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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Desenvolvimento de dispositivo de fototerapia para aumento de desempenho e recupera??o do exerc?cio f?sico de alta intensidade e curta dura??o

Telles, Maria Cec?lia 11 March 2014 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-18T12:20:01Z No. of bitstreams: 2 maria_cecilia_telles.pdf: 1910894 bytes, checksum: e7e1e8aa0a80714349919c73969b73cd (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-18T12:21:47Z (GMT) No. of bitstreams: 2 maria_cecilia_telles.pdf: 1910894 bytes, checksum: e7e1e8aa0a80714349919c73969b73cd (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-18T12:21:42Z (GMT) No. of bitstreams: 2 maria_cecilia_telles.pdf: 1910894 bytes, checksum: e7e1e8aa0a80714349919c73969b73cd (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-18T12:22:17Z (GMT) No. of bitstreams: 2 maria_cecilia_telles.pdf: 1910894 bytes, checksum: e7e1e8aa0a80714349919c73969b73cd (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Made available in DSpace on 2014-12-18T12:22:17Z (GMT). No. of bitstreams: 2 maria_cecilia_telles.pdf: 1910894 bytes, checksum: e7e1e8aa0a80714349919c73969b73cd (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Previous issue date: 2014 / Introdu??o: A capacidade de um indiv?duo gerar e manter pot?ncia pico elevada ? fundamental para o desempenho no exerc?cio f?sico de alta intensidade. Assim, o desenvolvimento e o estudo de novas tecnologias que possam aprimorar a desempenho ou minimizar a ocorr?ncia de les?es durante a recupera??o de exerc?cio de alta intensidade poderiam contribuir para a melhora da prepara??o e planejamento do treinamento. Objetivos: Confeccionar um aparelho para terapia com diodo emissor de luz, em um ?nico comprimento de onda, com uma maior ?rea de irradia??o e avaliar a influ?ncia desta terapia no desempenho f?sico, bem como em componentes metab?licos, par?metros inflamat?rios e de les?o muscular durante o per?odo de recupera??o de exerc?cio de alta intensidade e curta dura??o (30-s) no cicloerg?metro em homens fisicamente ativos e ciclistas. Metodologia: Primeira fase: (Estudo 1) Realizou-se estudo randomizado e balanceado para avaliar o desempenho, onde foram irradiadas 4 doses de terapia LED: LED placebo (0 J/cm2), LED 21s (3,6J/cm2), LED 42s (7,2J/cm2), LED 84s (14,4J/cm2), em dias distintos, com 24h de intervalo, antes de cada teste de Wingate (TW). (Estudo 2) 4 homens foram submetidos a coletas de sangue antes e ap?s (3, 60, 120 minutos e 24 horas) a realiza??o de TW para mensura??o das concentra??es plasm?ticas de CK, PCR, FIB. Segunda fase: (Estudo 3) Realizou-se estudo randomizado e balanceado onde foi realizado 2 TW, antes e ap?s tratamento com LED placebo(0 J/cm2) ou experimental (3,6J/cm2) em dias distintos, com 24h de intervalo para avalia??o do desempenho f?sico. Coletas de sangue antes o primeiro TW, bem como 3 minutos ap?s o primeiro e segundo TW e 24 horas ap?s o segundo TW foram realizadas para mensura??o de CK, PCR e FIB. A concentra??o sangu?nea de am?nia foi mensurada antes do primeiro TW e 4 minutos ap?s o segundo TW. Terceira fase: (Estudo 4) Realizou-se estudo randomizado e balanceado onde tr?s doses de terapia LED foram testadas: LED placebo (0 J/cm2), LED 23s (3,94 J/cm2) ou LED 46s (7,88 J/cm2), em dias distintos, com 24h de intervalo para avalia??o do desempenho f?sico. (Estudo 5) Realizou-se estudo randomizado e balanceado onde ciclistas foram submetidos a 3 condi??es experimentais: terapia LED, aquecimento no cicloerg?metro e controle, em dias distintos, com 24h de intervalo, antes de cada TW. Vari?veis de desempenho f?sico e atividade eletromiogr?fica do m?sculo vasto lateral foram avaliadas durante os 3 TW. Coletas de sangue antes, imediatamente ap?s cada condi??o experimental e 3 e 4 minutos ap?s o TW foram realizadas para mensura??o de lactato e am?nia. Resultados: O prot?tipo 1 e 2 n?o foram eficazes na melhora do desempenho f?sico de alta intensidade e curta dura??o, bem como em componentes metab?lico, par?metros inflamat?rios e de les?o muscular. Al?m disso, o TW pareceu n?o ter dura??o suficiente para promover les?o muscular e consequente altera??o em componentes metab?licos e inflamat?rios. A modalidade de aquecimento levou a melhora do desempenho f?sico quando comparada com a terapia LED e controle. Conclus?o: Os achados dos estudos realizados n?o evidenciaram a efetividade da terapia LED, nas condi??es experimentais propostas, no desempenho f?sico de alta intensidade e curta dura??o. / Introduction: The ability of an individual to generate and maintain high peak power is critical to performance in high intensity exercise. Thus, the development and study of new technologies that can improve the performance or minimize the occurrence of injuries during recovery from high intensity exercise could contribute to the improvement of the preparation and planning of training. Objectives: Prepare a device for therapy LED, on a single wavelength, with a larger irradiation area and to evaluate the influence of therapy in physical performance, as well as metabolic components, and inflammatory parameters during muscle injury recovery period of exercise of high intensity and short duration (30s) on a cycle ergometer in physically active men and cyclists. Methodology: First stage (Study 1) was conducted randomized and balanced study to evaluate the performance, where 4 doses of therapy were irradiated LED: LED placebo (0 J/cm2), LED 21s (3.6 J/cm2), LED 42s (7.2 J/cm2), LED 84s (14.4 J/cm2), on different days, with 24 hours of interval before each Wingate test (TW). (Study 2) 4 men underwent blood sampling before and after (3, 60, 120 minutes and 24 hours) to make TW to measure plasma concentrations of CK, CRP, and FIB. Second phase: (Study 3) was performed randomized and balanced study which was performed 2 TW before and after treatment with placebo (0 J/cm2) or experimental (3.6 J/cm2) LED on different days, with 24 hours of interval for evaluation of physical performance. Blood samples before the first TW as well as 3 minutes after the first and second TW and 24 hours after the second TW were performed for the measurement of CK, PCR, and FIB. The blood concentration of ammonia was measured before the first TW and 4 minutes after the second TW. Third phase: (Study 4) was performed randomized and balanced study in which three doses of therapy were tested LED: LED placebo (0 J/cm2) , LED 23s (3.94 J/cm2) or LED 46s (7.88 J / cm2), on different days, with 24h interval for evaluation of physical performance. (Study 5) was performed randomized and balanced study where cyclists underwent 3 experimental conditions: LED therapy, heating in the cycle ergometer and control, on different days, with 24 hours of interval before each TW Variables of physical performance and electromyographic activity of the vastus lateralis muscle were assessed during the 3 TW. Blood samples before and immediately after each experimental condition and 3 to 4 minutes after the TW were performed for measurement of lactate and ammonia. Results: The prototype 1 and 2 was not effective in improving the physical performance of high intensity and short duration, as well as metabolic components, inflammatory parameters and muscle injury. Moreover, TW did not seem sufficient to promote muscle injury and the consequent inflammatory and metabolic changes in component life. The mode of heating led to improved muscle performance compared to LED therapy and control. Conclusion: The findings of the studies did not demonstrate the efficacy of LED therapy, in the experimental conditions proposed, on physical performance of high intensity and short duration. / Disserta??o (Mestrado) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri,2014.
12

Snabbhet. Ett avgörande moment i elitfotboll. En studie om forskning, utbildning och praktiskt utförande av snabbhetsträning i svensk elitfotboll. - Speed - a crucial moment in elite soccer. A study on research, education and practical execution of explosive training in elite Swedish soccer

Crépin, Fredrik January 2008 (has links)
Bakgrund: Syftet med studien var att undersöka svenska fotbollsspelaresrörelsemönster och kravprofil för att analysera betydelsen av explosivitets- ochsnabbhetsträning och dessutom analysera prioriteten och värdet av den här träningen iden vetenskapliga litteraturen, i tränarutbildningen och i praktiken.Metod: Begreppet snabbhetsträning har analyserats utifrån tre perspektiv;Forskningens, Utbildningens och det Praktiska utförandets perspektiv.Forskningsperspektivet har analyserats genom relevanta forskningsresultat inomområdet. Utbildningsperspektivet har analyserats utifrån Svenska Fotbollförbundetstränarutbildning och det Praktiska utförandet har analyserats genom en intervjustudiemed representativa tränare i svensk elitfotboll. Dessa perspektiv har ställts mot varandrai en modell som skall ses som en kunskapsstege där information och kunskap skapasgenom forskning, där utbildningen fungerar som länk och där det praktiska utförandetspeglar den kunskapsinhämtning och kompetensutveckling som skett över tid.Resultat: Explosiviteten kan bevisligen ökas väsentligt genom funktionell träning. Bådeforskningen och kurslitteraturen till tränarutbildningen visar att förbättringar kan nåsgenom isolerad snabbhetsträning i t.ex. sprintövningar eller genom relevantstyrketräning men att det mest optimala är att träna snabbhetsförmågan ifotbollsspecifika situationer med boll. Ändå verkar det fortfarande vara underprioriterati praktiken Tränarna i studien genomför främst isolerade snabbhetsövningar utan boll.Trots att den explosiva förmågan är en färskvara som kontinuerligt behöver stimuleras,förklarar tränarna att de inte genomför någon form av snabbhetsträning underförsäsongen. / Aim: The objective of the study is to examine the Swedish soccer players movementpatterns to justify the importance of high-intensity and sprint training, and further toanalyse the priority and the value of this training in the scientific literature, in trainerseducation and in practice.Method: The concept of high-intensity and sprint training is analyzed from threeangles; Research, Education and the Practical execution perspective. The researchperspective has been analyzed through the relevant results in the field. The educationperspective has been analyzed according to the Swedish Football Federation trainereducation and the practical performance has been analyzed by a interview study onrelevant coaches in Swedish professional soccer teams. These perspectives have beendiscussed against each other in a model that can be viewed as a ladder of knowledge,where information and knowledge is generated by research, where education serves as alink and where the practical performance reflects the knowledge and competencydevelopment that has taken place over time.Conclusion: High-intensity sprints can be shown to be substantially increased byfunctional training. Both the research and the literature in coach education shows thatimprovements can be achieved by isolated sprint training or through relevant resistanttraining, but that the most optimal is to train this aspect in soccerspecific situations withthe ball. Yet it seems that this still has a low priority in practice. The coaches in thestudy carries out mainly isolated sprint exercises without the ball. Although theexplosive capacity is a fresh product that continuously needs to be stimulated, thetrainers explains that they do not implement form of training at all during pre-season.
13

Determination of Critical Rest Interval using Repeated Sprint Ability Testing

La Monica, Michael 01 January 2014 (has links)
The critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete’s ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity domains. The primary purpose of this study was to determine the CRI from the work-time relationship given by RSA testing using varying work to rest ratios. The secondary purpose was to determine the validity of CRI by evaluation of physiological responses above and below estimated rest interval values during intermittent cycling. Twelve recreationally trained males (mean ± SD; age 24.1 ± 3.6yr; height 175.8 ± 7.0cm; weight 77.6 ± 12.8kg; V̇ O2peak 43.3 ± 5.6ml/kg/min; Body Fat (%) 24.5 ± 4.4) were recruited for this study. Participants performed a graded exercise test to determine V̇ O2peak and peak heart rate. Eight participants completed the same three RSA protocols with 6s maximal sprints and varying rest intervals (12-24s) on a cycle ergometer. Intermittent critical power (ICP) was calculated through the linear total work (TW) and time-to-exhaustion (TTE) relationship, whereas CRI was estimated using the average work per sprint and ICP. Seven subjects completed trials above and below estimated CRI to evaluate the validity of this estimate through the examination of the physiological responses. Breath-by-breath oxygen consumption (V̇ O2) and heart rate (HR) values were recorded during the validation trials. One-way repeated measures analysis of variance (ANOVA) was used to analyze the variables from the RSA trials. Paired samples t-tests were performed to compare performance and physiological variables above or below CRI during the validation trials. Two-way repeated measures ANOVA was used to examined the changes in oxygen consumption (V̇ O2), HR, mean power (MP), and TW throughout the validation trials. Significant differences (p < 0.1) were found for the number of intervals completed, TTE, average work per sprint, peak and mean V̇ O2 between RSA protocols. Linearity between TW and TTE was r2 = 0.952 ± 0.081. During the validation trials, TTE was significantly greater in the above versus the below CRI trial (2270.43 ± 941.15s vs. 1511.00 ± 811.0s). Furthermore, blood lactate concentration (8.94 ± 4.89mmol/L vs. 6.56 ± 3.45mmol/L), AveV̇ O2 (2.05 ± 0.36L/min vs. 1.78 ± 0.26L/min), V̇ O2peak (2.84 ± 0.48L/min vs. 2.61 ± 0.43L/min), and AveHR (151.14 ± 18.46bpm vs. 138.14 ± 17.51L/min) were significantly greater in the below CRI trial when compared to the above CRI trial. Significant interactions were found between above and below trials within minimal V̇ O2 response (F = 6.886, p = 0.024, η2 = 0.534) to the recovery intervals and maximal HR (F = 4.51, p = 0.016, η2 = 0.429) response to the work intervals. During the above CRI trial, minimal V̇ O2 response decreased over time (51-43%V̇ O2 peak) while maximal HR response achieved a steady state level (81-84%HRpeak). Conversely, minimal V̇ O2 response during the below CRI trial achieved a steady state level (54-58%V̇ O2 peak), whereas maximal HR response increased over time (84-90%HRpeak). The relationship between TW and TTE is appropriate for use with RSA testing with varying rest intervals. The differing physiological response during the validation trials may reflect changes in energy system contribution. In conclusion, CRI distinguished between physiological responses related to exercise intensity domains in a manner similar to CP estimates determined from other testing and exercise modalities.
14

The Effects of a Combined Supplementation of Creatine and Sodium Bicarbonate on Repeated Sprint Performance

Barber, James Jeremy, Hagobian, Todd, McGaughey, Karen, McDermott, Ann Yelmokas, Olmstead, Jennifer Davis 01 September 2010 (has links) (PDF)
Abstract The Effects of a Combined Supplementation of Creatine and Sodium Bicarbonate on Repeated Sprint Performance James Jeremy Barber There is well-established research that suggests both creatine and sodium bicarbonate are effective ergogenic aids. However, only one published study has examined the combined effects of creatine and sodium bicarbonate. The primary purpose of this study was to determine if a combined supplementation of creatine monohydrate and sodium bicarbonate would further enhance the well-documented effects of creatine supplementation alone on repeated sprint performance. Thirteen healthy and fit males (Mean age = 21.15 ± 0.65 years and mean VO2 max = 66.72 ± 5.78) participated in this experimental study using a double-blinded crossover study design in which each subject was used as his own control. All subjects completed 3 conditions, followed by a 3-week washout period between each condition: 1) Placebo (Pl; 5 g maltodextrin + 0.5 g/kg maltodextrin), 2) Creatine (Cr; 5 g + 0.5 g/kg maltodextrin), and 3) Creatine plus sodium bicarbonate (Cr+Sb; 5g + 0.5 g/kg sodium bicarbonate). Each condition was a 2-day supplementation. In the morning after each supplementation, peak power, RPP, mean power, RMP, fatigue index, and perceptions of fatigue and GI distress were assessed during six 10-second repeated Wingate tests. Blood bicarbonate, pH, and lactate were measured 5 minutes before testing and immediately after the last Wingate sprint. The main findings were; 1) Cr+Sb produced 7% greater relative peak power and 4.6% greater peak power values than placebo, and 2) Cr+Sb demonstrated the greatest attenuation of decline in relative peak power over six repeated sprints. However, in contrast to our hypotheses, no benefits from either supplementation were observed for relative mean power, fatigue index, and perception of fatigue. Considering that this current study found benefits from combining creatine and sodium bicarbonate, it suggests that combining the supplements may improve repeated sprint performance. Future research on a greater sample size, a specific athletic population, various exercise modes, and comparing results with a sodium bicarbonate alone supplementation would be beneficial in determining if this combined supplementation is worthwhile.
15

The Placebo Effect: Influence on Recovery During Repeated Intermittent Sprints

Tolusso, Danilo V. 08 April 2014 (has links)
No description available.
16

Kombination av linjära och iterativa metoder i produktutvecklingsprocessen : En studie om hur processerna, och en kombination av processerna påverkar innovation hos företag inom tillverkningsindustrin / Combination of Linear and Iterative Methods in the Product Development Process : A study about how the processes, and a combination of the processes affect innovation in companies in the manufacturing industry

Arvidsson, Sara, Johansson, Lisa, Sjöstrand, Fanny January 2022 (has links)
Traditionellt sett är en linjär produktutvecklingsprocess det självklara valet, däremot med den teknikutveckling som skett och fortsätter att utvecklas i samhället arbetar många företag mot ett mer agilt arbetssätt. Val av produktutvecklingsprocess har en direkt påverkan på organisationens innovationsförmåga. Valet är mycket viktigt vid projekt vars mål är att ta fram något nytt som uppfyller kundens behov eller önskemål, samt för företag som vill hålla sig konkurrenskraftiga på marknaden. Syftet med detta kandidatexamensarbete är att undersöka hur företag använder sig av olika produktutvecklingsprocesser samt om en kombination av agila och linjära processer är gynnsam. Arbetet undersöker studiens frågeställningar som tar upp hur och när agila samt linjära processeranvänds. När och hur kombineras de två processerna och bakgrunden till en eventuell kombination utav dessa. Undersöka när är den ena, den andra eller kombinationen av båda processerna är mest fördelaktigt. Samt vilka för- och nackdelar processerna har, även vilken korrelation processerna har när det kommer till främjande av innovationsgrad. Arbetet inleddes med en litteraturstudie inom de olika områdena; innovation, linjära processer, agila processer samt en möjlig kombination av dessa. Efter litteraturstudien genomfördes en empirisk studie av två företag med tre respondenter från vardera. Detta gjordes i form av semistrukturerade intervjuer. Respondenterna hade olika roller på företagen, men samtliga innefattande arbetsuppgifter berörde produktutvecklingsprocesser. Resultatet från intervjuerna har sedan analyserats och diskuterats och presenterats i en slutsats. Från den genomförda studien kan konklusionen dras att de undersökta företagen till den större delen av projekt använder sig av egna processer som i grunden är likt den traditionella Stage-Gateprocessen, men med en mer flexibel process liknande agilt vid uppstarten av projekt. En kombination av Stage-Gate och Design thinking är vanligt förekommande och kombinationen krävs för att matcha kraven på flexibilitet som ställs på företag som verkar på en ständigt föränderlig marknad. Till största utsträckning implementeras dock dessa processer separat och oftast används Design thinking som ett komplement till deras redan befintliga linjära process. / Traditionally, a linear product development process has been the obvious choice. However, with the continuously rapid technological development in society, many companies are working towards a more agile approach of developing. The choice of the product development process has a direct impact on the company's ability to innovate within projects. And, if the aim of developing something new that meets the customer’s wishes, and in the meantime stay competitive on the market. The purpose of this bachelor’s thesis is to investigate how companies use different product development processes, and if a combination of linear or agile processes are favorable. The thesis investigates when and how agile and linear processes are used. When and how the two processes are combined, and the reason for a potential combination. To investigate when one or the other or the combination of the two processes are most favorable. As well as which pros and cons the processes have, in correlation to the promotion of the degree of innovation. The study began with a literature study in the different areas; innovation, linear processes, agile processes and a possible combination of agile and linear processes. Then, an empirical study of two companies took place, with three respondents from each company. This study was conducted via semi-structured interviews. The respondents had different roles at the company, but all were within the field of product development processes. The result from the interviews was analyzed and discussed and, finally, presented in a conclusion. From the completed study, the conclusion can be drawn that the surveyed companies for most projects use their own processes that are like the traditional Stage-Gate process, but with a more flexible process like agile at the start of projects. A combination of Stage-Gate and Design thinking is common but also indispensable to match the flexibility placed on companies in today's constant development of the market. To the greatest extent, however, these processes are implemented separately, and Design thinking is most often used as a complement to their already existing linear process.
17

Entrainement, préparation physique et physiologique cardio-respiratoire appliquée au rugby à XV / Training, physical training and cardiovascular physiology applied to the rugby union

Fornasier Santos, Charly 20 December 2018 (has links)
Le rugby à XV est un sport collectif qui se caractérise en match par des courses et des collisions de hauteintensité très variables selon les positions. La première partie des travaux, qui s’est centrée sur l’analyse del’activité par centrale d’analyse cinématique, a mis en évidence une activité de haute intensité plus importante enCoupe d’Europe qu’en TOP14 qui varie selon les cinq postes de jeu en termes de répétitions d’efforts et dedistances parcourues à haute intensité notamment chez les avants. De plus, ces activités de haute intensitédiminuent en première et deuxième mi-temps et sont différentes selon les positions. En effet, une diminution plusprécoce est observée chez les avants et les trois-quarts ailes, qui est majorée au niveau des accélérations entre lesdeux dernières périodes d’un match pour les avants démontrant un impact de la fatigue. A l’inverse, les arrièresarrivent globalement à maintenir une intensité élevée. Ainsi, au regard des résultats de la première partie, ladeuxième partie des travaux a consisté en la mise en place d’un entraînement par répétition de sprints en hypoxieinduite par hypoventilation à bas volume pulmonaire. Celui-ci a permis une amélioration significative de lacapacité à répéter des sprints après sept séances d’entraînement par hypoventilation chez les joueurs très entraînés,alors qu’aucun changement n’a été observé dans le groupe normoxie. L’entraînement en rugby à XV se caractérisepar la répétition d’efforts de haute intensité à dominante dynamique (courses) et statique (musculation, phases decombat) qui vont impacter le remodelage du ventricule gauche de manière spécifique. La troisième partie a montré,à partir d’échocardiographies de repos en mode 2D-strain, une hypertrophie physiologique majorée chez les avantscomparativement aux arrières. Cette hypertrophie s’accompagne d’une augmentation des pressions de remplissageet une diminution de la relaxation lors de la diastole, notamment chez les avants. Enfin, malgré une torsionventriculaire inchangée, les rotations et les vitesses de rotation sont plus grandes au niveau basal et plus faibles auniveau apical chez les joueurs de rugby à XV. Ainsi, cette thèse CIFRE apporte de nouvelles données au niveaude l’analyse de l’activité, des méthodes d’entraînement facilement applicables pour l’entraîneur, ainsi que desdonnées plus spécifiques à l’évaluation cardiaque de repos pour le clinicien. / Rugby union is a team sport characterized by high-intensity collisions and running efforts during gameswhich are position-dependent. Accounting for the five different positional groups, the first part of this thesisdemonstrated greater high-intensity activity in European cup when compared to the TOP14 rugby unioncompetition; with position-dependent variations in the frequency of repeated high-intensity efforts and the relativedistance of high-speed movements in forwards. A decrease in high-intensity movement parameters was observedduring the first and second halves of a competitive rugby union match. Indeed, the decrease in high-intensitymovements was earlier in forwards and outside backs who peaked in high-intensity accelerations between the lasttwo periods of the game, while backs were able to maintain their high-intensity activity throughout the match.Collectively, the capacity for a player to repeat high-intensity efforts during a rugby union game varied by thelevel of competition and was influenced by the onset of fatigue. In this context, the second part of this thesis was to conduct a repeated-sprint training in hypoxia. Hypoxia was induced by voluntary hypoventilation at low lungvolume. This training protocol has largely improved the repeated-sprint ability performance in highly-trainedrugby union players after seven training sessions of hypoventilation, whereas it was unaltered in the controlnormoxic group. Such training demands in rugby union (characterised by repeated high-intensity efforts indynamic (running) and static (weightlifting, fighting)) have a specific impact on left ventricular remodelling. Thelast part of this thesis, using 2D-speckle-tracking resting echocardiography, demonstrated that LV hypertrophywas greater in forwards when compared to backs and to control group. Systolic function remained unchanged, butdiastolic function was altered, mainly in forwards, with an increase in filling pressures and a decrease in leftventricular relaxation. Finally, left ventricular twisting was similar while rugby union players exhibited lowerapical and higher basal rotations velocities compared to controls. Collectively, this CIFRE research programprovided new data in activity analysis and training methods that are widely applicable to a range of rugby unionprograms and data on left ventricular morphology, function and mechanics for the clinician.

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