115 research outputs found

    Effects of acute supplementation of caffeine and Panax ginseng on endurance running performance in a hot and humid environment

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    Acute supplementation of Panax ginseng (PG) is known not to impose any significant effect on endurance performance of recreational Malaysian runners, while caffeine augments the ergogenic property of some herbs. The present study was aimed to examine the effects of acute supplementation of caffeine and PG on endurance running performance in a hot and humid condition. Nine heat adapted Malaysian recreational runners (age : 25.4 ± 6.9 years, body mass : 57.6 ± 8.4 kg; body height : 168.3 ± 7.6 cm) ingested either placebo or combined dose of 5 mg x kg(-1) of body weight of caffeine and 200 mg of PG one hour before the running on treadmill at 70% of VO2(max) in this placebo-controlled double blind randomised study in a laboratory environment of 31 degrees C and 70% relative humidity. They drank 3 ml x kg(-1) of body weight of cool water every 20 minutes during the exercise to prevent dehydration. Blood samples were withdrawn and oxygen uptake was recorded every 20 minutes while heart rate, core body temperature, skin temperature and ratings of perceived exertion (RPE) were recorded every 10 minutes during the trials. Endurance time was significantly different (P < 0.05) between experimental and placebo trials. Heart rate, skin temperature, core body temperature, oxygen uptake, RPE, plasma insulin, glucose, free fatty acid and lactate levels during the endurance exercise did not show any significant difference between the trials. Thus, we conclude that combined and acute supplementation of caffeine and PG in the said doses improved the endurance running performance of the heat-adapted male recreational runners

    1st. International Conference on Sports and Exercise Science 2009 Bangkok, Thailand 01-03 Disember 2009

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    Introduction: Athletes in Malaysia need to perfonn in a hot and humid environment due to the climatic nature of the country, Alteration in endurance perfonnance following acute and chronic supplementation of caffeine has been studied in different populations but concurrent research in the Malaysian context has not been attempted before, Equivocal findings of the ergogenic properties of Panax ginseng in enhancing physical performance were reported, However, data on the effect of acute supplementation of Panax ginseng on physical performance among Malaysian population is still lacking. Furthennore, combination of caffeine and Panax ginseng has never been investigated before on endurance running perfonnance in the heat. Methods: In the present study, we examined the effect of acute supplementation of 5 mg caffeine per kg of body weight (C), 200 mg Panax ginseng (PG), combination of 5 mg caffeine per kg of body weight and 200 mg Panax ginseng (CPG) or placebo (PL) consumed one hour prior to the endurance performance. Supplements and placebo were given in the fonn of capsules in a randomised double blind cross-over trial. Nine heat acclimated recreational runners (aged: 25A ± 6.9 years) as well as nonusers of caffeine (23.7± 12.6 mg per day) participated in this study. Subjects ran at 70% of their V02m, on a motorised treadmill in a heat-controlled laboratory (31 'C, 70% relative humidity). Subjects drank 3 mL of cool water per kg of body weight every 20 minutes during the trials to avoid any possible adverse effects of dehydration. Heart rate, mean skin temperaiure, rectal temperature and RPE were recorded at intervals of I 0 minutes. Oxygen consumption, fluid sensory scale and blood samples were collected at intervals of 20 minutes. Results: Running time to exhaustion was significantly longer (p<0.05) in C trial compared to PL trial. However, the longer time to exhaustion in the CPG trial did not reach statistical significance (P=0.07). Exhaustion time in PG trial showed no significant difference in comparison with PL trial. Heart rate, rectal temperatures, mean skin temperature, oxygen uptake, plasma insulin, glucose, lactate in the C, CPG and PG were not significantly different from the PL trial. Plasma free fatty acid in the C and CPG trial were significantly higher (p<0.05) in comparison with PL trials. RPE were lowest in C trial and followed by CPG, PG and PL trials. Heart rate, rectal temperature, mean skin temperature, oxygen uptake, plasma insulin, glucose, lactate and fatty acid increased significantly during exercise from their respective resting values in all trials. Gastrointestinal discomfort was not reported during endurance performance in all trials. Conclusion: Ingestion of 5 mg of caffeine per kg of body weight has an ergogenic effect on the nonusers of caffeine and heat-acclimatised recreational runners in a hot and humid environment

    Effect of sago starch paste ingestion during steady-state cycling on subsequent time-real performance

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    This study was undertaken to determine the effects of ingesting a specific form of a sago starch preparation before and during prolonged steady state cycling exercise in the heat on subsequent time-trial performance. Fifteen, heat acclimatised recreational cyclists completed two separate, randomised trials of 90 minutes cycling at 60% of VOzmax. followed by a 15-min performance ride in a temperature and humidity controlled chamber maintained at - 31°C and a relative humidity of -70%. Pre-exercise feedings consisted of sago starch paste (SBEx) amounting to 0.75g carbohydrate (CHO/kg body weight or a similarly flavoured, coloured and textured placebo (PBEx). During the steady state ride, subjects either consumed liquid sago starch paste supplying 15g CHO (SDEx) or a placebo (PBDex) at 20-minute intervals. To promote thermoregulation, subjects were fan cooled throughout both exercise periods. Core body temperatures were measured and recorded at 10-minute intervals during the steady-state ride and on completion of the performance ride. The amount of work produced in kilojoules (kJ) during the performance ride was taken as a measure of performance. Results indicated that the SBExSDEx trial produced significantly higher mean work output during the performance ride (146.9±21.5kJ or 33.2% improvement, p<0.001) compared to the PBExPDEx trial (110.3±26.2 kJ). Core body temperatures prior to exercise were similar for both trials (p=0.45) but at completion of the steady state ride, it was significantly higher during the PBExPDEx trial (38.4±0.4°C) compared to the SBExSDEx trial (38.1°C,p=0.001). Similarly, core body temperature at the end of the time-trial was significantly higher during the PBExPDEx trial (38.5±0.4°C) compare to SBExSDEx trial (38.3±0.3°C),p=0.017). This present study indicated that sago starch paste feedings before and during prolonged sub-maximal exercise can improve time-trial performance while at the same time attenuating the rise in core body temperature

    The Effects of Walking with a Load in the Heat on Physiological Responses among Military Reserve Female Cadets

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    International Journal of Exercise Science 13(2): 900-911, 2020. This study aimed to investigate the effects of walking in a hot and humid environment while wearing a combat suit with a load on physiological responses among the Malaysian Military Reserve Officer Training Unit (ROTU) female cadets. Eight healthy female ROTU cadets (age: 21.3 ± 1.0 years old; height: 156.3 ± 4.9 cm; weight: 55.6 ± 7.5 kg) participated in this randomised, crossover trial. They walked for 1 h on a treadmill at 3 km.h-1 while carrying either 8.2 kg load (WL) or without load (WOL) in a room maintained at 30°C and 70% relative humidity. Heart rate, rate of perceived exertion (RPE), and tympanic temperature were recorded at regular intervals during the trials. Nude body weight was recorded before and after the walk to determine body weight loss and sweat rate. Urine samples were also collected before and after the walk to determine urine specific gravity of the participants. There was a significant main effect of time and interaction for heart rate (p \u3c 0.001) during the experimental trials. Tympanic temperature was significantly higher at 60th min in WL trial (p \u3c 0.05) compared to the WOL trial. Similarly, RPE was found to be significantly higher in WL trial (p \u3c 0.01) compared to the WOL trial. However, the percentage of body weight loss and sweat rate was significantly different between trials (p \u3c 0.05). Wearing a combat suit with a load showed significantly increased metabolic demands compared to wearing combat suit alone during prolonged walking in a hot and humid environment

    Physiological demands and time motion analysis of Singles' badminton play following implementation of 21 point scoring system

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    The purpose of this study was to investigate and compare the time motion and notational variables of21 point singles' badminton play and of the old scoring system (15 points for males and 11 for females). Sixteen (8 males and 8 females) state-level badminton players with a mean age of 15.7 ± 1.2 years participated in this study. They were initially tested using incremental treadmill test following Bruce protocol to obtain individual maximum oxygen consumption (V02max) value. V02max of the male and female participants were 47.1 ± 5.2 ml·kg-l·min-1 and 39.8 ± 6.2 ml·kg-l·min-1 respectively. On a separate day, they played a simulated badminton match using 21 points (Trial I) and 15/11 points (Trial2) scoring system. During the trials, a video camera was used for time~motion and notational analysis throughout the match. The statistical analysis showed that total number of shots and rallies in a match were the only variables which were significantly higher in the 15 points compared to 21 points in men's singles match play [331.2 ± 51.6 vs 463.5 ± 24.7 (total shots) and 70.2 ± 1.2 vs 97 ± 6.6 (total rallies) respectively]. Even though female players had a greater point difference (I 0 points) in the new scoring system compared to the male counterparts, there were no significant differences in all parameters measured. The patterns of play which were analyzed on the basis of notational variables were also similar in both scoring systems. However, some differences in the time motion and notational analysis were found between genders suggesting that there should be different training regimens for men and women in their respective disciplines due to greater intensity, speed of play and the longer rally lengths in men's singles. Therefore, it is recommended that players should impart more emphasis in the development and improvement of the skills/techniques rather than making any drastic changes to the training programme to develop their physical fitness to meet the demands of the match with the 21 point scoring system

    Effects of acute supplementation of caffeine on cardiorespiratory responses during endurance running in a hot and humid climate

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    BACKGROUND & OBJECTIVES: Athletes in Malaysia need to perform in a hot and humid climate. Chronic supplementation of caffeine on endurance performance have been studied extensively in different populations. However, concurrent research on the effects of acute supplementation of caffeine on cardiorespiratory responses during endurance exercise in the Malaysian context especially in a hot and humid environment is unavailable. METHODS: Nine heat adapted recreational Malaysian male runners (aged: 25.4+/-6.9 yr) who were nonusers of caffeine (23.7+/-12.6 mg per day) were recruited in this placebo--controlled double--blind randomized study. Caffeine (5 mg per kg of body weight) or placebo was ingested in the form of a capsule one hour prior to the running exercise trial at 70 per cent of VO2max on a motorised treadmill in a heat-controlled laboratory (31 degrees C, 70% relative humidity). Subjects drank 3 ml of cool water per kg of body weight every 20 min during the running trials to avoid the adverse effects of dehydration. Heart rate, core body temperature and rate of perceived exertion (RPE) were recorded at intervals of 10 min, while oxygen consumption was measured at intervals of 20 min. RESULTS: Running time to exhaustion was significantly (P<0.05) higher in the caffeine trial compared to the placebo trial. Heart rate, core body temperature, oxygen uptake and RPE did not show any significant variation between the trials but it increased significantly during exercise from their respective resting values in both trials (P<0.001). INTERPRETATION & CONCLUSION: Our study showed that ingestion of 5 mg of caffeine per kg of body weight improved the endurance running performance but did not impose any significant effect on other individual cardiorespiratory parameters of heat-acclimated recreational runners in hot and humid conditions

    Effects of Bee Bread Supplementation on Isokinetic Knee Extension and Flexion of Lower Limb

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    A nutritional strategy is the common types of ergogenic aid used by athlete to enhance their sport performance. Athlete usually consumes bee products before a sports competition to make sure they have adequate nutrition, maximize their energy storage and enhance their sport performance. Scientific data on the ergogenic effects of bee products consumed at pre exercise on isokinetic knee extension and flexion of lower limb is scanty. This study investigated the effects of 8 weeks of bee bread supplementation at pre exercise on isokinetic knee extension and flexion of lower limb among athletes. Twelve volunteer athletes were recruited in this scientific study. Subjects consumed either bee bread at a dosage of 20 g.d-1 or placebo for 8 weeks prior to the experimental trial. Subjects’ isokinetic knee extension and flexion of lower limb were measured before and after 8 weeks of experimental period. Statistical analyses were performed using ANOVA with repeated measures. This present study found that bee bread supplementation showed some positives impact on few measured parameters of isokinetic knee extension and flexion of lower limb

    Effects of Bee Bread Supplementation on Total Antioxidant Status and F2-Isoprostane Among Athletes

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    Antioxidant is a substance that helps to reduce the severity of oxidative stress. Many chronic diseases have been reported related the increasing of free radical and oxidative stress in the human. There is still scanty information on antioxidant property of bee bread at pre and post exercise after short term supplementation. This present study investigated effects of eight weeks supplementation of bee bread on antioxidant status at pre and post exercise among athletes. Twelve male athletes were recruited in this randomised crossover study. For the exercise trial test, subjects were required to run at 60% of their respective VO2max on a motorised treadmill for 90 minutes and immediately followed by a time trial performance. Blood samples were collected at pre and post exercise to determine total antioxidant status (TAS) and F2-Isoprostane. Statistical analyses were performed using descriptive statistic and ANOVA with repeated measures. TAS was significantly higher, whereas F2-Isoprostane was significantly lower in the bee bread trial in comparison with placebo trial after eight weeks of supplementation. This present study found that bee bread supplementation showed positives impact on antioxidant status among athletes

    Label-efficient Time Series Representation Learning: A Review

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    The scarcity of labeled data is one of the main challenges of applying deep learning models on time series data in the real world. Therefore, several approaches, e.g., transfer learning, self-supervised learning, and semi-supervised learning, have been recently developed to promote the learning capability of deep learning models from the limited time series labels. In this survey, for the first time, we provide a novel taxonomy to categorize existing approaches that address the scarcity of labeled data problem in time series data based on their dependency on external data sources. Moreover, we present a review of the recent advances in each approach and conclude the limitations of the current works and provide future directions that could yield better progress in the field.Comment: Under Revie
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