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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.
421

Escape transitório da viremia plasmática de HIV-1 e falência virológica em indivíduos sob terapêutica anti-retroviral: incidência e fatores associados / Intermittent HIV-1 viremia (blips) and virologic failure in patients under antiretroviral therapy: incidence and associated factors

Ibrahim, Karim Yaqub 20 September 2010 (has links)
INTRODUÇÃO: Pacientes em terapia anti-retroviral podem apresentar escapes transitórios de viremia plasmática (blip), porém os preditores desse evento e seu impacto sobre a incidência de falência virológica são ainda controversos na literatura. Neste estudo de coorte estimou-se a incidência de blip e de falência virológica e investigaram-se possíveis preditores de tais desfechos. Blip foi definido como carga viral superior a 50 cópias/mL com subseqüente supressão da viremia plasmática e falência virológica como duas medidas consecutivas de carga viral plasmática superiores a 50 cópias/mL. Adicionalmente, pesquisou-se, por ocasião desses eventos, a presença de mutações genotípicas de HIV capazes de conferir resistência aos anti-retrovirais e as concentrações plasmáticas de inibidores não nucleosídicos da transcriptase reversa e inibidores da protease, comparando-as com o relato dos participantes sobre adesão à medicação. MÉTODOS: 350 participantes infectados pelo HIV (250 homens e 100 mulheres) foram selecionados no Serviço de Extensão ao Atendimento de Pacientes com HIV/Aids Casa da Aids do Hospital das Clínicas da FMUSP, São Paulo, Brasil. Na admissão ao estudo e trimestralmente, ao longo de 78 semanas, foram coletadas informações sobre dados sóciodemográficos, forma presumida de aquisição do vírus, uso de e adesão a medicações anti-retrovirais, ocorrência de outras comorbidades, bem como uso de álcool e de drogas ilícitas. Investigaram-se fatores potencialmente associados à incidência dos desfechos de interesse, tais como ocorrência de outras doenças, exposição a imunizações e falha na adesão a práticas de sexo mais seguro. Amostras de sangue periférico foram coletadas a cada visita para determinação de carga viral plasmática por RT-PCR ultrassensível, e contagem de linfócitos T CD4+ por citometria de fluxo. Nos indivíduos que apresentaram os desfechos de interesse do estudo, procedeu-se ao seqüenciamento dos genes da transcriptase reversa e da protease de HIV e à dosagem plasmática dos anti-retrovirais por método de Cromatografia Líquida de Alta Performance. As incidências de blip e falência virológica foram estimadas e os fatores associados a ambos investigados em modelo de regressão logística múltipla. RESULTADOS: As incidências de blip e falência virológica foram 9,4 e 4,2/100 pessoas-ano, respectivamente. Três indivíduos apresentaram falência virológica precedidos por blip. À análise multivariada, a não adesão às praticas de sexo mais seguro no mês precedente se mostrou independentemente associada à ocorrência de blip (OR 24,64, IC 95% 4,40 137,88, p<0,001) e de falência virológica (OR 24,69, IC 95% 4,20 145,18, p<0,001). Adicionalmente, observou-se que a exposição prévia a maior número de esquemas anti-retrovirais foi preditora dos eventos blip (OR 1,82, IC 95% 1,41 2,36, p<0,001) e falência virológica (OR 1,67, IC 95% 1,19 2,35, p=0,003). A ocorrência de blip não se associou ao desenvolvimento posterior de falência virológica. Um maior número de mutações conferidoras de resistência medicamentosa foi identificado no momento de falência virológica, quando comparado ao momento de blip, com predomínio de mutações no gene da transcriptase reversa, refletindo o maior uso desses fármacos. Das 122 concentrações plasmáticas de anti-retrovirais analisadas em 120 amostras, 84 estavam em níveis terapêuticos adequados. Porém, tais resultados apresentaram apenas 69% de concordância com a adesão auto-referida à medicação. Este estudo mostra que apresentar blip em uma medida isolada pode ser um evento benigno; por outro lado, falência virológica pode ser conseqüente a acúmulo de mutações conferidoras de resistência a pelo menos um dos anti-retrovirais em uso, podendo comprometer a eficácia do esquema terapêutico utilizado. Ambos os desfechos mostraram-se mais incidentes na população multiexperimentada à terapêutica, que, portanto, merece atenção particular. Uma importante contribuição deste estudo foi a avaliação da dosagem plasmática dos antiretrovirais, método simples e de baixo custo, que, implantado na rotina laboratorial, pode contribuir para o monitoramento da adesão aos antiretrovirais e reduzir a demanda por testes genotípicos / BACKGROUND: HIV-1-infected patients under antiretroviral therapy may present intermittent viremia (blip); however, predictors of this outcome and its influence on the incidence of virologic failure remain controversial in the literature. The aim of this study is to estimate the incidence of blip and virologic failure in a cohort of patients under stable antiretroviral therapy and to investigate their associated factors. Blip was defined as a plasma HIVRNA load above 50 copies/mL followed by a subsequent value below 50 copies/mL. Virologic failure was defined as two consecutives measures of viral load above 50 copies/mL. Moreover, at time of occurrence of these outcomes, HIV genotyping assays were performed in search of drug resistance-associated mutations, and plasma concentrations of nonnucleoside reverse transcriptase and protease inhibitors assessed and compared with self-reported adhrence to therapy. METHODS: 350 subjects (250 male and 100 female) were enrolled at the HIV Clinic, School of Medicine, University of São Paulo, Brazil and followed for 78 weeks. At baseline and in 3-month interval follow-up visits we collected sociodemographic data and information on presumed mode of HIV acquisition, use of and adherence to antiretrovirals, comorbidities and use of alcohol and illicit drugs. Additionally, patients were questioned about potential predictors of the outcomes, including occurrence of other diseases, immunizations and risky sexual behavior. Blood samples were drawn for assessment of HIV plasma viral loads, using ultrasensitive RT-PCR, and T CD4+ cell counts by flow cytometry. Individuals who presented blip and/or virologic failure were submitted to HIV genotyping assays and assessment of antiretroviral plasma concentrations by high-performance liquid chromatography. Incidences of blip and virological failure were estimated and associated factors investigated, using a multiple logistic regression model. RESULTS: The incidence of blip and of virologic failure were 9.4/100 and 4.2/100 person-years, respectively. Three individuals presented virologic failure after blip episodes. On multivariate analysis, non-adherence to safer sex measures in the previous month was shown independently associated with the occurrence of blip (OR 24.64, 95%CI 4.40 137.88, p<0.001) and virologic failure (OR 24.69, 95%CI 4.20 145.18, p<0.001). In addition, history of multiple exposures to antiretroviral regimens was also a predictor of blip (OR 1.82, 95%CI 1.41 2.36, p<0.001) and virologic failure (OR 1.67, 95%CI 1.19 2.35, p<0.001). Blips were not predictive of virologic failure. A larger number of HIV mutations were identified at time of virologic failure, as compared to blip episodes, with mutations detected predominantly in the reverse transcriptase (RT) gene, probably due to larger exposure to RT inhibitors. Eighty-four out of 122 assessments of antiretroviral plasma concentrations analyzed in 120 samples resulted in the therapeutic range. However, these results were concordant with self-reported adherence to therapy in 69% of cases only. This study shows that a single blip episode may be considered benign, whereas virologic failure could result from accumulation of HIV drug resistance-associated mutations that may impair the efficacy of therapy. Both study outcomes occurred more frequently among patients with larger exposure to antiretrovirals, and therefore they should be monitored in this regard. An important contribution of this study concerns the assessment of antiretroviral plasma concentrations, a simple and low cost laboratory tool. Incorporated routinely in patient follow-up, it would help monitoring adherence to therapy and reduce the need for HIV genotyping assays
422

Att växa upp i en sjöfartsfamilj : Hur unga vuxna upplevt sin uppväxt med en periodvis bortavarande förälder / Growing up in a seafaring family : Young adult’s perception of growing up with an intermittently absent parent

Kindsjö, Alexander, Hermander, Daniel January 2019 (has links)
I en sjöfartsfamilj kretsar mycket av vardagen kring de olika perioderna i sjöfararens yrke - hemmaperioder, bortaperioder och perioderna kring hemkomst och avresa. Det finns undersökningar på hur sjöfararen och dennes partner upplever dessa perioder men det saknas kunskap om hur det är att växa upp i en sjöfartsfamilj. Mot denna bakgrund var syftet med denna undersökning att undersöka hur unga vuxna, uppväxta i en sjöfartsfamilj med en periodvis bortavarande sjöfarare, upplevt perioderna när sjöfararen var hemma, borta och kring avresa eller hemkomst. En kvalitativ metod användes och åtta semistrukturerade intervjuer med åtta respondenter gjordes. Respondenternas upplevelser varierade men en övergripande känsla var att perioderna av lång sammansatt ledighet när sjöfararen var hemma övervägde nackdelarna med att bara ha en förälder under bortaperioderna. Under sjöfararens bortavaro upplevde alla respondenterna varierande grader av saknad, framförallt vid speciella tillfällen eller högtider, men för många var det en normalitet då de inte kände till något annat. / In a seafaring family a considerable part of everyday life revolves around the different periods of the seafarers working cycle - when the seafarer is home, away and the periods just before and after leaving or coming home. There are studies on how seafarers and their partners experience these periods, but very little on what it’s like to grow up in a seafaring family. Against that background, the purpose of this study was to examine how young adults, brought up in a seafaring family with an intermittently absent parent, have experienced the different periods connected to the seafarers working cycle. The study used a qualitative method and it comprised of eight semi structured interviews with eight respondents. The respondents’ experiences varied but the overall sentiment was that the seafarers long leave periods made up for the disadvantages of only having one parent while the seafarer was away. All respondents reported feeling varying degrees of sadness when the seafarer left and having feelings of longing around holidays and special occasions. Many respondents referred to it as a normality and that it was all they knew.
423

Continuity in intermittent organisations : the organising practices of festival and community of a UK film festival

Irvine, Elizabeth J. January 2015 (has links)
This thesis considers the relationship between practices, communities and continuity in intermittent organisational arrangements. Cultural festivals are argued to offer one such particularly rich and nuanced research context; within this study their potential to transcend intermittent enactment emerged as a significant avenue of enquiry. The engagement of organisation studies with theories of practice has produced a rich practice-based corpus, diverse in both theoretical concerns and empirical approaches to the study of practice. Nevertheless, continuity presents an, as yet, under-theorised aspect of this field. Thus, the central questions of this thesis concern: the practices that underpin the enactment of festivals; the themes emerging from these practices for further consideration; and relationships between festivals and the wider context within which they are enacted. These issues were explored empirically through a qualitative study of the enactment of a community-centred film festival. Following from the adoption of a ‘practice-lens approach', this study yielded forty-eight practices, through which to explore five themes emerging from analysis: Safeguarding, Legitimising, Gatekeeping, Connecting and Negotiating Boundaries. This study revealed an aspect of the wider field of practice that has not yet been fully examined by practice-based studies: the cementing or anchoring mechanisms that contribute to temporal continuity in intermittent, temporary or project-based organisations. The findings of this thesis suggest a processual model, which collectively reinforces an organisational memory that survives periods of latency and facilitates the re-emergence of practice, thus potentially enabling organisations to endure across intermittent enactment and, ultimately, transcend temporality and ephemerality. The themes examined and insights offered in this thesis seek to contribute to: practice-based studies and film-festival studies; forging a new path linking these two disciplines; and generating both theoretical and practical insights of interest to festival organisers and stakeholders of project-based, temporary or intermittent organisational arrangements.
424

Estudo controlado e randomizado entre o uso de ventilação por pressão positiva intermitente e pressão positiva contínua em vias aéreas em recém-nascidos pré-termo após a extubação traqueal / Randomized controlled trial comparing nasal intermittent positive pressure ventilation and nasal continuous positive airway pressure in premature infants after tracheal extubation

Daniela Franco Rizzo Komatsu 06 September 2007 (has links)
Objetivos: Analisar a frequência de falha da extubação em recém-nascidos pré-termo em ventilação mecânica convencional após a extubação traqueal nos grupos submetidos a ventilação por pressão positiva intermitente por via nasal (nIPPV) e pressão positiva contínua em vias aéreas (nCPAP). Métodos: Foram estudados 72 recém-nascidos pré-termo portadores de insuficiência respiratória, com idade gestacional 750 gramas, que necessitaram de entubação traqueal e ventilação mecânica. Após terem preenchido os critérios de extubação, os recém-nascidos foram submetidos a nIPPV (n=36) ou nCPAP (n=36) de acordo com o resultado da randomização. Os parâmetros iniciais para os RN randomizados para nIPPV foram: FR = 12 ipm; PIP = 16 cm H20; PEEP= 6 cm H20; FiO2 ? 40%, e para aqueles randomizados para nCPAP foram P=6 cm H2O; FiO2 < 40%. O estudo foi finalizado após um tempo de extubação de 72 horas ou quando o RN preenchesse os critérios de falha na extubação. O projeto de pesquisa foi aprovado pela Comissão de Ética de ambos os Serviços. Resultados: A grande maioria dos RN recebeu pelo menos uma dose de surfactante exógeno (80,5% no grupo nIPPV e 83,3% no grupo nCPAP, P= 1). O tempo médio de permanência em ventilação mecânica também foi semelhante (6,2 e 7,3 dias, P= 0,59, respectivamente). Entre os 36 RN randomizados para nIPPV, 6 (16,6%) apresentaram falha de extubação em comparação a 11 (30,5%) dos 36 RN randomizados para nCPAP. Apesar de se ter observado redução relativa de risco de falha de extubação da ordem de 45% (IC 95%: 0,23 a 1,32) a favor da nIPPV, esta diferença não alcançou significância estatística. Constatamos uma chance de falha de extubação de 4,38 vezes no grupo nCPAP quando comparado ao grupo nIPPV após excluírmos os RN com peso de nascimento inferior a 1000 gramas, sendo esta diferença estatisticamente significativa (P= 0,045).Complicações gastrointestinais e neurológicas, além de outras complicações, não ocorreram nos recém nascidos pré-termo submetidos à nIPPV ou nCPAP após a extubação. Conclusões: Embora a distribuição de frequências de falha da extubação tenha mostrado numericamente um menor índice de falha nos RNPT submetidos a nIPPV em relação àqueles submetidos a nCPAP, não houve diferença estatísticamente significante entre os dois modos de suporte ventilatório após a extubação. Ao excluirmos da análise os RN com peso de nascimento inferior a 1000 gramas constatamos um aumento estatisticamente significante na chance de falha no grupo nCPAP. / Objetive: To analyze the frequency of failed extubation in premature infants following mechanical ventilation placed on either nasal intermittent positive pressure ventilation (nIPPV) or nasal continuous positive airway pressure (nCPAP) after endotracheal tube removal. Methods: Seventy two premature infants with respiratory insufficiency and gestacional age 750 grams, who needed endotracheal intubation and mechanical ventilation were studied. Once the babies reached the criteria for exubation, they were randomized to either nIPPV (n=36) or to nCPAP (n=36) in accordance with the randomization resulted. The inicial settings for those randomized to nIPPV were: rate=12; PIP=16 cm H20; PEEP=6 cm H20; FiO2 < 40%, and for those randomized to nCPAP were P=6 cm H2O; FiO2 < 40%. The study ended after 72 hours or when the infants reached the criteria of failure of the extubation. Ethical Approval was obtained from the Hospital. Results: Most received at least one dose of exogenous surfactant (80,5% in the nIPPV group and 83,3% in the nCPAP group, P= 1). The average time of mechanical ventilation also was similar (6.2 and 7.3 days respectively, P= 0.59). Of the 36 infants randomized to nIPPV, six (16,6%) failed extubation in comparison to 11 (30,5%) of the 36 newborn randomized to nCPAP. Although to have itself observed relative reduction of risk failure of extubation the order of 45% (95%CI: 0,23 to 1,32) in the group nIPPV, this difference did not reach significance statistics. We verified a increaset of failure extubation of 4,38 times in the nCPAP group when compared to the group nIPPV after excluded premature infant from birthweight less than 1000 grams, this difference was significant (P = 0,045). Gastrointestinal and neurological complications, beyond other complications, had no occurred in premature infants submitted to nIPPV or nCPAP after the extubation. Conclusions: Although the distribution of frequencies has numerically shown a lesser index of failure in premature infants submitted to nIPPV in relation to those submitted to nCPAP after extubation they did not have statistical significance difference between the two ways of ventilatory support. To the excluded of the analysis premature infant with birthweight less than 1000 grams, verified an increase significant in the failure extubation in the nCPAP.group .
425

Remoção de nutrientes do efluente de reator anaeróbio utilizando reatores microaeróbio e com aeração intermitente seguidos de flotação por ar dissolvido / Nutrient removal of anaerobic effluent reactor using microaerobic and intermittent aeration reactors followed by DAF

Marchetto, Margarida 07 December 2001 (has links)
O principal objetivo deste trabalho consistiu em avaliar o desempenho de um sistema experimental para pós-tratamento de reatores anaeróbios. Foram testados reator microaerado e reator com aeração intermitente, seguidos de flotação por ar dissolvido. Foram avaliadas condições para se obter nitrificação, desnitrificação e remoção de fósforo, em reator com baixa concentração de OD e em reator em que se alternaram fases aeróbia e anaeróbia. O trabalho foi desenvolvido em duas etapas distintas: a Etapa I constituiu de ensaios preliminares, utilizando instalação em escala de laboratório, alimentados com efluente de reator anaeróbio compartimentado, composta de sistema de aeração com quatro reatores em paralelo, com capacidade de 11,5 L cada, operando em regime hidráulico contínuo, com concentrações de OD na faixa de 0,2 a 0,9 mg/L, em temperatura controlada de 30±2°C. Na Etapa I também foram operados reatores com aeração intermitente. Na Etapa II, empregou-se instalação para tratamento aeróbio, com capacidade de 100 L, seguida de flotador, em temperatura ambiente de 25±6°C, sendo operado um reator microaerado e outro com aeração intermitente; ambos foram alimentados com efluente de um reator anaeróbio de leito expandido. O sistema com aeração intermitente (&#952h: 6 h) mostrou-se estável, apresentando elevada remoção média de DQO (92%), de P-PO4-3 (90%) e de nitrogênio (sem utilização de fonte externa de carbono; apenas com recirculação adequada do lodo). Para &#952h médio de 8 h, nos ensaios com ciclos alternados de 2 h, com aeração e 4 h, sem aeração, foi obtida remoção máxima de P-PO4-3, de 95% para as amostras brutas e 97% para as amostras filtradas, com remoção média de 84%, e 88%, respectivamente. Considerando apenas os valores médios, registrou-se ligeira queda de remoção de P-PO4-3, e de DQO em relação ao período com &#952h médio de 6 h. Os resultados com aeração intermitente foram sensivelmente melhores em relação aos obtidos com microaeração. / The aim of this research the performance evaluation of a pilot system for post treatment of anaerobic reactors. Microaeration and intermittent aeration reactors, followed by dissolved air flotation (DAF) were examined. It was assessed the conditions to obtain nitrification, denitrification and phosphorus removal, in reactor operated with low concentration of OD and in a reactor operated were alternated aerobic and anaerobic phases were used. The research was developed in two different stages. The first one, constituted of preliminary test, using installation in laboratory scale, fed with effiuent of compartment anaerobic reactor. This system was composed of aeration system with four reactors in parallel, with 11,5 L each, operating in continuous flow, with concentrations of DO between 0.2 to 0.9 mg/L, in controlled temperature of 30±2 ºC. The reactors were also operated with intermittent aeration. In the second stage, an installation with 100L was used for aerobic treatment, followed by DAF, in room temperature of 25±6°C. One reactor was operated under microaeration and another with intermittent aeration. Both were fed with effiuent of an expanded bed anaerobic reactor. The system with intermittent aeration (&#952h: 6 h) shown stable, presenting high COD removal of (92%) and phosphorus removal (90%), without use of external carbon source; just with adapted recirculation of the sludge. For an average hydraulic retention time of 8 h, in the test with alternate cycles of 2 h with aeration and 4 h without aeration, it was obtained a maximum removal of P-PO4-3 equal 95% for the raw samples and 97% for the filtered samples, with average removal of 84%, and 88%, respectively. The results with intermittent aeration were significantely better in relation to the obtained with microaeration.
426

Caractérisation de nouveaux modes de maintien en charge pour batteries stationnaires de secours

Dillenseger, Guillaume 14 December 2004 (has links) (PDF)
Les accumulateurs au plomb de secours sont traditionnellement maintenus à l'état chargé par floating, i.e. tension de charge constante.<br />Nous avons mené différentes études sur les batteries de démarrage, les moins chères du marché : cinétiques d'autodécharge des électrodes, influence des surtensions sur les états de charge et la corrosion, aptitude à la recharge.<br />Il en résulte des considérations sur les notions mêmes de fem d'un accumulateur au plomb, de charge complète, et un modèle de perte de capacité des matériaux actifs dans le temps. Une nouvelle technique de maintien en charge est proposée, réduisant au moins d'un facteur deux les quantités d'électricité fournies. Cette technique associe de longues périodes sous faibles courants de maintien, inférieurs d'un ordre de grandeur aux courants de floating habituels, et des phases courtes à régime plus élevé. Elle vise à réduire les coûts de service en conjuguant : batteries bon marché, peu ou pas d'entretien et durée de vie élevée.
427

Etude par modélisation de la commande optimale des systèmes de chauffage des bâtiments utilisant des chaudières à charbon

Zhao, Hong 24 June 1992 (has links) (PDF)
Les systèmes de chauffage utilisant des chaudières à charbon dans les bâtiments à occupation discontinue ont des caractéristiques particulières. Le travail présenté ici a pour objet l'étude de la gestion d'énergie de tels systèmes. Deux modèles de chaudière à charbon ont été développés : un modèle fin et un modèle simplifié. Le modèle fin a été élaboré dans le but de décrire le comportement dynamique de la chaudière. Le modèle simplifié a été développé pour répondre aux besoins du calcul de la commande. Une structure de commande optimale basée sur le principe d'optimisation quadratique a été étudiée, améliorée et adaptée au contrôle de systèmes de chauffage intermittent. En la complétant par une méthode d'auto-réglage, cette commande peut corriger automatiquement les erreurs de commande dues aux imprécisions du modèle utilisé ou à d'autres causes. Les études, par simulations, des applications de la commande optimale aux systèmes de chauffage à chaudière à charbon ont démontré l'efficacité et la souplesse de cette commande, ainsi qu'une économie énergétique importante par rapport à la commande classique.
428

THE EFFECTS OF INTERMITTENT FASTING AND A HIGH PROTEIN DIET IN INDIVIDUALS WITH TYPE 2 DIABETES MELLITUS

2015 September 1900 (has links)
Intermittent fasting (IF) is a recently popularized meal timing strategy whereby individuals abstain continuously from any energy intake for 16 to 20 hours each day, subsequently condensing energy intake into a short period spanning 4 to 8 hours. We aimed to test the effects of intermittent fasting in 10 individuals with Type 2 Diabetes Mellitus in conjunction with recommendations to consume a high protein diet in a 6 to 8 week withdrawal study. This study consisted of three phases: baseline, intervention, and follow-up. During the 2-week baseline and intervention phases participants consumed meals at regular times. Biochemical, anthropometric, and physical activity measurements were taken at the end of each phase. Participants reported morning, afternoon and evening self-monitored blood glucose and fasting duration on a daily basis, in addition to completing a remote food photography diary three times within each study phase. Despite the short duration of the intervention phase, intermittent fasting led to significant decreases in weight, BMI, morning SMBG, and overall reductions in waist circumference, C-reactive protein, energy intake, carbohydrate intake, and fat intake. There were significant variations between participants in response to intermittent fasting in respect to changes in lipids and insulin sensitivity, which could not be explained by baseline biochemical or anthropometric measures, fasting duration, energy intake, or physical activity. Upon cessation of intermittent fasting, biochemical changes regressed towards baseline values during the follow-up period. Intermittent fasting was well tolerated by most participants, and no severe adverse events were noted. Morning nausea was the most common complaint, which abruptly ceased when medication timing was changed.
429

周期的断続磁場を用いた磁気クロマトグラフィーの開発

野水, 勉, 田中, 智一 03 1900 (has links)
科学研究費補助金 研究種目:基盤研究(C)(2) 課題番号:09640721 研究代表者:野水 勉 研究期間:1997-1998年度
430

Réponses physiologiques au cours d'exercices intermittents en course à pied

Assadi, Hervé 08 June 2012 (has links) (PDF)
Les objectifs de ce travail étaient d'analyser les réponses physiologiques au cours d'exercices intermittents en course à pied et de déterminer i) un test d'évaluation de la vitesse maximale aérobie (VMA) adapté aux exercices intermittents ; ii) les exercices intermittents permettant une sollicitation maximale de la consommation d'oxygène (VO2max) ; iii) les facteurs physiologiques et neuromusculaires limitant la durée des exercices intermittents.La première étude a permis de montrer que la réalisation d'un exercice intermittent alternant des périodes d'effort de 30 s avec des périodes de récupération de 30 s (30s-30s), à la VMA atteinte à la fin du test intermittent incrémental 45-15FIT, permettait à la fois de réaliser un grand nombre de répétitions et de solliciter un fort pourcentage de la VO2max pendant la durée de l'exercice. Lors de la seconde étude nous avons montré que les exercices intermittents de type 5s-15s, 30s-30s et 60s-60s, courus à la VMA permettaient de solliciter un fort pourcentage de la VO2max. L'exercice intermittent de type 30s-30s est celui qui permet néanmoins de réaliser le plus grand nombre de répétitions. Une part plus importante de la glycolyse dans la production d'énergie réduit le nombre de répétitions lors de l'exercice de type 60s-60s par rapport à l'exercice de type 30s-30s ; une fatigue musculaire causée par un plus grand nombre d'accélérations et de décélérations réduit quant à elle le nombre de répétitions lors de l'exercice de type 15s-15s, par rapport à l'exercice de type 30s-30s. Les résultats de la troisième étude ont confirmé que les exercices intermittents de type 5s-15s, courus à la VMA, induisaient une fatigue musculaire plus importante, due essentiellement aux nombreuses accélérations et décélérations. Il a également été montré qu'à la suite d'un exercice pré-fatigant des muscles extenseurs du genou (contractions musculaires évoquées par électromyostimulation vs contractions volontaires isométriques), le nombre de répétitions lors de l'exercice intermittent 30s-30s était réduit, mais que le pourcentage de temps passé à plus de 90% de la VO2max n'était pas diminué par rapport à la réalisation sans pré-fatigue.L'ensemble de nos travaux permettent de définir un ensemble d'exercices intermittents qui, lorsqu'ils sont courus à la VMA évaluée lors du test 45-15FIT, permettent d'atteindre un niveau élevé de sollicitation du système aérobie, dont l'exercice de type 30s-30s pourrait constituer un exercice "standard"

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