<p> While several investigations have reported a higher proportion of lipid oxidation (lower carbohydrate oxidation) in females performing heavy endurance exercise at the same relative intensity as males, some studies have failed to support this. Possible factors contributing to the lack of agreement may be differences in subject training status and diet, or the hormonal status of female subjects related to menstrual phase. All these variables are known to affect substrate metabolism during submaximal exercise. These factors were controlled in the present study by selecting subjects who were matched for level of physical conditioning and performance experience and placing them on eucaloric identical diets for 3 days. The females were tested during the mid-follicular phase of their menstrual cycle. Six males and 6 females ran on a treadmill at 65% VO2 max for a total distance of 15.5 km (range in performance times, 90 to 101 min). Pre and post exercise needle biopsies of vastus lateralis were assayed for glycogen concentration. Plasma glycerol, glucose, free fatty acids and selected hormones (catecholamines, growth hormone, insulin and glucagon) were measured throughout and following the run by sampling from an indwelling venous catheter. Exercise protein catabolism was estimated from 24 hr (resting and exercise) urinary urea N excretion. </p> <p> Males were found to have significantly higher respiratory exchange ratios (X =0.94 vs 0.87), greater muscle glycogen utilization (by 25%) and greater urea nitrogen excretion (by 30%) than females. Changes in selected hormone concentrations could not explain the greater lipid utilization observed in females. The lower insulin and higher epinephrine levels seen in males could in part explain the greater glycogenolysis and protein catabolism observed inn this group. It is concluded that, during moderate intensity long duration exercise, females demonstrate greater lipid utilization and less carbohydrate and protein metabolism than equally trained and nourished males. </p> / Thesis / Master of Science (MSc)

The primary aim of this thesis was to investigate the gender-specific responses to supramaximal cycling and to examine the changes in anaerobic and aerobic metabolism that occur in response to high-intensity interval training (HIT). All subjects in the present experiments were untrained, healthy young adults aged between 18 and 35 yr. Cycle ergometry was used for all experimental test procedures and training programs. The accumulated oxygen (AO2) deficit was used to quantify the production of adenosine triphosphate (ATP) via anaerobic metabolism during supramaximal cycling. In addition, pulmonary oxygen uptake measured at the onset of exercise was described using mathematical modeling to determine the rate response of the aerobic energy system during exercise. The purpose of experiment one was to examine the test-retest reliability of the maximal accumulated oxygen deficit (MAOD) measured at 110% and 120% of peak oxygen uptake for cycling in seven untrained male and seven untrained female subjects. After one familiarization trial, all subjects performed two MAOD tests at a power output corresponding to 110% and two tests at 120% of peak oxygen uptake in random order. MAOD was calculated for each subject as the difference between the estimated AO2 demand and the AO2 uptake measured during the exercise bout. The mean±standard error time to exhaustion (TE) for the group was not significantly different between trial one (226±13 s) and trial two (223±14 s) of the 110% test. Likewise, the difference in the TE between trial one (158±11 s) and trial two (159±10 s) was not significant for the 120% test. The intra-class correlation coefficients for the TE were 0.95 for the 110% test and 0.98 for the 120% test. The mean MAOD value obtained in trial one (2.62±0.17 L) was not significantly different from the mean value obtained in trial two (2.54±0.19 L) for the 110% test. Additionally, the mean values for the two trials did not differ significantly for MAOD (2.64±0.21 L for trial one and 2.63±0.19 L for trial two) in the 120% test. The intra-class correlation coefficients for MAOD were 0.95 for the 110% test and 0.97 for the 120% test. All intra-class correlation coefficients were significant at p < 0.001. When conducted under standardized conditions, the determination of MAOD for cycling was highly repeatable at both 110% and 120% of peak oxygen uptake in untrained male and female subjects. The results observed in experiment one suggest that the MAOD may be used to compare the anaerobic capacity (AC) of men and women and to examine changes in the contribution of the anaerobic energy systems before and after training. Experiment two examined the gender-specific differences in MAOD before and after 4 and 8 wk of HIT. Untrained men (n=7) and women (n=7) cycled at 120% of pre-training peak oxygen uptake to exhaustion (MAOD test) pre-, mid-, and post-training. A post-training timed test was also completed at the MAOD test power output, but this test was stopped at the TE achieved during the pre-training MAOD test. The 14.3±5.2% increase in MAOD observed in males after 4 wk of training was not different from the 14.0±3.0% increase seen in females (p > 0.05). MAOD increased by a further 6.6±1.9% in males and this change was not different from the additional 5.1±2.3% increase observed in females after the final 4 wk of training. Peak oxygen uptake measured during incremental cycling increased significantly (p < 0.01) in male but not in female subjects after 8 wk of training. Moreover, the AO2 uptake was higher in men during the post-training timed test compared to the pre-training MAOD test (p < 0.01). In contrast, the AO2 uptake was unchanged from pre- to post-training in female subjects. The increase in MAOD with training was not different between men and women suggesting an enhanced ability to produce ATP anaerobically in both groups. However, the increase in peak oxygen uptake and AO2 uptake obtained in male subjects following training indicates improved oxidative metabolism in men but not in women. It was concluded that there are basic gender differences that may predispose males and females to specific metabolic adaptations following an 8-wk period of HIT. Increases in AO2 uptake during supramaximal cycling demonstrated in men after training led to the hypothesis that peak oxygen uptake kinetics are speeded in male subjects with short-term HIT. It was suggested that training does not improve peak oxygen uptake kinetics in women as no change in AO2 uptake was found after 8 wk of HIT in female subjects. The purpose of experiment three was to examine peak oxygen uptake kinetics before and after 8 wk of HIT in six men and six women during cycling at 50% (50% test) and 110% (110% test) of pre-training peak oxygen uptake. A single-term exponential equation was used to model the peak oxygen uptake response (after phase I) during the 50% and 110% tests pre- and post-training. In addition, phase II and III of the peak oxygen uptake response during the 110% tests were examined using a two-term equation. The end of the phase I peak oxygen uptake response was identified visually and omitted from the modeling process. The duration of phase I determined during all experimental tests was not different between men and women and did not change with training in either group. Before training, men obtained a phase II peak oxygen uptake time constant (t2) of 29.0±3.3 s during the 50% test which was not different to the t2 of 28.8±2.2 s attained by women. In addition, the t2 determined during the 50% test was unchanged after 8 wk of HIT in both groups. The peak oxygen uptake kinetics examined during the 110% tests before training were well described by a single-term model in all male and female subjects. The t2 determined before training for the 110% test was significantly faster in men than in women. Furthermore, peak oxygen uptake was unchanged in female subjects and the t2 remained unaltered with 8 wk HIT (pre 45.5±2.2; post 44.8±2.3 s). In contrast, male subjects achieved a significantly higher peak oxygen uptake after training and the t2 determined for men during the 110% test was faster after training (36.4±1.6 s) than before training (40.1± 1.9 s). Improved model fits were obtained with the two-term equation compared to the single-term equation in two of the six male subjects during the 110% test post-training. It was found that the onset of the peak oxygen uptake slow component occurred at a mean time of 63.5±2.5 s and the t2 was reduced to 18.4±1.7 s. Using a Wilcoxon Signed Ranks z-test, the t2 described by the single-term equation in the remaining four subjects was determined to be significantly faster after training than before training, thus confirming the results obtained from the original group (n=6) of male subjects. End exercise heart rate (HREE) values obtained during the 50% and 110% tests were not different between men and women. During the 50% test, HREE values were unchanged, whereas HREE was significantly decreased during the 110% test after training in both groups. These data show that HIT might improve oxidative metabolism in men but not in women as reflected by a greater peak oxygen uptake and faster peak oxygen uptake kinetics during supramaximal work rates. We further suggest that the faster peak oxygen uptake kinetics demonstrated in men after training are probably not due to an improvement in cardiac function. Finally, the augmentation of oxidative metabolism during exercise after HIT in men might be dependent on the intensity of the exercise bout at which the peak oxygen uptake response is examined. The findings presented in this thesis suggest that MAOD is a reliable measure in both male and female subjects and can be used to monitor changes in anaerobic ATP production during supramaximal cycling. Moreover, these data suggest that 4 and 8 wk of HIT produce similar changes in anaerobic ATP generation in men and women. Finally, 8 wk of HIT results in the increase of peak oxygen uptake and AO2 uptake as well as the speeding of peak oxygen uptake kinetics during supramaximal cycling in male subjects. There was no evidence to suggest that oxidative metabolism was improved in women after short-term HIT. In conclusion, improvement in supramaximal exercise performances should be examined specifically for changes in the anaerobic and aerobic contributions to energy production. In addition, it is suggested that gender should be of primary consideration when designing exercise-training programs where improvement in both anaerobic and aerobic metabolism is required.

No description available.

The purpose of this study was to examine the effects of event order on a cycling(C)/running(R) or R/C biathlon. Eight experienced male biathlete/triathletes with a mean age of 24.9 + 4.6 yr formed the sample of the study. Results show no significant interaction effects on oxygen consumption peak, oxygen consumption during steady-state, ventilation, and heart rate when C/R or R/C are performed at 70% oxygen consumption peak for subsequent R and C respectively. These results seem to indicate that the biathlete/triathlete is efficient in both C and R to the extent that event order does not significantly interact with metabolic response in submaximal cycling and running.

<p>Copper (Cu) is an essential trace metal, but many aspects of its toxicity remain unclear, particularly in seawater (SW) and little is known regarding the interaction effects of Cu and hypoxia. Few studies have examined the effects of excessive waterborne metals, like Cu, on fish species under saline environment conditions and in combination with other natural stressors, like hypoxia. I first examined the acute effects of sublethal waterborne Cu and hypoxia on the oxidative stress response in freshwater (FW)-acclimated adult killifish (<em>Fundulus heteroclitus</em>), a model euryhaline teleost, which highlighted the need to investigate metabolic responses including oxygen consumption rates (MO₂). I found that hypoxia had no effect on Cu accumulation and that Cu induced antioxidant protection pathways and reduced oxidative capacity in a tissue-specific manner. I found that hypoxia may have an antagonistic effect on Cu-induced lipid peroxidation, although this pattern was not observed in all tissues.</p> <p>I then examined the acute effects of sublethal waterborne Cu on oxidative stress and metabolic responses in FW- and SW-acclimated adult killifish. I found that the oxidative stress and metabolic responses induced by Cu in killifish acclimated to SW differed only slightly from those in FW. I found that Cu had no effect on oxygen consumption rates after 96-h exposure in both FW and SW-acclimated fish, however Cu greatly reduced opercular frequency. In addition, we found that Cu-induced antioxidant protection pathways, although the response differed depending on the specific enzyme. This thesis has advanced our understanding of Cu toxicology in terms of oxidative stress and metabolic responses in freshwater and marine environments and emphasized the importance of utilizing multiple physiological endpoints. Hopefully, this work will contribute to the future development of Cu water quality criteria and building more accurate predictive and regulatory models.</p> / Master of Science (MSc)

Populations that utilize deep water running (DWR) are described in Chapter I. A review of the literature concerning maximal and submaximal responses during DWR, shallow water running and swimming is presented in Chapter II. The protocols to elicit maximal responses during DWR and treadmill running (TMR), subject characteristics, and statistical methods employed are described in Chapter III. The results, presented in Chapter IV, indicate that the DWR protocol is a reliable test for eliciting peak oxygen consumption and heart rate. Furthermore, the metabolic responses during DWR are lower than TMR. Chapter V discusses factors which might limit maximal responses during DWR. Chapter VI contains suggestions for further research. Raw data are presented in Appendix A.

A crescente demanda pelo treinamento resistido tem incentivado a procura de metodologias para a prescrição deste tipo de exercício. Por isso, há uma busca incessante para se prescrever corretamente qual parâmetro e/ou intensidade seja a ideal para a execução do exercício resistido. Dessa forma protocolos incrementais podem ser interessantes, uma vez que podem determinar a magnitude das respostas fisiológicas (principalmente lactato e consumo de oxigênio) em diferentes domínios (leve, moderado e alto), pois através deles é possível identificar parâmetros de aptidão aeróbia e anaeróbia, como o limiar de lactato, limiar anaeróbio e carga crítica. No entanto, poucos estudos têm analisado de forma sistematizada diferentes intensidades de exercício resistido com o objetivo de determinar a magnitude das respostas cardiorrespiratórias, metabólicas e eletromiográficas para então propor estratégias reabilitadoras a indivíduos idosos baseada nestas respostas. Dessa forma, o objetivo principal desse estudo foi comparar as intensidades determinadas como limiar anaeróbio e carga crítica, em relação aos parâmetros de frequência cardíaca, ventilação, consumo de oxigênio, lactato, débito cardíaco, volume sistólico, além da análise eletromiográfica, entre jovens e idosos. Participaram deste estudo 35 homens ativos, sendo 20 jovens (média de idade de 23 ± 3 anos) e 15 idosos (média de idade de 70 ± 2,4 anos), aparentemente saudáveis. Todos os voluntários realizaram, de forma aleatória e em dias diferentes a: 1) teste de 1 RM em exercício resistido no Leg Press 45°; 2) teste de exercício físico resistido dinâmico crescente descontínuo; 3) três testes de exercícios resistidos de alta intensidade de carga constante (60%, 75% e 90% de 1 RM) até a fadiga e, após estes testes realizaram:, 4) teste de tolerabilidade no limiar anaeróbio, obtido através do teste crescente e, 5) teste de tolerabilidade da carga crítica obtida, pela regressão linear e relação hiperbólica entre carga e tempo de execução. Com relação ao limiar anaeróbio, obtido no teste incremental, foi possível determinar que este ocorreu em torno de 30% 1 RM e a carga crítica foi aproximadamente 52% 1 RM, para ambos os grupos. Com relação aos parâmetros estudados nas intensidades de exercício executadas, o envelhecimento mostrou ser determinante para uma redução nos valores relativos à capacidade aeróbia bem como na frequência cardíaca. Já com relação especificamente as intensidades do limiar anaeróbio e carga crítica, em ambos os grupos a ventilação, foi maior e consumo de oxigênio foi menor na intensidade da carga crítica. Já para as respostas de lactato, nós observamos menores valores para o grupo idoso, tanto para o limiar como na carga crítica. O débito cardíaco apresentou diferença apenas entre os grupos e não entre as intensidades, sendo que devido ao envelhecimento, houve redução dos valores. Já para a EMG, houve maiores quedas do slope da FM para idosos quando comparado aos jovens em 30%, e além disso, na intensidade de 30% acarretou em menor queda que em 52%. Ao comparar ao longo do tempo a FM e o RMS, o comportamento destes foi semelhantes nas duas intensidades, ou seja, de queda e aumento, respectivamente, o que é indicativo de maior fadigabilidade ao final do exercício. Além disso, a taxa de queda foi maior no grupo idoso, sendo que esse parâmetro é um indicador de maior fadiga muscular para este grupo. Entretanto, o comportamento do RMS ao final das duas intensidades foi menor nos idosos. Dessa forma, nossos resultados podem ter aplicações como uma forma de avaliar o desempenho funcional durante exercícios resistidos em diferentes populações e também pode ter utilidade na prescrição de um programa de treinamento dependo do objetivo a ser alcançado, elucidando a importância prática da aplicação de exercícios de resistência dinâmica. / The increasing demand for resistance training has motivated the search methodologies for prescribing this type of exercise. Therefore, there is a constant search to correctly prescribe which parameter and/or intensity is ideal for the implementation of resistance exercise. Thus incremental protocols may be interesting, since they can determine the magnitude of physiological responses (mainly lactate and oxygen consumption) in different domains (mild, moderate and high), because it is possible through them to identify parameters of aerobic and anaerobic fitness as the lactate threshold, anaerobic threshold and critical load. However, few studies have examined systematically different resistance exercise intensities form in order to determine the magnitude of the cardiorespiratory, metabolic and electromyographic responses and then propose the elderly rehabilitation strategies based on these answers. Thus, the aim of this study was to compare the intensities determined as anaerobic threshold and critical load, with respect to heart rate parameters, ventilation, oxygen consumption, lactate, cardiac output, stroke volume, besides the electromyographic analysis, between young and senior citizens. The study included 35 active men, 20 young (mean age 23 ± 3 years) and 15 older adults (mean age 70 ± 2.4 years), apparently healthy. All volunteers pertormed randomly on different days to: 1) 1 RM test in resistance exercise in Leg Press 45º; 2) dynamic resistance exercise test growing discontinuous; 3) three tests of resistance exercise high intensity constant load (60%, 75% and 90% of 1 RM) to failure and after these tests, performed 4) tolerance test at the anaerobic threshold, obtained by increasing test, 5) tolerability test critical load obtained by linear regression and hyperbolic relationship between load and runtime. Regarding the anaerobic threshold obtained in the incremental test, was determined that this occurred around 30% 1 RM and the critical load was approximately 52% 1 RM for both groups. As for the parameters studied in the exercise intensities performed, aging proved to be decisive for a reduction in the relative values of aerobic capacity and heart rate. In relation specifically the intensities of the anaerobic threshold and critical load in both grups, ventilation was higher and oxygen consumption was lower in the intensity of the critical load. As for the lactate responses, we observed lower values for the elderly group, both the threshold and the critical load. Cardiac output was difference only between groups and not between the intensities, and due to aging, decreased the values. As for EMG, was greater MF of the slope falls to elderly compared to 30% in young, and furthermore, intensity of 30% fall which resulted in less by 52%. Comparing over time RMS and MF, was similar in behavior of the two intensities, ie, increase and decrease, respectively, which is indicative of greater fatigue at the end of exercise. Furthermore, the decrease rate was higher in the elderly group, and this parameter is an indicator of increased muscle fatigue for this group. However, RMS behavior at the end of the two intensities were lower in the elderly. Thus, our results may have applications as a way to evaluate the functional performance during resistance training in different populations and can also be useful in prescribing a training program depend on the objective to be achieved, explaining the practical importance of the application of resistance exercise dynamics.

O treinamento físico resistido tem sido enfaticamente incentivado, proporcionando efeitos favoráveis na força e endurance muscular, na função cardiovascular, metabolismo e na redução do risco cardiovascular. No entanto, é escassa a literatura sobre os ajustes cardiovasculares, ventilatórios e metabólicos no exercício resistido na população idosa. Além disso, pouco é sabido sobre tais ajustes na carga crítica (CC), a qual demarcaria a transição do exercício moderado para o exercício intenso nesta modalidade de exercício. Dessa forma, os objetivos deste trabalho são: avaliar o comportamento das respostas cardiovasculares, respiratórias e metabólicas durante o exercício físico resistido (Leg Press 45º) em diferentes intensidades, bem como determinar a intensidade da CC e ainda nessa intensidade comparar as respostas da freqüência cardíaca (FC), pressão arterial sistólica (PAS), ventilação (VE), consumo de oxigênio (\'VO IND.2\'), produção de dióxido de carbono (\'VCO IND.2\'), quociente respiratório (QR), percepção subjetiva de esforço (PSE) e lactato sangüíneo ([Lac]) obtidas durante exercício entre dois grupos (jovens e idosos). Participaram deste estudo 28 indivíduos do sexo masculino, sendo 15 jovens e 13 idosos, aparentemente saudáveis, sendo que a média de idade dos jovens foi de 22,7 ± 2,5 anos, massa média de 77,6 ± 10,2 kg e estatura média de 180,0 ± 10,0 cm e nos idosos a média de idade foi de 68,6 ± 4,0 anos, massa média de 76,7 ± 7,5 kg e estatura média de 170,0 ± 1,0 cm, não etilistas, não tabagistas, e sem distúrbios cardiorrespiratórios, neurológicos, metabólicos e articulares. Durante todos os procedimentos foram monitoradas PA, FC e eletrocardiograma nas derivações MC5, DII e V2 modificadas, sendo que foram realizados: teste de 1RM em exercício resistido no Leg Press 45º; teste de esforço físico dinâmico resistido com diferentes percentuais de 1RM, testados de acordo para obtenção da carga crítica, pela regressão linear dos pontos apurados na construção do gráfico: carga X inverso do tempo (tempo = duração do exercício até a fadiga). Com relação ao tempo de execução e o número de repetições não houve diferenças entre os grupos (p = 0,25 e p = 0,49; respectivamente); para a FC e PAS, temos para o grupo jovem uma resposta exacerbada da FC comparada aos idosos durante exercício (p<0,0001), sendo que o comportamento da PAS revela-se de modo contrário, havendo assim uma resposta mais acentuado para o grupo idoso (p<0,0197). A [Lac] foi maior em jovens na intensidade da CC (p = 0,0014), bem como o valor de PSE (0,00021). Para os parâmetros ventilatórios (VE, \'VO IND.2\' e \'VCO IND.2\') temos maiores valores para o grupo jovem também na fase de exercício para diferentes intensidades, principalmente na CC (p<0,0001, para as três variáveis). Além disso, foi possível determinar a carga crítica para ambos os grupos, sendo que essa foi em torno de 38% 1RM (p = 0,22). Dessa forma, esse foi o primeiro estudo que avaliou e comparou as respostas fisiológicas entre jovens e idosos em diferentes intensidades da RM, no exercício de Leg Press 45º, assim como na CC. / The resistance training has been strongly encouraged, providing favorable effects on muscular strength and endurance, cardiovascular function, metabolism and cardiovascular risk reduction. However, there is little literature about the cardiovascular, ventilation and metabolic responses in resistance exercise in the elderly. Moreover, little is known about such adjustments in the critical load (CL), which indicates the transition of moderate to intense exercise in this type of exercise. Thus, the objectives of this study are: To evaluate the cardiovascular, respiratory and metabolic changes during resistance exercise (leg press 45º) at different intensities and to determine the intensity of the CL and even that intensity to compare the responses of heart rate (HR), systolic blood pressure (SBP), ventilation (VE), oxygen consumption (\'VO IND.2\'), production of carbon dioxide (\'VCO IND.2\'), respiratory quotient (RQ), perceived exertion (PSE) and blood lactate ([Lac]) obtained during exercise between two groups (young and old). Participated in this study 28 males, 15 young and 13 elderly, apparently healthy, with an average age of the young was 22.7 ± 2.5 years, mean weight 77.6 ± 10.2 kg and mean height of 180.0 ± 10.0 cm, and in the elderly the average age was 68.6 ± 4.0 years, mean weight 76.7 ± 7.5 kg and mean height of 170.0 ± 1.0 cm, non-alcoholic non-smoker, and without cardio-respiratory, neurological, metabolic and joints disorders. During all procedures were monitored BP, HR and ECG at MC5, DII and V2 modified, and were carried out: 1RM resistance exercise on the leg press at 45º; exercise stress test dynamic resistance with different percentages of 1RM tested agreement for obtaining the critical load, the linear regression of the points made during the construction of the graph: load X reverse of time (time = duration of exercise until fatigue). Regarding the execution time and number of repetitions no differences between the groups (p = 0.25 and p = 0.49, respectively) for the HR and SBP, we have exacerbated response of HR for a young group compared to elderly, during exercise (p < 0.0001), and the SBP appears to be so contrary, so there is more pronounced for the elderly group (p < 0.0197). The [Lac] was greater in young people in the CC intensity (p = 0.0014), as well as the value of PSE (0.00021). For the ventilatory parameters (VE, \'VO IND.2\' and \'VCO IND.2\') have higher values in the young group also during the exercise for different intensities, mainly in the CC (p < 0.0001 for the three variables). Furthermore, it was possible to determine the CL for both groups, and this was around 38% 1RM (p = 0.22). Thus, this was the first study that evaluated and compared the physiological responses between young and old in different intensities of 1RM in the exercise of Leg Press 45º, as in CL.

O treinamento físico resistido tem sido enfaticamente incentivado, proporcionando efeitos favoráveis na força e endurance muscular, na função cardiovascular, metabolismo e na redução do risco cardiovascular. No entanto, é escassa a literatura sobre os ajustes cardiovasculares, ventilatórios e metabólicos no exercício resistido na população idosa. Além disso, pouco é sabido sobre tais ajustes na carga crítica (CC), a qual demarcaria a transição do exercício moderado para o exercício intenso nesta modalidade de exercício. Dessa forma, os objetivos deste trabalho são: avaliar o comportamento das respostas cardiovasculares, respiratórias e metabólicas durante o exercício físico resistido (Leg Press 45º) em diferentes intensidades, bem como determinar a intensidade da CC e ainda nessa intensidade comparar as respostas da freqüência cardíaca (FC), pressão arterial sistólica (PAS), ventilação (VE), consumo de oxigênio (\'VO IND.2\'), produção de dióxido de carbono (\'VCO IND.2\'), quociente respiratório (QR), percepção subjetiva de esforço (PSE) e lactato sangüíneo ([Lac]) obtidas durante exercício entre dois grupos (jovens e idosos). Participaram deste estudo 28 indivíduos do sexo masculino, sendo 15 jovens e 13 idosos, aparentemente saudáveis, sendo que a média de idade dos jovens foi de 22,7 ± 2,5 anos, massa média de 77,6 ± 10,2 kg e estatura média de 180,0 ± 10,0 cm e nos idosos a média de idade foi de 68,6 ± 4,0 anos, massa média de 76,7 ± 7,5 kg e estatura média de 170,0 ± 1,0 cm, não etilistas, não tabagistas, e sem distúrbios cardiorrespiratórios, neurológicos, metabólicos e articulares. Durante todos os procedimentos foram monitoradas PA, FC e eletrocardiograma nas derivações MC5, DII e V2 modificadas, sendo que foram realizados: teste de 1RM em exercício resistido no Leg Press 45º; teste de esforço físico dinâmico resistido com diferentes percentuais de 1RM, testados de acordo para obtenção da carga crítica, pela regressão linear dos pontos apurados na construção do gráfico: carga X inverso do tempo (tempo = duração do exercício até a fadiga). Com relação ao tempo de execução e o número de repetições não houve diferenças entre os grupos (p = 0,25 e p = 0,49; respectivamente); para a FC e PAS, temos para o grupo jovem uma resposta exacerbada da FC comparada aos idosos durante exercício (p<0,0001), sendo que o comportamento da PAS revela-se de modo contrário, havendo assim uma resposta mais acentuado para o grupo idoso (p<0,0197). A [Lac] foi maior em jovens na intensidade da CC (p = 0,0014), bem como o valor de PSE (0,00021). Para os parâmetros ventilatórios (VE, \'VO IND.2\' e \'VCO IND.2\') temos maiores valores para o grupo jovem também na fase de exercício para diferentes intensidades, principalmente na CC (p<0,0001, para as três variáveis). Além disso, foi possível determinar a carga crítica para ambos os grupos, sendo que essa foi em torno de 38% 1RM (p = 0,22). Dessa forma, esse foi o primeiro estudo que avaliou e comparou as respostas fisiológicas entre jovens e idosos em diferentes intensidades da RM, no exercício de Leg Press 45º, assim como na CC. / The resistance training has been strongly encouraged, providing favorable effects on muscular strength and endurance, cardiovascular function, metabolism and cardiovascular risk reduction. However, there is little literature about the cardiovascular, ventilation and metabolic responses in resistance exercise in the elderly. Moreover, little is known about such adjustments in the critical load (CL), which indicates the transition of moderate to intense exercise in this type of exercise. Thus, the objectives of this study are: To evaluate the cardiovascular, respiratory and metabolic changes during resistance exercise (leg press 45º) at different intensities and to determine the intensity of the CL and even that intensity to compare the responses of heart rate (HR), systolic blood pressure (SBP), ventilation (VE), oxygen consumption (\'VO IND.2\'), production of carbon dioxide (\'VCO IND.2\'), respiratory quotient (RQ), perceived exertion (PSE) and blood lactate ([Lac]) obtained during exercise between two groups (young and old). Participated in this study 28 males, 15 young and 13 elderly, apparently healthy, with an average age of the young was 22.7 ± 2.5 years, mean weight 77.6 ± 10.2 kg and mean height of 180.0 ± 10.0 cm, and in the elderly the average age was 68.6 ± 4.0 years, mean weight 76.7 ± 7.5 kg and mean height of 170.0 ± 1.0 cm, non-alcoholic non-smoker, and without cardio-respiratory, neurological, metabolic and joints disorders. During all procedures were monitored BP, HR and ECG at MC5, DII and V2 modified, and were carried out: 1RM resistance exercise on the leg press at 45º; exercise stress test dynamic resistance with different percentages of 1RM tested agreement for obtaining the critical load, the linear regression of the points made during the construction of the graph: load X reverse of time (time = duration of exercise until fatigue). Regarding the execution time and number of repetitions no differences between the groups (p = 0.25 and p = 0.49, respectively) for the HR and SBP, we have exacerbated response of HR for a young group compared to elderly, during exercise (p < 0.0001), and the SBP appears to be so contrary, so there is more pronounced for the elderly group (p < 0.0197). The [Lac] was greater in young people in the CC intensity (p = 0.0014), as well as the value of PSE (0.00021). For the ventilatory parameters (VE, \'VO IND.2\' and \'VCO IND.2\') have higher values in the young group also during the exercise for different intensities, mainly in the CC (p < 0.0001 for the three variables). Furthermore, it was possible to determine the CL for both groups, and this was around 38% 1RM (p = 0.22). Thus, this was the first study that evaluated and compared the physiological responses between young and old in different intensities of 1RM in the exercise of Leg Press 45º, as in CL.

A crescente demanda pelo treinamento resistido tem incentivado a procura de metodologias para a prescrição deste tipo de exercício. Por isso, há uma busca incessante para se prescrever corretamente qual parâmetro e/ou intensidade seja a ideal para a execução do exercício resistido. Dessa forma protocolos incrementais podem ser interessantes, uma vez que podem determinar a magnitude das respostas fisiológicas (principalmente lactato e consumo de oxigênio) em diferentes domínios (leve, moderado e alto), pois através deles é possível identificar parâmetros de aptidão aeróbia e anaeróbia, como o limiar de lactato, limiar anaeróbio e carga crítica. No entanto, poucos estudos têm analisado de forma sistematizada diferentes intensidades de exercício resistido com o objetivo de determinar a magnitude das respostas cardiorrespiratórias, metabólicas e eletromiográficas para então propor estratégias reabilitadoras a indivíduos idosos baseada nestas respostas. Dessa forma, o objetivo principal desse estudo foi comparar as intensidades determinadas como limiar anaeróbio e carga crítica, em relação aos parâmetros de frequência cardíaca, ventilação, consumo de oxigênio, lactato, débito cardíaco, volume sistólico, além da análise eletromiográfica, entre jovens e idosos. Participaram deste estudo 35 homens ativos, sendo 20 jovens (média de idade de 23 ± 3 anos) e 15 idosos (média de idade de 70 ± 2,4 anos), aparentemente saudáveis. Todos os voluntários realizaram, de forma aleatória e em dias diferentes a: 1) teste de 1 RM em exercício resistido no Leg Press 45°; 2) teste de exercício físico resistido dinâmico crescente descontínuo; 3) três testes de exercícios resistidos de alta intensidade de carga constante (60%, 75% e 90% de 1 RM) até a fadiga e, após estes testes realizaram:, 4) teste de tolerabilidade no limiar anaeróbio, obtido através do teste crescente e, 5) teste de tolerabilidade da carga crítica obtida, pela regressão linear e relação hiperbólica entre carga e tempo de execução. Com relação ao limiar anaeróbio, obtido no teste incremental, foi possível determinar que este ocorreu em torno de 30% 1 RM e a carga crítica foi aproximadamente 52% 1 RM, para ambos os grupos. Com relação aos parâmetros estudados nas intensidades de exercício executadas, o envelhecimento mostrou ser determinante para uma redução nos valores relativos à capacidade aeróbia bem como na frequência cardíaca. Já com relação especificamente as intensidades do limiar anaeróbio e carga crítica, em ambos os grupos a ventilação, foi maior e consumo de oxigênio foi menor na intensidade da carga crítica. Já para as respostas de lactato, nós observamos menores valores para o grupo idoso, tanto para o limiar como na carga crítica. O débito cardíaco apresentou diferença apenas entre os grupos e não entre as intensidades, sendo que devido ao envelhecimento, houve redução dos valores. Já para a EMG, houve maiores quedas do slope da FM para idosos quando comparado aos jovens em 30%, e além disso, na intensidade de 30% acarretou em menor queda que em 52%. Ao comparar ao longo do tempo a FM e o RMS, o comportamento destes foi semelhantes nas duas intensidades, ou seja, de queda e aumento, respectivamente, o que é indicativo de maior fadigabilidade ao final do exercício. Além disso, a taxa de queda foi maior no grupo idoso, sendo que esse parâmetro é um indicador de maior fadiga muscular para este grupo. Entretanto, o comportamento do RMS ao final das duas intensidades foi menor nos idosos. Dessa forma, nossos resultados podem ter aplicações como uma forma de avaliar o desempenho funcional durante exercícios resistidos em diferentes populações e também pode ter utilidade na prescrição de um programa de treinamento dependo do objetivo a ser alcançado, elucidando a importância prática da aplicação de exercícios de resistência dinâmica. / The increasing demand for resistance training has motivated the search methodologies for prescribing this type of exercise. Therefore, there is a constant search to correctly prescribe which parameter and/or intensity is ideal for the implementation of resistance exercise. Thus incremental protocols may be interesting, since they can determine the magnitude of physiological responses (mainly lactate and oxygen consumption) in different domains (mild, moderate and high), because it is possible through them to identify parameters of aerobic and anaerobic fitness as the lactate threshold, anaerobic threshold and critical load. However, few studies have examined systematically different resistance exercise intensities form in order to determine the magnitude of the cardiorespiratory, metabolic and electromyographic responses and then propose the elderly rehabilitation strategies based on these answers. Thus, the aim of this study was to compare the intensities determined as anaerobic threshold and critical load, with respect to heart rate parameters, ventilation, oxygen consumption, lactate, cardiac output, stroke volume, besides the electromyographic analysis, between young and senior citizens. The study included 35 active men, 20 young (mean age 23 ± 3 years) and 15 older adults (mean age 70 ± 2.4 years), apparently healthy. All volunteers pertormed randomly on different days to: 1) 1 RM test in resistance exercise in Leg Press 45º; 2) dynamic resistance exercise test growing discontinuous; 3) three tests of resistance exercise high intensity constant load (60%, 75% and 90% of 1 RM) to failure and after these tests, performed 4) tolerance test at the anaerobic threshold, obtained by increasing test, 5) tolerability test critical load obtained by linear regression and hyperbolic relationship between load and runtime. Regarding the anaerobic threshold obtained in the incremental test, was determined that this occurred around 30% 1 RM and the critical load was approximately 52% 1 RM for both groups. As for the parameters studied in the exercise intensities performed, aging proved to be decisive for a reduction in the relative values of aerobic capacity and heart rate. In relation specifically the intensities of the anaerobic threshold and critical load in both grups, ventilation was higher and oxygen consumption was lower in the intensity of the critical load. As for the lactate responses, we observed lower values for the elderly group, both the threshold and the critical load. Cardiac output was difference only between groups and not between the intensities, and due to aging, decreased the values. As for EMG, was greater MF of the slope falls to elderly compared to 30% in young, and furthermore, intensity of 30% fall which resulted in less by 52%. Comparing over time RMS and MF, was similar in behavior of the two intensities, ie, increase and decrease, respectively, which is indicative of greater fatigue at the end of exercise. Furthermore, the decrease rate was higher in the elderly group, and this parameter is an indicator of increased muscle fatigue for this group. However, RMS behavior at the end of the two intensities were lower in the elderly. Thus, our results may have applications as a way to evaluate the functional performance during resistance training in different populations and can also be useful in prescribing a training program depend on the objective to be achieved, explaining the practical importance of the application of resistance exercise dynamics.