The impact of fatigue on the intermittent high intensity exercise undertaken during participation in team sports has not been extensively studied. Team sports are characterised not only by intennittent exercise, but also by the contribution of a wide range of skills. This thesis describes a series of studies conducted in a controlled environment to assess the influence of fluid ingestion and fatigue on selected soccer skills. The aim of the first study was to examine the effect of 90-min of high intensity shuttle running with and without water ingestion on a socc er-dribb ling test. The subjects were allocated to two randomly assigned trials either ingesting or abstaining from fluid intake during a 90 min intennittent exercise protocol (Loughborough Intermittent Shuttle Test: LIST). In the absence of water ingestion soccer skill deteriorated (p < 0.05) by 5% but was maintained when fluid was ingested. The principal aim of the second study was to understand further the mechanisms contributing to the deterioration observed during the LIST. Subjects completed the LIST ingesting a 6.4% carbohydrate electrolyte solution (CHO), placebo (CON) or no fluid (NON). Free fatty acids, cortisol and aldosterone responses were lower (P < 0.01) at the end of exercise during both CHO and CON in comparison to NON. There was no difference in respiratory exchange ratio between trials. Fluid ingestion did not appear to cause a shift in substrate metabolism even though there were differences in plasma FFA concentrations. The consumption of carbohydrate during exercise has been shown to increase physical performance, capacity and cognitive function. The aim of the third study was to assess the influence of a 6.4 % carbohydrate-electrolyte (CHO) placebo (CON) or no fluid (NON) on passing and dribbling soccer skills following the LIST. During the NON trial performance of the dribbling test followed a similar pattern to that in the first study and performance of the passing test decreased (p < 0.05). This reduction in performance was prevented during the CHO and CON trials. The purpose of the final study was to identify whether a rehydration strategy following the LIST would result in a recovery of skill performance. Subjects were allocated to two randomly assigned trials either ingesting a volume of fluid equivalent to 150% (L) or 9% (S) of body mass loss during the LIST, over a2h recovery period. During the recovery period serum sodium and osmolality returned to resting concentrations in the L trial but remained elevated in the S trial (P < 0.05). Despite body mass returning to resting values following the rehydration period, performance of the skills tests remained impaired. Deterioration in skill test performance may have been related to a reduction in neuromuscular control either by a reduction in muscle glycogen or by an increase in muscle damage during the no fluid trials. The mechanism responsible for the deterioration in skill performance remains to be elucidated.

Orientadores: Eduardo Galembeck, Denise Vaz de Macedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-13T04:47:20Z (GMT). No. of bitstreams: 1 Sarraipa_MarioFerreira_M.pdf: 5351663 bytes, checksum: 54171c332f541db2d4c1eda62a4f5ad7 (MD5) Previous issue date: 2009 / Resumo: O estudo de vias metabólicas é fundamental em todos os cursos das áreas biológicas. O metabolismo de carboidratos, lipídios e proteínas é usado como modelo para estudo de vias metabólicas na maioria das disciplinas de Bioquímica básica e o seu conhecimento é importante para a compreensão dos processos de obtenção e utilização de energia pelos seres vivos. O presente trabalho utilizou-se de uma nova abordagem para o estudo de vias metabólicas baseado na montagem, passo a passo, de uma via metabólica, sendo escolhida a glicólise anaeróbica como modelo. Foi desenvolvido um programa de computador para montagem das reações da via metabólica de maneira que os estudantes manuseassem independentemente com orientações localizadas em um tutorial e com uma seqüência de instruções dos componentes de cada reação Essa metodologia foi aplicada nos cursos de Educação Física, Enfermagem, Medicina e Biologia da Universidade Estadual de Campinas - UNICAMP e no curso de Educação Física do Instituto Adventista de São Paulo - IASP, nas disciplinas de bioquímica básica e fisiologia respectivamente. Como instrumento de coleta, foi estruturado e montado um banco de dados, de modo que, ao utilizar o programa, todas as informações de utilização do mesmo foram armazenadas. Analisando estatisticamente os dados, pudemos observar que durante a montagem da via metabólica os usuários apresentaram uma tendência à diminuição do número de tentativas ao longo das onze reações. Dentre as onze reações, os estudantes apresentaram maior dificuldade na primeira e na sexta, conforme demonstrado pelo percentual de usuários (21% para a 1ª reação e 14% para a 2ª reação) que não conseguiram concluir a reação até a vigésima tentativa. Ainda foi analisado o tipo de erro por reação, possibilitando a discussão individual de cada reação e dos possíveis motivos que ocasionaram este erro. Como instrumento didático, o programa foi muito bem aceito pelos estudantes, que tiveram uma alternativa em relação às "aulas tradicionais sobre glicólise anaeróbica", possibilitando uma abordagem diferenciada do conteúdo. Além disso, o programa permitiu aos estudantes construir as vias metabólicas prestando atenção em cada uma de suas reações e identificando pontos de maior dificuldade Para os professores, o programa serviu como uma ferramenta didática adicional, proporcionando uma apresentação diferenciada do assunto e o conhecimento das etapas de maior dificuldade para os estudantes, permitindo a retomada dos conceitos necessários para a montagem da via glicolítica. / Abstract: The study of metabolic pathways is fundamental for all Biology-related courses. Carbohydrates, lipids, and proteins metabolism is used as a model for the study of metabolic pathways in most Basic Biochemistry subjects, and having such knowledge is important for the understanding of processes such as energy attainment and use up by living beings. This project has used a new approach to study metabolic pathways based on their mounting step-by-step, choosing anaerobic glycolysis as a model. A computer program has been developed for mounting the metabolic pathways reactions so that students could handle it by themselves with support available at a tutorial, and also a sequence of instructions for each reaction components. This methodology was applied to the following courses: Physical Education, Nursing, Medicine, and Biology at Universidade Estadual de Campinas - UNICAMP, and Physical Education at Instituto Adventista de São Paulo - IASP, to the subjects of Basic Biochemistry and Physiology. To collect data, a database has been developed so that, whenever the software was used, every use information was stored. By analyzing data statistically, it was noted that, during metabolic pathways mounting, users were likely to decrease the number of attempts along the eleven reactions. Amongst them, students found it harder on first and sixth reactions, as shown by the percentage of users who were not able to complete the reaction by the twentieth attempt (21% on the first reaction, 14% on the second). Additionally, the type of mistake by reaction has also been analyzed, allowing discussion of each reaction individually, and of possible reasons for such mistakes. As a teaching tool, the program has been very well accepted by students, who had an alternative in relation to the "anaerobic glycolysis traditional classes", making it possible to have a different approach of contents. Furthermore, the program enabled students to build metabolic pathways paying attention to each one of their reactions, and also identifying the most difficult points. For teachers, the software was an additional tool, providing a different presentation of the topic, and also knowledge on the most difficult stages for students, allowing the resumption of the concepts necessary to assemble the glycolytic pathway. / Mestrado / Bioquimica / Mestre em Biologia Funcional e Molecular

The current understanding of lactate metabolism in fish is based almost entirely on interpretation of concentration measurements that cannot be used to infer changes in flux. Moreover, the transporters regulating these fluxes have never been characterized in rainbow trout. My goals were: (1) to quantify lactate fluxes in rainbow trout under normoxic resting conditions, during acute hypoxia, and exercise by continuous infusion of [U-14C] lactate; (2) to determine lactate uptake capacity of trout tissues by infusing exogenous lactate in fish rest and during graded exercise, and (3) to clone monocarboxylate transporters (MCTs) and determine the effects of exhausting exercise on their expression. Such information could prove important to understand the mechanisms underlying the classic “lactate retention” seen in trout white muscle after intense exercise. In normoxic resting fish, the rates of appearance (Ra) and disappearance (Rd) of lactate were always matched (~18 to 13 µmol kg-1 min-1), thereby maintaining a low baseline blood lactate concentration (~0.8 mM). In hypoxic fish, Ra lactate increased from baseline to 36.5 µmol kg-1 min-1, and was accompanied by an unexpected 52% increase in Rd reaching 30.3 µmol kg-1 min-1, accounting for a rise in blood lactate to 8.9 mM. In exercising fish, lactate flux was stimulated > 2.4 body lengths per second (BL s-1). As the fish reached critical swimming speed (Ucrit), Ra lactate was more stimulated (+67% to 40.4 μmol kg-1 min-1) than Rd (+41% to 34.7 μmol kg-1 min-1), causing an increase in blood lactate to 5.1mM. Fish infused with exogenous lactate stimulated Rd lactate by 300% (14 to 56 μmol kg-1 min-1) during graded exercise, whereas the Rd in resting fish increased by only 90% (21 to 40 µmol kg-1 min-1). Four MCT isoforms were partially cloned and characterized in rainbow trout: MCT1b was the most abundant in heart, and red muscle, but poorly expressed in gill and brain where MCT1a and MCT2 were prevalent. MCT4 was more expressed in the heart. Transcript levels of MCT2 (+260%; brain), MCT1a (+90%; heart) and MCT1b (+50%; heart) were stimulated by exhausting exercise. This study shows that: (i) the increase in Rd lactate plays a strategic role in reducing the lactate load imposed on the circulation. Without this response, blood lactate accumulation would double; (ii) a high capacity for lactate disposal in rainbow trout tissues is elicited by the increased blood-to-tissue lactate gradient when extra lactate is administered; and (iii) rainbow trout may be unable to release large lactate loads rapidly from white muscle after exhausting exercise (lactate retention) because they poorly express MCT4 in white muscle and fail to upregulate its expression during exercise.

The current understanding of lactate metabolism in fish is based almost entirely on interpretation of concentration measurements that cannot be used to infer changes in flux. Moreover, the transporters regulating these fluxes have never been characterized in rainbow trout. My goals were: (1) to quantify lactate fluxes in rainbow trout under normoxic resting conditions, during acute hypoxia, and exercise by continuous infusion of [U-14C] lactate; (2) to determine lactate uptake capacity of trout tissues by infusing exogenous lactate in fish rest and during graded exercise, and (3) to clone monocarboxylate transporters (MCTs) and determine the effects of exhausting exercise on their expression. Such information could prove important to understand the mechanisms underlying the classic “lactate retention” seen in trout white muscle after intense exercise. In normoxic resting fish, the rates of appearance (Ra) and disappearance (Rd) of lactate were always matched (~18 to 13 µmol kg-1 min-1), thereby maintaining a low baseline blood lactate concentration (~0.8 mM). In hypoxic fish, Ra lactate increased from baseline to 36.5 µmol kg-1 min-1, and was accompanied by an unexpected 52% increase in Rd reaching 30.3 µmol kg-1 min-1, accounting for a rise in blood lactate to 8.9 mM. In exercising fish, lactate flux was stimulated > 2.4 body lengths per second (BL s-1). As the fish reached critical swimming speed (Ucrit), Ra lactate was more stimulated (+67% to 40.4 μmol kg-1 min-1) than Rd (+41% to 34.7 μmol kg-1 min-1), causing an increase in blood lactate to 5.1mM. Fish infused with exogenous lactate stimulated Rd lactate by 300% (14 to 56 μmol kg-1 min-1) during graded exercise, whereas the Rd in resting fish increased by only 90% (21 to 40 µmol kg-1 min-1). Four MCT isoforms were partially cloned and characterized in rainbow trout: MCT1b was the most abundant in heart, and red muscle, but poorly expressed in gill and brain where MCT1a and MCT2 were prevalent. MCT4 was more expressed in the heart. Transcript levels of MCT2 (+260%; brain), MCT1a (+90%; heart) and MCT1b (+50%; heart) were stimulated by exhausting exercise. This study shows that: (i) the increase in Rd lactate plays a strategic role in reducing the lactate load imposed on the circulation. Without this response, blood lactate accumulation would double; (ii) a high capacity for lactate disposal in rainbow trout tissues is elicited by the increased blood-to-tissue lactate gradient when extra lactate is administered; and (iii) rainbow trout may be unable to release large lactate loads rapidly from white muscle after exhausting exercise (lactate retention) because they poorly express MCT4 in white muscle and fail to upregulate its expression during exercise.