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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.
91

Šildymo ir šaldymo poveikis raumens nuovargiui ir atsigavimui, jo priklausomumas nuo lyties ir raumens susitraukimo greičio / The effect of warming and cooling on muscle fatigue and recovery depending on gender and muscle contraction rate

Ramanauskienė, Irina 17 January 2007 (has links)
The majority of physiological processes and various other processes taking place in the body are closely related to changes in body temperature (Shellock & Prentince, 1985; Bennett, 1990). The temperature of the human body is constant throughout one’s life. It is approximately 37ºC and it constantly adjusts itself to changes in environment, relative air humidity, the level of radiation, atmosphere pressure and thermo isolation. During long-term physical load, in case of illness or in conditions of extreme body temperature may be in the range from 32ºC to 40ºC or even more (Wilmore & Costill, 2004). It could be hypothesized therefore that the muscle warmed prior to the load to be undertaken, when the leg is extended and flexed in the knee joint at high (500, 450o / s) and average (180o / s) speed depending on gender will increase muscle force and muscle capacity to a greater extent than the cooled muscle, but after lowering the temperature muscle resistance to fatigue will increase. Though considerable research has been done already certain questions still remain to be cleared up, namely: 1. how warming affects muscle fatigue and recovery of female knee extensors and flexors when the leg is being flexed and extended in the knee joint at the fixed 500o / s speed; 2. how muscle contraction function of female and male knee extensors and flexors depends on temperature when the leg is being flexed and extended in the knee joint at the fixed 450o / s and 180o / s peed. Though there... [to full text]
92

Skeletal muscle calcium homeostasis during fatigue : modulation by kinases and mitochondria /

Aydin, Jan, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
93

Effects of repetitive work on proprioception and of stretching on sensory mechanisms : implications for work-related neuromuscular disorders /

Björklund, Martin. January 2004 (has links)
Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 6 uppsatser.
94

Experimental studies of spinal mechanisms associated with muscle fatigue /

Kalezic, Ivana, January 2004 (has links)
Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 6 uppsatser.
95

La fonction neuromusculaire dans les maladies chroniques : évaluation, impact clinique et réentraînement / Locomotor and respiratory muscle fatigue in chronic diseases : evaluation and rehabilitation

Bachasson, Damien 13 December 2012 (has links)
La diminution de la force et l'exacerbation de la fatigue neuromusculaire sont fortement impliquées dans l'altération des capacités fonctionnelles, de la tolérance à l'effort et du pronostic de patients porteurs de pathologies chroniques variées. Ces altérations peuvent trouver leurs origines dans des atteintes primaires de la fonction neuromusculaire et/ou des atteintes secondaires causées par exemple, par une diminution de l'activité spontanée favorisée par une pathologie chronique. Ainsi, la faiblesse et la fatigabilité musculaire sont des symptômes très fréquemment rapportés dans les maladies neuromusculaires (myopathies/neuropathies d'origine génétique ou acquise), les pathologies impliquant le système cardiovasculaire (insuffisance cardiaque) et/ou respiratoire (broncho-pneumopathie chronique obstructive (BPCO)). Ces symptômes sont aussi fréquemment associés aux syndromes idiopathiques de douleurs chroniques accompagnées d'anomalies de la nociception (syndrome fibromyalgique). Le développement d'outils d'évaluation bien tolérés et fiables de la force, de l'endurance et de la fatigue neuromusculaire est d'une importance cruciale pour approfondir la compréhension des mécanismes physiopathologiques et pour disposer de critères de jugement de qualité dans le cadre d'études observationnelles et interventionnelles. Dans ce contexte, la stimulation artificielle électrique s'est révélée être un outil performant pour évaluer in situ la fonction musculaire chez l'humain au repos et au cours de l'exercice. Plus spécifiquement, la stimulation magnétique des troncs nerveux périphériques a montré des prédispositions intéressantes pour l'évaluation de la fonction des muscles locomoteurs et respiratoires dans le cadre clinique. Au cours de ce travail, nous avons développé des outils d'évaluation de la force, de l'endurance et de la fatigue neuromusculaire en utilisant la neurostimulation magnétique et des protocoles d'exercice potentiellement applicables chez le patient. Nous avons étudié leurs capacités à détecter des différences liées au sexe, l'âge et au statut d'entrainement. Dans un second temps, nous avons appliqué nos évaluations dans le cadre de maladies neuromusculaires et de syndromes douloureux chroniques. Chez le patient BPCO, nous avons étudié les phénomènes de fatigue des muscles respiratoires et locomoteurs, leur impact sur la réponse à l'effort ainsi que leurs relations entre eux et avec les symptômes perçus. Chez ces patients, nous avons recherché les effets d'un entraiment d'une prise en charge combinant un entrainement des muscles locomoteurs et un entrainement des muscles respiratoires sur ces paramètres. / Strength loss and enhanced neuromuscular fatigue are major contributing factors of impaired functional capacities, exercise tolerance and prognosis in patients with various chronic diseases. These alterations can rely on primary deficiencies of neuromuscular function and/or secondary impairments caused by decreased spontaneous physical activity promoted by a chronic disease. Consequently, muscle weakness and enhanced fatigability are frequently reported symptoms in neuromuscular (inherited or noninherited myopathies/neuropathies), cardiovascular (chronic cardiac failure) and respiratory diseases (chronic obstructive pulmonary disease (COPD)) and idiopathic painful syndromes associated with alteration of nociception (fibromyalgia syndrome). The development of reliable and well-tolerated evaluations of muscle strength, endurance and fatigue is of major interest to better understand the physiopathology of the diseases and to provide relevant outcomes for observational or interventional studies. Artificially muscular electrical stimulation has been recognized as a valuable tool for noninvasive assessments of neuromuscular function at rest and during exercise in human. Recently, magnetic stimulation showed interesting skills to assess both peripheral and respiratory muscles in the clinical field. During this work, we developed tools to assess muscle strength, endurance and fatigue using magnetic neurostimulation and exercise protocols usable in patients. We studied its ability to detect differences related to sex, age and training status. Then we used these procedures in neuromuscular diseases and fibromyalgia syndrome. In COPD patients, we assessed respiratory and locomotor muscle fatigue and studied how these phenomena impact on exercise response and perceived symptoms. In these patients, we also assessed the combined effects of locomotor and respiratory muscle training on these parameters.
96

A falha muscular não é necessária para maximizar as adaptações neuromusculares ao treinamento de força

Nóbrega, Sanmy Rocha 29 April 2016 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-10-11T18:40:53Z No. of bitstreams: 1 DissSRN.pdf: 925824 bytes, checksum: a11a80cba1cb31584bc593e3626fd32d (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:07:55Z (GMT) No. of bitstreams: 1 DissSRN.pdf: 925824 bytes, checksum: a11a80cba1cb31584bc593e3626fd32d (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:08:02Z (GMT) No. of bitstreams: 1 DissSRN.pdf: 925824 bytes, checksum: a11a80cba1cb31584bc593e3626fd32d (MD5) / Made available in DSpace on 2016-10-21T13:08:10Z (GMT). No. of bitstreams: 1 DissSRN.pdf: 925824 bytes, checksum: a11a80cba1cb31584bc593e3626fd32d (MD5) Previous issue date: 2016-04-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Resistance training (RT) is the main method to promote increases in muscle strength and hypertrophy, in which loads higher than 60% of one repetition maximum (1-RM) are commonly recommended. Other studies suggest performing RT to the point of muscle failure, which can be defined as the inability to move a load beyond a critical angle or as the inability to complete a repetition in a full range of motion due to fatigue, in order to maximize strength gains and hypertrophy. However, it is still unclear if RT to muscle failure is really necessary. Thus, the aim of this study was to discuss the effects of RT to failure on motor units (MUs) recruitment and adaptive responses, providing arguments to how RT to failure might differently affect muscle adaptations on different populations. In conclusion, evidence regarding untrained individuals suggests that high-intensity RT (HIRT) to failure is not necessary for maximal increases in strength and mass. On the other hand, performing RT to failure might be necessary for optimal increases in strength and mass when training at low intensities (LIRT). Regarding trained individuals, evidence point greater strength gains when HIRT is performed to failure. Nonetheless, muscle failure seems to be an interesting strategy when it comes to optimizing hypertrophy gains for trained individuals. / O treinamento de força (TF) é o principal método de exercício utilizado para promover aumentos na força e massa muscular esquelética, onde cargas superiores a 60% de uma repetição máxima (1-RM) são comumente recomendadas. Outros estudos sugerem que, para maximizar os aumentos na força e hipertrofia muscular, sejam realizadas repetições até a falha muscular, definida como a incapacidade de mover uma carga específica além de um ângulo crítico ou como a incapacidade de completar uma repetição na amplitude de movimento completa devido à fadiga. Contudo, ainda não está claro se o TF até a falha é realmente necessário. Assim, o objetivo deste estudo foi discutir os efeitos do TF até a falha no recrutamento de unidades motoras (UMs) e respostas adaptativas, fornecendo argumentos do por que o TF até a falha afetar diferentemente as adaptações musculares em diferentes populações. Em conclusão, as evidências acerca dos indivíduos destreinados parecem sugerir que o TF de alta intensidade (TFAI) até a falha muscular não é necessário para ganhos máximos na força e hipertrofia. Em contrapartida, realizar repetições até a falha parece essencial para que o TF de baixa intensidade (TFBI) resulte em aumentos significativos na força e massa muscular. Já para indivíduos treinados, as evidências apontam maiores ganhos de força no TF de alta intensidade até a falha. Porém, a falha muscular parece uma estratégia interessante na otimização dos ganhos hipertróficos de indivíduos treinados.
97

Efeito da fadiga muscular na simetria do controle postural em adultos jovens / Effect of muscle fatigue in the postural control symmetry in young adults

Penedo, Tiago 06 April 2018 (has links)
Submitted by TIAGO PENEDO (tp37_harry@hotmail.com) on 2018-04-19T16:00:51Z No. of bitstreams: 1 Dissertação_final.docx: 3848321 bytes, checksum: 2426bf1fb8e81aa6c6c1d91f4123a736 (MD5) / Rejected by Minervina Teixeira Lopes null (vina_lopes@bauru.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: - fazer a submissão de um arquivo em PDF; - inserir a ficha catalográfica após a folha de rosto; - inserir a Ata de defesa após a ficha catalográfica. Agradecemos a compreensão. on 2018-04-19T16:35:52Z (GMT) / Submitted by TIAGO PENEDO (tp37_harry@hotmail.com) on 2018-05-04T13:41:43Z No. of bitstreams: 1 Dissertação_final.pdf: 2290846 bytes, checksum: 55df0177b77cae283535bafcdcef98ad (MD5) / Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-05-07T17:07:09Z (GMT) No. of bitstreams: 1 penedo_t_me_bauru.pdf: 2008041 bytes, checksum: 672b9331fbf4c347f1107713c46e43d0 (MD5) / Made available in DSpace on 2018-05-07T17:07:09Z (GMT). No. of bitstreams: 1 penedo_t_me_bauru.pdf: 2008041 bytes, checksum: 672b9331fbf4c347f1107713c46e43d0 (MD5) Previous issue date: 2018-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O aumento da oscilação do centro de massa causado pela fadiga muscular bilateral afeta o controle da postura em pé. Entretanto, ainda não é claro como a fadiga muscular afeta o controle postural, especialmente relacionado à estratégia motora e à assimetria. Assim, os objetivos deste estudo foram: i) analisar e comparar o uso de estratégias motoras para o controle postural de adultos jovens após fadiga muscular bilateral da região do tornozelo e do quadril, considerando a simetria no controle postural e; ii) analisar o efeito da fadiga muscular unilateral e bilateral de tornozelo na simetria dos membros inferiores durante postura bipodal estática. Para responder as questões da dissertação, dois estudos foram desenvolvidos. Participaram em cada estudo 20 adultos jovens com idade entre 20 e 35 anos. Os participantes realizaram avaliação postural sobre duas plataformas de força, antes e após fadiga muscular bilateral de tornozelo ou de quadril (estudo 1) e fadiga bilateral, fadiga unilateral do membro preferido e unilateral do membro não-preferido de tornozelo (estudo 2), sendo cada tipo de fadiga muscular realizado em um dia específico. A indução à fadiga foi realizada pela tarefa de flexão plantar e dorsiflexão do tornozelo (fadiga de tornozelo) sobre um step ou pela flexão e extensão do quadril (fadiga de quadril) sentado em uma cadeira, com frequência de movimento controlada. Em ambos os estudos os parâmetros do centro de pressão foram mensurados, sendo utilizado o índice de simetria para analisar o nível de assimetria no controle postural. Para responder os objetivos dos estudos, os parâmetros de interesse foram comparados através de ANOVAs e MANOVAs com fatores de acordo com as variáveis independentes de cada estudo. Os principais achados da dissertação foram que não houve alteração da estratégia motora após fadiga muscular e houve diminuição da assimetria entre os membros inferiores após fadiga muscular de tornozelo. Ainda, a fadiga bilateral de tornozelo não causou assimetria postural. Por outro lado, as fadigas unilaterais, tanto do membro preferido quanto do não-preferido, geraram assimetrias durante o controle da postura, na qual o membro preferido assumiu o papel de controlador principal da tarefa, mesmo depois de fadigado. / Bilateral muscle fatigue affects postural control while standing , increasing the sway of the center of mass . However, it is still unclear how muscle fatigue affects postural control, especially related to the motor strategy and asymmetry. Th us, th e objective s of this study were: i) to analyze and compare the use of motor strategies for the postural control of young adults after bilateral muscular fatigue of the ankle and hip, considering symmetry in postural control and; ii) to analyze the effect s of unilateral and bilateral ankle muscle fatigue on the symmetry of the lower limbs during bipodal standing . To answer the questions of the research project , two studies were develop ed. Participate in each study 20 young adults aged 20 to 35 years. Participants performed the postural task on two force platforms, before and after bilateral ankle or hip muscle fatigue (study 1) and bilateral, and unilateral of the preferred limb and uni lateral of the non - preferred limb ankle muscle fatigue (study 2). E ach type of muscle fatigue was performed on a specific day. Fatigue induction was performed by the plantar flexion and dorsiflexion of the ankle (ankle fatigue) task on a step or by flexion and extension of the hip (hip fatigue) sitting on a chair, with controlled movement frequency. In both studies the center of pressure parameters were measured, using the symmetry index to analyze the level of asymmetry in the postural control. In order to answer the objectives of the studies, the parameters of interest were compared through ANOVAs and MANOVAs with factors according to the independent variables of each study. The main findings of the dissertation were that there was no change in the motor s trategy after muscle fatigue and there was a decrease in the asymmetry between the lower limbs after ankle muscle fatigue. Moreover , bilateral ankle fatigue did not cause postural asymmetry. On the other hand, unilateral fatigue of both the preferred and t he non - preferred limb generated asymmetries during posture control, in which the preferred member assumed the role of main controller of the task, even after fatigue.
98

Resposta pós-exercício vista na ressonância nuclear magnética do músculo quadriceps em mulheres pós-menopáusicas com ou sem osteoporose / Evaluate of specific physical changes in post-exercise muscle metabolism magnetic resonance imaging (MRI) of the postmenopausal women

Thalita Sousa de Paula 27 March 2018 (has links)
A menopausa é o final da vida reprodutiva da mulher e pode ter como consequência a perda da massa óssea e desenvolvimento da osteoporose. A sarcopenia decorrente do processo de envelhecimento acarreta na diminuição de massa e força muscular, déficit de desempenho e maior risco de quedas e fraturas. A Ressonância Nuclear Magnética (RNM) é uma ferramenta não invasiva e eficaz para a avaliação quantitativa e da dinâmica metabólica do músculo esquelético. Por meio do mapa T2 é possível captar as alterações musculares agudas causadas pela atividade física. A intensificação do sinal T2 é causada pelo movimento osmótico da água intramuscular, aumento da acidose e do volume do espaço intracelular. O objetivo desta pesquisa foi avaliar a influência da densidade mineral óssea no metabolismo muscular de mulheres pós-menopáusicas. Foram avaliadas 16 pacientes do sexo feminino, no período pós-menopausa há mais de 12 meses, com média de idade de 63 anos, divididas em Grupo-Osteoporose (GO=9) e Grupo Controle (CG=7). Todas foram submetidas ao exame de Ressonância Nuclear Magnética da região da coxa (RNM1) e em seguida fizeram uma dinamometria isocinética na velocidade de 180 graus/segundo (duas séries de 10 contrações voluntárias máximas) e exercícios específicos para ativação do músculo quadríceps (agachamento e \"step\"), e após os exercícios, fizeram a RNM2. Os resultados mostraram aumento do mapa T2, caracterizado pelo maior tempo de relaxamento nos dois grupos avaliados, sem diferença entre eles. Não se observou correlação significativa dos resultados da RNM2 com os parâmetros de força (pico de torque corrigido pela massa corporal) e potência (trabalho total das 10 repetições da segunda série) e com a dosagem de vitamina D. Também não houve correlação entre a dinamometria isocinética e dosagem de vitamina D. A osteoporose não afeta a resposta muscular do quadríceps ao exercício, avaliada pelo mapa T2 da ressonância nuclear magnética. A metodologia é robusta e eficiente, mostrando que a RM é um método sensível para medir mudanças metabólicas no músculo após o exercício / Menopause is the end of woman\'s reproductive life and consequences as loss of bone mass and osteoporosis may emerge. The ageing\'s sarcopenia entails the reduction of muscle mass and strength, deficit of physical performance and increases the risk of falls and fractures, which is also present in postmenopausal women. Magnetic resonance imaging (MRI) is a noninvasive and effective tool for quantitative assessment and metabolic dynamics of skeletal muscle. Through the T2 map is possible to capture acute muscle disorders caused by physical activity. Intensification of T2 sign is caused by osmotic movement of intramuscular water, increase of acidosis and intracellular space volume. The aim of this study was to evaluate bone mineral density in muscle metabolism in postmenopausal women. We evaluated 8 female patients in postmenopausal for more than 12 months, with a mean age of 63 years, divided into osteoporosis-group (GO=9) and control group (CG=7). They were submitted to MRI examination of thigh at rest (RM1), and then the isokinetic dynamometer at the speed of 180 degrees/second, 2 sets of 10 maximal voluntary contractions and specific exercises to activate the quadriceps muscle (squats and step) and then the RM2 to capture the muscle metabolic changes. For perception of fatigue level, samples of lactate were taken at rest (Lac1), after 1 minute (lac2) and 3 minutes (Lac3) from the end of the exercises. In both groups, it was observed variation of lac2 Lac3, confirming that fatigue levels and changes in RM2 compared to RM1 in the uptake of water were achieved due to intramuscular specific physical changes in post-exercise muscle metabolism. The results showed increased T2 map, characterized by the highest relaxation time in both groups and there are no difference between them. There was no significant correlation of the results of the RNM2 with the parameters of force (peak torque corrected by body mass) and potency (total work) and with the dosage of vitamin D. There was also no correlation between the isokinetic dinamometria and dosage of vitamin D. Osteoporosis does not affect the muscle response of the quadriceps to exercise, assessed by the T2 map of magnetic resonance imaging. The methodology proved to be robust and efficient, showing that MRI is a sensitive method to measure metabolic changes in muscle after exercise
99

Suplementação de beta-alanina e bicarbonato de sódio: efeitos sobre a utilização dos sistemas energéticos durante o exercício intermitente de alta intensidade / Supplementation of beta-alanine and sodium bicarbonate: effects on energetic systems contribution during high-intensity intermittent exercise

Rafael Pires da Silva 18 August 2016 (has links)
O acúmulo intramuscular de íons H+ decorrente do exercício de alta intensidade inibe enzimas da via glicolítica, além de prejudicar diversas etapas do processo contrátil levando à fadiga. Especula-se que a suplementação combinada de betaalanina (via aumento da concentração de carnosina) e bicarbonato de sódio aumentaria a capacidade tamponante intra e extracelular refletindo em efeitos sinérgicos no metabolismo energético e no desempenho, do que quando suplementados isoladamente. Poucos estudos investigaram a eficácia da combinação dos suplementos durante o exercício e não há informações sobre os efeitos desta combinação nos sistemas energéticos. Portanto, esse estudo teve por objetivo investigar a eficácia da suplementação combinada ou isolada de betaalanina e bicarbonato de sódio enquanto estratégias de aumento da capacidade tamponante, bem como seu potencial na modulação do metabolismo energético e no desempenho do exercício intermitente de alta intensidade. O estudo contou com um desenho duplo-cego em que 77 voluntários (idade 38,6 ± 9,9 anos; massa corporal 76,6 ± 8,4 kg; VO2pico 59,3 ± 5,2 ml.kg-1.min-1) foram randomizados e aleatoriamente alocados em um dos 4 grupos sendo; beta-alanina (BA; n= 19), bicarbonato de sódio (BIC; n = 19), beta-alanina e bicarbonato de sódio (BA + BIC; n = 20) ou dextrose (PLA; n = 19). A eficácia das substâncias na contribuição dos sistemas energéticos foi comparada antes e após um período de 28 dias de suplementação de 6,4g/dia de beta-alanina e de 0,3g/kg de massa corporal de bicarbonato de sódio administrada 60 minutos antes de um exercício intermitente em cicloergômetro, que consistia de 4 séries de 1 minuto a 110% da potência aeróbia máxima com 1 minuto de intervalo e cadência constante. Após 10 minutos de repouso passivo, o desempenho era avaliado em um teste time-trial cuja meta era completar um trabalho total de 30 kJ, no menor tempo possível. Foram mensuradas as concentrações sanguíneas de pH, bicarbonato, excesso de base e lactato antes, durante e após os exercícios. As frações dos sistemas oxidativo e alático (ATP-CP) foram estimadas com base no consumo de oxigênio e o glicolítico pelo delta da concentração do lactato. O perfil energético do exercício intermitente consistiu na maior parte do sistema oxidativo (45 - 55%), seguido do sistema ATP-CP (35 - 40%) e do glicolítico (8 - 15%). A suplementação de bicarbonato de sódio elevou (P<0,001) as concentrações sanguíneas de bicarbonato (~ 6 mmol/L) e pH (~ 0,06 unidades) nos grupos BIC e BA + BIC, gerando uma maior concentração do lactato nas séries iniciais o que refletiu no aumento do custo energético glicolítico na primeira série do exercício intermitente, sendo estatisticamente significativo somente no grupo BIC (9,9 ± 7,2 kJ vs 18,7 ± 9,4 kJ; pré vs pós-suplementação). Não houve efeito da suplementação no tempo para completar o time-trial entre os grupos ou períodos de suplementação (BA -0,5%; BIC -1,4%; BA + BIC -4% e PLA 0%). A suplementação de bicarbonato de sódio, independentemente da suplementação de beta-alanina melhorou as variáveis de controle do equilíbrio ácido-base sanguíneo resultando na maior participação da via glicolítica, entretanto não conferiu benefícios adicionais ao desempenho / Intramuscular accumulation of H+ ions during high-intensity exercise inhibits glycolytic pathway enzymes and impairs several steps in the muscle-contraction process, causing fatigue. It has been suggested that a combined supplementation of betaalanine (through an increase in carnosine concentration) and sodium bicarbonate would increase intra- and extracellular buffering capacity causing synergetic effects on energy metabolism and performance, more than each supplement alone. Few studies investigate the effectiveness of combined supplements during exercise and there is no literature on the effects of this combination on energy system contribution. Therefore, the present study investigated the effectiveness of both beta-alanine and sodium bicarbonate alone and together in increasing buffering capacity as well as the potential for modulating energy metabolism and performance during high-intensity intermittent exercise. The study was double-blind and 77 volunteers (aged 38.6 ± 9.9 year, body mass 76.6 ± 8.4 kg; VO2peak 59,3 ± 5,2 ml.kg-1.min-1) were randomly assigned to four groups: beta-alanine (BA; n = 19), sodium bicarbonate (BIC; n = 19), beta-alanine and sodium bicarbonate (BA + BIC; n = 20), dextrose (PLA; n = 19). The efficacy of the substances in contributing to energy systems was compared before and after a 28-day period of supplementing 6.4g/day of beta-alanine and of 0.3g/kg of body mass of sodium bicarbonate administered 60 minutes before a cycling intermittent exercise, consisting of 4 sets of 1-minute each at 110% of maximum aerobic power with 1-minute intervals between each set and at an even pace. After 10 minutes of passive rest, performance was measured during a time-trial test in which participants were asked the complete 30 kJ of total work as fast as possible. Blood concentration of pH, bicarbonate, base excess, and lactate were measured before, during, and after intermittent and time trial protocols. The contributions of oxidative and anaerobic alactic (ATP-CP) were estimated based on oxygen consumption and the glycolytic system by the delta of lactate concentration. The energy demand of the intermittent exercises mostly consisted of the oxidative system (45-55%), followed by the ATP-CP system (35-40%), lastly glycolytic (8-15%). The sodium bicarbonate supplement elevated (P>0.001) blood concentration of bicarbonate (~6mmol/L) and pH (~0.06) units in the BIC and BA + BIC groups, generated a high concentration of lactate in the first sets, reflecting the increase in glycolytic energy cost in the first set of intermittent exercise, but was only statistically significant in the BIC group (9.9 ± 7.2 KJ vs 18.7 ± 9.4 KJ; pre vs postsupplementation). Supplementation did not have an effect on the time-trial times between groups or supplement periods (BA -0.5%, BIC -1.4%, BA + BIC -4%, PLA 0%). Supplementing with sodium bicarbonate, both alone and together with betaalanine improved blood acid-base control during high-intensity intermittent exercise resulting in high participation of the glycolytic metabolism, however it did not lead to additional performance
100

Contribution à la conception d'un électromyostimulateur intelligent / Contribution to the design of a smart electromyostimulator

Yochum, Maxime 06 May 2013 (has links)
Cette thèse a pour but de mettre au point un nouvel outil de rééducation neuromusculaire. Elle a pour fonction, l'amélioration de la qualité et de la durée des séances de renforcement musculaire et de réentraînement de la motricité de sujets atteints de déconditionnement musculaire. Un électromyostimulateur "intelligent" utilisant en même temps des techniques d'électromyostimulation (EMS) couplées aux analyses de l'électromyogramme (EMG) est développé et permet d'asservir en temps réel les paramètres de stimulation d'un muscle en fonction de son état de fatigue physiologique. Le contrôle ainsi effectué sur les paramètres de stimulation en fonction de la réponse musculaire électrique (onde M) offre la possibilité de stimuler un muscle en prenant en compte une information sur la réaction du muscle à l'électrostimulation / This project aims to develop a new tool for neuromuscular reeducation. Its function is to improve the quality and the duration of muscular strengthening training sessions and training of motor function for patients suffering from muscle deconditioning. A "smart" electromyostimulator using, at the same time, techniques of electrostimulation (EMS) and analysis of electromyography (EMG) allows the control in real time electrical stimulation parameters considering the physiological fatigue of the stimulated muscle. This control, performed on stimulation parameters depending on electrical response of muscles (M wave), allows the muscle stimulation taking into account the muscular reaction to the electrical stimulation

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