dynamic Systems Theory. The environmental factor, which was considered as the control parameter affecting performance in both studies, was the music tempo. In the first study interjoint co-ordination responses were analysed in terms of a version of the Haken, Kelso and Bunz's (HKB) modal that considers detuning or frequency competition terms. Six novice and six expert females participated in the experiment performing a 'step-knee-up', a whole body rhythmical task, under different music tempos. They were tested at a slow tempo at 48 beat/min and at a fast tempo of 144 beat/min. Two hypotheses were proposed. Firstly, it was hypothesised that discrete relative phase variability of inter-joints co-ordination would be higher.at the fast tempo then at the slow tempo in both, novices and experts. It was further hypothesised that, in order to cope with changes in performance conditions and still achieve the criterion task, novices would demonstrate higher variability than experts at both the slow and fast tempo. Results showed that interjoint co-ordination in experts was more consistent (less variable) at both the slow and fast tempo compared to novices, in all couplings expect in the left leg. Furthermore, follow-up tests revealed that Tempo and Side effects in novices were not significant. In experts, however significant Side effect was found in shoulder joint coupling and hip-knee joint coupling. Higher variability was found in left leg interjoint coupling between hip and knee joints at both tempos, compared to the right leg. In shoulders joint coupling, however, higher variability was found only in the slow tempo for the right side observation of the L Shoulder-R Shoulder movement. Finally, it was observed that the initially specified arm movement direction (iso directional or in-phase movement) changed to anti-phase direction at fast tempo in novices. Therefore, in novices, in-phase arm movements were more sensitive to fast tempo perturbations compared to anti-phase. While these results may be in contrast to Haken, Kelso and Bunz's model predictions they are partly supported by Whittal, Forester and Song's (1999) findings. In the second study, whether practising the task under the fast music tempo would affect the interjoint co-ordination stability at the preferred tempo performance (without the music) was investigated. It was hypothesised that, after the training under the fast music tempo interjoint coupling variability at the preferred tempo would decrease. The hypothesis was partly accepted as variability decreased in the self- paced condition after training only in shoulder-shoulder interjoint couplings compared to the self-paced condition before training. Results in the second study were discussed in relation to Shaner and Kelso's (1988) dynamical theory of environmental function and motor learning transfer principles. It was found that training under the fast tempo did not significantly affect overall performance at self-paced and fast tempos. However, different changes in interjoint co-ordination strength were observed in different couplings before and after training as the function of (the left or right) body side. It was concluded that interjoint co-ordination flexibility is highly specific to the interaction between the task, body side, performance condition and skill level. Finally it was suggested that an individual approach to the analysis of variability in co-ordination dynamics in skilled and unskilled performance and learning be considered.
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Levitt, Danielle E. "Resistance Exercise and Alcohol: Combined Effects on Physiology and Performance." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248374/.
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Resistance exercise (RE) training is a well-known and effective method for promoting increases in muscle mass and strength. A single bout of RE induces physiological disturbances that require coordinated activation of the immune system and intramuscular signaling in order to return the tissue to homeostasis and adapt to the RE challenge. On the other hand, acute binge alcohol consumption can affect the immune response to an inflammatory challenge, intramuscular anabolic signaling, and muscle protein synthesis, and the effects of alcohol on these processes are opposite that of RE. Furthermore, individuals who report more frequent exercise also report a greater frequency of binge drinking. However, few investigations exist regarding the effects of binge alcohol consumed after a bout of RE on RE-induced physiological changes and performance recovery. Therefore, the overarching purpose of the investigations contained within this dissertation was to investigate the effect of alcohol consumed after RE on the RE-induced changes in mTOR pathway signaling, muscle protein synthesis, inflammatory capacity, strength recovery, and power recovery. Although RE increased mTOR pathway signaling and inflammatory capacity after exercise and reduced maximal strength and explosive power the day after exercise, we observed no effects of alcohol (1.09 g ethanol∙kg-1 lean body mass, designed to result in a peak blood alcohol concentration of approximately 0.12 g∙dl-1) consumed after RE on mTOR pathway signaling, 24-hour rates of muscle protein synthesis, inflammatory capacity, or strength and power recovery in resistance-trained individuals.
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Wright, Jonathan C. (Jonathan Caldwell). "Diving and exercise physiology in the estuarine crocodile, Crocodylus porosus." Thesis, The University of Sydney, 1985. https://hdl.handle.net/2123/26901.
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Metabolic and respiratory physiology of juvenile Estuarine Crocodiles, Crocodylus porosus, were examined under the following conditions: rest on land, voluntary submergence and exhaustive activity on land.
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Smith, Carine. "Exercise, stress and immune system functional responses." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16070.
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Dissertation (PhD)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Stress related to chronic exercise affects both the immune and endocrine systems, but there are still many issues that are poorly understood, particularly effects of stress on the functional capacity of immune cells. This thesis probed some of these issues using physiological models of physical and psychological stress. Both exercise training stress and chronic psychological stress in human subjects were shown to result in an up-regulation of spontaneous reactivity of white blood cells in vitro, using two different assays, namely a) a peripheral blood mononuclear cell (PBMC) culture assay measuring immune cell responsiveness and b) a relatively new flow cytometry technique for assessing activation status of cells by their expression of the surface marker CD69, in a lymphocyte subpopulation-specific manner. An up-regulation of immune cell activation in the absence of an additional stressor was associated with a decreased capacity to mount a response to a subsequent mitogen stimulus in vitro after chronic psychological stress and acute, extreme exercise stress. Another novel finding was that cortisol high-responders to chronic psychological stress exhibited a higher spontaneous reactivity of both CD4+ and CD8+ lymphocytes when compared to cortisol low-responders. This result indicates that chronic exposure to cortisol may decrease its usual inhibitory effect on spontaneous T lymphocyte responsiveness. After optimisation of an animal model of mild, psychological stress, we demonstrated (using an IL-6 antibody) that IL-6 is necessary for a full-blown cortisol response to chronic, intermittent mild stress. Results also suggest that IL-6 plays a role in regulation of its own secretion by PBMCs in response to a stressor, by maintaining the production of IL-1β in the face of stress. Basal serum corticosterone concentration was shown to be the main determinant of the magnitude of mitogen-stimulated PBMC secretion of IL-6 in vitro in the stress-free controls. However, after blocking of IL-6 in vivo, IL-1β was identified as a major regulator of IL-6 secretion by mitogen-stimulated PBMCs in vitro, independently of the presence or absence of stress. The implications of these novel findings are that proinflammatory cytokines are sensitively regulated during mild stress.Mean serum cortisol concentration at rest was not a useful tool to assess chronic exercise stress after training intervention. However, classification of athletes at baseline into two groups according to their resting serum cortisol concentration illustrated two distinct patterns for the responses of both cortisol and the cortisol:testosterone ratio to chronic stress. These studies on the effects of chronic stress on parameters of the endocrine stress-axis and the immune system led to the following main conclusions: a) chronic exposure to cortisol results in a decreased inhibition of spontaneous immune cell activity at rest, b) this increased spontaneous activation of immune cells at rest in the absence of a stressor, is associated with a suppression of immune capacity to respond to a subsequent challenge, c) the latter finding is not evident under stress-free conditions where cortisol promoted immune cell IL-6 secretion, and d) IL- 1β and IL-6 are involved in the regulation of each others’ secretion.
AFRIKAANSE OPSOMMING: Chroniese oefening-verwante stres beïnvloed beide the immuun- en endokriene sisteme, maar daar is nog baie aspekte wat swak begryp word, veral m.b.t. die effekte van stres op die funksionele kapasiteit van immuunselle. Hierdie tesis het sommige van dié vraagpunte ondersoek deur gebruik te maak van fisiologiese en psigologiese stres. Beide oefening program-verwante stres en chroniese psigologiese stres in proefpersone het ‘n op-regulering van spontane witbloedselreaktiwiteit in vitro tot gevolg gehad, wat d.m.v twee verskillende metodes aangetoon is, naamlik a) ‘n perifere bloed mononukluêre selkultuur (PBMS-kultuur) bepaling van immuunsel reaktiwiteit en b) ‘n relatief nuwe vloeisitometriese tegniek vir die assessering van aktiveringsstatus van selle, deur hul uitdrukking van die oppervlakmerker CD69, op ‘n limfosiet subpopulasie-spesifieke wyse. ‘n Opregulering van immuunselaktiwiteit in die afwesigheid van ‘n addisionele stressor is geassosieer met ‘n verlaagde kapsiteit om te reageer op ‘n latere mitogeniese prikkel in vitro, na chroniese psigologiese stres en akute, erge oefeningstres. Nog ‘n nuwe bevinding was dat kortisol hoog-respondeerders, in reaksie op chroniese psigologiese stres, ‘n hoër spontane reaktiwiteit van beide CD4+- and CD8+-limfosiete toon in vergelyking met kortisol laagresopndeerders. Hierdie bevinding toon aan dat chroniese blootstelling aan kortisol die inhiberende effek daarvan op spontane reaktiwiteit van T-limfosiete verminder. Na optimalisering van ‘n rotmodel van gematigde, psigologiese stres, het ons gedemonstreer (deur gebruik te maak van ‘n IL-6 teenliggaam) dat IL-6 nodig is vir ‘n volledige kortisolreaksie op chroniese, onderbroke, gematigde stres. Die resultate dui daarop dat IL-6 ‘n rol in die regulering van sy eie sekresie deur PBMSe in reaksie tot ‘n stressor speel, deur die handhawing van produksie van IL-1β in die teenwoordigheid van stres. Basale serum kortisolkonsentrasie is as die belangrikste beslissende faktor in die omvang van mitogeengestimuleerde PBMS sekresie van IL-6 in vitro in die stresvrye kontroles aangedui. Na blokkering van IL-6 in vivo, is IL-1β egter as ‘n belangrike reguleerder van IL-6 sekresie deur mitogeen-gestimuleerde PBMSe in vitro geïdentifiseer, onafhanklik van die teenwoordigheid of afwesigheid van stres. Die implikasie van hierdie nuwe bevindinge is dat proinflammatoriese sitokiene tydens gematigde stres sensitief gereguleer word.Die gemiddelde serum kortisolkonsentrasie in ‘n rustende toestand was nie ‘n gepaste instrument om chroniese oefeningstres na ‘n oefenprogram-ingreep te assesseer nie. Na basislyn klassifikasie van atlete in twee groepe volgens hul rustende serum kortisolkonsentrasie, is twee afsonderlike patrone vir die reaksie van beide kortisol en die kortisol:testosteroon verhouding egter aangetoon. Hierdie studies rakende die effekte van chroniese stres op parameters van die endokriene stres-as en die immuunsisteem het tot die volgende vernaamste gevolgtrekkings gelei: a) chroniese blootstelling aan kortisol het ‘n verlaagde inhibisie van spontane immuunselaktiwiteit tydens rustende toestande tot gevolg, b) hierdie verhoogde spontane aktivering van immuunselle tydens ‘n rustende toestand word geassosieer met ‘n onderdrukking van immuunkapasiteit om te reageer op ‘n daaropvolgende prikkel, c) laasgenoemde bevinding is nie sigbaar tydens stresvrye toestande, wanneer kortisol IL-6 sekresie bevorder, nie en d) IL- 1β en IL-6 is betrokke by die regulering van mekaar se sekresie.
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Delbridge, Andrew. "The physiological effects of fatiguing upper body exercise." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240428.
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Bailey, Damian Miles. "Chronic hypobaric hypoxia : physiological implications for exercise performance." Thesis, University of South Wales, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265718.
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Tonkonogi, Michail. "Mitochondrial function in human skeletal muscle : with special reference to exercise and training /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-628-4264-1/.
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Plattner, Kristina. "The association between exercise-induced muscle damage and cortical activity in the alpha and beta frequency range." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11524.
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Includes abstract.Includes bibliographical references (p. 139-178).
This thesis examines the regulation of muscle function following exercise-induced muscle damage (EIMD), in an attempt to determine whether regulation occurs primarily in the muscle (neuromuscular) or further upstream. Upstream regulation has been hypothesized to occur in the lower brain structures, but one may assume that the efferent output to the muscle should be guided by the motor and pre-motor cortex alongside other associated cortical areas.
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Leick, Katie. "A novel technique to study the time course of morphological and functional vascular responses to hypertension in conscious rats." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/696.
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Assessment of morphological vascular responses to exposure to cardiovascular risk factors in experimental animals requires ex vivo experiments that do not allow assessment of the time course of vascular alterations in individual subjects. We used a slit-lamp biomicroscope (resolution < 1 μm) to photograph the long posterior ciliary artery (LPCA) of the iris in conscious normotensive Wistar Kyoto rats (WKY, n=10) and spontaneously hypertensive rats (SHR, n=10) on normal-salt diet (NS) and in SHR (n=10) on high-salt diet (HS). The same segment along the LPCA was imaged in consecutive weekly imaging sessions and an imaging software was used to determine the wall to lumen (W/L) ratio. After 10 weeks, systolic blood pressure (SBP) did not change in WKY-NS, but increased significantly in SHR-NS and SHR-HS, (p < 0.05). The time course of the changes in W/L ratio of the LPCA mirrored the time course of the SBP changes. While W/L ratio did not change in WKY-RS, there was a significant increase in W/L ratio in SHR-NS and SHR-HS. Since the LPCA was not dilated pharmacologically the W/L ratio assessed in this study may reflect the combination of morphologic alterations and changes in vascular tone. In vivo imaging of the LPCA may allow assessment of the time course of morphological and functional vascular responses to hypertension in conscious rats.
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Floy, Brad Wayne. "Modulation of hamstrings reflexive responses during human gait." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/2871.
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In humans, it is thought that both central commands and peripheral feedback from sensory receptors contribute to the control of locomotion. An important problem that exists in human locomotion research is the interactions and balance between the individual contributions of the central (CNS) and peripheral (PNS) nervous systems to the control of muscles during movement are not fully understood. Applying external perturbations such as stretches, tendon taps, and electrical stimulation to the neuromuscular system during walking can help us learn more about how the response to afferent information is modulated during locomotion. To date, most of the research looking at modulation of the response during walking has investigated the soleus and quadriceps muscles. Very little research has focused on the hamstring muscles, which are important during walking, particularly during late swing. One reason for this is that it is difficult to detect H-reflexes in hamstrings following electrical stimulation of the sciatic nerve. The purpose of this study was to demonstrate a new sciatic nerve stimulation technique and use it to study the modulation of the response to afferent feedback during walking.
This study consisted of two parts: 1) Establish the presence of an afferent mediated response (H-reflex) during prone lying in hamstrings muscles, and 2) Investigate the modulation of this afferent feedback during walking. Subjects underwent single and double pulse stimulations to the sciatic nerve during prone lying, followed by electrical stimulation at 12 different phases of the gait cycle. For each phase, stimulus response curves were created in which maximal direct (M-wave) and afferent mediated responses (H-reflex) could be determined. Maximal H-reflex (Hmax) was normalized to maximal M-wave (Mmax) to create an H:M ratio that was used to compare modulation of the responses between phases and subjects. Electrical stimulation of the sciatic nerve elicited detectable H-reflexes in biceps femoris during prone lying and walking. The modulation of the response to afferent feedback is not the same for all phases of the gait cycle, particularly in late swing when it has a higher amplitude than the rest of the gait cycle. This modulation was not simply related to background EMG as would be expected during isometric contractions. Thus, there must be both central and peripheral influences on the response. Understanding the control of human locomotion is important for developing rehabilitation programs for patients with lesions of the central nervous system such as stroke or spinal cord injury.
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Jerome, Matthew. "Higher education: testing the efficacy of height adjustable sit-stand desks in college classrooms." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5525.
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Sedentary behavior has been found to have independent and negative associations with several cardiometabolic risk factors while interrupting prolonged sedentary time may ameliorate these associations. College classrooms are a traditionally sedentary microenvironment and understudied setting for sedentary interventions. Introducing sit-stand desks into college classrooms may be an effective and sustainable approach to reduce classroom sedentary time of college students. The objective of this study was to test the efficacy of replacing seated desks with sit-stand desks in a college classroom on student’s classroom standing time and sit-stand transitions, as well as health-related and academic behaviors.
We recruited 304 undergraduate college students taking one of 14 classes being taught in one of two small classrooms (25 seats per class) to participate. Using a cross-over design, each student’s classroom sitting and standing time were measured by self-report and objectively (direct observation via video camera surveillance) after having access to only seated desks or only sit-stand desks for six continuous weeks. A process evaluation survey was administered at the end of the study to explore student’s and instructor’s perceptions of the intervention and its impact on student engagement.
The results suggest that students stood about 9.1% of class time on average when given access to sit-stand desks and about 1.95% of class time when using traditional seated desks, as measured by objective video surveillance data. There was no significant change in sit-stand transitions between sit-stand desks and seated desks. Students reported that a number of academic and health outcomes were favorably impacted as a result of using the sit-stand desks. Social acceptability appeared to be the biggest barrier to use of the sit-stand desks. Overall, students reported a desire to use sit-stand desks again in future classes.
Students stood significantly more when provided access to sit-stand desks compared to seated desks. Sit-stand transitions were not significantly increased when sit-stand desks were implemented. Significantly more students reported improvements in academic and health related outcomes than students who reported declines in these areas as a result of using sit-stand desks. A majority of students reported they would use sit-stand desk again in the future and be supportive of adding sit-stand desks to other classrooms on campus. Sit-stand desks are a feasible environmental change in a college classroom to reduce student sedentary time.
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Curtis, Amanda Kay. ""Minimum essential adjustments": gender, physicality, and equality at the United States Military Academy, 1976-1980." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/2468.
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This study investigates the ways in which understandings of gender, physicality and equality influenced policy and thus constructed the identities and experiences of female cadets during the 1976 integration of women into the United States Military Academy at West Point. Policy decisions and the way in which they were put into practice set the precedent for all subsequent female cadets and so it is important to explore their origins and early impact. West Point is an ideal setting in which to explore two historically masculinist institutions, sport and the military, during a time when the women's movement was cresting and the military was redefining itself in a new post-Vietnam voluntary military. An exploration of the changing gender dynamics as this elite male military institution became co-ed at a particular historical moment shows that physicality was more integral to the process of integrating women than actual military training was.
This study is based on archival research conducted at the Special Collections and Archives of USMA and the personal accounts of female cadets who attended West Point from 1976-1980 to produce a qualitative picture of the integration of women into West Point. Focusing on military training, physical education, athletics, and covert training I found that women generally performed equally to men in military training yet struggled in certain aspects of physical training which seemed to validate those who doubted women's ability to be successful cadets. Women were also excluded from important physical activities because of "physiological differences," something that further served to separate them and construct them as "different" and "lesser." Based on the Academy's policy and practice with regard to physical training, along with a number of related matters, I conclude that while women were given equality in most respects, those in which they were not served to make them a second-class tier of cadet and soldier, judged not on combat and military skill and potential but rather on physical capabilities and attributes. As a consequence, even though West Point integrated women it did so in a way that served to protect the symbolic role of combat associated with masculinity.
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Dickerson, Nikolas. "Don't fear the reefer : producing the unproductive body in sport, film and advertisement." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/3283.
Full textAbstract:
This project examines mediated representations of marijuana users in film, advertisement, and sport. Situated within the recent Global Commission on Drugs denouncement of the War on Drugs, the rising medical marijuana movement, and the illegality of marijuana at the federal level in all fifty states, this project examines who gets to be a marijuana user in contemporary America. Using the tools of auto-ethnography, media analysis, genealogy, and narrative analysis this project deconstructs dominant conceptions about productive and unproductive bodies with a particular emphasis on the athletic body. How are we to understand a body that usually connotes exemplary health, and fitness when it uses a substance that is assumed to render the corporeal unproductive. In addition this project also explores how race and masculinity shape these understanding. A critical analysis of the narratives of five athletes- Michael Phelps, Tim Lincecum, Ricky Williams, Josh Howard, and Joakim Noah- provides the basis for deconstructing dominant understandings of the marijuana using body. This project seeks to generate new knowledge about the marijuana using body in order to help sick people obtain a helpful medicine and stop the imprisonment of non-violent drug offenders, who are disproportionately the poor and minorities.
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Barlow, Clifford William. "The role of potassium during exercise in heart failure." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240607.
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Brown, Stephen James. "Exercise induced damage to skeletal muscle and connective tissue." Thesis, University of Wolverhampton, 1997. http://hdl.handle.net/2436/88296.
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Lakomy, Henryk K. A. "Measurement of external power output during high intensity exercise." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/7511.
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Edens, Kolbi. "Effects of Evidence-Based Materials and Access to Local Resources on Physical Activity during Pregnancy." TopSCHOLAR®, 2019. https://digitalcommons.wku.edu/theses/3101.
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Pfeiffer, Beate. "Carbohydrate intake and metabolism during prolonged endurance exercise." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1091/.
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It is well accepted that CHO ingestion can improve endurance performance. However, a number of questions remain open regarding fine-tuning CHO intake recommendations during prolonged endurance events. A way to measure the bioavailability of ingested CHO is to measure exogenous CHO oxidation with the use of \(^{13}\)C or \(^{14}\)C tracers. This, however, has been studied only with CHO solutions, predominantly during cycling. In this thesis, we demonstrated that glucose+fructose ingested in the form of gel (1.8 g/min) is as effectively oxidized as an isocarbohydrate solution (1.44±0.29 g/min vs 1.42±0.23 g/min, respectively). Accordingly, the ingestion of glucose+fructose in a solid bar (1.55 g CHO/min) was demonstrated to be oxidized at high rates (1.25±0.15 g/min), comparable to a solution (1.34±0.27 g/min). A comparison of CHO ingestion (1.5 g/min) during cycling and running at the same relative, moderate-intensity (~60% exercise-specific VO\(_2\)max) resulted in similar exogenous CHO oxidation rates (1.25±0.10 g/min vs 1.19±0.08 g/min, respectively). The present thesis also tested the gastrointestinal (GI) tolerance of high CHO ingestion rates (1.4 g CHO/min), previously recommended to athletes. High intakes in the form of a glucose+fructose gel were, on average, well tolerated during a 16-km run, and there was no difference between tolerance of glucose and glucose+fructose gel. A questionnaire-based field study of 221 athletes during prolonged endurance events (running, cycling and triathlon) revealed that voluntary CHO intake rates vary greatly between events and individuals (6-136 g/h). High CHO intakes were related to increased scores for nausea and flatulence as well as to better performance. GI distress during all studies was correlated with a reported history of GI distress. Findings from those studies suggest a need for more individualized nutritional advice that optimizes CHO and fluid delivery to enhance performance, while minimizing GI discomfort
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Arroyo, Delgado Eliott. "Comparison of the Leukocyte Response to Interval Exercise versus Continuous Exercise." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1616695984469633.
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Douglass, Matthew D. "Age and muscle function : impact of aerobic exercise." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1391476.
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The purpose of this investigation was to comprehensively examine the influence of progressive aerobic exercise training on whole muscle size and function in older women (65-80 yr). Three sedentary, healthy, females (66±1 yrs, 167±2 cm, 70±7 kg) performed 12 weeks of supervised progressive cycle training (42 training sessions 3-4 sessions/week up to 80% HRR). Subjects were tested before and after training for maximum aerobic capacity (VO2max), quadriceps cross sectional area (CSA), whole muscle specific tension, concentric 1-RM, maximum voluntary contraction (MVC), and concentric peak power (wafts). On average, the three subjects improved VO2max (34%), quadriceps CSA (10%), MVC (37%), whole muscle specific tension (25%), and concentric peak power (19%). These positive changes indicate that aerobic exercise may positively influence muscle size and function in the elderly.School of Physical Education, Sport, and Exercise Science
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Alhowikan, Abdulrahman M. "Impact of exercise duration on maximal and sub-maximal markers during clinical cardio-pulmonary exercise testing." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3224/.
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Currently, the American College of Sports Medicine (ACSM) recommends that protocols for cardiopulmonary exercise testing (CPET) should last between eight and twelve minutes. However, the justification for these exercise durations rely on limited experimental data. These recommendations have a significant impact on the ability of frail patients to be assessed using CPET and should conform to evidence based practice. This thesis begins by assessing the validity of these recommendations in relation to maximal exercise responses before assessing the consequences of these recommendations on sub-maximal exercise measurements. These studies were conducted in a relatively large cohort (compared to the study that underpins the ACSM guidelines) of heterogeneous volunteers (they are both men and women, with a significant age range and varied functional capacity) to make the data more relevant to clinical exercise testing. The data presented in chapter three demonstrate that it is very difficult to obtain exercise duration conforming to the current ACSM guidelines by using a standardised ramp exercise protocol on both treadmill and cycle ergometer exercise. However, sub-group analyses for those subjects who achieved moderate (8-12 minutes) and short (less than 8 minutes) exercise durations. In addition, a separate analysis was carried out for a different sub-group of those who achieved moderate (8-12 minutes) and long (more than 12 minutes) of durations of exercise. Despite this, it was possible to demonstrate in sub-group analysis that there was no significant difference in peak oxygen uptake, peak carbon dioxide output, peak heart rate, peak ventilation and peak power output when exercise duration was less or more than that prescribed by the ACSM recommendations. In addition, the effects of long, moderate or short duration exercise per se were also analysed in this chapter and again exercise duration was shown to be without effect on the main maximal markers of exercise performance. In chapters four, five and six, the initial findings were extended to determine the effects of exercise duration on a range of clinically relevant sub-maximal markers of exercise performance. It was likely, since exercise duration did not affect maximal exercise that the physiological determinants of maximal performance were not significantly altered during short or long duration exercise and consequently it was likely that sub-maximal markers of functional capacity would not be affected. However, the quality of the data obtained during CPET can obviously influence the accurate measurement physiological responses during exercise and much of the analysis in these chapters focused on the validity of the data analysis. Chapter four investigated the limitations to measuring the break point in the relationship between oxygen uptake and carbon dioxide output during progressive exercise (the so called ventilatory threshold or ‘V-slope’). The accurate measurement of this break point was determined by standard gas exchange criteria and the effects of reducing the data available for analysis (by reducing the amount of breaths available for comparison at reduced exercise durations) were examined. The data showed that reducing the data available for analysis had an impact on the quality of the data (decreasing the goodness of fit) but no significant effect on the determination of the ventilatory threshold. Chapter five determined the effects of exercise duration on the oxygen uptake efficiency slope (OUES). As expected, the effects of exercise duration were not significant but additional investigation into the commonly employed data analysis procedures was performed. These data show that the log transformation of the relationship between ventilation and oxygen uptake allows reliable assessment of ventilatory efficiency in most cases, however, the impact of the lactate threshold on ventilation and the biological variability in where the threshold occurs as a proportion of functional capacity can impact on the sensitivity of this measurement to predict aerobic and/or anaerobic capacity. Chapter six determined the effects of exercise duration on the breathing reserve index and found no significant difference during short, moderate or long exercise duration exercise. Further analysis was performed to demonstrate limitations in the use of predicted maximum voluntary ventilation (rather than direct measurement). Taken together, these data demonstrate that the current ACSM recommendations for CPET are too restrictive and may limit the application of such testing in populations that cannot exercise for between eight and twelve minutes. The data further suggest that the testing and analysis procedures used during CPET are central to producing valid maximal and sub-maximal markers of functional capacity and the recommendations should focus include guidelines in relation to such aspects.
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Hudson, Annette. "Low intensity exercise, functional capacity and lipoprotein metabolism in women." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/27954.
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Walters-Edwards, Michelle. "Exercise-related sensorimotor and neuromuscular performance of the knee joint." Thesis, Bangor University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288129.
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Child, R. B. "Exercise and free radical induced damage to human skeletal muscle." Thesis, University of Wolverhampton, 1997. http://hdl.handle.net/2436/96616.
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Jentjens, Roy Leonardus Paulus Gerardus. "The role of carbohydrate in exercise metabolism, performance and recovery." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271380.
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Claxton, David B. "The measurement of oxygen uptake kinetics in children." Thesis, Sheffield Hallam University, 1999. http://shura.shu.ac.uk/3152/.
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Traditional approaches to exercise testing in children may not provide the most appropriate measures of a child's physiological responses to exercise, partly because they do not reflect children's normal intermittent activity patterns. The measurement of the rate and magnitude of change of oxygen uptake to dynamic exercise, oxygen uptake kinetics (V02 KINETICS provides an alternative approach to exercise testing. A submaximal, intermittent, pseudo-random binary sequence (PRBS) exercise test to measure V02 KINETICS may provide a useful method of measuring the metabolic responses of children to exercise. Traditional methods used in the analysis of V02 KINETICS require the fitting of explicit models in order to characterise the data. These models have not however been validated for use in children. As the responses to the PRBS protocol are analysed in the frequency domain, explicit models and their physiological correlates are not required to characterise the data. Another potential problem in the measurement of V02 KINETICS in children are the small work rate changes that can be employed to stimulate the exercise response whilst constraining the test to the aerobic range. In respiratory gas measurement, breath-by-breath variability (noise) can be large in comparison to the magnitude of the metabolic response and this signal noise can obscure some characteristics of the response. The aim of the study was to develop appropriate measurement techniques to reduce the effects of breath-by-breath variability and to apply the techniques to the measurement of V02 KINETICS in children. The main experimental study compared the V02 KINETICS of children with those of adults. Ten children (3 females) in the age range 8 to 13 and twenty adults (10 females) in the age range 20 to 28 years completed a PRBS test to measure V02 KINETICS and an incremental ramp protocol on a cycle ergometer (Bosch 550 ERG) to establish V02 MAX, T VENT and delta efficiency. Breath-by-breath respiratory gas analysis was undertaken using a respiratory mass spectrometer (MGA1100). Estimates of alveolar gas exchange were made using the algorithm of Beaver et al. (1981) and a post hoc value of an effective lung volume was calculated to minimise the breath-by-breath variability. A cross-correlation technique (CC) was used to filter out the effects of anomalous (nonphysiologic) V02 responses recorded during the PRBS protocol. Subsequent Fourier analysis of the auto-correlation and CC functions provided a description of V02 KINETICS in the frequency domain in terms of amplitude ratio and phase delay over the frequency range of 2.2-8.9mHz. At each of the frequencies assessed amplitude ratio was higher in children (P<0.001) than in either of the adult groups. Phase delay was also significantly shorter in children compared to adults males (P<0.01) and adult females (P<0.001) but this effect was not identifiable at any specific frequency. Maximal oxygen uptake was not significantly different in adult males (42.5 ml"kg "min) and children (44.7 ml-kg'-min') but was lower in adult females (36.9 ml"kg "min) than adult males (P<0.01) and children (P<0.001). Ventilatory threshold (% V02 MAX) was not different between groups. Delta efficiency was significantly lower in children than adult males (P<0.05) and adult females (P<0.01). These results support the contention that there are maturational differences between adults and children in the metabolic processes involved in the utilisation of oxygen during physical activity. It has been argued, theoretically, that in adults the control of V02 KINETICS is driven by ATP demand in the skeletal muscle. As the mitochondria] capacity and the concentration of oxidative enzymes is higher in children than in adults it is likely that the controlling factor(s) for V02 KINETICS in children also relates to some aspect of peripheral metabolism. It is suggested that the PRBS protocol, with appropriate noise reduction techniques, is considered a suitable method for investigating the metabolic responses of children to dynamic exercise.
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Williams, Craig. "Peripheral muscle fatigue during intense exercise." Thesis, University of Chichester, 2005. http://eprints.chi.ac.uk/840/.
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The role of adenine nucleotide metabolism is central to the electro-mechanical processes in muscular contraction. Interventions which alter the cellular micro-environment can impact on the fatigue response during exercise possibly mediated by the balance between ATP and ADP. This thesis examined the response of biochemical and physiological markers of muscle fatigue in dietary interventions aimed to alter the cellular environment. Contractile measures included force and relaxation times from contractions of the knee extensors, whilst biochemical markers included anunonia and lactate after voluntary isometric and incremental cycle exercise. Evoked contractile measurements afforded experimental objectivity independent of voluntary intervention whilst the voluntary measures afforded greater transferability. In Chapter 3 the relaxation time response to a train of evoked fatiguing contractions varied depending on the choice of relaxation method (upper exponential, lower exponential, 60-40 exponential, 100-75,95-45,75-37.5,75-25%). Methods describing the earlier portions of the relaxation curve slowed less during fatigue than those comprising the latter portions. Intra-session variability ranged from 1.3 to 5.02% and inter-session variation ranged from 2.85 to 6.97% dependent upon the adopted relaxation method. Such variability was comparable with other laboratories demonstrating significant intervention-induced changes. This has implications for future studies in the choice of relaxation method and magnitude of change necessary for identification of intervention-induced changes. In chapter 4 the magnitudes of change in MVC and time to fatigue in a voluntary isometric contraction between creatine and placebo supplementation were -3% and 2% respectively. The fatigue-induced slowing of evoked relaxation times was greater by -4% and these changes were not significant. The differences in markers of adenine nucleotide degradation after creatine and placebo supplementation were also insignificant. In chapter 5 the creatine supplementation-induced change in the decline in evoked force during a fatiguing train was -1 % but was insignificant. For the voluntary and evoked relaxation times, in chapter 5, the magnitude of changes between placebo and creatine supplementation were <1 %, and insignificant. The ingestion of NaHCO, accelerated the loss of evoked force during a fatiguing train, with a trend towards shorter relaxation times that was only evident in the 100-75% method. Bicarbonate ingestion resulted in higher plasma lactate but had minimal effect on markers of adenine nucleotide degradation. The rate of evoked force loss was greater when muscle glycogen stores were reduced by exercise and low CHO diet and this trend was reversed by additionally supplementing with creatine, but this was not associated with similar trends in markers of nucleotide degradation during incremental cycling. A novel finding of this study was that reducing muscle glycogen resulted in a more severe slowing of relaxation times that was reversed when combined with creatine supplementation. In this thesis the changes in the biochemical markers of ADP homeostasis (NH,) by dietary interventions were insignificant. However, the force and relaxation time responses may highlight the functional importance of maintaining ADP homeostasis. The fatigue-induced slowing of evoked relaxation times was different depending on the chosen method. Despite a smaller relative slowing during fatigue the 100-75% method appeared to be most sensitive to dietary interventions.
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Pegoraro, Roger V. "Electrical train stimulation to assess exercise associated muscle cramp." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2010. https://ro.ecu.edu.au/theses/1845.
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Muscle cramp is a forceful, involuntary contraction of skeletal muscle, but its underlying mechanisms are not well understood. Our limited understanding of muscle cramp may be due to its unreliable occurrence. Electrical train stimulation (ETS) has been reported to induce cramp in the small flexor muscles of the foot, and a relationship exists between the threshold frequency (TF) of ETS to induce cramp and muscle cramp susceptibility. The use of ETS to induce muscle cramp in the calf muscles however may be challenging, and the test-retest reliability of this method has not been examined in the calf muscles. Since athletes can experience muscle cramp in the calf muscles, in turn affecting their athletic performance, it is necessary to establish a method to assess calf muscle cramp. The first purpose of this study therefore was to determine the usefulness of the ETS application to the calf muscles, along with its reliability. Using a Compex 2 stimulator, ETS was applied to the calf muscles of both dominant and non-dominant legs in 10 men (33.5 ± 8.4 y) who reported experiencing cramp during training or competition. Each leg was treated separately in a counterbalanced order, with subjects in the supine position and legs supported by a bench that fixed the ankle at maximal plantarflexion. ETS consisted of 2 s (including 500 ms ramp time) of 300 μs square pulsed waves followed by 30 s rest. ETS commenced with two bouts of stimulation at 10 Hz during which the stimulation intensity was increased to the maximum tolerated, with values of 46.9 ± 6.5 and 45.4 ± 7.7 mA for the dominant and non-dominant legs, respectively. Subsequent stimulation trains increased by 3 Hz until cramp occurred, as confirmed by a spontaneous electromyograph (EMG) signal. The protocol was repeated 30 min after the first test, with the entire testing procedure repeated seven days later. Muscle cramp was induced in all subjects, but the TF varied amongst subjects (13-55 Hz). Mean TF value to induce muscle camp for the dominant leg was 25.0 ± 7.6 Hz for the first test and 23.7 ± 5.0 Hz for the second test. The non-dominant leg also showed similar values. Test-retest reliability, as indicated by the intraclass correlation coefficient (ICC), limits of agreement (LOA) and coefficient of variation (CV), were 0.94, 5.4 % and 9.2 %, respectively for the dominant leg, and 0.72, 9.8 % and 15.4 %, respectively for the non-dominant leg. These results show that ETS can induce muscle cramp in the calf muscles and that the TF of ETS was a reliable measure to assess the calf muscle cramp susceptibility. The second purpose of this thesis was to examine the influence of fatigue on the TF of ETS-induced muscle cramp in the calf muscles of 10 men (35.8 ± 9.2 y) who reported experiencing cramp during sporting activity. The previously described methods were used to assess muscle cramp in the calf muscles of the subject’s dominant leg with a stimulation intensity of 49.3 ± 4.9 mA before, immediately after, and 30 min after exercise. Exercise consisted of uphill treadmill walking, standing calf raises, skipping, drop jumps and cycling to fatigue, which was completed in 82.9 ± 2.0 min at an average heart rate of 141.7 ± 6.0 bpm. An isokinetic dynamometer was used to measure plantarflexor muscle torque of the dominant leg before and immediately after exercise, and following 30 mins of passive recovery. Blood and urine samples were obtained to assess electrolyte concentrations and hydration status before and immediately after exercise. Plantarflexor muscle torque decreased significantly (p < 0.05) approximately 20 % from the baseline (42.4 ± 17.1 Nm) immediately post exercise (34.6 ± 14.9 Nm), and was still significantly lower at 30 min post-exercise (37.4 ± 15.9 Nm). Serum (4.32 ± 0.35 vs 4.66 ± 0.38 mmol/L) and urine (56.3 ± 38.6 vs 87.2 ± 40.8 mmol/L) potassium concentrations, urine osmolality (551.1 ± 306.6 vs 683.9± 236.6 mmol/L), and urine specific gravity (1.014 ± 0.008 vs 1.022 ± 0.009) changed significantly from pre to post exercise, but serum osmolality, serum sodium and urine sodium concentrations remained unchanged. No significant changes in TF were evident before (23.2 ± 6.0 Hz), immediately after (22.6 ± 5.1 Hz) and 30 min post-exercise (25.3 ± 7.4 Hz). These results suggest that neither fatigue nor mild changes in hydration status affect the TF. Nevertheless, the duration of exercise used in this study might not have been sufficient to cause the physiological changes that may occur during training or racing. As muscle cramp can reliably be assessed by ETS, future investigations should use this method to uncover potential mechanisms related to muscle cramp, such as body temperature, hydration status and electrolyte concentrations.
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Jackson, Dwayne N. "Baroreceptor influence on post-exercise warm thermal response thresholds." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ57124.pdf.
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Fletcher, Gareth. "Dietary influences on exercise metabolism, health and endurance performance." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7244/.
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The capacity to oxidise lipid whilst physically active has been associated with markers of metabolic health and exercise performance. In a group of 305 active men and women, this thesis observed a substantial 6 fold inter-individual variability in the capacity to oxidise lipid during exercise, and explains 46% of the variability. This was largely attributed to aerobic capacity, biological sex, self-reported physical activity level and body composition, with new information provided to show that the dietary intake of carbohydrate and fat is also a significant contributor (~3%) to the explained inter-individual variability. Prior research in men, demonstrates that high fat, low carbohydrate diets enhance lipid oxidation during exercise. This thesis demonstrates that, like men, women respond to short-term (5 day) high fat, low carbohydrate diets by considerably (33%) increasing lipid oxidation during exercise. Further, by using a short term hypercaloric ‘fat supplementation’ without carbohydrate restriction diet, which did not alter lipid oxidation during exercise, this thesis suggests that carbohydrate restriction, not increased fat intake, drives the increased lipid oxidation observed during high fat, low carbohydrate diets. Finally, short-term dietary fat manipulation appears to have minimal impact upon markers of metabolic health or endurance exercise performance in the well-trained women studied.
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Denis, Paul. "Muscle temperature transients and post-exercise esophageal temperature elevation." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6309.
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The primary purpose of this research was to study esophageal temperature elevation and quadriceps and triceps intra-muscular temperature gradients during resting recovery from exercise. Eight physically active male participants and 24 +/- 4 years of age, rested in a buttocks supported upright posture for a 50 +/- 12.5 minutes in ambient conditions of 24.7 +/- 1.17°C and 24 +/- 4.6% relative humidity. Participants then performed a steady state cycle ergometry exercise at 70% VO2 max, until they reached until heat produced by exercise above metabolic rate accumulated to 1000 kJ. This was followed by 120 minutes of resting recovery. Active intra-muscular temperature was measured in the vastus medialis at four depths, with the tip of the probe being at 10 mm from the femur and deep femoral artery and the others sensor at 15, 30 and 45 mm from the tip of the probe. Pre-exercise resting esophageal temperature and quadriceps intra-muscular temperatures were 36.95 +/- 0.22°C (Tes), 36.31 +/- 0.39°C (Tmuq1), 36.10 +/- 0.50°C (Tmuq2), 35.75 +/- 0.84°C (Tmuq3) and 35.33 +/- 0.88°C (Tmuq4) respectively. Exercise resulted in a 0.94 +/- 0.32°C increase in esophageal temperature above pre-exercise resting values. End of exercise intra-muscular quadriceps temperatures were 38.81 +/- 0.42°C (T muq1), 38.61 +/- 0.60°C (Tmuq2), 38.13 +/- 0.75°C (Tmuq3) and 37.71 +/- 0.96°C (Tmuq4 ). Esophageal temperature remained significantly elevated from pre-exercise resting values for 10 minutes following exercise. These results indicate that post-exercise esophageal temperature elevation, following cycle ergometry exercise, is not dependent on a temperature gradient between esophageal temperature and deep muscle temperature from the previously active muscle. Further, a prolonged and sustained post-exercise esophageal temperature was not demonstrated following this cycle ergometry exercise.
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Limire, Bruno. "Cold water immersion after exercise-induced hyperthermia." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27703.
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Cold water immersion (CWI) is the most effective known cooling treatment against exercise-induced hyperthermia. However, sex differences related to body composition (i.e. body fat, muscle mass, surface area, etc.) may affect core cooling rates in hyperthermic males and females.
Purpose. To determine sex related differences in core cooling rates during CWI after exercise-induced hyperthermia.
Methods. Ten male (M) and nine female (F) participants matched for body surface area to mass ratio took part in this study. Participants exercised at 65% V˙O2max at an ambient temperature of 40°C until rectal temperature (Tre) increased to 39.5°C. Following exercise, subjects were immersed in a 2°C circulated water bath until Tre decreased to 37.5°C.
Results. Females had a significantly greater core cooling rate compared to males. This was paralleled by a lower skin temperature and a shorter time to reach the exit criterion.
Conclusion. We conclude that previously hyperthermic females have a 1.7 times greater Tre cooling rate compared to males. We attribute this difference to a smaller lean body mass (expressed by the body-surface-area-to-lean-body-mass ratio) in females compared to males.
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Budiono, Boris. "Mechanisms & Properties of Exercise-Induced Cardioprotection." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/370629.
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Regular physical activity, or exercise, is beneficial in the maintenance of health and
wellbeing of the human body. With respect to the cardiovascular system, the potential benefits of
physical activity in the prevention, reduction of frequency and severity, and enhanced
rehabilitation, of heart disease are clear. However, many questions remain regarding factors such
as the mode, duration, and intensity of physical activity and the cardiac impacts of these variables.
Moreover, underlying mechanisms remain to be detailed. The current narrative from health
organisations and governments worldwide has been the mantra of ‘exercise is medicine’, with a
two-pronged approach: to enable the population to meet the minimum standards of daily physical
activity, and to limit the amount of extended sedentariness. What is clear is that very few meet
these standards, and heart disease, along with other associated chronic diseases attributed to a
lack of activity and suboptimal diet, remain top of the list for all-cause mortality and morbidity.
The issues pertaining to this problem are as broad as the benefits of exercise itself, and they include
behavioral and societal issues beyond the scope of this thesis. The experiments in this thesis aim
to specifically investigate the molecular underpinnings of the cardiac and systemic changes that
occur in the exercised body. With this knowledge, it is possible to proceed further with potential
solutions, such as: personalised exercise protocols for a specific health outcome, determination of
short-term, long-term, and lifelong effects of activity or inactivity, and development of agents that
may mimic or promote some of the benefits of exercise, especially for those unable to undertake
physical exertion.
The first experimental studies in this thesis investigated whether short-term voluntary wheelrunning
in 8-week old mice beneficially modulates myocardial ischemic tolerance, signaling
kinases, and gene expression patterns (Chapter 3). Transcriptome analysis can provide insight into
molecular mechanisms. Prior animal studies have utilised forced activity measures, such as
treadmill running, expecting increases in heat shock protein or any other canonical stress
responses. However, we employed voluntary wheel-running as a ‘low-stress’ method to assess
responses to ischaemia-reperfusion insult. Phenotypic results showed that 1 week of wheelrunning
improved left ventricular developed pressure recovery from 25 min ischaemia/45 min
reperfusion (by 47%) and reduced diastolic dysfunction (by 30%). Analysis of known pro-survival
proteins showed limited changes, with only a 30% increase in cytosolic ERK1/2, whilst there were
no differences in total Akt, GSK3β and phospho-Akt, -GSK3β and -ERK1/2. Microarray
interrogation identified significant changes (!1.3 fold expression change, "5% FDR) in 142 known
genes, the majority of which (92%) were repressed. Significantly modified pathways/networks
related to inflammatory/immune function (particularly interferon-dependent), together with cell
movement, growth, and death signalling. Of only 14 induced transcripts, 3 encoded interrelated sarcomeric proteins titin, #-actinin, and myomesin-2.
The next series of studies were designed to investigate the sensitivity of cardiac ischaemictolerance
to both activity and inactivity. Studies assessed cardiac effects of voluntary activity (14
days) in running-naïve mice (Active), 7 days of subsequent inactivity (Inactive), and brief (3 day)
restoration of running (Re-Active); and tested whether 'cardiac:activity coupling' reflects common
modulation of pro-survival (AKT, AMPK, ERK1/2, HSP27, EGFR) and -injury (GSK3$) proteins
implicated in ischaemic preconditioning/calorie restriction responses (Chapter 4). Active mice
increased running speed and distance by 75-150% over 14 days and their hearts were significantly
resistant to post-ischemic dysfunction following 25 min ischaemia (40-50% improvements in
functional outcomes). This protection was accompanied by ~2-fold elevations in AKT, AMPK,
phosphorylation, and EGFR expression. Ischaemic tolerance was reversed in Inactive hearts,
and ERK1/2 phosphorylation (with AKT, AMPK, HSP27 phosphorylation unaltered). Running
characteristics, cardioprotection, EGFR expression and GSK3$ all returned to Active levels within
1-3 days of restored activity (with no significant changes in AKT, AMPK, HSP27 phosphorylation).
These data reveal sensitive coupling of myocardial stress-resistance to activity level, and show that
only initial activity in running-naïve animals induces a molecular profile characteristic of
and EGFR modulation more consistently parallel both activity- and inactivity-dependent shifts in
myocardial stress resistance. The findings also suggest a particular importance of recent activity
level in governing ischaemic tolerance of the heart.
After initial identification and characterisation of a cardioprotective phenotype of voluntary wheelrunning,
and analysis of responses to activity/inactivity transitions, a time-course analysis was
undertaken to determine whether dose-dependence existed in terms of wheel running, cardiac
protection and expression of survival and stress kinases. Interestingly, studying the effects at 2-, 7-
, 14-, and 28-days of running revealed maximal protection with only 7 days of VWR, and no
further improvements with longer running periods. Improvements in ischaemic tolerance were
associated with increased cardiac expression of phospho-AKT, phospho-GSK3$, phospho-ERK and
to a lesser degree, phospho-AMPK. Running also differentially modified gene transcription, with
potentially beneficial up-regulation of determinants of contractile function (Ttn), caveolar
signalling (Cav3) and mitochondrial biogenesis (Pgc1a), vs. repression of injurious/degradative
Mmp2 (and mitochondrial ketone metabolism - Bdh1). Intriguingly, I-R tolerance was also
improved in both 2EX and 2SED groups (i.e. independent of running) vs. mice subjected to longer
sedentary periods, suggesting a cardioprotective effect of environment enrichment independent of
running activity.
Given an absence of impact of running duration on the cardioprotected phenotype, final studies
were designed to test effects of differing periods of a more intense (potentially stressful) forced
swimming protocol (Chapter 6). Swimming is a well-known inducer of physiological
growth/hypertrophy, which itself may promote greater resistance to ischemia-reperfusion injury.
After an initial acclimation period, mice were assessed after 1 and 2 weeks of intensive swim
training and shown to exhibit modest cardiac hypertrophy (15% and 22% increases in heart:body
weight, respectively). Improved contractility and improved functional outcomes from I-R insult
was observed at 2 wks, but not 1 wk of swimming, contrasting voluntary running. Molecular
analyses in the 2 wk group revealed a reduction in NFkB expression without changes in prosurvival
kinase or caveolin-3 expression. Exploratory proteome arrays support differential changes
in growth factor signalling, and beneficial shifts in mediators of inflammation and remodelling in
other tissues (pancreas, white fat, thymus, lymph nodes, brain), involving a pattern of RANTES,
ICAM1 and MMP9 repression vs. LIF and VEGF induction across most tissues. It is likely these
cardiac and systemic shifts in growth factor and inflammatory signalling participate in beneficial
cardiovascular impacts of exercise.
Collectively, the studies within this thesis reveal close coupling between physical activity level
(both increased or decreased) and myocardial ischemic tolerance. While many potentially
beneficial adaptations in cardiac protein expression and signalling arise, only a handful are
consistently linked to cardiac ischemic tolerance including GSK3$ phospho-regulation and
expression of the EGFR receptor. Signalling via GSK3$ has been identified as a potentially valuable
target, while these are the first data to support a role for altered EGFR signalling in coupling cardiac
stress phenotype to physical activity level. Data are also incompatible with the view that exercise
represents a physiologic corollary of ischemic preconditioning or calorie restriction responses
(except perhaps in exercise naive subjects, in which this physiologic stimulus may present a greater
'stress'). Finally, the studies also reveal a diversity of beneficial changes in inflammatory, RTK and
growth factor signalling in the heart and systemically, highlighting the integrative nature of the
response to exercise. Unravelling these interactions is a challenge, yet may provide insights not only into normal physiology but management of heart disease and its consequences.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School Allied Health Sciences
Griffith Health
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Lee, Jonah D. "The effects of pre-exercise carbohydrate supplementation on anaerobic exercise performance in adolescent males." Virtual Press, 2007. http://liblink.bsu.edu/uhtbin/catkey/1366300.
Full textAbstract:
This study examined the effects of pre-exercise carbohydrate (CHO) supplementation on anaerobic exercise performance in adolescent males (n =11; 15.0 ± 0.9 yrs). On separate days, subjects consumed either a CHO or a placebo (PL) beverage followed by 2 Wingate anaerobic tests (WAnT) separated with ten by 10-second sprints. Peak (PP), mean power (MP) and fatigue index (FI) were assessed. Venous blood samples were obtained and analyzed for glucose, lactate, insulin, and catecholamines. A trial by time ANOVA (P < 0.05) was used in the analysis. PP and MP tended to be higher (P < 0.09) in CHO versus PL, and MP tended to decline more in CHO (P < 0.06); Fl for the two WAnT were similar. Glucose concentration significantly increased after CHO consumption and then returned to baseline post-exercise, whereas glucose level remained unchanged over time during PL; similarly observed for insulin. Lactate and catecholamine levels significantly increased over time, but a trial difference was only observed in epinephrine. The tendency for PP and MP to be higher in CHO might suggest a potential ergogenic benefit of pre-exercise CHO although the change in MP over time in CHO and the similarity in Fl might suggest otherwise.School of Physical Education, Sport, and Exercise Science
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Stade, Makenzie R. "The Physiological Effects of Wearing a Compression Garment during Resistance Exercise." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10638611.
Full textAbstract:
The purpose of this study was to evaluate the physiological effects of wearing a compression garment during resistance exercise. Muscle oxygenation and torque production were measured during exercise and leg circumference, ratings of perceived muscle soreness (RPMS) and plasma creatine kinase (CK) before, immediately after and 24, 48 and 72 hours after exercise were compared between two exercise trials: 1) wearing compression tights and 2) without compression (wearing loose fitting shorts).
The results suggest that compression did not attenuate muscular fatigue or damage as no differences between conditions for leg circumference, RPMS, plasma CK and average torque were observed. Concentrations of hemoglobin (Hb) and total Hb (tHb) were reduced during exercise with compression. Additionally, Hb was reduced and tissue oxygenation index (TOI) was increased post-exercise with compression. These findings suggest that wearing a compression garment during resistance exercise may improve venous return and the re-oxygenation of muscle tissue.
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Harris, Ryan A. "The flow-mediated dilation response to acute exercise in overweight men." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3274243.
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Mercer, Thomas H. "The validity of exercise intensity regulation via exertional perceptions and preferences." Thesis, Staffordshire University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272901.
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Galloway, Stuart D. R. "Ambient temperature and exercise capacity : effects of substrate and fluid provision." Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338331.
Full textAbstract:
This series of studies began with an examination of the effects of ambient temperature (4°C-31°C) on exercise capacity at approximately 70% of VO2max. In this first study, exercise capacity was greatest at 11°C (93.5(16.4) min) and shortest at 31°C (51.6(10.5) min) with intermediate exercise times at 4°C (81.4(27.2) min) and 21°C (81.2(16.3) min). In the trial at 31°C, Tre, Tsk, HR, RPE, and sweat rate were all significantly higher and total CHO oxidation was significantly lower than during any other trial. At 21°C Tre, Tsk, and sweat rate were all significantly higher, and total CHO oxidation lower, than during the 4°C and 11°C trials. These results suggest that heat stress and subsequent failure of thermoregulation or circulatory collapse rather than complete depletion of endogenous muscle glycogen were the possible limiting factors during exercise at 21 and 31°C. At 4°C and 11°C total CHO oxidation was similar suggesting that CHO depletion may have limited exercise capacity in these trials. The reduced exercise capacity at 4°C compared to 11°C can be explained by the observed increase in the rate of CHO oxidation during exercise in the 4°C trial. The second study of this series examined exercise capacity at approximately 60% of VO2max in a hot (30°C) environment with ingestion of either a dilute CHO drink (2%) aimed at fast fluid replacement or a concentrated CHO drink (15%) aimed at CHO provision. In this study we clearly observed that a 2% drink was most effective in delaying the onset of fatigue during prolonged exercise at 30°C but a 15% drink was also effective at delaying fatigue when compared with no fluid. The results of the studies performed in this series have implications for the optimisation of exercise performance in different environmental conditions and indicate that a drink with low CHO content and an emphasis on fluid replacement would be preferential in both cold and hot environments.
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Ball, Derek. "Diet, acid-base status and the performance of high intensity exercise." Thesis, University of Aberdeen, 1992. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU045175.
Full textAbstract:
The aim of the present experiments was to investigate the effects of dietary components and composition on acid-base status. It was hoped that those dietary components which exert the greatest effect on acid-base would be identified. In a second series of experiments the role of diet-induced changes on the performance of high intensity exercise was investigated. The sodium salts of weak organic acids were administered after an overnight fast and their effects on blood acid-base status were observed. An alkalinising effect on blood and urine was observed over 3 and 24 hours respectively. In the next study the sodium salts were administered for five consecutive days; blood and urine acid-base status were measured 24 hour after ingestion. Under these circumstances the salt-induced alkalosis was only observed on urine. Blood acid-base status had, after 24 hours, returned to pre-ingestion values. The alkalinising effect on urine was sustained for as long as the sodium salts were consumed. However, upon cessation of the salt ingestion urine acid-base status had returned to the pre-ingestion values within 24 hours. In the third experiment the chronic effects of different macro nutrient intakes was investigated in two groups of matched female subjects. The omnivorous group had a higher dietary intake of protein than the vegetarian subjects. There was no biologically significant difference in blood acid-base status between the two groups. As a consequence of the higher protein intake the urinary titratable acid output of the omnivorous women was higher than that of the vegetarians. Despite the same dietary intake of calcium the omnivorous subjects had a higher urinary excretion of calcium than the vegetarians. It is thought the acidifying effect on urine from the higher protein intake of the omnivorous women was responsible for their greater urinary calcium excretion.