The purpose of this study was to investigate the effects of 6 weeks of hydroxytyrosol (HT) supplementation on markers of muscle damage in healthy, recreationally active men before and throughout acute aerobic exercise bouts. Using a randomized, double-blind, repeated-measures, placebo-controlled design, sixty-one (n = 61) subjects (21.46 ± 0.22 yrs, 179.46 ± 0.79 cm, 78.91 ± 1.19 kg) consumed either a high dose (HI) HT supplement (150 mg HT), a low dose (LO) HT supplement (50 mg HT), or a placebo (PLA) every day for 6 weeks. Throughout the course of the study, the subjects performed four time trial rides (TT1-TT4) on a cycle ergometer. TT1 occurred before supplementation, TT2 halfway through the supplementation period, and TT3 and TT4 occurred in the sixth week and final two days of supplementation. Blood was drawn prior to (pre) and just before termination (end) of each time trial to measure markers of muscle damage during exercise. We observed that endurance exercise increased indicators of muscle damage, CPK and myoglobin, but an association between HT treatment and reduced muscle damage indicators during exercise were not demonstrated. However, the HT supplementation for 6 weeks in recreationally-active males improved time trial performance in the HT treatment groups over the course of the study and this improvement was accompanied by a lower increase in myoglobin concentration in blood in the HI treatment group than in the LO treatment group. Also, performance was improved after 6 weeks in the PLA group. This improvement was associated with an increase in rating of perceived exertion (RPE). RPE was not increased in either the LO and HI treatment groups, although time trial performance was significantly improved. It is possible that HT can improve performance by altering perception of effort. We conclude that chronic and acute HT supplementation did not reduce markers of muscle damage in this population at rest, during, or following exercise, but improved aerobic performance. / text

The use of nutritional supplements (NS) is common in able-bodied (AB) athletic populations and good evidence exists for a number of NS such as sports drinks, protein powder, creatine, caffeine and buffering agents. However, little evidence is available regarding the popularity and efficacy of NS in a population of athletes with physical impairments.

Orientador: Antonio Carlos de Moraes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-21T22:00:45Z (GMT). No. of bitstreams: 1 Smirmaul_BrunodePaulaCaraca_M.pdf: 4243812 bytes, checksum: 6a170352ba2b6b469396a6dd7c5d13f5 (MD5) Previous issue date: 2013 / Resumo: Introdução: Apesar de ser uma substância extensivamente estudada no âmbito do desempenho físico, a cafeína e seus efeitos no desempenho em altitude (hipóxia) foram estudados em apenas 2 investigações científicas (Berglund & Hemmingsson 1982; Fulco et al 1994), sugerindo que esta tem seus efeitos potencializados nesse ambiente. As únicas variáveis analisadas foram percepção de esforço e parâmetros cardiorrespiratórios. Porém, um dos mecanismos de ação sugeridos da cafeína é no sistema neuromuscular que, em hipóxia, sofre com uma mais rápida ocorrência de fadiga. Objetivo: Investigar o efeito da cafeína no desempenho aeróbio em hipóxia nos parâmetros psicofisiológicos, em particular seus efeitos na fadiga periférica e central. Métodos: Sete sujeitos (29 ± 6 anos, 179 ± 8 cm, 75 ± 8 kg, VO2máx 51 ± 5 ml.kg-1) participaram desse estudo duplo-cego e randomizado. Primeiro realizaram um teste incremental máximo em hipóxia (FIO2 = 0,15) para determinar a potência pico. A segunda e terceira visita consistiu em um período fixo de 6 min de exercício, seguido de um teste constante até a exaustão, ambos a _80% da potência pico e em hipóxia. Lactato, SpO2, percepção de esforço, frequência cardíaca, e fadiga periférica e central foram mensuradas. Resultados: Durante o teste incremental, a potência pico alcançada foi de 275 ± 38 W, com valores finais de percepção de esforço, lactato, frequência cardíaca e SpO2 de 18 ± 1, 13 ± 2 mmol/l, 179 ± 10 bpm, e 81 ± 5%, respectivamente. Tempo até a exaustão foi significativamente maior (11,8%) na condição cafeína (402 ± 137 s) comparado à condição placebo (356 ± 112 s) (P = 0,016). Tempos individuais foram maiores com cafeína em 6 dos 7 sujeitos. Variação intra-sujeito foi de -5 a 23% (-10 a 74 s). Cafeína teve um impacto significativo na subescala de humor fadiga, apresentando menores valores, enquanto a subescala vigor apresentou tendência a ser maior nessa condição. A percepção de esforço apresentou menores valores para o grupo cafeína durante o teste até exaustão. Tanto para o período de 6 minutos como durante o teste de tempo até a exaustão, a frequência cardíaca foi maior para o grupo cafeína. Enquanto SpO2 foi menor para o grupo cafeína apenas durante o período de 6 minutos, os valores de lactato não diferiram entre os grupos, mas apresentaram tendência a maiores valores na condição cafeína. Os valores de contração voluntária máxima apresentaram declínio significativo, com maior queda para o grupo cafeína. Já os valores de ativação voluntária e estímulos duplos, apesar de decrescerem, não foram diferentes entre as condições. Por fim, todos os parâmetros de oxigenação não diferiram entre as condições. Conclusão: O efeito ergogênico da cafeína em altitude ocorreu concomitantemente a alterações no estado de humor, percepção de esforço, sinais eletromiográficos, frequência cardíaca e contração voluntária máxima / Abstract: Introduction: Despite being a substance extensively studied in the physical performance scope, caffeine and its effects on performance in altitude (hypoxia) have been studied only in 2 scientific investigations (Berglund & Hemmingsson 1982; Fulco et al 1994), and it is suggested that is has greater effects in this environment. The variables analyzed were only perception of effort and cardiorespiratory parameters. However, one of the suggested caffeine's mechanisms of action is upon the neuromuscular system that, in hypoxia, presents a faster development of fatigue. Aim: Study the effects of caffeine during aerobic performance in hypoxia in the psychophysiological parameters, in particular its effects on peripheral and central fatigue. Methods: Seven subjects (29 ± 6 years, 179 ± 8 cm, 75 ± 8 kg, VO2max 51 ± 5 ml.kg-1) participated in this randomized double-blind study. First it was performed a maximal incremental test in hypoxia (FIO2 = 0.15) to determine peak power output. The second and third visits consisted of a fixed period of 6 min of exercise, followed by a time to exhaustion test, both at _80% of peak power output and in hypoxia. Lactate, SpO2, perception of effort, heart rate, and peripheral and central fatigue were measured. Results: During the incremental test, peak power output reached was 275 ± 38 W, with end-values of perception of effort, lactate, heart rate and SpO2 of 18 ± 1, 13 ± 2 mmol/l, 179 ± 10 bpm, and 81 ± 5%, respectively. Time to exhaustion was significantly longer (11.8%) with caffeine (402 ± 137 s) compared to placebo (356 ± 112 s) (P = 0.016). Individual times were longer with caffeine in 6 out of 7 subjects. Intra-subject variability was from -5 to 23% (-10 to 74s). Caffeine had a significant impact on the mood subscale fatigue, presenting lower values, while the subscale vigor presented a trend to be higher in this condition. Perception of effort presented lower values in the caffeine condition during time to exhaustion test. Both to the fixed period of 6 minutes and to the time to exhaustion test, heart rate was higher in the caffeine condition. While SpO2 was lower with caffeine only during the fixed period of 6 minutes, lactates values did not differ between groups, but presented a trend to be higher during the caffeine condition. Values of maximal voluntary contraction showed a significant reduction, with greater reduction in the caffeine condition. However, voluntary activation and doublet values, despite decreasing, were not different between conditions. Finally, all the brain oxygenation parameters did not differ between conditions. Conclusion: The ergogenic effect of caffeine at altitude occurred concomitantly with alterations in mood state, perception of effort, electromyographic signals, heart rate and maximal voluntary contraction / Mestrado / Biodinamica do Movimento e Esporte / Mestre em Educação Física

Title: The effect of citrulline and citrulline malate supplementation on selected physiological indicators - review study. Objectives: Systematic findings overview of the effect of citrulline and citrulline malate on healthy individual's locomotor system and other physiological indicators. Methods: The study is designed as a findings overview. Electronic databases pubmed.com and ukaz.cuni.cz were used as an information source. "Citrulline" or "citrulline malate" and "exercise performance" and "randomized controlled trial" keywords were used for the information search. Results: Eighteen studies and 307 individuals are included in the overview. Studies are categorized according to duration and type of supplementation substance. Four studies agree on the strength improvement after acute use of citrulline malate. Four studies agree on endurance improvement in case of citrulline long term use. Three studies conclude on pain mitigation in case of substance use 24, 48 and 72 hours after training. Also, studies agree on increase of the levels of citrulline, arginine and ornithine plasmatic concentration after use of citrulline and citrulline malate. Three studies indicate possible fatigue decrease during the training in case of use of citrulline. Conclusion: Use of citrulline and citrulline malate can be...

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Exercise or activity in high ambient temperatures offers a particular challenge to the thermoregulatory system. It is likely that mechanisms such as sweat evaporation alone are not sufficient for maintaining body temperature within a safe limit (~36.5-38.5˚C) and below 40˚C, which may result in impaired physiological function and performance. Exogenous cooling may be of benefit prior to, during and after events that place increased thermal strain due to increased metabolic heat production and elevated environmental temperatures upon the thermoregulatory system. Conversely, in situations where it is not possible to maintain body temperature via either continued physical activity or elevated ambient temperatures, exogenous heating may be required in order to allow optimal physiological performance. Few studies have directly aligned cooling devices with data detailing effective target regions for cooling to allow a pre-cooling garment to be of minimal weight but maximal cooling efficiency. Conversely, no study has considered the effect of muscle temperature maintenance during rest periods on subsequent power-based activities. The aim of this thesis was to determine ways in which body temperature manipulation is capable of improving exercise performance in both power and endurance-based events. It was hypothesised that the manipulation of body temperature will result in subsequent changes in body temperature that would improve performance. Specifically, the use of pre-cooling would result in a reduction of body temperature and improve endurance exercise performance. Conversely, maintaining Tm following warm up completion would have a beneficial effect on sprint and power related performance. Study one set out to determine differences in regional body heat loss in 12 individual anatomical zones using a water perfused suit. Data obtained from this initial study allowed for the specific targeting of regions that were identified as having high rates of heat loss in subsequent studies that focused on pre-cooling and performance. The anatomical regions identified as having high potential affinity for heat exchange with the surrounding environment and cooling devices were the hands, forearms, upper and lower back and torso. Subsequent studies demonstrated that cooling of these areas was capable of lowering thermal sensation and improving thermal comfort prior to and during exercise in moderate environmental conditions (24˚C, 50% RH). In these moderate conditions, there was no statistically significant improvement in treadmill based self-paced 5000m running performance. However, in hot conditions (35˚C 50% RH), the use of a cooling vest and sleeves did yield a significant improvement in cycling time trial performance, which equated to 4.8%. This leads to the suggestion that there may be a threshold ambient temperature, above which pre-cooling becomes an important tool in maximizing performance potential. A parallel area of investigation, on the other side of the temperature spectrum, was the effect of muscle temperature manipulation on power-based exercise performance. The relationship between increased muscle temperature and power output is well established, however little is known about the effect of enforced rest or recovery between two bouts of exercise. Therefore, two studies were conducted to establish what affect a delay between warm up completion and exercise has on muscle temperature and subsequent sprint cycling performance. It was shown that with 30-minutes of rest between exercise bouts wearing tracksuit trousers, muscle temperature declined significantly (~1-1.5˚C). This decline was attenuated with the use of external passive electrical heating during the recovery compared to recovery completed in tracksuit trousers alone. The attenuated decline in muscle temperature following the use of the heated trousers resulted in an improvement in sprint cycling performance (~9%), with the use of insulated trousers having no effect on any variables measured, all relative to wearing tracksuit trousers in the rest period. In a follow-up study, the effect of implementing the heated trousers during the warm up and in addition to the rest period had on muscle temperature increase and sprint performance. A secondary area of investigation in this study was to determine the linearity of muscle temperature decline following warm up cessation. This study demonstrated that there was no additional benefit of combining passive heating with an active warm up on either muscle temperature elevations or subsequent sprint performance compared to the active warm up alone. It was shown that when the no heating was used at any stage, muscle temperature declined exponentially. However, when the heated trousers were used during recovery and/or during warm up, muscle temperature levelled off at a higher value towards the end of the recovery period. This study was also able to show significant improvements in absolute, relative and mean power output following the use of the heated trousers in the warm up and recovery, or the recovery alone. This thesis has identified ways in which body temperature may be manipulated in order to benefit both sprint and endurance exercise performance, using both pre-cooling and active heating. A novel concept for minimizing muscle temperature decline during periods of inactivity between different rounds of competition was shown to maximize sprint performance yielding significant improvements in peak and mean power outputs.

These studies investigated the impact of intensity and body temperature on performance and cardiovascular regulation during high intensity and prolonged exercise. In study 1, polyphenol antioxidant supplementation proved to have no effect on exercise performance and related variables (gross efficiency, perceived exertion, maximal power) during exercise in the heat. Furthermore, there were no differences between the cardiovascular or thermoregulatory responses between control and antioxidant treatments. Study 2 utilized an integrative approach to investigate a classic topic in exercise physiology, namely, is the cardiac output to oxygen consumption relationship linear across a wide range of exercise intensities? The slope of the CO vs. VO2 relationship was significantly reduced from 70 to 100% of VO2max when compared to the slope from 40 to 70% of VO2max (2.0 ± 0.4 vs. 4.4 ± 0.3 l/min, p = 0.025). This finding, in combination with the plateau and eventual reduction in stroke volume at high intensity exercise compared to moderate intensity exercise (146.0 ± 16.6 vs. 138.5 ± 14.9 ml/beat, p = 0.015), argues in favor of a cardiac limitation to high intensity exercise. This study also showed that the pattern of oxygen extraction at the whole body level (arterial venous O2 difference) and the muscle level (deoxygenated hemoglobin) is not similar and that muscle specific differences exist regarding oxygen extraction. Study 3 determined that hyperthermia (elevation of skin temperature by 4.3°C and core temperature by 0.8°C) did not reduce SV independent of the increase in HR. Even under conditions of moderate hyperthermia the reduction in SV is due to the increase in HR and temporally unrelated to increases in cutaneous blood flow. In summary, antioxidant supplementation had no effect on performance, cardiovascular, or thermoregulatory responses to exercise in the heat in well trained subjects. High intensity exercise is associated with a reduced rate of increase in the CO vs. VO2 relationship. Finally, hyperthermia does not reduce SV during exercise when HR is maintained at normal levels. / text

Student Number : 9404757K - PhD thesis - School of Physiology - Faculty of Science / Natural secretions of oestrogen and progesterone vary according to menstrual phase in eumenorrhoeic women and have an affect on physiological systems that could consequentially influence exercise performance. In a series of menstrual phase comparative investigations (considering mainly the early follicular (EF), late follicular (LF) and mid-luteal (ML) phase), I aimed to elucidate the physiological relation of oestrogen and progesterone to fat metabolism and ventilation during endurance exercise and exercise performance. I measured plasma free fatty acid (FFA) kinetics during prolonged exercise from an intravenous infusion of K+[1-13C]palmitate in eumenorrhoeic women and found the change in palmitate rate of appearance and disappearance between menstrual phases to be related to the oestrogen/progesterone (E/P) ratio. Overall the results from this study suggest that oestrogen promotes increases in FFA availability during exercise, while progesterone mitigates this response. Therefore, a high oestrogen concentration and E/P ratio in the ML phase is required in order to produce a favourable FFA metabolic response for endurance events. In order to estimate plasma FFA oxidation rate using carbon-FFA tracers, the acetate correction factor which accounts for carbon-label retention in secondary metabolic pools, must be applied. When I derived the acetate correction factor by measuring fractional recovery of carbon-13 in expired CO2 from a constant infusion of Na+[1- 13C]acetate during submaximal exercise we found the acetate correction factor to be significantly lower in the ML than EF phase (average change from EF phase -1.8± 0.5%, p<0.05). Failure to account for the lower correction factor in the ML phase will result in a 6% underestimation of plasma FFA oxidation rate. Furthermore, since human serum albumin (HSA) routinely used as a carrier for parenteral delivery of FFA tracers has various disadvantages, I tested the feasibility of using 2-hydroxypropyl-b- cyclodextrin (HP-b-CD) as a possible alternative carrier. A comparison of expired CO2 enrichment following HSA-FFA (7.4±2.0 %o) and HP-b-CD-FFA (8.6±2.1%o) infusion during exercise showed that the HP-b-CD does not compromise natural in vivo behaviour of the FFA tracer (p=0.4). Progesterone-induced hyperventilation is occasionally reported during exercise in the luteal phase. I found that the change in ventilatory parameters (minute ventilation and respiratory rate) during exercise from EF to ML phase is related to both the oestrogen and progesterone concentration in the ML phase. However, the associated increase in respiratory rate throughout prolonged exercise in the ML versus EF phase did not increase metabolic demand and therefore could not be expected to exacerbate fatigue. When exercise performance was evaluated by means of a cycling time trial, I found a trend for best performance in the LF phase versus the EF phase (8 of 11 subjects improved by 5.2±2.9%, p=0.027), while no differences occurred between other menstrual phases. Metabolic and performance benefits of oestrogen may be concealed in the ML phase by the coincident increase in progesterone in this phase and thus a significant effect is often only evident with a high E/P ratio in the ML phase. The transient LF phase, characterised by the pre-ovulatory surge in oestrogen, reveals the maximum benefits of oestrogen on metabolism and performance during submaximal exercise.

Following on from Rio de Janeiro 2016, the Tokyo 2020 Paralympic Games will present a unique challenge for athletes, needing to prepare and adapt to the potential challenging environmental conditions of 20-27°C and ~73% relative humidity. It is well known that during exercise in hot and/or humid climates, able-bodied athletes experience an increase in thermal strain and a reduction in performance compared to cooler/drier conditions. Yet these conditions prove even more problematic for athletes, who as a consequence of their impairment have a dysfunctional thermoregulatory system, such as athletes with a spinal cord injury (SCI). To date, the thermoregulatory responses of athletes with an SCI have been an under-studied area of research. To gain a greater understanding of how heat balance is altered in individuals with an SCI and the thermoregulatory consequences as a result, studies need to first be conducted at rest, removing the additional metabolic heat production from exercise. Although a large majority of athletes with an SCI compete indoors in wheelchair court sports (e.g. wheelchair basketball and rugby), exercising even in these climate-controlled environments has been shown to place these athletes under considerable thermal strain. In light of this, it is remarkable that existing research on the thermoregulatory responses of athletes with an SCI during exercise is scarce, especially studies encompassing real-world sporting environments. Athletes with high level lesions (tetraplegia, TP) are a particularly under-studied population group shown to have a greater thermoregulatory impairment than individuals with low level lesions (paraplegia, PA) during continuous exercise. Thus the aim of this thesis was to investigate the thermoregulatory responses of athletes with an SCI at rest and during real-world sporting scenarios, with specific focus on athletes with TP. Study 1 aimed to determine how evaporative heat loss is altered, as a result of an SCI, compared to the able-bodied (AB), and the effect lesion level has on this response. The results provide evidence that in individuals with TP, even at rest, evaporative heat loss is not large enough to balance the heat load, when evaporation is the primary source of heat dissipation. Even though in individuals with PA Tgi increased by a smaller magnitude and they possessed a greater sweating capacity than individuals with TP, at ambient temperatures above Tsk latent heat loss is insufficient to attain heat balance, compared to the AB. To investigate the thermoregulatory responses of athletes with an SCI during real-world sporting scenarios Study 2 examined athletes with TP compared to athletes with PA during 60 min of intermittent sprint wheelchair exercise on a wheelchair ergometer. The study was conducted in conditions representative of an indoor playing environment for wheelchair rugby and basketball (~21°C, 40% relative humidity). Results demonstrated that, despite similar external work, athletes with TP were under greater thermal strain than athletes with PA. Study 3 s novel approach investigated both physiological responses and activity profiles of wheelchair rugby players during competitive match play. Despite players with TP covering 17% less distance and pushing on average 10% slower, they were under a greater amount of thermal strain than players with non-spinal related physical impairments (NON-SCI). Furthermore, this study demonstrated that players with TP that had a larger body mass, larger lean mass, covered a greater relative distance and/or were a higher point player had a greater end Tgi. These data provide an insight for coaches and support staff regarding which players may need greater attention in regards to cooling strategies or breaks in play. The effectiveness of cooling practices currently employed by athletes with TP has not been previously investigated. Study 4 determined the effectiveness of pre-cooling, using an ice vest alone and in combination with water sprays between quarters, at attenuating thermal strain in athletes with TP. Using the activity profile data from Study 3, an intermittent sprint protocol, conducted on a wheelchair ergometer, was used to represent a wheelchair rugby match. The combination of cooling methods lowered Tgi and Tsk to a greater extent than pre-cooling only, despite neither cooling condition having a positive or negative effect on performance. Unexpectedly, the pre-cooling only condition lowered Tgi, compared to no cooling, throughout the subsequent exercise protocol, even though the reduction in Tsk was not long lasting. This thesis provides comprehensive evidence that athletes with TP experience heightened thermal strain during both rest and real-world sporting scenarios compared to the AB, athletes with PA, and within the sport of wheelchair rugby. Athletes with TP should employ practices, such as appropriate cooling methods or alter playing tactics to reduce thermal strain and the likelihood of attaining a heat related injury.