This thesis examined the effects of exhaustive exercise and post-exercise recovery on metabolism and respiratory gas exchange in juvenile rainbow trout, in relation to the classical oxygen (O₂) debt hypothesis (Hill & Lupton, 1923). The initial study was a detailed quantitative analysis of the metabolic cost of post-exercise recovery in terms of O₂ and ATP equivalents. A 5 min bout of exhaustive exercise resulted in about a 2.0-2.5 fold increase in O₂ consumption (MO₂), a 6-8 fold increase in whole-body lactate (LAC) levels and a near depletion in whole-body glycogen (GLY), adenosine triphosphate (ATP) and creatine phosphate (CP) stores. Recovery of MO₂, LAC and GLY was usually complete by 6 h, though GLY did not always return to resting levels. Recovery of resting whole-body ATP required 1.0-1.5 h, whereas restoration of CP required only 5 min. Quantitative budgets of the cost of recovery were prepared, based on two opposite assumptions. The first scenario (A) assumed that all the GLY resynthesized came from LAC, and that the remaining 25% of the total LAC cleared was oxidized. This scenario accounted for 48% of the excess post-exercise O₂ consumption (EPOC) and 94% of the ATP budget. The alternative scenario (B), attributed 100% of the EPOC to LAC oxidation (64% of the total LAC cleared), while the remaining LAC (36%) was resynthesized into GLY. As scenario B accounted for only 35% of the ATP budget, scenario (A) appeared more probable. Subsequent experiments attempted to experimentally dissociate LAC disappearance from EPOC, via repetitive exercise bouts and prior GLY depletion. A 2nd bout of exhaustive exercise, given 6 h after the 1st, significantly reduced EPOC by 40%, whereas metabolite status (LAC disappearance and GLY, ATP, and CP restoration) remained essentially unchanged. In contrast, prior GLY depletion by 5 days starvation significantly lowered the LAC burden while EPOC remained unchanged. Neither the two scenarios of the theoretical analysis could adequately explain the relationships between EPOC and the various metabolites. It is likely that some blend of the two approaches may be more realistic. Nevertheless, these approaches all point to the conclusion that the EPOC is not directly related to the metabolism of LAC after exercise in the rainbow trout. Thus, in contrast to the classical O₂ debt hypothesis, LAC disappearance does not determine the magnitude EPOC after exhaustive exercise in rainbow trout. / Thesis / Master of Science (MS)

O propósito do presente estudo foi investigar as contribuições dos sistemas bioenergéticos e do gasto energético total durante a escalada esportiva indoor. As variáveis antropométricas, a composição corporal, a potência aeróbia máxima de membros superiores e o teste de Wingate para membros superiores foram avaliados em 13 escaladores (Grupo de Elite = 6; Grupo Recreacional = 7). Além disso, o grupo de elite escalou três rotas com diferentes níveis de intensidades (fácil, moderada e difícil) com a mensuração contínua do consumo de oxigênio e com a medida das concentrações sangüíneas de lactato de pico durante a recuperação, ao passo que o grupo dos escaladores recreacionais escalou apenas a rota fácil sobe as mesmas condições. As estimativas dos sistemas aeróbio, glicolítico e ATP-CP foram feitas por meio da mensuração do consumo de oxigênio, das concentrações sanguíneas de lactato de pico e do débito alático de oxigênio, respectivamente. A estimativa do gasto energético total foi realizada pela somatória desses três sistemas. Os principais resultados foram: a) as variáveis antropométricas influenciam apenas em situações específicas da escalada; b) o consumo de oxigênio de pico e a freqüência cardíaca de pico têm uma relação não-linear durante as ascensões das rotas de escalada; c) os sistemas oxidativo e o ATP-CP são os prioritários na transferência da energia na escalada esportiva indoor, independentemente da intensidade das rotas estudadas ou do nível de aptidão dos indivíduos; d) o perfil metabólico e o gasto energético total não apresentam relação linear com o incremento da dificuldade das rotas; e) o menor gasto energético total durante as ascensões está mais relacionado ao desempenho nesse esporte que o aprimoramento dos sistemas bioenergéticos. / The purpose of the present study was to investigate the contributions of the energetic systems and the total energetic cost, during the indoor rock climbing. The anthropometric variables, body composition, upper limbs maximal aerobic power and the Wingate test for the upper limbs were evaluated in 14 climbers (Elite group = 7; Recreation group = 7). Besides, the Elite group have climbed three routes with different levels of intensity (easy, moderate and hard) with the continue measurement of the oxygen uptake during these tasks and with the measurement of the peak blood lactate concentrations during the recovery, while as the recreational climbers group have climbed only the easy route under the same conditions. The calculation of the aerobic, glycolytic and ATP-CP systems were made by the measurement of the oxygen consumption, peak blood lactate concentrations and alactacid oxygen debt, respectively. The calculation of the total energetic cost was made by the sum of these three systems. The main results were: a) the anthropometric variables have secondary contribution on the rock climbers performance, b) the oxygen consumption and the heart rate have a non-linear relation during the ascension of the climbing routes, c) the aerobic and the ATP-CP systems have priority on the energy transference in the indoor rock climbing, independently on the routes intensity or the ability level of the individual, d) the metabolic profile and cost energetic don’t have a linear relationship with the route’s difficult increment; e) the minor energetic cost is more important for the performance in this sport than the improvement of the bioenergetic systems.

O propósito do presente estudo foi investigar as contribuições dos sistemas bioenergéticos e do gasto energético total durante a escalada esportiva indoor. As variáveis antropométricas, a composição corporal, a potência aeróbia máxima de membros superiores e o teste de Wingate para membros superiores foram avaliados em 13 escaladores (Grupo de Elite = 6; Grupo Recreacional = 7). Além disso, o grupo de elite escalou três rotas com diferentes níveis de intensidades (fácil, moderada e difícil) com a mensuração contínua do consumo de oxigênio e com a medida das concentrações sangüíneas de lactato de pico durante a recuperação, ao passo que o grupo dos escaladores recreacionais escalou apenas a rota fácil sobe as mesmas condições. As estimativas dos sistemas aeróbio, glicolítico e ATP-CP foram feitas por meio da mensuração do consumo de oxigênio, das concentrações sanguíneas de lactato de pico e do débito alático de oxigênio, respectivamente. A estimativa do gasto energético total foi realizada pela somatória desses três sistemas. Os principais resultados foram: a) as variáveis antropométricas influenciam apenas em situações específicas da escalada; b) o consumo de oxigênio de pico e a freqüência cardíaca de pico têm uma relação não-linear durante as ascensões das rotas de escalada; c) os sistemas oxidativo e o ATP-CP são os prioritários na transferência da energia na escalada esportiva indoor, independentemente da intensidade das rotas estudadas ou do nível de aptidão dos indivíduos; d) o perfil metabólico e o gasto energético total não apresentam relação linear com o incremento da dificuldade das rotas; e) o menor gasto energético total durante as ascensões está mais relacionado ao desempenho nesse esporte que o aprimoramento dos sistemas bioenergéticos. / The purpose of the present study was to investigate the contributions of the energetic systems and the total energetic cost, during the indoor rock climbing. The anthropometric variables, body composition, upper limbs maximal aerobic power and the Wingate test for the upper limbs were evaluated in 14 climbers (Elite group = 7; Recreation group = 7). Besides, the Elite group have climbed three routes with different levels of intensity (easy, moderate and hard) with the continue measurement of the oxygen uptake during these tasks and with the measurement of the peak blood lactate concentrations during the recovery, while as the recreational climbers group have climbed only the easy route under the same conditions. The calculation of the aerobic, glycolytic and ATP-CP systems were made by the measurement of the oxygen consumption, peak blood lactate concentrations and alactacid oxygen debt, respectively. The calculation of the total energetic cost was made by the sum of these three systems. The main results were: a) the anthropometric variables have secondary contribution on the rock climbers performance, b) the oxygen consumption and the heart rate have a non-linear relation during the ascension of the climbing routes, c) the aerobic and the ATP-CP systems have priority on the energy transference in the indoor rock climbing, independently on the routes intensity or the ability level of the individual, d) the metabolic profile and cost energetic don’t have a linear relationship with the route’s difficult increment; e) the minor energetic cost is more important for the performance in this sport than the improvement of the bioenergetic systems.