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Orientador: Vilmar Baldissera / Resumo: A organização das variáveis do exercício resistido altera respostas do estresse psicobiológico, da demanda energética, predominância do substrato energético utilizado durante a prática do exercício e também de lipólise. Desta maneira é fundamental estudar os efeitos das variáveis do exercício resistido sobre as respostas citadas. Os estudos sobre as respostas ao estresse provocado pelo exercício resistido estão voltados, principalmente, para o volume e intensidade. Outra variável pode influenciar sobre estas respostas, a duração da carga. Assim os objetivos deste estudo são: a) Verificar a influência da duração da carga sobre o estresse psicobiológico; b) Avaliar as respostas da demanda energética a diferente duração de carga; c) Determinar o substrato energético predominante durante a execução dos protocolos; d) Investigar o efeito da duração da carga sobre a lipólise. Participaram da pesquisa 16 voluntários do sexo masculino com mais de três meses de pratica em musculação, portanto familiarizados com os exercícios convencionais de academias propostos neste trabalho, com idade média de 29,31 ± 5,26 anos, saudáveis, sem diagnósticos de doenças que impossibilitem a prática de atividade física. Os participantes visitaram o laboratório em cinco ocasiões: na primeira assinaram o TCLE, ocorreu a aplicação do PAR-Q e teste de 1RM em todos exercícios que constituem as sessões. Na segunda visita foi realizada a familiarização com os procedimentos experimentais. Na terceira e quarta v... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The organization of the variables of the resistance exercise changes the responses of psychobiological stress, energy expenditure, predominance of the energy substrate used during exercise and lipolysis. In this way it is fundamental to study the effects of the variables of the resistance exercise on the cited answers. Studies on the responses to stress caused by resistance exercise are mainly focused on volume and intensity. Another variable can influence on these responses is the time under load. Thus the purpose of this study was: a) To verify the influence of the time under load on the psychobiological stress; b) Evaluate the responses of the energy expenditure to different time under load; c) Determine the predominant energy substrate during the execution of the protocols; d) Investigate the effect of the time under load on lipolysis. Sixteen male subjects with more than three months of practice in bodybuilding participated in the study, so they were familiar with the conventional exercises of academies proposed in this project, with a mean age of 29.31 ± 5.26 years, healthy, without diagnoses of diseases that make it impossible the practice of physical activity. The subjects visited the laboratory on five occasions: the first one signed the informed consent, the application of the PAR-Q and the 1RM test occurred in all exercises that constitute the sessions. During the second visit, familiarization with the experimental procedures was performed. In the third and fourth ... (Complete abstract click electronic access below) / Doutor

O objetivo deste estudo foi investigar as contribuições dos sistemas energéticos e do gasto energético total em situação de luta. A amostra foi composta de 10 atletas do sexo masculino de nível nacional/internacional (21±6 anos; 176.2±5.3cm; 67.2±9.0kg), competindo em nível internacional. Para a estimativa das contribuições energéticas e do gasto energético total, foram realizados três protocolos simulando combate (um round, dois rounds e três rounds). As lutas foram filmadas para quantificação das ações motoras em cada round. A estimativa dos sistemas energéticos aeróbio (WAER), anaeróbio alático (WPCR) e anaeróbio lático (W[La-]) foi realizada através do consumo de oxigênio durante a atividade, do delta da concentração sanguínea de lactato de cada round e do débito alático de oxigênio (DAO2), respectivamente. A razão entre as ações de elevada intensidade e momentos de baixa intensidade (step e pausa) no protocolo 3 foi ~1:7. Os resultados dos sistemas WAER, WPCR e W[La-] no protocolo 3 foi 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectivamente. Assim, as sessões de treinamento devem ser direcionadas principalmente para a melhoria do sistema anaeróbio alático (responsável pelas ações de alta intensidade), e do sistema aeróbio (responsável pelo processo de recuperação entre as ações de alta intensidade) / The purpose of this study was to investigate energy system contributions and energy cost in combat situation. The sample was constituted by 10 male taekwondo athletes at national/international level (age: 21±6 years old; height: 176.2±5.3cm; body mass: 67.2±9.0kg) competing at national/international level. To estimate the energy contributions and total energy cost of the fights, athletes performed a three different protocols simulated competition (1 round, 2 rounds and 3 rounds). The combats were filmed in order to quantify the actual time spent fighting in each round. The estimate of the aerobic (WAER), anaerobic alactic (WPCR) and anaerobic lactic (W[La-]) energy systems was carried out through the oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the delta of blood lactate concentration in each round, respectively. The mean data between the high intensity actions and moments of low intensity (step and pause) was ~1:7. The results of WAER, WPCR and W[La-] system contributions were 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity)

O objetivo deste estudo foi investigar as contribuições dos sistemas energéticos e do gasto energético total em situação de luta. A amostra foi composta de 10 atletas do sexo masculino de nível nacional/internacional (21±6 anos; 176.2±5.3cm; 67.2±9.0kg), competindo em nível internacional. Para a estimativa das contribuições energéticas e do gasto energético total, foram realizados três protocolos simulando combate (um round, dois rounds e três rounds). As lutas foram filmadas para quantificação das ações motoras em cada round. A estimativa dos sistemas energéticos aeróbio (WAER), anaeróbio alático (WPCR) e anaeróbio lático (W[La-]) foi realizada através do consumo de oxigênio durante a atividade, do delta da concentração sanguínea de lactato de cada round e do débito alático de oxigênio (DAO2), respectivamente. A razão entre as ações de elevada intensidade e momentos de baixa intensidade (step e pausa) no protocolo 3 foi ~1:7. Os resultados dos sistemas WAER, WPCR e W[La-] no protocolo 3 foi 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectivamente. Assim, as sessões de treinamento devem ser direcionadas principalmente para a melhoria do sistema anaeróbio alático (responsável pelas ações de alta intensidade), e do sistema aeróbio (responsável pelo processo de recuperação entre as ações de alta intensidade) / The purpose of this study was to investigate energy system contributions and energy cost in combat situation. The sample was constituted by 10 male taekwondo athletes at national/international level (age: 21±6 years old; height: 176.2±5.3cm; body mass: 67.2±9.0kg) competing at national/international level. To estimate the energy contributions and total energy cost of the fights, athletes performed a three different protocols simulated competition (1 round, 2 rounds and 3 rounds). The combats were filmed in order to quantify the actual time spent fighting in each round. The estimate of the aerobic (WAER), anaerobic alactic (WPCR) and anaerobic lactic (W[La-]) energy systems was carried out through the oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the delta of blood lactate concentration in each round, respectively. The mean data between the high intensity actions and moments of low intensity (step and pause) was ~1:7. The results of WAER, WPCR and W[La-] system contributions were 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity)

Alternation of indicators of lactate and vegetative systems during heightening of load. Purpose of the investigation was to compare alternation of vegetative systems indicators and blood lactate concentrations and during iterative load heightening. Tasks of the investigation: to compare alternation of vegetative systems indicators during replacement and recovery under different loads in respect of lactate threshold. Eight young healthy males took part in the investigation. Average age of subjects was 21,7 years. Investigation was carried out in Laboratory of Sports Physiology of Lithuania Physical Education Academy. Every subjects has undergone two different investigations: working with veloergometer. One –interval increasing load (3 min of work and 3 min of rest), mill-pedalling frequency – 70 times per minute; the other one – continuous increasing load until subject’s inability to maintain required pedalling frequency. The first load was 70 W. Capillary blood sampling was done from finger at the end of the third min of each load during interval test. While doing continuous increasing load subjects after the warming-up (5 min of work with 50 W of capacity) with the help of the veloergemeter produced continuous load that was heightened by 21 W every minute. Wheeling frequency was 70 times per minute. Starting load was 70 W. Load was continuously heightened until the fatigue, i.e. until the subject was able to take a new load for one minute. During the whole investigation and... [to full text]

Rock climbing is thought to rely upon the interaction of various performance components, and has previously been described as a complex multi-faceted sport. It has been suggested that psychological aspects of performance, such as task perception and the interaction of resulting pre-climb anxieties, contribute greatly to the physiological responses and the overall performance during ascent. However, research which seeks to investigate both psychological and physiological responses during specific bouts of rock climbing are few in number. This thesis attempts to contribute to the novel yet limited body of field based psychophysological research relating to rock climbing. To this end, the studies contained within this thesis investigated psychological and physiological responses as a result of difficult on-sight rock climbing. Elaborating upon previous research, additonal factors which are thought to influence these responses were explored. More specifically, differences in responses between ability groups, style of ascent, and route type were investigated. In study one, differences in psychological and physiological responses with respect to ability level and ascent style were investigated, during a single on-sight ascent. Seventy-two climbers were split into ability groups defined as lower-grade, intermediate, advanced and elite based on self-reported on-sight grades (Ewbank) of ≤17, 18-20, 21-24 and ≥ 25 respectively. Each climber attempted an on-sight ascent of a designated test route set on an indoor artificial climbing wall. A separate test route was set for each ability group which targeted their self-reported ability with respect to best on-sight. Participants were randomly assigned to either a lead or top-rope ascent and climbers were not informed of their style of ascent until 15 min prior to climbing. Responses to the climbing task were measured pre, during, and post-climb using a number of psychological and physiological markers. In total fifty-two participants successfully completed their on-sight ascents, and data for successful ascents were analysed and compared. Pre-climb variables were considered together in order to investigate pre-climb state, more specifically levels of anxiety, prior to ascent. Results indicated that there were no significant differences for grouped pre-climb variables with respect to ascent style. These results suggest that irrespective of ascent style, successful climbers exhibited similar psychophysiological responses prior to attempting an on-sight ascent. Furthermore, this trend was replicated across all ability groups. These findings were thought to be indicative of the high demand and level of uncerainty imposed by the on-sight condition of ascent, lending support to previous suggestion that an on-sight ascent induces the highest anxiety response. During the climb, HR and were measured and averaged across the entirety of the ascent. When expressed as a percentage of and the average HR and responses during ascent were found to be comparable across ability groups. As such, all ability groups appeared to utilise similar fractions of maximal capacity, with elite climbers successfully ascending a route up to eight difficulty grades harder than those of lower ability, whilst still performing at the same workload intensity. It would appear that oxygen uptake during rock climbing may not be directly related to difficulty or personal ability. A technical advantage, personal climbing style, and possible physiological adaptations may be contributors to more strategic and efficient ascents resulting in the capacity to climb at higher grades of difficulty. The second study presented within this thesis was comprised of two phases of investigation; (1) to investigate whether psychological and physiological responses to competition-style climbing differed with respect to ability level, and (2) to investigate potential psychological and physiological differences based on route type and outcome (success and failure). In phase 1 of study two, intermediate, advanced and elite climbers attempted an lead on-sight ascent of a competition-style route which increased in difficulty as the climber progressed. The route was set with the intention of being just beyond the upper limits of the elite climbers self-reported best on-sight ability (~26 Ewbank). This was done in order to ensure that a fall from the route was highly likely, even for the elite climbers. All climbers failed to successfuly ascend the test route and as such all climbed to the point of failure resulting in a fall. The results obtained both prior to, and during ascent suggest that the intermediate and advanced climbers in the current study may have been limited by technical ability as opposed to physical exhaustion, or increased levels of anxiety. Elite climbers were to be able to maintain a more sustained physical effort during the more difficult phases of the climb. This appeared to be reflected in post-climb blood lactate concentration and ratings of task demand with respect to both physical demand and effort. As such it may be that elite climbers are more accustomed to maximal effort and demonstrate an increased tolerance to the higher exercise intensity required during more difficult ascents. In the second phase of study two the psychological and physiological responses of climbers in a competitive setting obtained in phase 1, were compared with those exhibited by participants during both successful and unsuccessful lead on-sight ascents in study one. The aim of study two phase 2 was to determine whether the responses of successful climbers differed from those who succeeded by reaching the top of a route, and performances in a competitive context where success is denoted by the distance achieved by a climbers on their ascent. The main findings in this instance were that although there were no significant differences observed between categories of ascent (successful, unsuccessful and competition) for grouped pre-climb variables, trends in CSAI-2R responses indicated high cognitive anxiety coupled with lower self-confidence prior to unsuccessful ascents. As such it may be that self-confidence acts as a buffer in moderating success in rock climbing, demonstrating the role of positive emotions and their impact upon performance as opposed to the detrimental effect of the negative. A second finding of this study was that there appeared to be a differing HR- relationship based on ascent category. Modest increases in were shown for all ascents, irrespective of ability level. A plateau in response was accompanied by a similar plateau in HR response during successful ascents, yet HR was shown to increase in a linear fashion until point of failure during unsuccessful ascents. It is possible that these findings highlight the presence of a climbing specific limitation.

[Truncated abstract] In this thesis the role of lactate measurement has been evaluated in intrapartum assessment of fetal wellbeing. Specifically, I have addressed the question of whether fetal lactate measurement is better than the assessment of fetal heart rate patterns or the measurement of pH at predicting fetal brain injury after intrapartum asphyxia. Using an ovine model of repeated umbilical cord occlusion designed to mimic events which may occur during human labour, I have shown that the measurement of fetal lactate levels after repeated cord occlusion is significantly associated with the severity of brain injury after the asphyxial insult. No significant associations were identified with fetal pH measurements or with the duration of decelerative or compound fetal heart rate patterns; however, this is the first study to describe an association between the duration of both increased fetal heart rate variability and fetal heart rate overshoot with the severity of subsequent brain injury. Although no significant association was identified between fetal arterial pressure measured between umbilical cord occlusions and the grade of brain injury, the studies performed in this thesis are the first to show a strong correlation between the duration of specific arterial pressure responses during cord occlusions and the grade of brain injury, accounting for approximately 90% of the variability seen in the severity of injury. The mechanism responsible for the improved ability of lactate measurement to predict fetal brain injury is unknown. It may be because fetal lactate levels are a more stable marker of anaerobic metabolism of glucose than fetal pH levels, which are influenced by both increasing levels of carbon dioxide and anaerobic metabolism of amino-acids and fatty acids. In addition fetal pH levels can be rapidly normalised through placental exchange of carbon dioxide whereas fetal lactate levels are slow to normalise across the placenta as they rely on facilitated diffusion.

Please read the abstract in the section 00front of this document / Dissertation (MA (Human Movement Science))--University of Pretoria, 2006. / Biokinetics, Sport and Leisure Sciences / unrestricted