Dans ce travail nous nous sommes centré sur les effets d’une hyperventilation volontaire (alcalose respiratoire) sur la fatigue lors d’un sprint prolongé. Il s’agit de mesurer les effets d’une augmentation pré exercice du pH lors de type d’exercice anaérobique. Dans un premier temps, sept sujets ont réalisé le test de Wingate, soit dans des conditions normales, soit après six cycles inspiration/expiration maximaux réalisés en 30 secondes (HV). Les échanges gazeux étaient mesurés en cycle à cycle durant tout le test. Les performances pic mesurées n’ont pas différées significativement entre les deux tests, en revanche, l’index de fatigabilité a été supérieur lorsque le test fut réalisé après une hyperventilation. Lors d’une seconde étude, 11 sujets ont réalisé le test de Wingate soit dans des conditions normales soit 1 minute après avoir réalisé une hyperventilation de 30 secondes. L’hyperventilation a entrainé une diminution significative de la pression partielle en CO2 dans l’air de fin d’expiration (PETCO2) en dessous de 30 mmHg suggérant une baisse significative du pH sanguin. Cependant, la puissance pic, la puissance moyenne et la contribution aérobie n’étaient pas significativement différentes entre les deux tests. Enfin, lors d’une dernière étude, nous avons recruté 9 nageurs de bon niveau, pour effectuer un 50m crawl ce soit dans des conditions normales ou bien après une HV suivie de 30 secondes de récupération passive. Dans cette étude, la vitesse moyenne de nage sur 50m crawl était significativement plus élevée dans lesconditions HV comparées aux conditions normales. Le nombre de cycles respiratoire enregistrés durant chaque course était significativement inférieur dans les conditions HV. Nous avons ainsi pu conclure qu’une hyperventilation volontaire maximale pré exercice peut significativement augmenter les performances de nageurs de bon niveau lors d’un 50m crawl / In this work we study the effects of a voluntary hyperventilation (respiratory alkalosis) on fatigue during a prolonged sprint. We measured the effects of a pre exercise increase of pH during anaerobic exercise. In the first test, seven subjects performed the test of Wingate, either under normal conditions, or after six maximal inspiration/expiry cycles carried out in 30 seconds (HV). The gaseous exchange were measured cycle with cycle during the entire test. The measured peak performances did not differ significantly between the two tests, on the other hand, the index of fatigability was higher when the test was carried out after a hyperventilation. In a second study, 11 subjects performed the test of Wingate either under normal conditions or 1 minute after 30 seconds of hyperventilation. Hyperventilation led to a significant reduction in the partial pressure of CO2 in the air of the end of expiration (PETCO2) below 30 mmHg suggesting a significant decrease of the blood ph. However, the peak power, the average power and the aerobic contribution were not significantly different between the two tests. Finally, in the last study, we recruited 9 high level swimmers, to carry out a 50m crawl either under normal conditions or after a HV followed by 30 seconds of passive recovery. In this study, average speed of the 50m crawls was significantly higher under HV conditions compared to normal conditions. The respiratory number of cycles recorded during each race was significantly lower in the HV conditions. We thus could conclude that a maximal voluntary pre exercise hyperventilation can significantly increase the performances of swimmers of good level at during a 50m crawl

Dans ce travail nous nous sommes centré sur les effets d'une hyperventilation volontaire (alcalose respiratoire) sur la fatigue lors d'un sprint prolongé. Il s'agit de mesurer les effets d'une augmentation pré exercice du pH lors de type d'exercice anaérobique. Dans un premier temps, sept sujets ont réalisé le test de Wingate, soit dans des conditions normales, soit après six cycles inspiration/expiration maximaux réalisés en 30 secondes (HV). Les échanges gazeux étaient mesurés en cycle à cycle durant tout le test. Les performances pic mesurées n'ont pas différées significativement entre les deux tests, en revanche, l'index de fatigabilité a été supérieur lorsque le test fut réalisé après une hyperventilation. Lors d'une seconde étude, 11 sujets ont réalisé le test de Wingate soit dans des conditions normales soit 1 minute après avoir réalisé une hyperventilation de 30 secondes. L'hyperventilation a entrainé une diminution significative de la pression partielle en CO2 dans l'air de fin d'expiration (PETCO2) en dessous de 30 mmHg suggérant une baisse significative du pH sanguin. Cependant, la puissance pic, la puissance moyenne et la contribution aérobie n'étaient pas significativement différentes entre les deux tests. Enfin, lors d'une dernière étude, nous avons recruté 9 nageurs de bon niveau, pour effectuer un 50m crawl ce soit dans des conditions normales ou bien après une HV suivie de 30 secondes de récupération passive. Dans cette étude, la vitesse moyenne de nage sur 50m crawl était significativement plus élevée dans lesconditions HV comparées aux conditions normales. Le nombre de cycles respiratoire enregistrés durant chaque course était significativement inférieur dans les conditions HV. Nous avons ainsi pu conclure qu'une hyperventilation volontaire maximale pré exercice peut significativement augmenter les performances de nageurs de bon niveau lors d'un 50m crawl

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-15T16:27:12Z No. of bitstreams: 1 PGCA16MA211.pdf: 910415 bytes, checksum: 51ae39dddf70a9c249c0895146f82c99 (MD5) / Made available in DSpace on 2018-03-15T16:27:12Z (GMT). No. of bitstreams: 1 PGCA16MA211.pdf: 910415 bytes, checksum: 51ae39dddf70a9c249c0895146f82c99 (MD5) Previous issue date: 2016-11-11 / Capes / More productive and efficient animals in the feed conversion and who can dribble more stressfull transition period are critical to improving performance in intensive milk production. Crossovers arise as an alternative by the search for healthier and more profitable animals. Blood gas analysis has a great importance on the evaluation of acidbase balance and electrolyte profile, providing essential information for the diagnosis and prognosis of several diseases in domestic animal. Dairy cows are more susceptible to metabolic disorders on the transition period and blood gas analysis provides important information to decision making and prevention of the development of many disorders. The objective was to determinate and compare the blood gas profile, feeding behavior and feed efficiency of Holstein and crossbreeding Holstein x Jersey cows in postpartum. Weekly, blood samples were collected from 24 Holstein and crossbred Holstein x Jersey cows. After blood sampling, a complete blood gas analysis was performed including pH, bicarbonate (HCO3 -), partial pressure of carbon dioxide (pCO2) and ionized calcium throughout the portable clinical analyzer for blood gas analysis, I-STAT using the CG8 + cartridge. The ingestive behavior, dry matter intake and milk production was evaluated. Data were submitted to analysis of variance with repeated measures, using the MIXED procedure of SAS statistical package. There were differences between genetic groups for pH values (P = 0.005), ionized calcium (P = 0.0203), base excess, BE (P = 0.0311), glucose (P = 0.0468) and hematocrit (P = 0.0209). The ionic calcium levels found were below the reference values throughout the evaluation period. However, crossbred cows showed higher levels of ionic calcium when compared to Holstein cows from prepartum period to parturition, being that and important health parameter of dairy cows, which is a positive characteristic feature on the choice for crossbreeding. The blood gas analysis has identified differences between Holstein and crossbred Holstein x Jersey cows in transition period. Crossbred cows Holstein x Jersey and Holstein cows have a similar dry matter intake and feed efficiency. Crossbred Holstein x Jersey cows tended to have higher feed efficiency for milk corrected to 4% fat and higher feed efficiency for fat production of. Crossbred Holstein x Jersey cows spend more time throughout the day feeding when compared to Holstein cows. Ruminations time was similar between Holstein and Holstein x Jersey cows / A busca por animais mais produtivos e eficientes na conversão de alimentos e que conseguem driblar mais os efeitos estressores do período de transição são fundamentais para melhorar o desempenho na produção intensiva de leite. Os cruzamentos surgem como uma alternativa pela busca de animais mais saudáveis e rentáveis. Vacas de leite no período de transição são muito suscetíveis a transtornos metabólicos, sendo que o exame hemogasométrico pode fornecer informações importantes, em nível de rebanho, para a tomada de decisão e prevenção da evolução de muitos distúrbios. O exame hemogasométrico é de grande importância na avaliação do equilíbrio ácido-básico e do perfil eletrolítico, fornecendo informações fundamentais para o diagnóstico e o prognóstico de várias enfermidades de animais domésticos. O objetivo deste trabalho foi determinar e comparar o perfil hemogasométrico, o comportamento ingestivo e a eficiência alimentar de vacas Holandês e Holandês x Jersey no período de transição pré e pós-parto. Coletaram-se semanalmente, amostras de sangue de 24 vacas Holandês e mestiças Holandês x Jersey, entre duas semanas pré e oito semanas pós-parto. Após o parto, as vacas foram alojadas em baias individualmente. Avaliou-se o pH sanguíneo, bicarbonato (HCO3 -), pressão de dióxido de carbono (pCO2) e cálcio ionizado através do analisador clínico portátil de gases sanguíneos, I-STAT utilizando o cartucho CG8+. Avaliou-se também, o comportamento ingestivo, o consumo de matéria seca e a eficiência alimentar das vacas. Os dados foram submetidos à análise de variância com medidas repetidas no tempo, utilizando-se o procedimento MIXED do pacote estatístico SAS. Houve diferença entre grupamentos genéticos nos valores de pH (P = 0,005), cálcio iônico (P = 0,0203), excesso de base, BE (P = 0,0311), glicose (P = 0,0468) e hematócrito (P = 0,0209). Os níveis de cálcio iônico encontraram-se abaixo dos valores de referência ao longo de todo o período de avaliação, mas, as vacas mestiças apresentaram níveis superiores de cálcio iônico quando comparadas às vacas Holandês, do pré-parto ao parto. O exame hemogasométrico permitiu identificar diferenças entre vacas Holandês e mestiças Holandês x Jersey no período de transição. Vacas mestiças Holandês x Jersey apresentam consumo de matéria seca diária e eficiência alimentar similar que as vacas puras Holandês. As vacas mestiças Holandês x Jersey tiveram tendência de maior eficiência alimentar para produção de leite corrigido a 4% de gordura e maior eficiência alimentar para produção de gordura. Vacas mestiças Holandês x Jersey passam mais tempo ao longo do dia se alimentando quando comparadas com as vacas Holandês, sem diferença no tempo de ruminação