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Journal ArticleDOI

Nutritional approaches to counter performance constraints in high level sports competition

11 Nov 2021-Experimental Physiology (John Wiley & Sons, Ltd)-Vol. 106, Iss: 12, pp 2304-2323
TL;DR: In this paper, a range of nutritional strategies can be used by competitive athletes, alone or in combination, to address various event-specific factors that constrain event performance and why they use them.
Abstract: New findings What is the central question of this study? What are the nutritional strategies that athletes use during competition events to optimise performance and why do they use them? What is the main finding and its importance? A range of nutritional strategies can be used by competitive athletes, alone or in combination, to address various event-specific factors that constrain event performance. Evidence for such practices is constantly evolving but must be combined with understanding of the complexities of real-life sport for optimal implementation. Abstract High performance athletes share a common goal despite the unique nature of their sport: to pace or manage their performance to achieve the highest sustainable outputs over the duration of the event. Periodic or sustained decline in the optimal performance of event tasks, involves an interplay between central and peripheral phenomena that can often be reduced or delayed in onset by nutritional strategies. Contemporary nutrition practices undertaken before, during, or between events include strategies to ensure the availability of limited muscle fuel stores. This includes creatine supplementation to increase muscle phosphocreatine content, and consideration of the type, amount and timing of dietary carbohydrate intake to optimise muscle and liver glycogen stores or to provide additional exogenous substrate. Although there is interest in ketogenic low-carbohydrate high-fat diets and exogenous ketone supplements to provide alternative fuels to spare muscle carbohydrate use, present evidence suggests a limited utility of these strategies. Mouth sensing of a range of food tastants (e.g. carbohydrate, quinine, menthol, caffeine, fluid, acetic acid) may provide a central nervous system derived boost to sports performance. Finally, despite decades of research on hypohydration and exercise capacity, there is still contention around its effect on sports performance and the best guidance around hydration for sporting events. A unifying model proposes that some scenarios require personalised fluid plans while others might be managed by an ad hoc approach (ad libitum or thirst-driven drinking) to fluid intake. This article is protected by copyright. All rights reserved.
Citations
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TL;DR: In this article , the Pearson Product Moment Correlation Coefficient was used to determine the relationship between coaching commitment and physical development of student-athletes from various public schools in Angeles City, Pampanga, Philippines.
Abstract: This present study aims to determine the relationship between coaching commitment and physical development of student-athletes from various public schools in Angeles City, Pampanga, Philippines. Respondents on the study are student-athletes from Senior High School Public Schools from Grade 11 and 12. Descriptive statistics such as Mean and Standard Deviation were used to describe the level of coaching commitment and physical development according to categories, and Pearson Product Moment Correlation Coefficient was used to determine the relationship between coaching commitment and physical development. The findings revealed that the level of coaching commitment is very high and the level of physical development of the respondents is highly developed. From the correlational analysis, result findings revealed that competition strategies, goal setting, physical training and condition, teamwork, technical skills, and time management were observed to have no significant relationship to caring, character, competence, confidence, and connection of the respondents. On one hand, mental preparation was observed to have a significant negative relationship on caring. Additionally, Personal Rapport/ Negative Personal Rapport were observed to have a significant positive relationship on Caring, Character and Connection.

3 citations

Journal ArticleDOI
TL;DR: The potential role of nutrition in exertional heat stroke is explored in this paper , where the authors discuss how selected nutritional considerations may influence EHS risk focusing on their impact on the key pathophysiological processes of EHS, and provide recommendations for future research.
Abstract: What is the topic of this review? The potential role of nutrition in exertional heat stroke. What advances does it highlight? Certain nutritional and dietary strategies used by athletes and workers may exert a protective effect the pathophysiological processes of exertional heat stroke, whereas others may be detrimental. While current evidence suggests that some of these practices may be leveraged as a potential countermeasure to exertional heat stroke, further research on injury-related outcomes in humans is required.Exertional heat stroke (EHS) is a life-threatening illness and an enduring problem among athletes, military servicemen and -women, and occupational labourers who regularly perform strenuous activity, often under hot and humid conditions or when wearing personal protective equipment. Risk factors for EHS and mitigation strategies have generally focused on the environment, health status, clothing, heat acclimatization and aerobic conditioning, but the potential role of nutrition is largely underexplored. Various nutritional and dietary strategies have shown beneficial effects on exercise performance and health and are widely used by athletes and other physically active populations. There is also evidence that some of these practices may dampen the pathophysiological features of EHS, suggesting possible protection or abatement of injury severity. Promising candidates include carbohydrate ingestion, appropriate fluid intake and glutamine supplementation. Conversely, some nutritional factors and low energy availability may facilitate the development of EHS, and individuals should be cognizant of these. Therefore, the aims of this review are to present an overview of EHS along with its mechanisms and pathophysiology, discuss how selected nutritional considerations may influence EHS risk focusing on their impact on the key pathophysiological processes of EHS, and provide recommendations for future research. With climate change expected to increase EHS risk and incidence in the coming years, further investigation on how diet and nutrition may be optimized to protect against EHS would be highly beneficial.

2 citations

Journal ArticleDOI
TL;DR: The literature that underpins the current guidelines for CHO intake in the acute periods around exercise is lacking in high-quality research that can contribute knowledge specific to the female athlete and sex-based differences.
Abstract: ABSTRACT Purpose The aim of this audit was to assess the representation of female athletes within the literature that has led to current guidelines for carbohydrate (CHO) intake in the acute periods surrounding exercise and the quality of this research. Methods We conducted a standardized audit of research assessing CHO loading protocols, CHO mouth rinse, and CHO intake before, during, and after exercise. Results A total of 937 studies were identified in this audit. There were a total of 11,202 participants across these studies, with only ~11% being women. Most studies involved male-only cohorts (~79%), with a mere 38 studies (~4%) involving female-only cohorts and 14 studies (~2%) including a methodological design for comparison of sex-based responses. The frequent use of incorrect terminology surrounding menstrual status and the failure of most studies (~69%) to provide sufficient information on the menstrual status of participants suggests incomplete understanding and concern for female-specific considerations among researchers. Of the 197 studies that included women, only 13 (~7%) provided evidence of acceptable methodological control of ovarian hormones, and no study met all best-practice recommendations. Of these 13 studies, only half also provided sufficient information regarding the athletic caliber of participants. The topics that received such scrutiny were CHO loading protocols and CHO intake during exercise. Conclusions The literature that underpins the current guidelines for CHO intake in the acute periods around exercise is lacking in high-quality research that can contribute knowledge specific to the female athlete and sex-based differences. New research that considers ovarian hormones and sex-based differences is needed to ensure that the recommendations for acute CHO fueling provided to female athletes are evidence based.

2 citations

Journal ArticleDOI
TL;DR: While current evidence suggests that some nutritional practices used by athletes and workers may be leveraged as a potential countermeasure to exertional heat stroke, further research on injury‐related outcomes in humans is required.
Abstract: What is the topic of this review? The potential role of nutrition in exertional heat stroke. What advances does it highlight? Certain nutritional and dietary strategies used by athletes and workers may exert a protective effect the pathophysiological processes of exertional heat stroke, whereas others may be detrimental. While current evidence suggests that some of these practices may be leveraged as a potential countermeasure to exertional heat stroke, further research on injury‐related outcomes in humans is required.

1 citations

Journal ArticleDOI
TL;DR: In this article , the relevance of the ketogenic diet for endurance cyclists riding greater than 90 min was discussed, and a review of macronutrients and micronutrient, periodized training and nutrition was presented.
Abstract: Cycling is a growing sport worldwide since the COVID-19 pandemic. With the growing availability and interest in long distance events, professional and amateur cyclists are pushing themselves further and harder than ever before. Training and nutrition should be understood by the sports medicine professional in order to guide counseling toward proper fueling to avoid health consequences. This article reviews macronutrients and micronutrients, periodized training and nutrition, and the relevance of the ketogenic diet for endurance cyclists riding greater than 90 min.
References
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Journal ArticleDOI
TL;DR: It has been shown that the glycogen content and, consequently, the long-term work capacity can be appreciably varied by instituting different diets after glycogen depletion.
Abstract: The muscle glycogen content of the quadriceps femoris muscle was determined in 9 healthy subjects with the aid of the needle biopsy technique. The glycogen content could be varied in the individual subjects by instituting different diets after exhaustion of the glycogen store by hard exercise. Thus, the glycogen content after a fat ± protein (P) and a carbohydrate-rich (C) diet varied maximally from 0.6 g/100g muscle to 4.7 g. In all subjects, the glycogen content after the C diet was higher than the normal range for muscle glycogen, determined after the mixed (M) diet. After each diet period, the subjects worked on a bicycle ergometer at a work load corresponding to 75 per cent of their maximal O2 uptake, to complete exhaustion. The average work time was 59, 126 and 189 min after diets P, M and C, and a good correlation was noted between work time and the initial muscle glycogen content. The total carbohydrate utilization during the work periods (54–798 g) was well correlated to the decrease in glycogen content. It is therefore concluded that the glycogen content of the working muscle is a determinant for the capacity to perform long-term heavy exercise. Moreover, it has been shown that the glycogen content and, consequently, the long-term work capacity can be appreciably varied by instituting different diets after glycogen depletion.

1,601 citations

Journal ArticleDOI
TL;DR: Competition with 5g of creatine monohydrate, four or six times a day for 2 or more days resulted in a significant increase in the total creatine content of the quadriceps femoris muscle measured in 17 subjects, and in some the increase was as much as 50%.
Abstract: 1. The present study was undertaken to test whether creatine given as a supplement to normal subjects was absorbed, and if continued resulted in an increase in the total creatine pool in muscle. An additional effect of exercise upon uptake into muscle was also investigated. 2. Low doses (1g of creatine monohydrate or less in water) produced only a modest rise in the plasma creatine concentration, whereas 5g resulted in a mean peak after 1h of 795 (SD 104) mumol/l in three subjects weighing 76-87 kg. Repeated dosing with 5g every 2h sustained the plasma concentration at around 1000 mumol/l. A single 5g dose corresponds to the creatine content of 1.1 kg of fresh, uncooked steak. 3. Supplementation with 5g of creatine monohydrate, four or six times a day for 2 or more days resulted in a significant increase in the total creatine content of the quadriceps femoris muscle measured in 17 subjects. This was greatest in subjects with a low initial total creatine content and the effect was to raise the content in these subjects closer to the upper limit of the normal range. In some the increase was as much as 50%. 4. Uptake into muscle was greatest during the first 2 days of supplementation accounting for 32% of the dose administered in three subjects receiving 6 x 5g of creatine monohydrate/day. In these subjects renal excretion was 40, 61 and 68% of the creatine dose over the first 3 days. Approximately 20% or more of the creatine taken up was measured as phosphocreatine. No changes were apparent in the muscle ATP content.(ABSTRACT TRUNCATED AT 250 WORDS)

1,071 citations

Journal ArticleDOI
TL;DR: This position paper outlines the Academy's, DC's and ACSM's stance on nutrition factors that have been determined to influence athletic performance and emerging trends in the field of sports nutrition.
Abstract: It is the position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine that the performance of, and recovery from, sporting activities are enhanced by well-chosen nutrition strategies. These organizations provide guidelines for the appropriate type, amount, and timing of intake of food, fluids, and supplements to promote optimal health and performance across different scenarios of training and competitive sport. This position paper was prepared for members of the Academy of Nutrition and Dietetics, Dietitians of Canada (DC), and American College of Sports Medicine (ACSM), other professional associations, government agencies, industry, and the public. It outlines the Academy's, DC's and ACSM's stance on nutrition factors that have been determined to influence athletic performance and emerging trends in the field of sports nutrition. Athletes should be referred to a registered dietitian/nutritionist for a personalized nutrition plan. In the United States and in Canada, the Certified Specialist in Sports Dietetics (CSSD) is a registered dietitian/nutritionist and a credentialed sports nutrition expert.

796 citations

Journal ArticleDOI
TL;DR: The magnitude of increase in core temperature and HR and the decline in SV are graded in proportion to the amount of dehydration accrued during exercise, which was linearly related with the increase in Tes, HR, and SV.
Abstract: This investigation determined the effect of different rates of dehydration, induced by ingesting different volumes of fluid during prolonged exercise, on hyperthermia, heart rate (HR), and stroke v...

792 citations

Journal ArticleDOI
TL;DR: The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important, and caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents.
Abstract: Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also ben shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.

760 citations

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What are the best nutritional strategies for athletes?

The best nutritional strategies for athletes include creatine supplementation, carbohydrate intake, mouth sensing of food tastants, and personalized fluid plans for hydration.