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Contemporary Nutrition Strategies to Optimize Performance in Distance Runners and Race Walkers
Abstract
Distance events in Athletics include cross country, 10,000-m track race, half-marathon and marathon road races, and 20- and 50-km race walking events over different terrain and environmental conditions. Race times for elite performers span ∼26 min to >4 hr, with key factors for success being a high aerobic power, the ability to exercise at a large fraction of this power, and high running/walking economy. Nutrition-related contributors include body mass and anthropometry, capacity to use fuels, particularly carbohydrate (CHO) to produce adenosine triphosphate economically over the duration of the event, and maintenance of reasonable hydration status in the face of sweat losses induced by exercise intensity and the environment. Race nutrition strategies include CHO-rich eating in the hours per days prior to the event to store glycogen in amounts sufficient for event fuel needs, and in some cases, in-race consumption of CHO and fluid to offset event losses. Beneficial CHO intakes range from small amounts, including mouth rinsing, in the case of shorter events to high rates of intake (75-90 g/hr) in the longest races. A personalized and practiced race nutrition plan should balance the benefits of fluid and CHO consumed within practical opportunities, against the time, cost, and risk of gut discomfort. In hot environments, prerace hyperhydration or cooling strategies may provide a small but useful offset to the accrued thermal challenge and fluid deficit. Sports foods (drinks, gels, etc.) may assist in meeting training/race nutrition plans, with caffeine, and, perhaps nitrate being used as evidence-based performance supplements.
... In general, mountain runners are aware of the importance of carbohydrate and liquid consumption during this type of event. Specifically, the three most used SS were supplements, which are usually used in this type of competition due to their ease of transport and tolerance, as well as their provision of carbohydrates [37][38][39][40]. In general, these results coincide with those reported in other studies, in which the most consumed SS were sports bars, isotonic or sports drinks, and multivitamins, with no statistically significant differences between sexes [15][16][17][18][19][20]22]. ...
... There are many factors that can influence the success or failure of mountain runners [6][7][8][10][11][12]. The physiological characteristics of the MR explain the choice of the most consumed SS, i.e., the use of energy substrates by the body during these tests, which the athletes will have to provide exogenously in order to obtain the desired performance to carry out the competition [1,[37][38][39][40]. The bars and gels provide large amounts of carbohydrates in a small amount of product, which in addition to producing less gastrointestinal discomfort, allows the athletes to optimize the space they have in their means of food transport (backpacks, belts, pockets.) ...
... The bars and gels provide large amounts of carbohydrates in a small amount of product, which in addition to producing less gastrointestinal discomfort, allows the athletes to optimize the space they have in their means of food transport (backpacks, belts, pockets.) [1,4,24,36,38]. Another important reason that can explain the consumption of sports drinks is thermoregulation [43][44][45][46]. Especially when the race takes place in hot environmental conditions, there is an increase in the production of internal body heat that must be controlled through different strategies (acclimatization, hydration . . . ) to maintain body homeostasis, which will allow the athlete to have greater success [43][44][45][46][47]. ...
Background:
The use of sports supplements (SS) to improve sports performance is widespread in all types of athletes, however, the specific characteristics of mountain races may require the use of certain SS. Despite being a sport where the consumption of SS seems widespread, few studies have been conducted in this regard. The objective of this study is to analyze the pattern of SS consumption of mountain runners in relation to the degree of scientific evidence, sex, and level of competition.
Methods:
Descriptive and cross-sectional study on the consumption and habitual use of SS of 357 federated mountain runners in Spain. Data were collected through a validated questionnaire.
Results:
From the total sample, 93.84% of the athletes stated that they consumed SS, with no differences observed based on the competitive level or in terms of sex; however, there were significant differences according to the competitive level in terms of the number of SS consumed, with consumption being greater at a higher competitive level (p = 0.009). The most consumed SS were sports bars (66.1%), sports drinks (60.5%), sports gels (52.9%), and caffeine (46.2%).
Conclusions:
The consumption of SS in mountain races is high, and the number of SS consumed is higher as the competition level increases. The four SS most consumed by the participants in this study were all included in category A in the classification of the Australian Institute of Sport (AIS), this category is the one with the greatest scientific evidence.
... Aerobic or cardiorespiratory endurance exercise places high physiological and metabolic demands on the human body's organic regulatory systems [1]. From a physiological point of view, performance in cardiorespiratory endurance sports, where the effort generally lasts longer than 5 min, depends primarily on three related factors: maximal oxygen uptake (VO 2 max), which can be defined as the maximum oxygen-carrying capacity of a subject; the individual lactate threshold (ILT), which has many names and is related to different physiological concepts but which, in short, refers to the intensity of exercise at which the concentration of lactate in the blood increases exponentially compared to basal levels due to the inability to be oxidized in the mitochondria; and the efficiency or running economy, defined as the oxygen consumption or energy required by an individual to maintain a given running pace [2][3][4][5][6]. In addition, the importance of psychological sensation is of the utmost importance in sport, as it is considered a form of biofeedback integrated into the information and effort regulation system between the central command and the local peripheral mechanisms [7,8]. ...
... To improve sports performance, athletes work with complex, carefully planned training and nutrition systems [10,11]. Nutrition and supplementation are therefore important tools in optimizing performance, especially in endurance and aerobic disciplines [6,12]. In their search for the ultimate performance improvement, athletes often make use of a variety of sports supplements [13]. ...
... Likewise, for the analysis of lactate, the measurement of this biomarker was analyzed in the different studies in the same way as for the RPE, using the Modified Borg Scale (0-10) or Borg Rating of Perceived Exertion Scale (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). In turn, different related variables were used to analyze the responses for VO 2 kinetics. ...
Supplementation with Citrulline (Cit) has been shown to have a positive impact on aerobic exercise performance and related outcomes such as lactate, oxygen uptake (VO2) kinetics, and the rate of perceived exertion (RPE), probably due to its relationship to endogenous nitric oxide production. However, current research has shown this to be controversial. The main objective of this systematic review and meta-analysis was to analyze and assess the effects of Cit supplementation on aerobic exercise performance and related outcomes, as well as to show the most suitable doses and timing of ingestion. A structured literature search was carried out by the PRISMA® (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and PICOS guidelines in the following databases: Pubmed/Medline, Scopus, and Web of Science (WOS). A total of 10 studies were included in the analysis, all of which exclusively compared the effects of Cit supplementation with those of a placebo group on aerobic performance, lactate, VO2, and the RPE. Those articles that used other supplements and measured other outcomes were excluded. The meta-analysis was carried out using Hedges’ g random effects model and pooled standardized mean differences (SMD). The results showed no positive effects of Cit supplementation on aerobic performance (pooled SMD = 0.15; 95% CI (−0.02 to 0.32); I2, 0%; p = 0.08), the RPE (pooled SMD = −0.03; 95% CI (−0.43 to 0.38); I2, 49%; p = 0.9), VO2 kinetics (pooled SMD = 0.01; 95% CI (−0.16 to 0.17); I2, 0%; p = 0.94), and lactate (pooled SMD = 0.25; 95% CI (−0.10 to 0.59); I2, 0%; p = 0.16). In conclusion, Cit supplementation did not prove to have any benefits for aerobic exercise performance and related outcomes. Where chronic protocols seemed to show a positive tendency, more studies in the field are needed to better understand the effects.
... Elite endurance athletes sustain high-power outputs and extremely high relative exercise intensities, typically well above the crossover point of carbohydrate (CHO) and lipid metabolism. For example, elite marathon runners race at a sustained oxygen (O 2 ) uptake of~85-90% VO 2 max with high rates of substrate turnover [1,2]. Attempts to replace the muscle's reliance on the relatively finite body CHO stores have been shown to achieve dramatic alterations to muscle substrate use. ...
... However, at the intensities at which competitive endurance events are conducted, such increases in fat utilisation do not translate to performance improvements [5][6][7]; indeed, they are harmful to sustained speed or power output, possibly due to the increased oxygen cost associated with fat oxidation (for review, see Burke [8]). Empirical evidence of the reduction in exercise economy associated with adaptation to ketogenic LCHF diets has led to calculations of theoretical advantages to economy and performance following further increases in the contribution of CHO to exercise substrate use [2]. However, our recent investigation of this hypothesis failed to detect a measurable change in oxygen use when elite athletes implemented dietary strategies to increase CHO availability and oxidation during exercise [9]. ...
... Meanwhile, glucose uptake into the skeletal muscle occurs via GLUT4 transport at the plasma membrane, with ATP production via oxidative pathways being dependent on aerobic adaptations within the muscle (e.g., mitochondrial density), as well as the activation of key enzymes (e.g., the pyruvate dehydrogenase complex) [12]. Contemporary guidelines for CHO intake during endurance/ultra-endurance athletic events recommend the consumption of 60-90 g·h −1 [2,13] with a potential dose response for performance in longer events raising interest in strategies to maximise the effectiveness of exogenous CHO oxidation [14]. To facilitate this, it has been proposed that the gastrointestinal tract should be trained by regularly consuming high doses of exogenous CHO during exercise [15,16], targeting adaptations to: (1) increase tolerance to intragastric pressure and enhance gastric emptying [17,18], (2) improve efficient intestinal transit and avoid peristaltic braking mechanisms [19,20], and/or (3) increase CHO transporters at the villi apical brush border to increase absorption capacity [18][19][20]. ...
We implemented a multi-pronged strategy (MAX) involving chronic (2 weeks high carbohydrate [CHO] diet + gut-training) and acute (CHO loading + 90 g·h −1 CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON) in two groups of athletes. Nineteen elite male race walkers (MAX: 9; CON:10) undertook a 26 km race-walking session before and after the respective interventions to investigate gastrointestinal function (absorption capacity), integrity (epithelial injury), and symptoms (GIS). We observed considerable individual variability in responses, resulting in a statistically significant (p < 0.001) yet likely clinically insignificant increase (∆ 736 pg·mL −1) in I-FABP after exercise across all trials, with no significant differences in breath H 2 across exercise (p = 0.970). MAX was associated with increased GIS in the second half of the exercise, especially in upper GIS (p < 0.01). Eighteen highly trained male and female distance runners (MAX: 10; CON: 8) then completed a 35 km run (28 km steady-state + 7 km time-trial) supported by either a slightly modified MAX or CON strategy. Inter-individual variability was observed, without major differences in epithelial cell intestinal fatty acid binding protein (I-FABP) or GIS, due to exercise, trial, or group, despite the 3-fold increase in exercise CHO intake in MAX post-intervention. The tight-junction (claudin-3) response decreased in both groups from pre-to post-intervention. Groups achieved a similar performance improvement from pre-to post-intervention (CON = 39 s [95 CI 15-63 s]; MAX = 36 s [13-59 s]; p = 0.002). Although this suggests that further increases in CHO availability above current guidelines do not confer additional advantages, limitations in our study execution (e.g., confounding loss of BM in several individuals despite a live-in training camp environment and significant increases in aerobic capacity due to intensified training) may have masked small differences. Therefore, athletes should meet the minimum CHO guidelines for training and competition goals, noting that, with practice, increased CHO intake can be tolerated, and may contribute to performance outcomes.
... The planning and preparation undertaken by elite athletes for events in hot and/or humid conditions typically include periodized environmental training practices such as heat acclimation (repeated heat exposures within a heat chamber or heated room) and acclimatization (living and training in a natural similar environment to the competition), and in some cases passive heat exposure (passive heat acclimation), achieved via sauna bathing or hot water immersion in either an intermittent or continuous approach (Périard et al., 2015;Mujika et al., 2019;Racinais et al., 2019;Saunders et al., 2019). Strategies used by athletes to lessen the expected increases in core body temperature and skin temperature when competing in hot, humid conditions may also include internal cooling methods including ice slurry ingestion and menthol gel ingestion, and external cooling methods such as cold water immersion and application of ice and cold water to the skin (Ross et al., 2013;Stevens and Best, 2017;Burke et al., 2019b;Périard et al., 2021). Recently, the use of such strategies by elite race walkers and marathon runners has been documented during international championship events (Stevens et al., 2020;Racinais et al., 2021). ...
... Nutritional strategies that improve hydration status and modify body composition can support athletes' performance in hot, humid conditions (Burke et al., 2019b;Saunders et al., 2019;Areta et al., 2021). The addition of specific osmotic agents (e.g., glycerol and sodium) to a pre-event fluid bolus has been demonstrated to enhance hydration status and significantly increase pre-exercise blood plasma volume, significantly decrease core temperature during exercise, and modify body mass, urine specific gravity and plasma osmolality (Sims et al., 2007a,b;Goulet et al., 2018;Maughan et al., 2018;Saunders et al., 2019). ...
... The addition of specific osmotic agents (e.g., glycerol and sodium) to a pre-event fluid bolus has been demonstrated to enhance hydration status and significantly increase pre-exercise blood plasma volume, significantly decrease core temperature during exercise, and modify body mass, urine specific gravity and plasma osmolality (Sims et al., 2007a,b;Goulet et al., 2018;Maughan et al., 2018;Saunders et al., 2019). Short-term exposure to low energy availability (LEA) can facilitate a reduction in body mass, which when periodized appropriately and managed by sports dietitians, might lead to improved performance in endurance events without the negative health implications of chronic LEA such as impaired endocrine and immune function, and impaired bone health (Stellingwerff, 2018;Burke et al., 2019b;Mujika et al., 2019;Areta et al., 2021). Nutritional and hydration strategies used by national teams within holding camps prior to Olympic Games have been previously reported (Maughan, 1997) as have outcomes of periodized nutritional strategies for individual athletes (Stellingwerff, 2018). ...
IntroductionThe Tokyo 2021 Olympic Games was anticipated to expose athletes to the most challenging climatic conditions experienced in the history of the modern Olympic Games. This study documents strategies executed by Australian endurance athletes during the team holding camp and Olympic Games experiences, including (1) baseline physiological data, training data, and heat acclimation/acclimatization practices; (2) pre- and in-race cooling and nutritional strategies, and (3) Olympic Games race performance data.Methods
Six athletes (three males, three females; age 24 ± 4 years; VO2max 63.2 ± 8.7 mL⋅kg–1⋅min–1; sum of 7 skinfolds 53.1 ± 23.4 mm) were observed prior to and during the team holding camp held in Cairns, QLD, Australia. Athletes completed 6–7 weeks of intermittent heat acclimation training, utilizing a combination of 2–4 passive and active acclimation sessions per week. Active acclimation was systematically increased via exposure time, exercise intensity, temperature, and humidity. In the team holding camp, athletes undertook a further 23 heat acclimatization training sessions over 18 days in a continuous fashion. Hyperhydration (using sodium and glycerol osmolytes), and internal and external pre-and in-race cooling methods were also utilized. A low energy availability intervention was implemented with two athletes, as a strategy to periodize ideal race body composition. Race performance data and environmental conditions from the 2021 Olympic Games were also documented.ResultsThe highest values for aerobic capacity were 63.6 mL⋅kg–1⋅min–1 for female race walkers and 73.7 mL⋅kg–1⋅min–1 for males. Training volume for the six athletes was the highest in the second week of the team holding camp, and training intensity was lowest in the first week of the team holding camp. Performance outcomes included 6th place in the women’s 20 km event (1:30:39), which was within 2% of her 20 km personal best time, and 8th place in the men’s 50 km event (3:52:01), which was a personal best performance time.Conclusion
Periodized training, heat acclimation/acclimatization, cooling and nutritional strategies study may have contributed to the race outcomes in Olympic Games held hot, humid conditions, for the race walkers within this observational study.
... For example, in weightrestricted sports (e.g., combat sports, weightlifting, lightweight rowing), reducing BM allows athletes to compete in lower weight categories, against opponents with shorter limb length and lower power to mass ratios (Burke et al., 2021). In weight-bearing sports (e.g., road cycling, some disciplines of track and field, ski jump, etc), athletes may also strive to improve their power/work capacity relative to their BM (Burke et al., 2019;Phillips & Hopkins, 2020). Strategies to reduce BM can be broadly categorized according to acute (hours and days) and chronic (weeks and months) time scales . ...
... We have also observed the use of such interventions in both combat sports and endurance athletes, the latter among Grand Tour winning cyclists several days before a high-mountain stage (authors' unpublished observations). Anecdotally, we and others (Burke et al., 2019) have observed that a LOW may result in a BM loss ∼0.5-1.0 kg when consumed for 2-4 days. However, although one study has previously reported a 1.5% BM loss after 2 days of reduced fiber diet (10-13 g/day), the concomitant introduction of a mild energy deficit and the absence of a group with habitual fiber intake makes it difficult to establish the net contribution of reduced fiber intake to the reported weight loss (Reale, Slater, Cox, et al., 2018). ...
... To our knowledge, this is the first study directly assessing the effect of a LOW on BM compared against a control condition. The BM reducing effects of a LOW which we reported are in line with the suggested absolute BM loss of 0.5 kg (Burke et al., 2019), though it is lower than the ∼1%-2% and ∼1.2 kg BM loss reported by and Holte et al. (2004), respectively. Differences from the latter two studies may be related to the fact that also induced a caloric deficit and controlled fluid intake during Days 1-2 and had no experimental group with a habitual fiber intake. ...
Athletes from weight-sensitive sports are reported to consume low-fiber diets (LOW) to induce acute reductions in body mass (BM). However, evidence supporting their efficacy is anecdotal. Therefore, we aimed to determine the effect of a LOW on acute changes in BM. Nineteen healthy males (32 ± 10 years, 1.79 ± 0.07 m, 77.5 ± 8.1 kg) consumed their habitual diet (∼30 g fiber/ day) for 7 consecutive days followed by 4 days of a LOW (<10 g fiber/day) that was matched for energy and macronutrient content. Participants also matched their daily exercise load during LOW to that completed during habitual diet (p = .669, average 257 ± 141 arbitrary units). BM was significantly reduced in LOW versus habitual diet after 4 days (Δ = 0.40 ± 0.77 kg or 0.49% ± 0.91%, p < .05, effect size [ES] [95% confidence interval] = −0.53 [−1.17, 0.12]) and on the morning of Day 5 (Δ = 0.58 ± 0.83 kg or 0.74% ± 0.99%, p < .01, ES = −0.69 [−1.34, −0.03]). LOW resulted in moderately higher hunger (Δ = 5 ± 9 mm, p = .015, ES = 0.55 [−0.09, 1.20]), a decline in stool frequency from 2 ± 0 to 1 ± 0 bowel movements per day (p = .012, ES = 0.64 [−0.02, 1.29]) and stool softness decrease (p = .005). Nonetheless, participants reported the diet to be tolerable (n = 18/19) and were willing to repeat it (n = 16/19). Data demonstrate for the first time that consumption of a short-term LOW induces reductions in BM.
... So, in order to sustain an adequate glycogen supply and prevent hypoglycemia in exercise events lasting >1 h, a 6-8% CHO solution was generally recommended in many reviews [12,146,218,219]. Briefly, most modern reviews give more appreciation to solutions of 6-8% CHO concentration than to less or more concentrated drinks, and more credit to solutions composed of MTC than to single-source CHO solutions (e.g., GL or MD-only), in order to achieve high oxidation rates (>90 g·h −1 ), and consequently ensure better performance during prolonged exercise [7,9,12,143,145,146,216,[218][219][220][221]. Similarly, the present meta-analysis provides evidence that CHO supplementation composed of GL:FRU is superior to other MTC compositions (fixed effect analysis; Figure S14). ...
... It also appears that performance is benefited significantly more from a CHO dose of 80-100 g·h −1 in comparison to a CHO dose >100 g·h −1 (Figure 7), and also more in comparison to 60-80 g·h −1 , though not significantly (p = 0.15). On the other hand, some reviews consider that CHO intake of up to 60 g·h −1 for exercise lasting up to 2.5 h and up to 90 g·h −1 when the exercise duration exceeds 2.5 h should be recommended [7,9,220]. For the most part, these recommendations seem based on a previous review [221], which in turn seems to have premised its arguments on four previous studies about trained male endurance cyclists only [68,129,215,222]. ...
... We only found a total of 11 relevant studies that satisfied our inclusion criteria ( Figure S9). Regardless of this, most modern reviews recommend a CHO intake up to 60 g·h −1 during an endurance event lasting up to 2.5 h, and up to 90 g·h −1 when the duration of exercise exceeds 2.5 h [7,9,143,220]. Nevertheless, as the duration of an all-out endurance exercise decreases and the intensity increases accordingly, performance should depend more on the availability of CHOs, since CHOs will contribute to a higher energy percentage than fats [19,[170][171][172][173]. ...
Citation: Bourdas, D.I.; Souglis, A.; Zacharakis, E.D.; Geladas, N.D.; Travlos, A.K. Meta-Analysis of Carbohydrate Solution Intake during Prolonged Exercise in Adults: From the Last 45+ Years' Perspective. Nutrients 2021, 13, 4223. https:// Abstract: Carbohydrate (CHO) supplementation during prolonged exercise postpones fatigue. However , the optimum administration timing, dosage, type of CHO intake, and possible interaction of the ergogenic effect with athletes' cardiorespiratory fitness (CRF) are not clear. Ninety-six studies (from relevant databases based on predefined eligibility criteria) were selected for meta-analysis to investigate the acute effect of ≤20% CHO solutions on prolonged exercise performance. The between-subject standardized mean difference [SMD = ([mean post-value treatment group-mean post-value control group]/pooled variance)] was assessed. Overall, SMD [95% CI] of 0.43 [0.35, 0.51] was significant (p < 0.001). Subgroup analysis showed that SMD was reduced as the subjects' CRF level increased, with a 6-8% CHO solution composed of GL:FRU improving performance (exercise: 1-4 h); administration during the event led to a superior performance compared to administration before the exercise, with a 6-8% single-source CHO solution increasing performance in intermittent and 'stop and start' sports and an~6% CHO solution appearing beneficial for 45-60 min exercises, but there were no significant differences between subjects' gender and age groups, varied CHO concentrations, doses, or types in the effect measurement. The evidence found was sound enough to support the hypothesis that CHO solutions, when ingested during endurance exercise, have ergogenic action and a possible crossover interaction with the subject's CRF.
... Therefore, these events represent an interesting and invaluable source of data to explore the various challenges that may be experienced among distance runners [3,4]. It is well established that endurance runners are generally recommended to consume high-carbohydrate meals in the days leading up to a specific event, in conjunction with avoiding foods high in fat, protein, and fibre in precompetition hours [5,6]. Regardless of in-race nutritional strategies and the higher exercise-induced energy needs, endurance athletes may have different physiological requirements for macronutrients and micronutrients in optimizing their physiological adaptations during different preparation phases compared to other athletes [7]. ...
... Comprehensive characteristics of supplements and the scenarios in which they contribute to nutritional requirements of endurance athletes were recently presented by Burke et al. [6] and Maughan et al. [13]. In general, performance improvements and meeting nutrient requirements to optimize training demands and recovery are two major goals that persuade endurance runners to use supplements [6,13]. ...
... Comprehensive characteristics of supplements and the scenarios in which they contribute to nutritional requirements of endurance athletes were recently presented by Burke et al. [6] and Maughan et al. [13]. In general, performance improvements and meeting nutrient requirements to optimize training demands and recovery are two major goals that persuade endurance runners to use supplements [6,13]. In the present study, one out of two endurance runners consumed supplements regularly, which is lower compared to previous reports by other European [20,52,53], Canadian [54] and Japanese [19] studies on elite athletes. ...
The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences.
In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners ( n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis.
While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake ( p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %).
The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition.
Trial registration : ISRCTN73074080. Retrospectively registered 12th June 2015.
... VO 2peak ), the fraction of . VO 2peak that can be sustained for the event distance, and the oxygen (O 2 ) cost of movement (e.g., running/walking economy) [1][2][3][4][5]. Training and nutrition strategies for endurance performance aim to enhance various aspects of these characteristics [6], including ensuring that suitable substrates are able to fuel the event over its entire duration [4,7]. ...
... VO 2peak that can be sustained for the event distance, and the oxygen (O 2 ) cost of movement (e.g., running/walking economy) [1][2][3][4][5]. Training and nutrition strategies for endurance performance aim to enhance various aspects of these characteristics [6], including ensuring that suitable substrates are able to fuel the event over its entire duration [4,7]. The economy of running or walking represents the relationship between oxygen utilisation and speed of locomotion [8], with a higher economy (lower oxygen cost for a given speed) at event-specific speeds being a better predictor of performance among a group of subelite/elite runners than . ...
... Although contemporary sports nutrition guidelines for endurance performance already promote strategies to match CHO availability to the fuel demands of the event [7,33], it is worth considering whether further, even subtle, increases in CHO utilisation during the event might enhance economy in a meaningful way; either allowing the athlete to increase their speed for the same oxygen utilisation or reducing the oxygen and metabolic cost of a given speed. For example, according to our modelling [4], a 55 kg marathon runner with a sustainable . VO 2 of 3.75 L/min and energy cost of 180 mL/kg/km would achieve a sustainable marathon running speed of 20.83 km/hr, with a finishing time of 2:01: 33. ...
Given the importance of exercise economy to endurance performance, we implemented two strategies purported to reduce the oxygen cost of exercise within a 4 week training camp in 21 elite male race walkers. Fourteen athletes undertook a crossover investigation with beetroot juice (BRJ) or placebo (PLA) [2 d preload, 2 h pre-exercise + 35 min during exercise] during a 26 km race walking at speeds simulating competitive events. Separately, 19 athletes undertook a parallel group investigation of a multi-pronged strategy (MAX; n = 9) involving chronic (2 w high carbohydrate [CHO] diet + gut training) and acute (CHO loading + 90 g/h CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON; n = 10). There were no differences between BRJ and PLA trials for rates of CHO (p = 0.203) or fat (p = 0.818) oxidation or oxygen consumption (p = 0.090). Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, p < 0.001). High rates of exogenous CHO use were achieved prior to gut training, without further improvement, suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices. No differences in exercise economy were detected despite small differences in substrate use. Future studies should investigate the impact of these strategies on sub-elite athletes’ economy as well as the performance effects in elite groups.
... Nutritional planning is highly relevant in most competitions, especially in endurance sports such as cycling [6,14,39]. A wide range of ergogenic aids with a variety of flavours, shapes, and textures are currently available [40]. ...
... Finally, although energy bars can help during sporting events by slowing down the feeling of fatigue and improving performance [14,16], the organoleptic sensations they can provoke may allow the food to be accepted or rejected [18,56,57]. Indeed, the sensations generated by the texture and organoleptic characteristics of foods can vary a large amount from one person to another [58]. ...
In cycling, a wide range of ergogenic foods with a variety of flavours, shapes, and textures are available. The timing of their consumption and their correct oral processing can influence the performance of athletes. Furthermore, the differences in the texture of energy bars could result in differences in the chewing required. Nonetheless, research in this area is still scarce. The aim of this study was to analyse how the consumption of two energy bars with different textures (viscous versus hard) influenced the variables of oral processing, pedalling intensity, and the perception of satisfaction among cyclists. Ten cyclists performed two 15 min sections on a cycle ergometer at a moderate intensity (120–130 W) and consumed one of the two energy bars at random in each of the sections. The results showed that a shorter chewing duration and a fewer number of chews were required to consume the softer bar (p < 0.05, ES > 0.7). However, no differences among the cyclists were observed in the intensity of pedalling or perception of satisfaction. Nevertheless, participants were able to distinguish between the two different textures while pedalling. In conclusion, the texture of energy bars altered the oral processing of cyclists but did not affect pedalling intensity or perception of satisfaction.
... However, the increased effort in sustained training program and decreased recovery period trigger fatigue and limit performances. The new determinant of sports performance relied mostly on dietary supplements or energetic drink from plant extract to enhance exercise capacity and improve performance [4,5]. Interestingly, sports performers are orientated toward plant extracts, fatty and high carbohydrate diets as source of energy supply in replacement of identified substances that trigger excess release of catecholamine [6,7]. ...
... A recent study has shown an upsurge in the use of natural products in African countries to ameliorate sport performance and improve on the threshold of fatigue [5]. Fatigue is the complexity to commence and maintain a voluntary effort, characterise by the sensation of physical or mental tiredness and impotence, occurring after a prolong period of stress, sustained physical and mental activities [8,9]. ...
Ethnopharmacological relevance: Traditionally, Mimosa pudica Linn. (Fabaceae) is used for its anti-inflammatory, sedative, anxiolytic, antioxidant and antifatigue properties. Aim: To determine the antifatigue effects of Mimosa pudica aqueous extracts in experimental model of weight loaded force swimming test. Materials and methods: Mice were divided into seven groups and treated for 28 consecutive days as follows: groups one and two received orally distilled water (10 mL/kg) and served as normal group and negative control group, respectively. Groups three to six, (test groups) received orally graded doses of Mimosa pudica (20, 40, 80 and 160 mg/kg) and group seven (positive control) received vitamin C (50 mg/kg), respectively. One hour after the treatment, mice were subjected to the weight loaded force swimming test with tail load, except for the normal group; and the swimming duration, body weight, food and water intake were measured. Twenty-four hours after the last treatment the serum level of noradrenaline, dopamine and serotonin, and the relative organs weight were measured. Results: Mimosa pudica aqueous extracts significantly and dose-dependently increased the swimming duration and the weight of heart and lungs. The extracts did not induce a significant variation in the level of food and water intake, body weight, and serum of noradrenaline, dopamine and serotonin. Conclusion: Pretreatment of mice with Mimosa pudica aqueous extracts was observed to have better antifatigue properties mediated via amelioration of swimming capacity and physical aptitude in the weight loaded force swimming model.
... Nutritional strategies and dietary patterns may predict the nutrient requirements of athletes and play significant roles in the adaptations and performance of endurance runners [5,6]. While the consumption of high-carbohydrate meals has been recommended to endurance runners on pre-event days and hours within carbohydrate loading strategies as part tapering strategies, they are advised to avoid high-fat, high-protein, and high-fiber ...
... Nevertheless, while FFQs have been found to be a simple, fast, and low-cost assessment tool with a low burden on participants [46], reports indicate that the FFQ is the most proper survey method to assess the dietary intake of athletes [46,47]. Compared to sedentary people, athletes are shown to be at a higher risk of low energy supply, and this risk increases for athletes with unbalanced or inappropriately planned diets [5,48]. Given the importance of diet and nutritional supply in health and performance, dietary assessment is the first and most crucial step in any sports nutrition practice and is necessary for personalized nutritional strategies [45]. ...
While the popularity of distance running is growing worldwide, endurance runners’ dietary challenges associated with their prolonged training and racing activities have not yet been fully understood. The present investigation was conducted with the aim of examining the association between race distance and dietary intake of distance runners. A total of 317 runners initially participated, and after data clearance, 211 endurance runners (57% females) were finally considered the study sample. Runners were assigned to three race distance groups: 10-km (n = 74), half-marathon (n = 83), and marathon/ultra-marathon (n = 54). An online survey was used to collect data; dietary intake was monitored using a comprehensive food frequency questionnaire, including 53 food groups categorized in 14 basic and three umbrella clusters. There was no significant difference (p > 0.05) between race distance groups in consumption of most food clusters except for “fruits and vegetables” and “total of protein”, with a predominance of 10-km runners compared to half-marathoners and (ultra-)marathoners (p ≤ 0.05). Age was a significant predictor for the consumption of only five (out of 17) food clusters (p ≤ 0.05), including “fruit and vegetables”, “unprocessed meat”, “processed meat”, “eggs”, and “plant protein”. Future investigations with a larger sample size and more differentiated (sub)groups may help provide comparable data to develop a better understanding of the dietary behaviors among shorter versus longer distance runners.
... • As the additional cost of muscle fuel comes to cover the increased workload, there is consequently an increase in carbohydrate intake during altitude training. The athlete should be more consistent with refueling strategies during training as well as throughout the day [33][34][35]. ...
... This can lead to a significant increase in fluid losses at moderate altitudes relative to sea level. The athlete should take extra care to check his hydration status during the day and exercise sessions when moving at higher altitudes, as normal fluid intake patterns may need to be adjusted to keep up with these losses [34]. As movement and training at higher altitudes can increase oxidative damage during exercise, athletes should ensure that their diet is rich in fruits and vegetables to provide the body with the necessary antioxidants. ...
The main goal of this narrative review was to incorporate the recent scientific knowledge on the special nutritional needs that are necessary for specific populations of athletes and exercisers (e.g., children, females, vegans) under several training conditions and sports, in addition to proper recommendations for safe administration. The association between nutrition, exercise, and health is an essential part of athletes' and exercisers' competitive and training programs. The quality, quantity, composition, and timing of food consumption are significant to make sure that athletes could train more efficiently to decrease the risk of illness and injury. Athletes who deteriorate their energy intake or use uncontrolled weight loss practices, eliminate certain food groups from their diet, or follow other extreme nutritional philosophies, are at greater risk for micronutrient deficiencies. Fluid intake before, during, and after exercise training or/and competition is significant, particularly in specific circumstances such as hot climates, altitude, etc. Vegetarian and vegan athletes may be at higher risk for low energy, protein, fat, creatine, carnosine, omega-3 fatty acids, as well as essential micronutrients such as iron, calcium, riboflavin, zinc, and β12. Athletes should be adequately informed about the proper use of sports nutrition and ergogenic supplements. These products should only be used after careful evaluation for safety, efficacy, effectiveness, and compliance with relevant legislation. The most significant point to achieving complete and effective nutrition among travelling athletes is planning and preparation while eating properly and hydrated could decrease the potential adverse effects of jet lag and long flights. An effective, healthy, targeted, and complete diet among athletes of different sports should make available sufficient amounts of energy, protein, and carbohydrates depending on the specific sport to make certain sustained exercise training performance and to maintain and improve exercise performance.
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... Likewise, the nutritional demands of each of these phases will vary with the demands of the training sessions. As such, it has been suggested that nutrition periodization may be crucial in some sporting environments to help maximize adaptation 165,[197][198][199][200] . Macro-periodization refers to month-to-month nutritional strategies, whereas microperiodization refers to within-day or week nutrition. ...
... However, some suggested strategies that may be relevant over a wide range of sports include reducing the amount of fibrous foods within 1-2 h of training sessions to avoid gut disturbances, prioritizing appropriate carbohydrate and protein intake immediately following sessions, and incorporating snacks throughout a 24-h period to avoid the depletion of energy stores. 199,200 Finally, coaches must understand that body composition management should be undertaken only for elite-level athletes using scientifically sound approaches assisted by qualified professionals 94 (Figure 3). Indeed, losing weight is neither easy to achieve nor necessarily beneficial because of the compensation in resting metabolic rate, the detrimental effects of reduced carbohydrate on performance, and the loss of muscle mass. ...
The Female Athlete Triad (Triad) and the more encompassing Relative Energy Deficiency in Sport (RED-S) are disorders caused by low energy availability (LEA). LEA is a state of insufficient energy intake by an athlete relative to their energy expenditure. Persistent LEA results in the deleterious consequences to health and performance that comprise RED-S. With respect to both the Triad and RED-S, researchers have called for more education of those involved with sport, particularly coaches, to help reduce the incidence of these disorders. Recent studies have shown that as few as 15% of coaches are aware of the Triad, with up to 89% unable to identify even one of its symptoms. RED-S is a more recently established concept such that coach knowledge regarding it has only begun to be assessed, but the results of these initial studies indicate similar trends as for the Triad. In this review, we synthesize research findings from 1986 to 2021 that pertains to LEA and RED-S, which coaches should know so they can better guide their athletes.
... As a key modulator of training adaptations and racing performance, nutrition plays a critical role in endurance running success [19]. During the past decades, vegan (i.e., devoid of foods or ingredients from animal sources) and vegetarian diets (i.e., devoid of meat and flesh foods) are increasingly followed for various reasons, including health, performance, ethical, and environmental concerns [20][21][22][23]. ...
... However, no study has examined and compared training/racing profiles of vegan, vegetarian, and omnivorous endurance runners to date. Therefore, considering the importance of nutritional demands of endurance athletes in general, particularly of vegan/vegetarian athletes, and given the strong association between nutrition and running/racing behaviors [19], the present study was conducted to test the hypothesis whether vegan, vegetarian, and omnivorous endurance runners have different training and racing patterns. ...
As a key modulator of training adaptations and racing performance, nutrition plays a critical role in endurance runners’ success, and the training/racing behaviors of runners are potentially affected by their diet types. The present study aimed to investigate whether distance runners with a vegan diet (i.e., devoid of foods or ingredients from animal sources), vegetarian diet (i.e., devoid of meat and flesh foods), and omnivorous diet (i.e., a mixed diet with no restriction on food sources) have different training and racing patterns in general and based on race distance subgroups. A total of 3835 recreational runners completed an online survey. Runners were assigned to dietary (om-nivorous, vegetarian, and vegan) and race distance (<21 km, half-marathon, and mara-thon/ultra-marathon) groups. In addition to sociodemographic information, a complete profile of data sets focusing on running and racing behaviors/patterns was evaluated using a question-naire-based epidemiological approach. There were 1272 omnivores (47% females), 598 vegetarians (64% females), and 994 vegans (65% females). Compared to vegans and vegetarians, omnivorous runners prepared for a longer time period for running events, had a higher number of half-marathons and marathons completed with a better finish time, and had more reliance on training under supervision (p < 0.05). The present findings indicate an important association of diet types with patterns of training and racing amongst endurance runners that may be related to different motives of omnivorous, vegetarian, and vegan runners for participating in events.
... After the development of WADA, various rules and regulations have been formulated to curb the menace of Doping, amongst them is the WADA code [4] Various countries across the world have also established their own rules and regulations in accordance with the WADA Code to regulate doping. In South Africa, for example, the Current Approaches in Science and Technology Research Vol. 6 ...
... Distance Runners 8 South African Institute of Drug-Free Sport Act 14 of 1997 was enacted [4] Athletics as a sporting activity is an exclusive collection of sporting events that involve competitive running, jumping, throwing, and walking. Globally in the athletic arena Kenyan athletes are world-famous and it's through this success in medium and long distance running that athletic stars and champions have been created [5][6][7]. ...
... In prolonged strenuous exercise, such as in SOUT events, nutritional planning and suitable CHO intake during the event reduce fatigue time [18,19], and consequently, high CHO intake rates were significantly correlated with faster finishing times [20]. Moreover, although it seems there is no linear dose-response to CHO ingestion [21], an optimal CHO intake could maintain plasma glucose and CHO oxidation rates [22] and augment exercise performance via multiple mechanisms, consisting of muscle glycogen sparing [23], and liver glycogen sparing [24] deemed necessary for optimal sports performance [11,13,[25][26][27]. As such, different international nutrition societies recommend a 90 g/h intake of CHO in exercises of more than 3 h duration (with a combination of CHO that use different absorption transporters such as glucose or fructose) to improve athletic performance by gastric emptying, maximize their oxidation and reduce possible GI discomfort via suitable gut training [13,[26][27][28]. ...
... Thus, it has been demonstrated that it is possible to improve EIMD markers with an intake of 120 g CHO/h. The highest levels of these indicators (CK, LDH) usually appear after 24-72 h, requiring several days to return to reference values [24,25]. In the study by Viribay et al. [4] the blood markers of GOT, LDH, CK evidenced better values in the group that consumed 120 g CHO/h (HIGH) compared to groups with an intake of 90 or 60g CHO/h (CON and LOW respectively). ...
Due to the high metabolic and physical demands in single-stage one-day ultra-trail (SOUT) races, athletes should be properly prepared in both physical and nutritional aspects in order to delay fatigue and avoid associated difficulties. However, high carbohydrate (CHO) intake would seem to increase gastrointestinal (GI) problems. The main purpose of this systematic review was to evaluate CHO intake during SOUT events as well as its relationship with fatigue (in terms of internal exercise load, exercise-induced muscle damage (EIMD) and post-exercise recovery) and GI problems. A structured search was carried out in accordance with PRISMA guidelines in the following: Web of Science, Cochrane Library and Scopus databases up to 16 March 2021. After conducting the search and applying the inclusion/exclusion criteria, eight articles in total were included in this systematic review, in all of which CHO intake involved gels, energy bars and sports drinks. Two studies associated higher CHO consumption (120 g/h) with an improvement in internal exercise load. Likewise, these studies observed that SOUT runners whose intake was 120 g/h could benefit by limiting the EIMD observed by CK (creatine kinase), LDH (lactate dehydrogenase) and GOT (aspartate aminotransferase), and also improve recovery of high intensity running capacity 24 h after a trail marathon. In six studies, athletes had GI symptoms between 65–82%. In summary, most of the runners did not meet CHO intake standard recommendations for SOUT events (90 g/h), while athletes who consumed more CHO experienced a reduction in internal exercise load, limited EIMD and improvement in post-exercise recovery. Conversely, the GI symptoms were recurrent in SOUT athletes depending on altitude, environmental conditions and running speed. Therefore, a high CHO intake during SOUT events is important to delay fatigue and avoid GI complications, and to ensure high intake, it is necessary to implement intestinal training protocols.
... Gastrointestinal symptomology can be affected by a plethora of nutritional factors; therefore, runners with IBS/IBD and reflux may adhere to stricter diets in an attempt to avoid exacerbated GIS. The most commonly avoided foods were milk products, high-protein, and high-fibre foods, all of which align with the recommendations to limit consumption of protein, fat, and fibre before exercise [22,36,37]. ...
... Prior to our research, it has been reported that endurance runners limit dietary fibre intake [41,42] albeit not specifically pre-exercise. Low-fibre intake prior to exercise is recommended [22,36] based on evidence of dietary fibre causing intestinal cramps [43]. Importantly, different types of fibre have a variety of actions on the gut including regulating gastrointestinal transit time and glucose homeostasis [44]. ...
Individuals with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and reflux frequently experience gastrointestinal symptoms (GIS), potentially enhanced by high-intensity running. Food avoidances, food choices, and GIS in runners with IBS/IBD (n = 53) and reflux (n = 37) were evaluated using a reliability and validity tested questionnaire. Comparisons to a control group of runners (n = 375) were made using a Fisher’s Exact test. Runners with IBS/IBD experienced the greatest amount of exercise-induced GIS followed by those with reflux. Commonly reported GIS were stomach pain/cramps (77%; 53%), bloating (52%; 50%), intestinal pain/cramps (58%; 33%), and diarrhea (58%; 39%) in IBS/IBD and reflux groups respectively. In the pre-race meal, those with IBS/IBD frequently avoided milk products (53%), legumes (37%), and meat (31%); whereas, runners with reflux avoided milk (38%), meat (36%), and high-fibre foods (33%). When considering food choices pre-race, runners with IBS/IBD chose grains containing gluten (40%), high fermentable oligo-, di-, mono-saccharides and polyols (FODMAP) fruits (38%), and water (38%). Runners with reflux chose water (51%), grains containing gluten (37%), and eggs (31%). In conclusion, while many runners with IBS/IBD and reflux are avoiding trigger foods in their pre-race meals, they are also consuming potentially aggravating foods, suggesting nutrition advice may be warranted.
... After the development of WADA, various rules and regulations have been formulated to curb the menace of Doping, amongst them is the WADA code [4] Various countries across the world have also established their own rules and regulations in accordance with the WADA Code to regulate doping. In South Africa, for example, the Current Approaches in Science and Technology Research Vol. 6 ...
... Distance Runners 8 South African Institute of Drug-Free Sport Act 14 of 1997 was enacted [4] Athletics as a sporting activity is an exclusive collection of sporting events that involve competitive running, jumping, throwing, and walking. Globally in the athletic arena Kenyan athletes are world-famous and it's through this success in medium and long distance running that athletic stars and champions have been created [5][6][7]. ...
Research has demonstrated that elite athletes use supplements to enhance performance. The purpose of the study was to assess the current practices on the use of banned substances among elite athletes. The study hypothesised that there would be no significant difference in the use of supplements by Kenyan elite middle and long distance runners. This study was guided by the descriptive survey research design. The target population comprised of 1960 elite athletes registered with Athletics Kenya (AK), coaches and managers. Stratified sampling technique gave 600 participants based on age and gender. Data was collected using a questionnaire that featured WADA Code 2011. ANOVA and Independent T-test determined statistical significance level at p< 0.05.
Results revealed no statistically significant difference in the use of supplements by Kenyan elite distance athletes. This study recommends further research regarding experience, gender and current practices of banned substances among elite middle and long distance athletes.
Keywords: Elite, Performance, Practices, Supplements, Substances
... Snacks included in the daily diet plan facilitate exercise needs and any usual doses of insulin. It is essential to assess blood glucose through continuous glucose monitoring (CGM) [64], which is necessary to optimize possible dietary changes throughout physical activity, especially in insulin-treated patients. A technique used by athletes to increase the sources of glycogen ...
... Snacks included in the daily diet plan facilitate exercise needs and any usual doses of insulin. It is essential to assess blood glucose through continuous glucose monitoring (CGM) [64], which is necessary to optimize possible dietary changes throughout physical activity, especially in insulin-treated patients. A technique used by athletes to increase the sources of glycogen in case of long-term sporting events is a GL [65]. ...
Diabetes is a worldwide disease also affecting the sports field. The two main forms of diabetes, namely type 1 diabetes (T1D) and type 2 diabetes (T2D), differ in both their pathological and pharmacological characteristics and thus require a distinct nutritional treatment. Diet plays an important role in the management of athletes with diabetes and is crucial to achieving their best performance. This review aims to investigate the objectives of nutritional therapy before, during and after training, in order to improve the best composition of macronutrients during meals. In this review, we provide a brief overview of recent studies about nutritional approaches to people with diabetes for performance optimization and for the control of diabetes-related complications. Thereafter, we discuss the differences between macronutrients and dietary intake before, during and after training. It can be concluded that each sport has particular characteristics in terms of endurance and power, hence demanding a specific energy expenditure and consequent nutritional adjustments. Therefore, the management of athletes with diabetes must be personalized and supported by medical professionals, including a diabetologist, physiologist and a nutritionist.
... Traditional physiological factors that have been proposed to exert an important influence in this regard include the runner's maximal oxygen (O 2 ) uptake (V _ O 2max ), the fraction of the V _ O 2max that can be sustained during the marathon which is, in turn, related to the lactate threshold (LT) or critical speed (CS), and the O 2 cost of submaximal running (i.e., running economy in units of milliliter of O 2 /kg/km), (2,4,5). Other important "external" factors include the course profile, environmental conditions (altitude, ambient temperature, relative humidity, and wind speed), pacing strategy, drafting, pre-and in-race nutrition, and footwear and apparel (1,(6)(7)(8). ...
... To this end, events to date targeting the 2-h marathon have made great efforts both to minimize O 2 cost and to protect against its deterioration over time. This has included strategies designed to: maintain the rate of carbohydrate oxidation and therefore keep RER high and V _ O 2 low via regular carbohydrate ingestion (6,62); minimize air resistance and therefore O 2 cost by drafting behind a rotating shield of human pacemakers (11); enable a relatively even pace with minimal changes of course direction or elevation and therefore energy demand (64); and minimize athlete energy loss to the ground via running shoe innovations (8). In this light, it is important to recognize that numerous factors, over and above extraordinary athlete physiology, must conflate to enable the achievement of a sub 2-h marathon. ...
The requirements of running a 2 hour marathon have been extensively debated but the actual physiological demands of running at ~21.1 km/h have never been reported. We therefore conducted laboratory-based physiological evaluations and measured running economy (O2 cost) while running outdoors at ~21.1 km/h, in world-class distance runners as part of Nike's 'Breaking 2' marathon project. On separate days, 16 male distance runners (age, 29 ± 4 years; height, 1.72 ± 0.04 m; mass, 58.9 ± 3.3 kg) completed an incremental treadmill test for the assessment of V̇O2peak, O2 cost of submaximal running, lactate threshold and lactate turn-point, and a track test during which they ran continuously at 21.1 km/h. The laboratory-determined V̇O2peak was 71.0 ± 5.7 ml/kg/min with lactate threshold and lactate turn-point occurring at 18.9 ± 0.4 and 20.2 ± 0.6 km/h, corresponding to 83 ± 5 % and 92 ± 3 % V̇O2peak, respectively. Seven athletes were able to attain a steady-state V̇O2 when running outdoors at 21.1 km/h. The mean O2 cost for these athletes was 191 ± 19 ml/kg/km such that running at 21.1 km/h required an absolute V̇O2 of ~4.0 L/min and represented 94 ± 3 % V̇O2peak. We report novel data on the O2 cost of running outdoors at 21.1 km/h, which enables better modelling of possible marathon performances by elite athletes. Using the value for O2 cost measured in this study, a sub-2 hour marathon would require a 59 kg runner to sustain a V̇O2 of approximately 4.0 L/min or 67 ml/kg/min.
... This might explain the divergence of opinions found in our study. For example, distance runners, who are highly advised to include strategies to store muscle glycogen prior to the race [28], considered the stage of competition more important than throwers, who do not depend considerably on these nutritional strategies. Our data revealed that middle-distance runners considered protein to be a more important macronutrient compared with sprinters. ...
In competitive events, athletes’ performances can be affected by their food choices. In addition, nutrition labels are essential to sustain informed decisions and to allow athletes to comply with their dietary planning. Knowing what influences athletes’ food choices will help to improve the food provision in future championships. Therefore, we aimed to study the factors influencing athletes’ choices, their knowledge on nutrition labels, and their opinion on the food service at two European Athletics Championships. Questionnaires were completed by 339 athletes (57% males, 19.6 ± 1.3 years) competing at the 2019 European Athletics Under 20 and Under 23 Championships. Factors that may impact performance (time of the day and nutrient composition) were rated as important and very important by a higher percentage of athletes (78% and 74%, respectively) compared to the presence of teammates (32%) and the coach (23%). Among the athletes who knew what nutrition labels are (49%), 72% would like to have additional nutritional information in future championships. Furthermore, our study revealed that for most athletes (72%), food temperature is important or very important for food choices. Overall, food provision had positive results, but further research is needed to help organizers better tailor food provision to athletes’ needs.
... The results obtained showed a greater use of SS on competition days as compared to the rest of the options (81.9 %), regardless of gender or level of competition. This may be due to the importance of the availability/use of energy substrates and hydration during competition in this type of competitions, as well as the possibility and variety of existing SS for it, since its alternated consumption is very useful for complying with the carbohydrate, sodium and fluid intake recommendations during competition (7,19,28). Proof of this is observed when verifying that sport bars (81.9 %) and sport drinks (75.0 %) were the two most commonly consumed SS by the study sample. Both supplements are important for hydration and nutrient replenishment during competitions, for providing energy and nutrients or seeking to counteract the high sweating rates generated by climatic conditions in this type of event (29). ...
Introduction:
sports supplements (SS) are widely used by all types of athletes to improve their performance. These SS are classified according to the ABCD system of the Australian Institute of Sports (AIS) from higher to lower scientific evidence. In mountain runners, their use could be necessary due to the physiological demands required by this sport. However, the literature on the use of SS by mountain runners is scarce.
Objective:
to analyze the pattern of SS consumption in mountain runners by studying differences according to sex and competitive level (regional vs national).
Methodology:
this was a descriptive and cross-sectional study on the consumption and use of SS by mountain runners participating in the Alcoy Solidarity Trail. Data were collected through a validated questionnaire based on content, applicability, structure, and presentation. This questionnaire was completed online by the athletes, who could fill it out voluntarily and at their convenience, as well as anonymously.
Results:
the results showed that 87.5 % of participants reported consuming SS, with no significant differences observed with respect to competitive level, although differences were found with respect to sex (92.7 % in men vs 70.6 % in women; p = 0.029), with a higher consumption found in men compared to women. The most consumed SS were sports bars (81.9 %), sports drinks (75.0 %), caffeine (48.6 %), magnesium (38.9 %), and electrolytes (27.8 %).
Conclusions:
among mountain runners consumption of SS is high, and 4 of the 5 most habitually consumed SS belong in the category of greater scientific evidence.
... A low dietary fiber diet (<10 g/d) can reduce fecal matter and gastrointestinal secretions and thereby extend gastrointestinal tract transit time (40). However, due to variable gastrointestinal tract transit times, a low-fiber diet may require implementation 1-3 days before exercise (41), which may not be practical habitually. Furthermore, adult women and men are recommended to consume 25-30 g/d of dietary fiber to ensure proper gastrointestinal tract function and reduce the risk of several chronic diseases, including diabetes, heart disease, and certain cancers (42). ...
This exploratory study investigated endurance athletes self-reported exercise-associated gastrointestinal symptoms (Ex-GIS) and associated strategies to manage symptomology. Adult endurance athletes with a history of Ex-GIS (n = 137) participating in events ≥ 60 min completed an online validated questionnaire. Respondents included runners (55%, n = 75), triathletes (22%, n = 30), and non-running sports (23%, n = 32), participating at a recreationally competitive (37%, n = 51), recreationally non-competitive (32%, n = 44), and competitive regional/national/international (31%, n = 42) levels. Athletes identified when Ex-GIS developed most frequently either around training (AT), around competitions (AC), or equally around both training (ET) and competitions (EC). Athletes reported the severity of each symptom before, during, and after exercise. Athletes predominantly categorized Ex-GIS severity as mild (< 5/10) on a 0 (no symptoms) to 10 (extremely severe symptoms) visual analog symptomology scale. The Friedman test and post hoc analysis with Wilcoxon signed rank test was conducted with a Bonferroni correction applied to determine differences between repeated measures. The only severe symptom of significance was the urge to defecate during training in the ET group (Z = –0.536, p = 0.01). Ex-GIS incidence was significantly higher during training and competitions in all categories. A content review of self-reported strategies (n = 277) to reduce Ex-GIS indicated popular dietary strategies were dietary fiber reduction (15.2%, n = 42), dairy avoidance (5.8%, n = 16), and a low fermentable oligosaccharides, monosaccharides, and polyols (FODMAP) diet (5.4%, n = 15). In contrast, non-dietary strategies included the use of medications (4.7%, n = 13) and relaxation/meditation (4.0%, n = 11). On a Likert scale of 1–5, the most successful dietary strategies implemented were dietary fiber reduction (median = 4, IQR = 4, 5), low FODMAP diets (median = 4, IQR = 4, 5), dairy-free diets (median = 4, IQR = 4, 5), and increasing carbohydrates (median = 4, IQR = 3, 4). Accredited practicing dietitians were rated as the most important sources of information for Ex-GIS management (n = 29). Endurance athletes use a variety of strategies to manage their Ex-GIS, with dietary manipulation being the most common.
... The approach developed in this narrative review can be applied to a broad spectrum of endurance disciplines. Most endurance events or competitions are developed at intensities > GET/LT (moderate or highintensity domain) [79,[103][104][105] and executed at a steady constant speed. For instance, in middle and longdistance events, the best results for running [106,107] and cycling [79,104,108] were characterized by a pacing strategy with minor changes in speed or power. ...
Endurance training results in diverse adaptations that lead to increased performance and health benefits. A commonly measured training response is the analysis of oxygen uptake kinetics, representing the demand of a determined load (speed/work) on the cardiovascular, respiratory, and metabolic systems, providing useful information for the prescription of constant load or interval-type aerobic exercise. There is evidence that during high-intensity aerobic exercise some interventions prescribe brief interval times (<1-min), which may lead to a dissociation between the load prescribed and the oxygen uptake demanded, potentially affecting training outcomes. Therefore, this review explored the time to achieve a close association between the speed/work prescribed and the oxygen uptake demanded after the onset of high-intensity aerobic exercise. The evidence assessed revealed that at least 80% of the oxygen uptake amplitude is reached when phase II of oxygen uptake kinetics is completed (1-2 minutes after the onset of exercise, depending on the training status). We propose that the minimum work-time during high-intensity aerobic interval training sessions should be at least 1 minute for athletes and 2 minutes for non-athletes. This suggestion could be used by coaches, physical trainers, clinicians, and sports or health scientists for the prescription of high-intensity aerobic interval training
... It has been reported that the FFQ is considered the most appropriate survey method to evaluate the dietary intake of athletic populations [51,52]. Athletes, particularly those with unbalanced and/or restrictive diets, are at a higher risk of low energy availability compared to sedentary people [17,53]. In line with the importance of diet regarding health and performance, assessing/monitoring dietary intake is the first and most important step in sports nutrition practice and any personalized sports nutrition counseling [50]. ...
Nowadays, the growing popularity of distance running has been accompanied by the increasing prevalence of vegan and vegetarian diets, especially among endurance athletes. The present study aimed to examine the association between diet type and dietary intake of distance runners competing at distances longer than 10 km. From a total of 317 participants, 211 endurance runners (57% females) were considered the final sample after applying the exclusion criteria. Runners were assigned to three groups based on the self-reported diet types: 95 omnivores, 40 vegetarians, and 76 vegans. Data collection was conducted using an online survey with questions about sociodemographic information, dietary intake, and dietary-associated motives. A comprehensive food frequency questionnaire with 53 food groups (categorized in 14 basic—plus three umbrella—food clusters) was used to assess dietary intake. Vegan runners had a higher intake of “beans and seeds”, “fruit and vegetables”, and “dairy alternatives”, as well as lower intakes of “oils” than other two groups. Vegetarian runners had a lower intake of “dairy products” and “eggs” than omnivores. A greater intake of “alcohol” and a lower intake of “meat alternatives” was observed in omnivorous runners compared to vegans and vegetarians. Despite the existence of a tendency toward the consumption of health-related food clusters by vegan runners, further investigations are needed to verify the predominance of vegans in health-oriented dietary patterns.
... It is well-established that the nutritional requirements of athletes are potentially affected by physical and physiological differences between males and females [2,3]. These sex-based differences seem to be more predominant in ultra-endurance athletes who are recommended to pay superior attention to their specific nutritional needs due to the prolonged training/racing activities [4,5]. ...
Sex has been recognized to be an important indicator of physiological, psychological, and nutritional characteristics among endurance athletes. However, there are limited data addressing sex-based differences in dietary behaviors of distance runners. The aim of the present study is to explore the sex-specific differences in dietary intake of female and male distance runners competing at >10-km distances. From the initial number of 317 participants, 211 endurance runners (121 females and 90 males) were selected as the final sample after a multi-level data clearance. Participants were classified to race distance (10-km, half-marathon, marathon/ultra-marathon) and type of diet (omnivorous, vegetarian, vegan) subgroups. An online survey was conducted to collect data on sociodemographic information and dietary intake (using a comprehensive food frequency questionnaire with 53 food groups categorized in 14 basic and three umbrella food clusters). Compared to male runners, female runners had a significantly greater intake in four food clusters, including “beans and seeds”, “fruit and vegetables”, “dairy alternatives”, and “water”. Males reported higher intakes of seven food clusters, including “meat”, “fish”, “eggs”, “oils”, “grains”, “alcohol”, and “processed foods”. Generally, it can be suggested that female runners have a tendency to consume healthier foods than males. The predominance of females with healthy dietary behavior can be potentially linked to the well-known differences between females and males in health attitudes and lifestyle patterns.
... Analysis of the diaries were performed by two experienced dietitians via the Food Processor Program (version 7.4,ESHA Research Salem,Oregon), with the inclusion of national-traditional foods. Macro-nutrient intakes were controlled according to the guidelines-recommendations for endurance/marathon athletes (Burke et al. 2019). The intraclass correlation coefficient (ICC) ranged from 0.850 to 0.901 (95% CI: ...
Background/objective:
Aetiology and significance of exercise-induced troponin release remains a contentious issue. We investigated the effect of a 28 km mountain run on cardiac troponin I (cTnI), in relation to training, performance, nutritional, biochemical and echocardiography variables, in a group of 25 recreational male master athletes.
Material and methods:
A comprehensive list of variables related with nutrition, training, performance and echocardiography, was collected pre- and post-race. Twenty-four months later, outcomes regarding cardiovascular events were obtained.
Results:
Serum cTnI values were increased after the race, with mean values rising from 7.2 ± 2.2 (before) to 80.0 ± 33.2 ng/L (post race), (p < 0.001) and 23/25(92%) exceeding Upper Reference limit (50 ng/L). Echocardiography did not reveal significant alterations, or correlations with cTnI values. The percentage difference in hs-cTnI concentrations pre- and post-race correlated positively with age, race-induced changes of selected muscle damage indices, resistance training volume and negatively with endurance capacity and training volume (r: -0.727 to 0.725, p < 0.05). All athletes reported no cardiovascular event during the 24-month period post-race.
Conclusion:
cTnI elevation induced by a 28 km mountain running race was not correlated with echocardiographic, nutritional parameters and was less pronounced in athletes with larger endurance training history, in contrast with resistance training and age.
... However, there are also scenarios, often found in high-performance sports, in which predictions or experiences confirm the likelihood of accruing a large fluid deficit and suggest that the athlete would benefit from a deliberate and personalized plan to increase fluid intake. Real-world examples include the high prevalence (93%) of self-reported use of personalized experience-based fluid plans by elite distance runners and race walkers during the extreme heat experienced at the 2019 Doha World Athletics Championships (Racinais et al., 2021); implementation of an increased frequency of aid stations (from every 5 to 2.5 km) by organizers of some elite marathon events to facilitate in-race nutrition support towards faster finishing times (Burke, Jeukendrup, et al., 2019) and the strategy of unhampered access to nutrition support (feeds provided by an accompanying bike rider) during the 2019 successful bid to break the 2 h marathon (albeit unrecognized as an official world record due to the non-adherence to World Athletics race rules) (Burgess, 2019). This model of a unified approach to fluid intake during sports competition should enable sports scientists, coaches and athletes to learn from published data and personal experience to identify the scenarios in which their events might require different -for example, ad hoc or planned -approaches to hydration. ...
New findings:
What is the topic of this review? The nutritional strategies that athletes use during competition events to optimize performance and the reasons they use them. What advances does it highlight? 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 optimize 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 their effect on sports performance and the best guidance around hydration for sporting events. A unifying model proposes that some scenarios require personalized fluid plans while others might be managed by an ad hoc approach (ad libitum or thirst-driven drinking) to fluid intake.
... Notwithstanding these specialised training needs, the increased requirement for protein, possibly requiring individual prescription, is also evident by the later stages of BMT (Chapman et al. 2020). Thus, these optimal provisions of macronutrients, carbohydrate and protein is ubiquitous to all forms of training adaptation and performance (Burke et al. 2019), be it athletics or military (Lutz et al. 2019). Yet, often overlooked is the potential of fatty acids as a dietary opportunity to enhance health and performance, beyond simplistically restricting saturated fatty acids. ...
This study described the whole blood fatty acid profile and Omega-3 Index (O3I) of Australian Army recruits at the commencement and completion of basic military training (BMT). Eighty males (17–34 y, 77.4 ± 13.0 kg, 43.5 ± 4.3 mL/kg/min) and 37 females (17–45 y, 64.3 ± 8.8 kg, 39.3 ± 2.7 mL/kg/min) volunteered to participate (N = 117). Whole blood samples of each recruit were collected using a finger prick in weeks 1 and 11 (n = 82) and analysed via gas chromatography for the relative proportions of each fatty acid (mean [95% confidence interval]). The macronutrient characteristics of the diet offerings was also determined. At commencement there was a low omega-3 status (sum of omega-3; 4.95% [4.82–5.07]) and O3I (5.03% [4.90–5.16]) and no recruit recorded an O3I >8% (desirable). The omega-6/omega-3 (7.04 [6.85–7.23]) and arachidonic acid/eicosapentaenoic acid (AA/EPA) (18.70 [17.86–19.53]) ratios for the cohort were also undesirable. The BMT mess menu provided a maximum of 190 mg/day of EPA and 260 mg/day of docosahexaenoic acid (DHA). The O3I of the recruits was lower by week 11 (4.62% [4.51–4.78], p < 0.05), the omega-6/omega-3 increased (7.27 [7.07–7.47], p < 0.05) and the AA/EPA remained elevated (17.85 [16.89–18.81]). In conclusion, Australian Army recruits’ omega-3 status remained undesirable during BMT and deserves nutritional attention.
Novelty: Australian Army recruits’ Omega-3 Index, at the commencement of BMT, was reflective of the Western-style diet. The BMT diet offered minimum opportunity for daily EPA and DHA consumption. Every recruit experienced a further reduction of their Omega-3 Index during BMT.
... When extrapolating effort from this time trial relative to VO 2 peak effort from each subject, the time trial mean HR corresponds with the mean HR equivalent observed at 80.2 ± 0.1% of the VO 2 peak of the subjects, as determined during the familiarization visit. This effort reflects the expected oxygen uptake estimates of 75-92% VO 2 peak for distance running, with top competitors functioning ≥90% VO 2 peak [44]. This result indicates that 4 weeks of adherence to a TRF diet had neutral effects on performance for a 10 km distance event. ...
Background:
Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, but there is insufficient data regarding its effects on performance and metabolism in this population. The purpose of this investigation was to examine the effects of a 16/8 TRF dietary pattern on exercise performance in trained male endurance runners.
Methods:
A 4-week randomized crossover intervention was used to compare an 8-h TRF to a 12-h normal diet (ND) feeding window. Exercise training and dietary intake were similar across interventions. Runners completed a dual-energy X-ray absorptiometry (DXA) scan to assess body composition, a graded treadmill running test to assess substrate utilization, and ran a 10 km time trial to assess performance.
Results:
There was a significant decrease in fat mass in the TRF intervention (-0.8 ± 1.3 kg with TRF (p = 0.05), vs. +0.1 ± 4.3 kg with ND), with no significant change in fat-free mass. Exercise carbon dioxide production (VCO2) and blood lactate concentration were significantly lower with the TRF intervention (p ≤ 0.02). No significant changes were seen in exercise respiratory exchange ratio or 10 km time trial performance (-00:20 ± 3:34 min:s TRF vs. -00:36 ± 2:57 min:s ND).
Conclusion:
This investigation demonstrated that adherence to a 4-week 16/8 TRF dietary intervention decreased fat mass and maintained fat-free mass, while not affecting running performance, in trained male endurance runners.
... Recent scientific advancements in sex-specific differences as well as an understanding of endurance athletes' nutritional requirements have led to a remarkable progression of female endurance runners (4%) than males (1.8%) in the world records from 1985 to 2004 [5]. While the importance of sex-specific nutritional strategies is emphasized by the literature, insufficient nutrient intake in athletes may result in detrimental effects in health, performance, and adaptations [6], particularly in female and male athletes with long-term involvement in training and racing activities [7]. ...
It has been well-documented that female and male athletes differ in many physiological and psychological characteristics related to endurance performance. This sex-based difference appears to be associated with their nutritional demands including the patterns of supplement intake. However, there is a paucity of research addressing the sex differences in supplement intake amongst distance runners. The present study aimed to investigate and compare supplement intake between female and male distance runners (10 km, half-marathon, (ultra-)marathon) and the po-tential associations with diet type and race distance. A total of 317 runners participated in an online survey, and 220 distance runners (127 females and 93 males) made up the final sample after a multi-stage data clearance. Participants were also assigned to dietary (omnivorous, vegetarian, vegan) and race distance (10-km, half-marathon, marathon/ultra-marathon) subgroups. Socio-demographic characteristics and the patterns of supplement intake including type, frequency, dosage, and brands were collected using a questionnaire. One-way ANOVA and logistic regression were used for data analysis. A total of 54.3% of female runners and 47.3% male runners reported consuming supplements regularly. The frequency of supplement intake was similar between females and males (generally or across dietary and distance subgroups). There was no significant relationship for sex alone or sex interactions with diet type and race distance on supplement intake (p < 0.05). However, a non-significant higher intake of vitamin and mineral (but not CHO/protein) supplements was reported by vegan and vegetarian (but not by omnivorous) females compared to their male counterparts. In summary, despite the reported findings, sex could not be considered as a strong modulator of supplement intake among different groups of endurance runners.
... Pre and post-ride CHO intake were also substantially below suggested ranges, further compromising performance during races or 'key' sessions. Whilst shorter sessions may not benefit from pre-exercise CHO, sessions lasting >/=60 minutes benefit from replenishing liver glycogen stores following overnight fasts or periods between meals [28,29]. Therefore, the target of consuming 1-4 g.kg -1 in the 1-4 hours prior to exercise is broad, and we speculate this may cause some confusion as to specific, individualised approaches needed for different athletes and sessions. ...
Cycling is a sport characterised by high training load and adequate nutrition is essential for training and race performance. With increased popularity of indoor trainers, cyclists have a unique opportunity to practice and implement key nutritional strategies. This study aimed to assess carbohydrate intake and nutrition knowledge of cyclists training or racing in this unique scenario for optimising exercise nutrition. A mixed-methods approach consisting of a multiple-pass self-report food recall and questionnaire was used to determine total carbohydrate intake pre, during and post training or racing using a stationary trainer and compared to current guidelines for endurance exercise. Sub-analyses were also made for higher ability cyclists (>4.W.kg ⁻¹ functional threshold power), races vs. non-races and ‘key’ training sessions. Mean CHO intake pre and post ride was 0.7±0.6 and 1.0±0.8 g.kgBM ⁻¹ and 39.3±27.5 g.h ⁻¹ during. Carbohydrate intake was not different for races (pre/during/post, p=0.31, 0.23, 0.18 respectively), ‘key sessions’ (p=0.26, 0.89, 0.98), or higher ability cyclists (p=0.26, 0.76, 0.45). The total proportion of cyclists who failed to meet CHO recommendations was higher than those who met guidelines (pre=79%, during=86%, post=89%). Cyclists training or racing indoors do not meet current CHO recommendations for cycling performance. Due to the short and frequently high-intensity nature of some sessions, opportunity for during exercise feeding may be limited or unnecessary.
... The exercise intensity equivalent to 76% ofVO 2peak employed during the 25 km hybrid walk test in this study aligns closely with intensity sustained during a 50 km race. Similarly, stage 3 of the submaximal progressive test was performed at 84%VO 2peak exercise intensity, equivalent to 20 km race intensity (Burke, Jeukendrup, Jones, & Mooses, 2019). Our 25 km hybrid walk protocol was designed to be challenging for the walkers without needing to complete the full 50 km. ...
Race walkers must conform to a unique gait pattern with no visible loss of contact with the ground. However, how the gait pattern affects race walking economy is unclear. We investigated the energy cost (amount of energy spent per distance unit) at different race walking velocities and over a 25 km hybrid walk. Twenty-one international-level male race walkers ( O2peak 63.8 ± 4.3 ml·kg-1·min-1, age 31 ± 5 y, body mass 68.1 ± 7.0 kg) performed an incremental treadmill test consisting of 4x4 min submaximal stages with 1 km·h-1 increments, and a 25 km submaximal hybrid walk (treadmill-overground) on separate days. Energy cost was measured continuously during the submaximal test and at km 0-1, 6-7, 12-13, 18-19, 23-24 of the 25 km hybrid walk. The CRW was similar across the 4 submaximal stages where half the athletes completed them at a higher (1 km.h-1) absolute velocity (-0.01 to 0.15 0.65; range of standardised differences 90% CL, with a tendency for higher performing athletes to have a lower CRW when this was analysed during absolute race walking velocities of 12, 13, and 14 km.-1 for the entire cohort (0.46 to 0.49 0.67). There was no substantial change in CRW from the start to the end of the 25 km walk for the entire cohort (0.08 2.2; standardised change 90% CL). Elite race walkers are characterised by having a similar energy cost among athletes who perform at the same relative exercise intensity, and substantially higher energetics than counterpart elite endurance runners.
... However, personalized drinking strategies depend importantly on an athlete's personal goals, as well as the rules and conventions of a particular sport which dictate the availability of fluid and fuel in competition. [12][13][14][15][16][17] The provision of fuel 18 interacts with required drink volumes in important ways that are infrequently discussed but are of utmost practical concern. This review details some challenges related to the optimized coupling of fluid and fuel needs during prolonged exercise in the heat and the need for personalization. ...
It is well appreciated that a loss of body water (dehydration) can impair endurance performance and that the effect is magnified by environmental heat stress. A majority of professional sports medicine and nutrition organizations recommend drinking during exercise to replace sweat losses and prevent dehydration, while also avoiding frank over-hydration. Knowledge of sweating rate, which is highest in the heat for any given metabolic rate, is therefore considered key to developing a sound drinking strategy. Exercise duration and the provision of liquid fuel interacts with required drink volumes in important ways that are infrequently discussed but are of utmost practical concern. This review details some challenges related to the optimized coupling of fluid and fuel needs during prolonged exercise in the heat and the need for personalization.
... En la actualidad, con un entrenamiento adecuado del estómago se pueden oxidar al menos 90 g/h y digerir al menos 120 g/h de HC (6). Algunas revisiones bibliográficas (7) y metaanálisis (8) han encontrado que un elevado consumo de HC promueve un mejor rendimiento en eventos como la maratón y los 50 km marcha, con ingestas óptimas de 75-90 g/h (9). Recientemente, el trabajo de Viribay y cols. ...
Introduction:
there has been an increase in the number of endurance sports events during the last 20 years, as well as in the number of their participants. An adequate nutritional plan is essential for a satisfactory performance in this type of events, both in professional and amateur athletes.
Objectives:
the objective was to determine, evaluate, and compare with the current scientific recommendations the consumption of carbohydrates, water, and sodium by participants in a trail-running event.
Methods:
the competition completed by the athletes was the "Medio Trail de Alcoy 2019" (Alcoy, Spain), with a distance of 30 km. After completing the race, participants filled out a questionnaire about their food and drink consumption during the event, in addition to other questions about their nutritional habits in general. Eleven participants who met the inclusion criteria were included in the study.
Results:
the result obtained for average carbohydrate intake was 14.93 g/h, for sodium intake was 146.42 mg/h, and for water intake was 399.73 mL/h. In all, 27 % of participants visited a dietitian-nutritionist on a regular basis, and none reported gastrointestinal tract issues during the race.
Conclusions:
the carbohydrate and sodium consumption of participants was low as compared to current scientific recommendations; however, water consumption was adequate according to them. Our advice for endurance athletes is visit a specialized dietitian-nutritionist to achieve optimal performance in competitions.
... In the modern sports system, the second option of measures has recently become more acceptable (Vorobyeva et al., 2011;Jeukendrup, 2017). Many authors analysing the change in athletes' physical abilities suggest that the relationship between the quality of an athlete's health nutrition and his or her athletic excellence is very close, as a rational diet is the basis for good functioning of all body organs and systems (Rozenblium, 2006;Vorobyeva et al.., 2011;Stellingwerff et al., 2011;Burke et al., 2019). If the diet of athletes meets the physiological needs of the body, then it will help maintain health, increase work capacity, and promote recovery after exercising (Jeukendrup & Gleeson, 2010;Turner, 2018). ...
The aim of the study was to investigate the effect of high energy diets, which were elaborated by the study authors, on the change of physical fitness of athletes of various sports. 90 athletes aged 17–30 years participated in the research. They were divided into three groups of 30 each. Our research has shown that prepared high-energy diets, used during 3 months in the preparatory period, per week-long training microcycles, had a greater positive effect on changes in the fitness of elite athletes of various sports compared to changes in the fitness of lower-performance athletes.
Endurance athletes are defined as those who take part in competitive events and workouts that last more than 30 minutes. The high physical demand in this type of event, as well as the possibility that any small gain obtained may provide a real improvement in sports performance, encourages athletes to consider the use of various tools and/or strategies, among which we find the use of sports supplements. Sports supplements are defined as a food, food component, nutrient, or non-food compound that is purposefully ingested in addition to the habitually consumed diet, to obtain a specific health and/or performance benefit. It is important to know and compare the benefits of consuming sports supplements in specific sports situations using evidence-based protocols. As part of dietary-nutritional planning for training and competition, a nutritional chronology should be established for ingesting food, liquids and/or sports supplements for each hour of physical exercise, considering the sports equipment of the athlete, characteristics of the training or competition, and nutritional needs. This chapter describes potentially beneficial sports supplements for endurance athletes, and their possible use, through examples according to best practice protocols.
Marathon running is a physical and mental activity. Runners consume high-energy food products to fill their glycogen stores for maintaining their marathon performance. This makes consuming carbohydrates, mainly in the form of energy gels, an essential part of marathon running. While previous research demonstrates significant physiological effects of these high-energy food products on performance, their psychological effects, which could benefit from and shed light on food design studies, have been underexplored. This article explores these effects with two participant studies, a narrative study ( n = 10) and a survey ( n = 39). The inquiries start with understanding the psychology of marathon runners and examining the psychological effects of energy gels on marathon running. The results showed that the marathon runners follow a self-identified energy gel consumption strategy during marathon running. Several qualities of energy gels influence these strategies and the meanings marathon runners attach to energy gel consumption. The findings elucidated a novel area of food design research by unveiling the nature of the non-nutritional interactions between runner and energy gels consumed in marathon running.
We examined the effects of carbohydrate (CHO) delivery form on exogenous CHO oxidation, gastrointestinal discomfort, and exercise capacity. In a randomised repeated measures design (after 24 h of high CHO intake (8 g·kg-1) and pre-exercise meal (2 g·kg-1)), nine trained males ingested 120 g CHO·h-1 from fluid (DRINK), semi-solid gel (GEL), solid jelly chew (CHEW), or a co-ingestion approach (MIX). Participants cycled for 180 min at 95% lactate threshold followed by an exercise capacity test (150% lactate threshold). Peak rates of exogenous CHO oxidation (DRINK, 1.56 ± 0.16; GEL, 1.58 ± 0.13; CHEW, 1.59 ± 0.08; MIX, 1.66 ± 0.02 g·min-1) and oxidation efficiency (DRINK, 72 ± 8; GEL, 72 ± 5; CHEW, 75 ± 5; MIX, 75 ± 6%) were not different between trials (all P > 0.05). Despite ingesting 120 g·h-1, participants reported minimal symptoms of gastrointestinal distress across all trials. Exercise capacity was also not significantly different (all P < 0.05) between conditions (DRINK, 446 ± 350; GEL, 529 ± 396; CHEW, 596 ± 416; MIX, 469 ± 395 sec). Data represent the first time that rates of exogenous CHO oxidation (via stable isotope methodology) have been simultaneously assessed using feeding strategies (i.e., pre-exercise CHO feeding and the different forms and combinations of CHO during exercise) commonly adopted by elite endurance athletes. We conclude 120 g·h-1 CHO (in a 1:0.8 ratio of maltodextrin or glucose:fructose) is a practically tolerable strategy to promote high CHO availability and oxidation during exercise.
The aim of dietary recommendations is to optimize performance in track running, long-distance running, and ultra-running athletes, as well as to maintain good health and ease recovery. These nutrition tips must be adapted to each situation of short and repetitive races or endurance races because metabolism during exercise is very different from one athlete to another, and one race to another (as concerns time, distance, altitude, intensity of exercise). The nutritional recommendations are in favour of a moderate-to-high carbohydrates diet and an adapted hydration during training and before the race. A personalized and practical nutrition plan would be pertinent to balance the intake of fluids and carbohydrates (CHO) consumed during the race, to prevent gut discomfort or digestive problems. Further, the post-exercise nutritional window is also essential for competitive runners.
Libro que describe el qué, el cómo y el por qué se hace lo que se hace en relación a las Ciencias Aplicadas al Deporte en el Deporte de Alto Rendimiento en Chile. Estas ciencias apoyan el proceso de preparación y competencia de los atletas chilenos, con el propósito de mejorar el rendimiento deportivo a nivel internacional.
Accompanied by the growing popularity of distance running, the prevalence of vegan and vegetarian diets in endurance runners has increased across the globe and especially in German-speaking (D-A-CH: Germany, Austria, Switzerland) countries. The present study aimed to investigate and compare the epidemiological characteristics associated with diet types and running behaviors of recreational endurance runners. From a total number of 7422 runners who started to fill in the online survey, 3835 runners completed the questionnaire. After data clearance, 2455 distance runners (mean age: 37 years; 56% females, 44% males) were selected as the final sample and classified as 1162 omnivores (47.4%), 529 vegetarians (21.5%), and 764 vegans (31.1%). Sociodemographic information and general characteristics in training and competition were evaluated using a questionnaire-based approach. A significant association was found between diet type and race distance (p < 0.001). In females, vegan ultra-marathoners and omnivorous half-marathoners had better individual running records among dietary groups. Sex differences in running performance had a minimizing trend with increasing race distance. Most runners reported independent race preparation (90%) over less than four months (73%). From an epidemiological viewpoint, the present findings suggest a central role of plant-based diets in running performance and behaviors among active distance runners in D-A-CH countries and that vegetarian and vegan diets are compatible with competitive running.
Objective: Exercise-associated Muscle Cramp (EAMC) is an intense, painful, and involuntary contraction of skeletal muscles during a physical activity. Runners are more prone to this syndrome than other athletes. The present paper aims to review of the literature on EAMC in runners to determine the reasons and nature of EAMC in this sports field.
Methods: A search was conducted for related studies from 1997 to 2021 in MEDLINE/PubMed, EMBASE/SCOPUS, LILACS, CINAHL, CENTRAL, Web of Science, PEDro, Google Scholar as well as MagIran, IranDoc, IranMedex, MedLib using MeSH Keywords. The reference section of the studies were also checked to find more studies. Finally, 15 eligible papers on EAMC in runners were reviewed and findings were reported.
Results: Several factors were found to be effective in EAMC among runners, including dehydration, electrolyte deficit, cold, long training or competition period, increased body temperature during training or competition, history of injury or muscle cramp, increased training intensity in short time, and dietary restrictions.
Conclusion: The cause of EAMC in runners seems to be multifactorial.
Bone health in the athlete should not be taken for granted, and, while the benefits of regular exercise across the lifespan are well-recognised, there are numerous factors concerning training, nutrition and hormones that need to be considered. In this chapter, we give an overview of skeletal physiology which provides the basis for understanding how bone adapts to loading through exercise, and examine bone strength in athletes from sports with different skeletal loading characteristics. We address low bone density and fracture, which are issues that the athlete may encounter, often because of low energy availability, hormonal alterations and overtraining. This chapter concludes with steps for supporting bone health in athletes.
Creatine is a popular and widely used ergogenic dietary supplement among athletes, for which studies have consistently shown increased lean muscle mass and exercise capacity when used with short-duration, high-intensity exercise. In addition to strength gains, research has shown that creatine supplementation may provide additional benefits including enhanced postexercise recovery, injury prevention, rehabilitation, as well as a number of potential neurologic benefits that may be relevant to sports. Studies show that short- and long-term supplementation is safe and well tolerated in healthy individuals and in a number of patient populations.
Since Pheidippides’ times, the first Marathon runner in history, this running has become an attractive and inspiring activity to many runners around the world. A marathon is a type of endurance race that moves runners’ imagination because it defies athletes’ body limits; it also offers them a fantastic moment of joy and celebration for overcoming this challenge. All of this explains why marathon becomes a passion or sometimes an obsession for many elite and recreational athletes. This chapter explores a runners’ line of thinking; the “Forrest Gump” syndrome; physiological demands in the marathon; relevant clinical injuries in marathon such as dehydration/hyponatremia; sudden cardiac arrest; knee pain; shin pain, and runner’s toe.
Are you looking for a training buddy to prepare for your next marathon race? Have you ever considered that your father could be the right person? Would not it be great to cross the finish line side by side and get on the podium together? You probably think that your father is not young enough for such an effort, do not you? We believe that your father may also be capable of exceptional physical performance, despite his older age. In this article, you will see how a father and son (with a 25-year age difference) managed to break the world record for a combined father-and-son marathon in 2019.
Five years ago, with the editorial board of Frontiers in Nutrition, we took a leap of faith to outline the Goals for Nutrition Science – the way we see it ( 1 ). Now, in 2020, we can put ourselves to the test and take a look back. Without a doubt we got it right with several of the key directions. To name a few, Sustainable Development Goals (SDGs) for Food and Nutrition are part of the global public agenda, and the SDGs contribute to the structuring of international science and research. Nutritional Science has become a critical element in strengthening work on the SDGs, and the development of appropriate methodologies is built on the groundwork of acquiring and analyzing big datasets. Investigation of the Human Microbiome is providing novel insight on the interrelationship between nutrition, the immune system and disease. Finally, with an advanced definition of the gut-brain-axis we are getting a glimpse into the potential for Nutrition and Brain Health. Various milestones have been achieved, and any look into the future will have to consider the lessons learned from Covid-19 and the sobering awareness about the frailty of our food systems in ensuring global food security. With a view into the coming 5 years from 2020 to 2025, the editorial board has taken a slightly different approach as compared to the previous Goals article. A mind map has been created to outline the key topics in nutrition science. Not surprisingly, when looking ahead, the majority of scientific investigation required will be in the areas of health and sustainability.
Johannes le Coutre, Field Chief Editor, Frontiers in Nutrition.
Personalized supplementation has found recent momentum with an estimated global market size of USD 1.6 billion in 2019 and an expected CAGR of 8.5% between 2020 – 2028. Alongside this rising trend, a simple, accurate, inexpensive and flexible method to produce personalized dosage forms of a wide variety of supplements would be beneficial to both the industry players and individual consumers. Here, we present a 3D printing method to fabricate a four-in-one oral polypill with multiple release profiles for personalized delivery of caffeine and vitamin B analogues. The 3D printable formulations were fabricated and optimized from existing FDA GRAS excipients based on their viscosity, shear thinning properties, recovery of paste and mechanical strength. In the polypill, vitamin B analogues and caffeine were used as the model dietary ingredients. We performed a standard 2 stage USP in vitro dissolution test of the polypill, and demonstrated that vitamin B1, B3 and B6 could be immediately released within 30 minutes, while caffeine could be slowly released over a period of 4 hours. This demonstrated the ability dietary supplement containing different ingredients with varying release profiles, all within a single polypill. Throughout the formulation and 3D printing process, there were no detectable changes to the dietary ingredients nor any interactions with the excipients. This method serves as an intriguing complement to traditional manufacturing of oral tablets, especially when flexibility in design, dose, volume and release profiles of each dietary ingredient is required, as exemplified in personalized supplementation.
The reported prevalence of low energy availability (LEA) in female and male track and field athletes is between 18% and 58% with the highest prevalence among athletes in endurance and jump events. In male athletes, LEA may result in reduced testosterone levels and libido along with impaired training capacity. In female track and field athletes, functional hypothalamic amenorrhea as consequence of LEA has been reported among 60% of elite middle- and long-distance athletes and 23% among elite sprinters. Health concerns with functional hypothalamic amenorrhea include impaired bone health, elevated risk for bone stress injury, and cardiovascular disease. Furthermore, LEA negatively affects recovery, muscle mass, neuromuscular function, and increases the risk of injuries and illness that may affect performance negatively. LEA in track and field athletes may occur due to intentional alterations in body mass or body composition, appetite changes, time constraints, or disordered eating behavior. Long-term LEA causes metabolic and physiological adaptations to prevent further weight loss, and athletes may therefore be weight stable yet have impaired physiological function secondary to LEA. Achieving or maintaining a lower body mass or fat levels through long-term LEA may therefore result in impaired health and performance as proposed in the Relative Energy Deficiency in Sport model. Preventive educational programs and screening to identify athletes with LEA are important for early intervention to prevent long-term secondary health consequences. Treatment for athletes is primarily to increase energy availability and often requires a team approach including a sport physician, sports dietitian, physiologist, and psychologist.
The main focus of this review is illness among elite athletes, how and why it occurs, and whether any measures can be taken to combat it or to prevent its onset. In particular, there is particular interest in exercise-induced immunodepression, which is a result of the immune system regarding exercise (e.g., prolonged, exhaustive exercise) as a challenge to its function. This promotes the inflammatory response. There is often a high incidence of illness in athletes after undertaking strenuous exercise, particularly among those competing in endurance events, not only mainly in terms of upper respiratory tract illness, but also involving gastrointestinal problems. It may well be that this high incidence is largely due to insufficient recovery time being allowed after, for example, a marathon, a triathlon, or other endurance events. Two examples of the incidence of upper respiratory tract illness in moderate versus endurance exercise are provided. In recent years, increasing numbers of research studies have investigated the origins, symptoms, and incidence of these bouts of illness and have attempted to alleviate the symptoms with supplements, sports foods, or immunonutrition. One aspect of the present review discusses iron deficiency, which has been primarily suggested to have an impact upon cell-mediated immunity. Immunonutrition is also discussed, as are new techniques for investigating links between metabolism and immune function.
Athletes should achieve event-specific physiological requirements through careful periodization of training, underpinned by individualized and targeted nutrition strategies. However, evidence of whether, and how, elite endurance athletes periodize nutrition is scarce. Accordingly, elite international female (n = 67) and male (n = 37) middle/long-distance athletes (IAAF score: 1129 ± 54, corresponds to 13:22.49 [males] and 15:17.93 [females] in the 5000 m) completed an online survey (February–May 2018) examining self-reported practices of dietary periodization for micro (within/between-days), meso (weeks/months) and macro (across the year) contexts. Data are shown as the percentage of all athletes practicing a given strategy followed by the % of athletes reporting various beliefs or practices within this strategy. Differences according to sex, event (middle-distance [800 m/1500 m] vs. track-distance [3000 m-10000 m] vs. road-distance [marathon/race walks]), caliber (high [major championship qualifier] vs. lower), and training volume (low/moderate/high male and female tertiles) were analyzed using Chi-square test or Kruskal–Wallis Test and indicated statistically different when p ≤ 0.05. Most athletes reported eating more on hard training days (92%) and focusing on nutrition before (84%; carbohydrate intake [63%] and timing [58%]) and after (95%; protein goals [59%], timing [55%], carbohydrate goals [50%]) key sessions. Road-distance were the most (62 and 57%), and middle-distance the least (30 and 30%) likely to train fasted (p = 0.037) or restrict carbohydrates periodically (p = 0.050), respectively. Carbohydrate intake during training (58% of total) was more common in males (79%; p = 0.004) and road-distance (90%; p < 0.001) than females (53%) or middle/track-distance (48 and 37%). Most athletes (83%) reported following a specific diet before and during race day, with half of the athletes focusing on carbohydrates. Nearly all (97%) road-distance athletes reported following a during-race nutrition plan (carbohydrates/fluids:89%). Only 32% reported taking advice from a dietitian/nutritionist. Based on our analysis: (1) Road-distance athletes periodize carbohydrate availability while track/middle-distance avoid low carbohydrate availability; (2) Middle-distance runners emphasize physique goals to guide their nutrition strategies; (3) Females seem to be more cautious of increasing energy/carbohydrate intake; (4) Among all athletes, nutrition strategies are chosen primarily to improve performance, followed by reasons related to physique, adaptation and health outcomes. Overall, these athletes appear to possess good knowledge of nutrition for supporting training and competition performance.
The exploits of elite athletes delight, frustrate, and confound us as they strive to reach their physiological, psychological, and biomechanical limits. We dissect nutritional approaches to optimal performance, showcasing the contribution of modern sports science to gold medals and world titles. Despite an enduring belief in a single, superior “athletic diet,” diversity in sports nutrition practices among successful athletes arises from the specificity of the metabolic demands of different sports and the periodization of training and competition goals. Pragmatic implementation of nutrition strategies in real-world scenarios and the prioritization of important strategies when nutrition themes are in conflict add to this variation. Lastly, differences in athlete practices both promote and reflect areas of controversy and disagreement among sports nutrition experts.
Caffeine use is widespread among athletes following its removal from the World Anti-Doping Agency banned list, with approximately 75% of competitive athletes using caffeine. While literature supports that caffeine has a small positive ergogenic effect for most forms of sports and exercise, there exists a significant amount of inter-individual difference in the response to caffeine ingestion and the subsequent effect on exercise performance. In this narrative review, we discuss some of the potential mechanisms and focus on the role that genetics has in these differences. CYP1A2 and ADORA2A are two of the genes which are thought to have the largest impact on the ergogenicity of caffeine. CYP1A2 is responsible for the majority of the metabolism of caffeine, and ADORA2A has been linked to caffeine-induced anxiety. The effects of CYP1A2 and ADORA2A genes on responses to caffeine will be discussed in detail and an overview of the current literature will be presented. The role of these two genes may explain a large portion of the inter-individual variance reported by studies following caffeine ingestion. Elucidating the extent to which these genes moderate responses to caffeine during exercise will ensure caffeine supplementation programs can be tailored to individual athletes in order to maximize the potential ergogenic effect.
Low energy availability (LEA) is a key element of the Female Athlete Triad. Causes of LEA include failure to match high exercise energy expenditure (unintentional) or pathological behaviors of disordered eating (compulsive) and overzealous weight control programs (misguided but intentional). Recognition of such scenarios in male athletes contributed to the pronouncement of the more inclusive Relative Energy Deficiency in Sport (RED-S) syndrome. This commentary describes the insights and experience of the current group of authors around the apparently heightened risk of LEA in some populations of male athletes: road cyclists, rowers (lightweight and open weight), athletes in combat sports, distance runners, and jockeys. The frequency, duration, and magnitude of the LEA state appear to vary between populations. Common risk factors include cyclical management of challenging body mass and composition targets (including "making weight") and the high energy cost of some training programs or events that is not easily matched by energy intake. However, additional factors such as food insecurity and lack of finances may also contribute to impaired nutrition in some populations. Collectively, these insights substantiate the concept of RED-S in male athletes and suggest that a specific understanding of a sport, subpopulation, or culture may identify a complex series of factors that can contribute to LEA and the type and severity of its outcomes. This commentary provides a perspective on the range of risk factors that should be addressed in future surveys of RED-S in athletic populations and targeted for specific investigation and modification.
The human body requires energy for numerous functions including, growth, thermogenesis, reproduction, cellular maintenance, and movement. In sports nutrition, energy availability (EA) is defined as the energy available to support these basic physiological functions and good health once the energy cost of exercise is deducted from energy intake (EI), relative to an athlete's fat-free mass (FFM). Low EA provides a unifying theory to link numerous disorders seen in both female and male athletes, described by the syndrome Relative Energy Deficiency in Sport, and related to restricted energy intake, excessive exercise or a combination of both. These outcomes are incurred in different dose-response patterns relative to the reduction in EA below a "healthy" level of ∼45 kcal·kg FFM-1·day-1. Although EA estimates are being used to guide and monitor athletic practices, as well as support a diagnosis of Relative Energy Deficiency in Sport, problems associated with the measurement and interpretation of EA in the field should be explored. These include the lack of a universal protocol for the calculation of EA, the resources needed to achieve estimates of each of the components of the equation, and the residual errors in these estimates. The lack of a clear definition of the value for EA that is considered "low" reflects problems around its measurement, as well as differences between individuals and individual components of "normal"/"healthy" function. Finally, further investigation of nutrition and exercise behavior including within- and between-day energy spread and dietary characteristics is warranted since it may directly contribute to low EA or its secondary problems.
Background:
Caffeine is a widely used ergogenic aid with most research suggesting it confers the greatest effects during endurance activities. Despite the growing body of literature around the use of caffeine as an ergogenic aid, there are few recent meta-analyses that quantitatively assess the effect of caffeine on endurance exercise.
Objectives:
To summarise studies that have investigated the ergogenic effects of caffeine on endurance time-trial performance and to quantitatively analyse the results of these studies to gain a better understanding of the magnitude of the ergogenic effect of caffeine on endurance time-trial performance.
Methods:
A systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance.
Results:
Forty-six studies met the inclusion criteria and were included in the meta-analysis. Caffeine has a small but evident effect on endurance performance when taken in moderate doses (3-6 mg/kg) as well as an overall improvement following caffeine compared to placebo in mean power output (3.03 ± 3.07%; effect size = 0.23 ± 0.15) and time-trial completion time (2.22 ± 2.59%; effect size = 0.41 ± 0.2). However, differences in responses to caffeine ingestion have been shown, with two studies reporting slower time-trial performance, while five studies reported lower mean power output during the time-trial.
Conclusion:
Caffeine can be used effectively as an ergogenic aid when taken in moderate doses, such as during sports when a small increase in endurance performance can lead to significant differences in placements as athletes are often separated by small margins.
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.
Cold water or ice slurry ingestion during exercise seems to be an effective and practical means to improve endurance exercise performance in the heat. However, transient reductions in sweating appear to decrease the potential for evaporative heat loss from the skin by a magnitude that at least negates the additional internal heat loss as a cold ingested fluid warms up to equilibrate with body temperature; thus explaining equivalent core temperatures during exercise at a fixed heat production irrespective of the ingested fluid temperature. Internal heat transfer with cold fluid/ice is always 100% efficient; therefore, when a decrement occurs in the efficiency that sweat evaporates from the skin surface (i.e. sweating efficiency), a net cooling effect should begin to develop. Using established relationships between activity, climate and sweating efficiency, the boundary conditions beyond which cold ingested fluids are beneficial in terms of increasing net heat loss can be calculated. These conditions are warmer and more humid for cycling relative to running by virtue of the greater skin surface airflow, which promotes evaporation, for a given metabolic heat production and thus sweat rate. Within these boundary conditions, athletes should ingest fluids at the temperature they find most palatable, which likely varies from athlete to athlete, and therefore best maintain hydration status. The cooling benefits of cold fluid/ice ingestion during exercise are likely disproportionately greater for athletes with physiological disruptions to sweating, such as those with a spinal cord injury or burn injuries, as their capacity for skin surface evaporative heat loss is much lower; however, more research examining these groups is needed.
Purpose:
This study investigated whether reported improvements in blood flow distribution, and the possible related effects on thermoregulation during exercise following supplementation with beetroot juice (BR), a rich source of dietary nitrate (NO3-), are mitigated in the heat.
Methods:
12 male endurance-trained cyclists (age 27 ± 6 years, VO2peak 68.6 ± 8.1 ml kg-1 min-1) completed two 60 min submaximal cycling trials at 60% of VO2peak power output. Trials were performed in hot environmental conditions (33.3 ± 0.4 °C, 48.8 ± 3.0% RH) following 3 days of supplementation with either NO3--rich BR (6.5 mmol NO3- for 2 days and 13 mmol NO3- on the final day) or NO3--depleted placebo (PLA). Salivary NO3- and nitrite (NO2-) were measured before and after the supplementation period. During exercise, cutaneous blood flow, blood pressure (MAP), core temperature (Tc), mean skin temperature (Tsk), indices of muscle oxygenation and oxygen (O2) consumption were measured.
Results:
Salivary NO3- and NO2- increased significantly following BR by 680 and 890%, respectively. There were no significant differences observed for cutaneous blood flow, MAP, Tc, Tsk, muscle oxygenation, or O2 consumption between BR and PLA.
Conclusion:
This investigation shows that the ergogenic effects and health benefits of BR supplementation, such as augmented cutaneous blood flow, reduced MAP, increased muscle oxygenation, and improved aerobic efficiency may be attenuated when exercise is performed in hot conditions.
Nitrate-rich beetroot juice (BR) supplementation has been shown to increase biomarkers of nitric oxide availability with implications for the physiological responses to exercise. We hypothesized that BR supplementation before and during prolonged moderate-intensity exercise would maintain an elevated plasma nitrite concentration ([[Formula: see text]]), attenuate the expected progressive increase in V̇o 2 over time, and improve performance in a subsequent time trial (TT). In a double-blind, randomized, crossover design, 12 men completed 2 h of moderate-intensity cycle exercise followed by a 100-kJ TT in three conditions: 1) BR before and 1 h into exercise (BR + BR); 2) BR before and placebo (PL) 1 h into exercise (BR + PL); and 3) PL before and 1 h into exercise (PL + PL). During the 2-h moderate-intensity exercise bout, plasma [[Formula: see text]] declined by ~17% in BR + PL but increased by ~8% in BR + BR such that, at 2 h, plasma [[Formula: see text]] was greater in BR + BR than both BR + PL and PL + PL ( P < 0.05). V̇o 2 was not different among conditions over the first 90 min of exercise but was lower at 120 min in BR + BR (1.73 ± 0.24 l/min) compared with BR + PL (1.80 ± 0.21 l/min; P = 0.08) and PL + PL (1.83 ± 0.27 l/min; P < 0.01). The decline in muscle glycogen concentration over the 2-h exercise bout was attenuated in BR + BR (~28% decline) compared with BR + PL (~44% decline) and PL + PL (~44% decline; n = 9, P < 0.05). TT performance was not different among conditions ( P > 0.05). BR supplementation before and during prolonged moderate-intensity exercise attenuated the progressive rise in V̇o 2 over time and appeared to reduce muscle glycogen depletion but did not enhance subsequent TT performance.
NEW & NOTEWORTHY We show for the first time that ingestion of nitrate during exercise preserves elevated plasma [nitrite] and negates the progressive rise in O 2 uptake during prolonged moderate-intensity exercise.
It is becoming increasingly clear that adaptations, initiated by exercise, can be amplified or reduced by nutrition. Various methods have been discussed to optimize training adaptations and some of these methods have been subject to extensive study. To date, most methods have focused on skeletal muscle, but it is important to note that training effects also include adaptations in other tissues (e.g., brain, vasculature), improvements in the absorptive capacity of the intestine, increases in tolerance to dehydration, and other effects that have received less attention in the literature. The purpose of this review is to define the concept of periodized nutrition (also referred to as nutritional training) and summarize the wide variety of methods available to athletes. The reader is referred to several other recent review articles that have discussed aspects of periodized nutrition in much more detail with primarily a focus on adaptations in the muscle. The purpose of this review is not to discuss the literature in great detail but to clearly define the concept and to give a complete overview of the methods available, with an emphasis on adaptations that are not in the muscle. Whilst there is good evidence for some methods, other proposed methods are mere theories that remain to be tested. ‘Periodized nutrition’ refers to the strategic combined use of exercise training and nutrition, or nutrition only, with the overall aim to obtain adaptations that support exercise performance. The term nutritional training is sometimes used to describe the same methods and these terms can be used interchangeably. In this review, an overview is given of some of the most common methods of periodized nutrition including ‘training low’ and ‘training high’, and training with low- and high-carbohydrate availability, respectively. ‘Training low’ in particular has received considerable attention and several variations of ‘train low’ have been proposed. ‘Training-low’ studies have generally shown beneficial effects in terms of signaling and transcription, but to date, few studies have been able to show any effects on performance. In addition to ‘train low’ and ‘train high’, methods have been developed to ‘train the gut’, train hypohydrated (to reduce the negative effects of dehydration), and train with various supplements that may increase the training adaptations longer term. Which of these methods should be used depends on the specific goals of the individual and there is no method (or diet) that will address all needs of an individual in all situations. Therefore, appropriate practical application lies in the optimal combination of different nutritional training methods. Some of these methods have already found their way into training practices of athletes, even though evidence for their efficacy is sometimes scarce at best. Many pragmatic questions remain unanswered and another goal of this review is to identify some of the remaining questions that may have great practical relevance and should be the focus of future research.
The gastrointestinal (GI) tract plays a critical role in delivering carbohydrate and fluid during prolonged exercise and can therefore be a major determinant of performance. The incidence of GI problems in athletes participating in endurance events is high, indicating that GI function is not always optimal in those conditions. A substantial body of evidence suggests that the GI system is highly adaptable. Gastric emptying as well as stomach comfort can be “trained” and perceptions of fullness decreased; some studies have suggested that nutrient-specific increases in gastric emptying may occur. Evidence also shows that diet has an impact on the capacity of the intestine to absorb nutrients. Again, the adaptations that occur appear to be nutrient specific. For example, a high-carbohydrate diet will increase the density of sodium-dependent glucose-1 (SGLT1) transporters in the intestine as well as the activity of the transporter, allowing greater carbohydrate absorption and oxidation during exercise. It is also likely that, when such adaptations occur, the chances of developing GI distress are smaller. Future studies should include more human studies and focus on a number of areas, including the most effective methods to induce gut adaptations and the timeline of adaptations. To develop effective strategies, a better understanding of the exact mechanisms underlying these adaptations is important. It is clear that “nutritional training” can improve gastric emptying and absorption and likely reduce the chances and/or severity of GI problems, thereby improving endurance performance as well as providing a better experience for the athlete. The gut is an important organ for endurance athletes and should be trained for the conditions in which it will be required to function.
The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship ‘levels off’ at a ‘critical power’ (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake (\( \dot{V}{\text{O}}_{2} \)), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W′) is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W′ is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W′ may be assumed to be linear, studies indicate that the reconstitution of W′ may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in which the balance of W′ remaining (\( W_{\text{BAL}}^{\prime } \)) may be calculated with greater accuracy. Field trials of athletes performing stochastic exercise indicate that this \( W_{\text{BAL}}^{\prime } \) model can accurately predict the time at which W′ tends to zero and exhaustion is imminent. The \( W_{\text{BAL}}^{\prime } \) model potentially has important applications in the real-time monitoring of athlete fatigue progression in endurance and team sports, which may inform tactics and influence pacing strategy.
Abstract
Purpose This study evaluated the effects of dietary nitrate (NO3-) supplementation on physiological functioning and exercise performance in trained runners/ triathletes conducting short and longer distance treadmill running time-trials (TT).
Method Eight trained male runners or triathletes completed four exercise performance tests comprising a 10 minute warm up followed by either a 1500 m or 10,000 m treadmill TT. Exercise performance tests were preceded 3 hours before the exercise by supplementation with either 140 ml concentrated nitrate-rich (~ 12.5 mmol nitrate) (BRJ) or nitrate-deplete (~ 0.01 mmol nitrate) (PLA) beetroot juice.
Results BRJ supplementation significantly elevated plasma [NO2-] (P < 0.05). Resting blood pressure and exercise V̇O2 were not significantly different between BRJ and PLA (P > 0.05). However, post-exercise blood [lactate] was significantly greater in BRJ following the 1500 m TT (6.6 ± 1.2 vs. 6.1 ± 1.5 mM; P < 0.05), but not significantly different between conditions in the 10,000 m TT (P > 0.05). Performance in the 1500 m TT was significantly faster in BRJ versus PLA (319.6 ± 36.2 vs. 325.7 ± 38.8 s; P < 0.05). Conversely, there was no significant difference in 10,000 m TT performance between conditions (2643.1 ± 324. 1 vs. 2649.9 ± 319.8 s, P > 0.05).
Conclusion Acute BRJ supplementation significantly enhanced 1500 m but not 10,000 m TT performance. These findings suggest that BRJ might be ergogenic during shorter-distance TTs which allow for a high work rate, but not during longer-distance TTs, completed at a lower work rate.
The application of menthol has recently been researched as a performance-enhancing aid for various aspects of athletic performance including endurance, speed, strength and joint range of motion. A range of application methods has been used including a mouth rinse, ingestion of a beverage containing menthol or external application to the skin or clothing via a gel or spray. The majority of research has focussed on the use of menthol to impart a cooling sensation on athletes performing endurance exercise in the heat. In this situation, menthol appears to have the greatest beneficial effect on performance when applied internally. In contrast, the majority of investigations into the external application of menthol demonstrated no performance benefit. While studies are limited in number, menthol has not yet proven to be beneficial for speed or strength, and only effective at increasing joint range of motion following exercise that induced delayed-onset muscle soreness. Internal application of menthol may provoke such performance-enhancing effects via mechanisms related to its thermal, ventilatory, analgesic and arousing properties. Future research should focus on well-trained subjects and investigate the addition of menthol to nutritional sports products.
Maximal oxygen uptake (VO2max), fractional utilization of VO2max during running and running economy (RE) are crucial factors for running success for all endurance athletes. Although evidence is limited, investigations of these key factors indicate that the East Africans superiority in distance running is to a large exent due to a unique combination of these factors. East African runners appear to have a very high level of RE most likely associated, at least partly, with anthropometric characteristics rather than with any specific metabolic property of the working muscle. That is, evidence suggest that anthropometrics and body composition might have important parameters as determinants of superior performance of East African distance runners. Regrettably, this role is often overlooked and mentioned as a descriptive parameter rather than explanatory one in many research studies. This brief review article provides an overview of the evidence to support the critical role anthropometrics and body composition has on the distance running success of East African athletes. The structural form and shape of these athletes also has a downside, as having very low BMI or body fat increases the risk for Relative Energy Deficiency in Sport (RED-S) conditions in both, male and female runners which can have serious health consequences.
Background
Recent research into the use of dietary nitrates and their role in vascular function has led to it becoming progressively more popular amongst athletes attempting to enhance performance. Objective
The objective of this review was to perform a systematic review and meta-analysis of the literature to evaluate the effect of dietary nitrate (NO3−) supplementation on endurance exercise performance. An additional aim was to determine whether the performance outcomes are affected by potential moderator variables. Data sourcesRelevant databases such as Cochrane Library, Embase, PubMed, Ovid, Scopus and Web of Science were searched for the following search terms ‘nitrates OR nitrate OR beetroot OR table beet OR garden beet OR red beet AND exercise AND performance’ from inception to October 2015. Study selectionStudies were included if a placebo versus dietary nitrate-only supplementation protocol was able to be compared, and if a quantifiable measure of exercise performance was ≥30 s (for a single bout of exercise or the combined total for multiple bouts). Study appraisal and synthesisThe literature search identified 1038 studies, with 47 (76 trials) meeting the inclusion criteria. Data from the 76 trials were extracted for inclusion in the meta-analysis. A fixed-effects meta-analysis was conducted for time trial (TT) (n = 28), time to exhaustion (TTE) (n = 22) and graded-exercise test (GXT) (n = 8) protocols. Univariate meta-regression was used to assess potential moderator variables (exercise type, dose duration, NO3− type, study quality, fitness level and percentage nitrite change). ResultsPooled analysis identified a trivial but non-significant effect in favour of dietary NO3− supplementation [effect size (ES) = −0.10, 95 % Cl = −0.27 to 0.06, p > 0.05]. TTE trials had a small to moderate statistically significant effect in favour of dietary NO3− supplementation (ES = 0.33, 95 % Cl = 0.15–0.50, p < 0.01). GXT trials had a small but non-significant effect in favour of dietary NO3− supplementation in GXT performance measures (ES = 0.25, 95 % Cl = −0.06 to 0.56, p > 0.05). No significant heterogeneity was detected in the meta-analysis. No statistically significant effects were observed from the meta-regression analysis. Conclusion
Dietary NO3− supplementation is likely to elicit a positive outcome when testing endurance exercise capacity, whereas dietary NO3− supplementation is less likely to be effective for time-trial performance. Further work is needed to understand the optimal dosing strategies, which population is most likely to benefit, and under which conditions dietary nitrates are likely to be most effective for performance.