Standardization of overreaching model for rats detected by performance decrement : development and perspectives in swimming and treadmill research

Orientador: Denise Vaz de MacedoTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O empirismo do treinamento pode levar a um desequilíbrio entre estímulo da atividade motora e tempo de recuperação do esforço. Como conseqüência o atleta pode experimentar um estado agudo de fadiga e queda de desempenho denominado de overreaching, revertido em poucos dias. A persistência desta situação de desequilíbrio pode levar a um quadro crônico de sensação de fadiga acompanhado de queda de desempenho denominado de síndrome do overtraining (OTS), que pode durar semanas ou meses. O objetivo deste trabalho foi padronizar um protocolo controlado e reprodutível de treinamento em ratos que contivesse um período de desequilíbrio entre o estímulo do exercício e o tempo de recuperação que gerasse queda de desempenho. Há duas formas de exercício em ratos amplamente utilizadas na literatura: a natação e a corrida em esteira. Os primeiros dois capítulos deste trabalho descrevem a padronização de um teste de desempenho em natação, reprodutível ao longo do crescimento animal, para ser utilizado em estudos longitudinais. Para isso, precisávamos considerar o empuxo sofrido pelo animal no meio líquido e validamos (Capítulo I) um aparato de medição de volume para animais vivos e conscientes (AMV). No capítulo II apresentamos os dados da comparação da reprodutibilidade de dois testes de desempenho até a exaustão na natação durante os cinco primeiros meses de vida dos ratos. Um teste com adição de cargas ajustadas de acordo com o porcentual da massa corporal (MC) e outro com cargas constantes (CC). Utilizando o AMV constatamos que a densidade dos animais não variava e, como conseqüência, o teste MC diminuía o tempo de exaustão conforme os ratos aumentavam a massa durante o crescimento, enquanto o teste CC mantinha o tempo de exaustão ao longo do tempo. Paralelamente, iniciamos os estudos com exercício em esteira. No Capítulo III apresentamos um protocolo de 11 semanas, onde o desequilíbrio entre exercício e recuperação foi determinado pelo aumento das sessões diárias nas três últimas semanas em 2, 3 e 4 vezes, com diminuição no tempo de recuperação entre elas. Selecionamos no final desse treinamento dois grupos de ratos, aqueles que apresentaram baixo desempenho (BD) e aqueles que apresentaram aumento ou manutenção do desempenho (AD). Embora ambos os grupos tenham apresentado uma diminuição da massa corporal durante o aumento da freqüência de treinamento, o grupo BD precisou de uma semana a mais de repouso para voltar a aumentar a massa, sem modificar o desempenho. No Capítulo IV comparamos quatro grupos de ratos obtidos desse protocolo (Controle (CO), Treinados (T), BD e AD) em análises no sangue (glutamina, glutamato, alanina e hemograma) e músculo (citrato sintase (CS), lactato desidrogenase e glicogênio). Comparando BD com T e AD observamos: (1) diminuição da concentração plasmática de glutamina e aumento na de glutamato, com valores semelhantes aos do grupo CO; (2) diminuição da capacidade oxidativa (CS) e manutenção dos estoques de glicogênio; (3) leucocitose. Em vista das diferenças encontrada entre os grupos BD e AD, concluímos que o protocolo de treinamento de indução de overreaching representa uma ferramenta metodológica importante, que pode auxiliar no desvendamento dos mecanismos causadores da queda de desempenho nos estados de overreaching/OTSAbstract: The empirical training can lead to an imbalance between the motor activity stress and recovery. As consequence, the athlete can try an acute state of fatigue and performance decrement called overreaching, reverted in a few days. This continuous unbalance can lead to a chronic fatigue state called as overtraining syndrome (OTS), that may last weeks or months. Our goal was to standardize a controlled and reproducible training protocol in rats that contained an unbalance period between exercise stress and recovery with performance decrement. Two forms of exercise is widely used for rats training in literature: swimming and treadmill running. Chapters I and II describe an adequate standardization for workload in swimming tests when applied to longitudinal studies with sedentary rats. Therefore, considering the rats' buoyance, we validate (Chapter I) an apparatus for measuring conscientious living rat body volume (AMV). In chapter II, we evaluated two types of swimming tests with overload in sedentary rats: one with the load adjusted according to percentage of body weight (BW) and another one with constant load (CL) over time. Through the AMV, we found that the rats' density did not vary significantly, as consequence, MC test showed performance decrement as the rats had their mass increased, while CC test maintained performance along rats growth. In time, we initiate the studies with treadmill exercise. In Chapter III, we present an eleven weeks training protocol where the unbalance between exercise stress and recovery was determined by the increase of the daily sessions in 2, 3 and 4 times in the last three weeks, reducing the recovery time between sessions. We selected two groups of rats in the end of the training protocol, those that presented low performance (BD) and those that presented performance increase or maintenance (AD). Although both groups (AD and BD) showed corporal mass reduction during the increase of the daily frequency, BD group return to increase the mass one week later than AD group, without modifying the performance. In Chapter IV, we compare four groups of rats after the eleven weeks training protocol (Control (CO), Trained (T), AD and BD) in blood (glutamine, glutamate, alanine and hematological variables) and muscle analyses (citrate synthase (CS), lactate dehydrogenase and glycogen). Comparing BD with AD and T groups, we observe: (1) reduction of the glutamine plasma concentration and increase of glutamate, with similar CO values; (2) reduction of the oxidative capacity (CS) and maintenance of the glycogen stores; (3) leucocitosys. We conclude that the training protocol induces the rats to overreaching and it represents a relevant methodological tool in overreaching / OTS metabolical mechanisms research envolved in performance decrementDoutoradoFisiologiaDoutor em Biologia Funcional e Molecula

Effect of an endurance training-overtraining protocol on rat muscular oxidative capacity

Overtraining may outcomes for functional overreaching (FOR), a short term decline in performance that leads eventually to an improvement in performance after recovery, or nonfunctional overreaching (NFOR) when performance decline may be reversed only by a longer regenerative period. Recently we developed a training-overtraining protocol for rats with increased workload: eight weeks of daily exercise sessions, followed by three weeks of increasing daily training frequency (2, 3 and 4 times) with decreasing recovery time between sessions (4, 3 and 2h), characterized by analyses of performance before training (T1) and after the 4th(T2), 8th(T3), 9th(T4), 10th(T5) and 11th(T6) training weeks. All rats showed significantly increased performance at T4 and eight rats constitute the trained group (Tr). After T6, two groups were distinguishable by differences in the slope (α) of a line fitted to the individual performances at T4, T5 and T6: NFOR: α\u3c-15.05Kgm and FOR: α≥-15.05Kgm. Our goal was to verify the muscle’s oxidative capacity of Tr, FOR and NFOR groups. Skeletal muscle mitochondrial complexes I, IV and citrate synthase (CS) activity were quantified through Histochemical-staining-BN-PAGE and spectrophotometer analysis, respectively. The area of complexes I and IV was expressed relative to the area for comassie-stained complex V. Significant decreases were found in complex IV (17.2±5.84) and CS activity (22.7±3.21U/gwet) in NFOR group when compared with Tr (35.39±11.33, 32.8±5.24U/gwet) and FOR (28.9±11.37, 31.8±2.75U/gwet). There is a relationship between NFOR and the reduction of muscle oxidative capacity. Thus, aerobic tests should be performed in training routine to monitor performance alterations preventing these situations

Effect of Body Weight Variation on Swimming Exercise Workload in Rats With Constant and Size-Adjusted Loads

In swimming animal models, weights are added according to some percentage of body weight (%BW) or as a constant load (CL) to equalize the workload of each animal or to reduce the time in swimming-to-exhaustion endurance tests. The objective of the present study was to evaluate the effect of body weight variation on swimming exercise workload through the reliability analysis of swimming-to-exhaustion endurance tests. We examined the reliability by comparing the mean time to exhaustion (TEx) in trials performed on the 30th, 60th, 90th, 120th and 150th days of life of Wistar rats using three %BW and CL workloads (4%, 6% and 8% and 7 g, 11 g and 15 g, respectively). We also examined the within-subject variation of TEx over three trials of a CL test (15 g) within one week (when variability in body weight is minimal). The rats’ body density was maintained during growth (mean (SD) 1.031 (0.026) g/ml – 1.026 (0.005) g/ml) despite their significant increase in body weight (mean(SD) 109.05(13.80) g - 442.92(29.39) g). Thus, the absolute loads in longitudinal %BW tests increased gradually, causing a decrease in TEx under all workloads. The CV confidence limits for TEx in CL tests showed high within subjects variation (17.1-111%) compared to the body weight variation (0.4-2.8%). We conclude that load adjustment based on %BW does not adequately equate to the workload between rats of different sizes. The methodology also showed high within-subject variation between trials (not related to body mass changes) that compromises the significance of small effects

Protótipo didático demonstra o efeito da pressão intracraniana sobre a pressão de perfusão cerebral

A pressão de perfusão cerebral (PPC) resulta da diferença entre pressão arterial média e pressão intracraniana (PIC). A compreensão dos princípios biofísicos que explicam como a PIC influencia a PPC exigem abstração e podem ser explicados por analogia utilizando protótipos de baixo custo. Objetivo: Apresentar um protótipo didático desenvolvido com materiais recicláveis que mostre a influência da PIC sobre a PPC. Método: Foi construído um protótipo com uma garrafa PET de 200 ml, ultrapassada por 6cm de uma bola de látex (padrão 5:150cm), simulando, respectivamente, o crânio e um vaso cerebral. Uma seringa de 10ml foi conectada ao PET para reduzir o volume do sistema e elevar a pressão no seu interior. Um bulbo de látex, com válvula unidirecional, foi conectado à bola através de um equipo de duplo lúmen, no qual um dos ramos foi utilizado para direcionar fluxo de ar para a bola. Para demonstrar a variação de pressão no interior do PET (∆P1) e da bola de látex (∆P2) foram utilizados dois manômetros aneroides (M1 e M2, respectivamente) conectados com mangueiras de látex. Todas as conexões foram vedadas com silicone. Resultados: A compressão do êmbolo da seringa reduziu o volume do sistema e aumentou ∆P1 = 30mmHg, implicando colapso da bola, elevação da resistência à passagem do fluxo de ar (com um aumento de ∆P2 = 30mmHg em M2) quando o bulbo era pressionado. Uma maior sensação de esforço manual para comprimir o bulbo foi percebida com ∆P1 aumentado. O protótipo permitiu a analogia intuitiva garrafa PET /crânio e bola/ vaso sanguíneo, sendo possível perceber como a elevação da PIC altera a PPC. Conclusão: Protótipos com materiais de baixo custo são ferramentas intuitivas e de fácil acesso que podem ser utilizados para ilustrar didaticamente os fenômenos biofísicos fundamentais da PIC sobre a PPC em humanos.Cerebral perfusion pressure (CPP) results from the difference between mean arterial pressure and intracranial pressure (ICP). The comprehension of the biophysical principles that explain how ICP influences CPP dynamics requires abstraction and can be explained by analogy using low-cost prototypes. Objective: To come up with a didactic prototype developed with recyclable materials that shows the influence of ICP on CPP. Method: A prototype was built with a 200 ml PET bottle, overpassed by a 06 cm latex ball (standard: 5:150 cm), simulating respectively, the skull and a single cerebral vessel. A 10 ml syringe was connected to the PET in order to reduce the volume of the system and increase the pressure inside it. A latex bulb, containing an unidirectional valve, was connected to the latex ball through a double-lumen tube, in which, one of the branches was used to direct an airflow to the latex ball. To demonstrate the pressure variation inside the PET (∆P1) and inside the latex ball (∆P2), two aneroid manometers (M1 and M2, respectively), connected with latex hoses, were used. All connections have been sealed with silicone. Results: The syringe plunger compression reduced the system volume and increased ∆P1 = 30mmHg, resulting in a collapsed ball and increased resistance to the air flow (with an increase of ∆P2 = 30 mmHg in M2) when the bulb was pressed. The perceived handgrip effort to compress the bulb was higher when ∆P1 was increased. The prototype allowed a direct intuitive comparison between the PET/skull and the ball/blood vessel, and it was also possible to see how the elevation of the ICP plays an important role in the CPP. Conclusion: Prototypes with low-cost materials are intuitive and easily accessible tools that can be used to didactically illustrate the fundamental biophysical influence of ICP on CPP in humans

Protótipo didático automatizado de ventilação pulmonar exibe uma simulação de variações de pressão intratorácica durante a função diafragmática

The movement of air from the environment to the alveoli is a vital and complex phenomenon that occurs due to variations in intrathoracic and airway pressures in relation to the atmosphere. The construction of didactic prototypes can minimize the abstraction required in these in vivo phenomena. In this study, we automated a didactic prototype of pulmonary ventilation already described in literature to simulate and exhibit variations in intrathoracic pressure during diaphragmatic function. A pulmonary ventilation (PV) prototype was produced with recyclable materials, and automated by adapting a pressure sensor in the system to generate pressure curves as a function of time during the simulation of diaphragmatic function. The automated plunger’s downward traction induced by the servomotor (such as diaphragmatic) reduced the pressure inside the bottle (intrathoracic), and this variation can be observed graphically on a computer interface while the balloon was expanded, and atmospheric air invaded its interior. Conclusion: The incorporation of technology into a simple PV prototype allowed a safe and simulated demonstration of how the diaphragm induces the variation of the intrathoracic pressure in relation to the atmosphere concomitantly with the pulmonary deformation that occurs during inspiration and exhalation.O movimento do ar do ambiente para os alvéolos é um fenômeno vital e complexo que ocorre devido às variações nas pressões intratorácicas e nas vias aéreas em relação à atmosfera. A construção de protótipos didáticos pode minimizar a abstração necessária nestes fenômenos in vivo. Neste estudo, automatizamos um protótipo didático de ventilação pulmonar já descrito na literatura para simular e exibir variações na pressão intratorácica durante a função diafragmática. Um protótipo de ventilação pulmonar (PV) foi produzido com materiais recicláveis, e automatizado adaptando um sensor de pressão no sistema para gerar curvas de pressão em função do tempo durante a simulação da função diafragmática. A tração descendente do êmbolo automatizado induzida pelo servomotor (como o diafragmático) reduziu a pressão dentro da garrafa (intratorácica), e esta variação pode ser observada graficamente em uma interface de computador enquanto o balão foi expandido, e o ar atmosférico invadiu seu interior. Conclusão: A incorporação da tecnologia em um protótipo PV simples permitiu uma demonstração segura e simulada de como o diafragma induz a variação da pressão intratorácica em relação à atmosfera concomitantemente com a deformação pulmonar que ocorre durante a inspiração e a exalação

Interprofessional and interdisciplinary simulation-based training leads to safe sedation procedures in the emergency department

BACKGROUND Sedation is a procedure required for many interventions in the Emergency department (ED) such as reductions, surgical procedures or cardioversions. However, especially under emergency conditions with high risk patients and rapidly changing interdisciplinary and interprofessional teams, the procedure caries important risks. It is thus vital but difficult to implement a standard operating procedure for sedation procedures in any ED. Reports on both, implementation strategies as well as their success are currently lacking. This study describes the development, implementation and clinical evaluation of an interprofessional and interdisciplinary simulation-based sedation training concept. METHODS All physicians and nurses with specialised training in emergency medicine at the Berne University Department of Emergency Medicine participated in a mandatory interdisciplinary and interprofessional simulation-based sedation training. The curriculum consisted of an individual self-learning module, an airway skill training course, three simulation-based team training cases, and a final practical learning course in the operating theatre. Before and after each training session, self-efficacy, awareness of emergency procedures, knowledge of sedation medication and crisis resource management were assessed with a questionnaire. Changes in these measures were compared via paired tests, separately for groups formed based on experience and profession. To assess the clinical effect of training, we collected patient and team satisfaction as well as duration and complications for all sedations in the ED within the year after implementation. We further compared time to beginning of procedure, time for duration of procedure and time until discharge after implementation with the one year period before the implementation. Cohen's d was calculated as effect size for all statistically significant tests. RESULTS Fifty staff members (26 nurses and 24 physicians) participated in the training. In all subgroups, there is a significant increase in self-efficacy and knowledge with high effect size (d z  = 1.8). The learning is independent of profession and experience level. In the clinical evaluation after implementation, we found no major complications among the sedations performed. Time to procedure significantly improved after the introduction of the training (d = 0.88). DISCUSSION Learning is independent of previous working experience and equally effective in raising the self-efficacy and knowledge in all professional groups. Clinical outcome evaluation confirms the concepts safety and feasibility. CONCLUSION An interprofessional and interdisciplinary simulation-based sedation training is an efficient way to implement a conscious sedation concept in an ED

Vitamin C and E Supplementation Effects in Professional Soccer Players Under Regular Training

Exercise training is known to induce an increase in free radical production potentially leading to enhanced muscle injury. Vitamins C and E are well known antioxidants that may prevent muscle cell damage. The purpose of this study was to determine the effects of these supplemental antioxidant vitamins on markers of oxidative stress, muscle damage and performance of elite soccer players. Ten male young soccer players were divided into two groups. Supplementation group (n = 5) received vitamins C and E supplementation daily during the pre-competitive season (S group), while the placebo group (PL group, n = 5) received a pill containing maltodextrin. Both groups performed the same training load during the three-month pre-season training period. Erythrocyte antioxidant enzymes glutathione reductase, catalase and plasma carbonyl derivatives did not show any significant variation among the experimental groups. Similarly, fitness level markers did not differ among the experimental groups. However, S group demonstrated lower lipid peroxidation and muscle damage levels (p < 0.05) compared to PL group at the final phase of pre-competitive season. In conclusion, our data demonstrated that vitamin C and E supplementation in soccer players may reduce lipid peroxidation and muscle damage during high intensity efforts, but did not enhance performance

Relação entre velocidade de limiar anaerobio e resistencia de sprint em jogadores de futebol : influencia da suplementação de creatina

Esse trabalho teve dois objetivos, propor um novo protocolo para quantificar a capacidade de resistência de sprint e quantificar tanto o efeito de três blocos (A=Resistência, B= Força, C= Velocidade) distintos de preparação física para o Campeonato Paulista de Futebol2001 quanto o efeito do período competitivo (D) em uma equipe da Categoria Sub-20 (N=Il) nos seguintes parâmetros: velocidade em 30m, aceleração, número de sprints (NS), fudice de fadiga e limiar anaeróbio (LA). Nosso objetivo específico foi verificar, em cada momento, se havia relação entre as capacidades de resistência de sprint e limiar anaeróbio. Em um dos blocos (B) os atletas foram submetidos a uma suplementação com creatina. Métodos: Cinco fotocélulas foram dispostas no gramado a cada 7,5m, totalizando 30m. Os exercícios foram feitos com chuteiras, em intensidade máxima, com 20s de pausa entre os tiros. O teste era encerrado quando o atleta atingia decréscimo de 1 00/o na sua melhor velocidade máxima atingida. O LA foi verificado através do protocolo de lactato mínimo, proposto por Tegt bur (1993). Resultados: A melhor velocidade em 30m não se alterou significativamente entre as diferentes fases. O tempo para atingir a velocidade máxima (TVM) e a velocidade máxima atingida em cada sprint melhoraram significativamente em dois dos blocos (C e O) quando comparados ao bloco A. O índice de fadiga caiu de 20% (A) para 7% (C) e 13%(D). O NS aumentou somente após o bloco B, quando os atletas foram suplementados com creatina. Não houve diferença significativa nos valores de NS nos demais blocos. O LA apresentou valores significativamente maiores em B e D quando comparados aos blocos A. Não houve correlação entre a velocidade de LA e o NS (rA= 0,27, r8=0,30, rç=0,23, r0=0,41; P<O,OS) em nenhum dos momentos analisados. Conclusão: O novo protocolo de resistência de sprint proposto mostrou-se eficiente para analisar essa capacidade. O número de sprints sofreu uma interferência maior pela suplementação com creatina do que o limiar anaeróbio. A capacidade de regeneração de fosfocreatina parece não ser o que diferencia atletas do mesmo nível em exercícios de alta intensidade com 20s de pausa. O período competitivo forneceu estimulo adequado para que os atletas permanecessem próximos aos valores adquiridos durante a longa preparação física a que foram submetidos.Not informed

Manuscript clarification for ischemic preconditioning improves strength endurance performance

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