ArticleLiterature Review
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Over the last decade, in support of training periodization, there has been an emergence around the concept of nutritional periodization. Within athletics (track and field), the science and art of periodization is a cornerstone concept with recent commentaries emphasizing the underappreciated complexity associated with predictable performance on demand. Nevertheless, with varying levels of evidence, sport and event specific sequencing of various training units and sessions (long [macrocycle; months], medium [mesocycle; weeks], and short [microcycle; days and within-day duration]) is a routine approach to training periodization. Indeed, implementation of strategic temporal nutrition interventions (macro, meso, and micro) can support and enhance training prescription and adaptation, as well as acute event specific performance. However, a general framework on how, why, and when nutritional periodization could be implemented has not yet been established. It is beyond the scope of this review to highlight every potential nutritional periodization application. Instead, this review will focus on a generalized framework, with specific examples of macro-, meso-, and microperiodization for the macronutrients of carbohydrates, and, by extension, fat. More specifically, the authors establish the evidence and rationale for situations of acute high carbohydrate availability, as well as the evidence for more chronic manipulation of carbohydrates coupled with training. The topic of periodized nutrition has made considerable gains over the last decade but is ripe for further scientific progress and field application.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Despite decades of interest in the periodization of training, it is only recently that a holistic approach to periodization across a range of themes that affect competition preparation has been suggested Mujika et al., 2018;Stellingwerff et al., 2018). In fact, the concept of integrating a periodized nutrition plan within the annual training program was formally proposed in a previous expert panel around nutrition for track and field athletes by Stellingwerff et al. (2007). ...
... In fact, the concept of integrating a periodized nutrition plan within the annual training program was formally proposed in a previous expert panel around nutrition for track and field athletes by Stellingwerff et al. (2007). The principles, practices and terminology around the periodization of nutrition have been summarized in several recent reviews (Jeukendrup, 2017;Burke et al., 2018;Stellingwerff et al., 2018). The underlying theme is that strategic and targeted nutritional interventions can be used to augment the outcomes of the various specific training cycles [micro (within-day to days), meso (several weeks) and macro (months to years)]. ...
... A variety of aspects of nutrition can be periodized in support of different training goals, ranging from fundamental issues such as energy intake through to the more specialized and "fine tuning" aspects of supplement use (Jeukendrup, 2017;Stellingwerff et al., 2018). From a macro perspective, energy intake needs to be manipulated across, and within, training days according to fluctuations in the energy cost of the athlete's training program, as well as strategic integration of periods of alterations to energy balance to manipulate body mass/composition Stellingwerff, 2018). ...
Article
Full-text available
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.
... However, exercise-induced adaptations may be promoted or impaired by nutrition [6]. In fact, nutrition should be periodized to support the different goals of the training and to optimize competition performance [7,8]. Furthermore, XC ski training consumes high amounts of energy, which needs to be compensated for with high energy intake (EI) to maintain adequate energy availability (EA; the amount of dietary energy remaining after exercise for all other metabolic processes) and to avoid negative performance and health outcomes such as poor training response, hormonal dysfunction, impairment of bone health, and increased injury risk [9,10]. ...
... XC skiers compete and perform most of their key training sessions at intensities that are highly dependent on carbohydrate (CHO) based fuels for muscle metabolism [2,3,12]. Thus, pre-exercise meals should ensure adequate CHO availability in key training sessions, while this is less important before easy sessions [6,8,13]. As restoration of muscle CHO stores may take up to 24 h, the recovery process should be started as soon as possible after the high intensity training session in situations when recovery time between key training sessions is limited [14]. ...
... As restoration of muscle CHO stores may take up to 24 h, the recovery process should be started as soon as possible after the high intensity training session in situations when recovery time between key training sessions is limited [14]. Meanwhile, performing part of the easy sessions with low CHO availability may increase the muscle adaptations to endurance training and therefore it might be beneficial to limit CHO intake before the training session where training intensity and quality are less important [6,8]. While CHO is an important macronutrient as a fuel, protein is needed for tissue repair and adaptation as it acts both as a trigger and substrate in anabolic processes [13,15]. ...
Article
Full-text available
The aim of this study was to provide information on energy availability (EA), macronutrient intake, nutritional periodization practices, and nutrition knowledge in young female cross-country skiers. A total of 19 skiers filled in weighted food and training logs before and during a training camp. Nutrition knowledge was assessed via a validated questionnaire. EA was optimal in 11% of athletes at home (mean 33.7 ± 9.6 kcal·kgFFM−1·d−1) and in 42% at camp (mean 40.3 ± 17.3 kcal·kgFFM−1·d−1). Most athletes (74%) failed to meet recommendations for carbohydrate intake at home (mean 5.0 ± 1.2 g·kg−1·d−1) and 63% failed to do so at camp (mean 7.1 ± 1.6 g·kg−1·d−1). The lower threshold of the pre-exercise carbohydrate recommendations was met by 58% and 89% of athletes while percentages were 26% and 89% within 1 h after exercise, at home and at camp, respectively. None of the athletes met the recommendations within 4 h after exercise. Nutrition knowledge was associated with EA at home (r = 0.52, p = 0.023), and with daily carbohydrate intake at home (r = 0.62, p = 0.005) and at camp (r = 0.52, p = 0.023). Carbohydrate intake within 1 and 4 h post-exercise at home was associated with better nutrition knowledge (r = 0.65, p = 0.003; r = 0.53, p = 0.019, respectively). In conclusion, young female cross-county skiers had difficulties meeting recommendations for optimal EA and carbohydrate intake. Better nutrition knowledge may help young athletes to meet these recommendations.
... enhance performance longer term" [9]. Periodized nutrition has been primarily studied in terms of carbohydrate utilisation within aerobic endurance athletes, whereby carbohydrate availability is manipulated to drive desired molecular and physiological adaptations to exercise [8,10]. Interest in nutritional periodization techniques has grown, with the principles applied to strength athletes [2], and a general framework in the scientific literature has been recently proposed [10]. ...
... Periodized nutrition has been primarily studied in terms of carbohydrate utilisation within aerobic endurance athletes, whereby carbohydrate availability is manipulated to drive desired molecular and physiological adaptations to exercise [8,10]. Interest in nutritional periodization techniques has grown, with the principles applied to strength athletes [2], and a general framework in the scientific literature has been recently proposed [10]. Here, we expand the concept of nutritional periodization by applying it to caffeine, a widely-used, effective ergogenic aid [11], exploring how manipulation of caffeine's use may support athlete performance across the training year. ...
... If long-term caffeine ingestion indeed attenuates its ergogenic potential, this adaptation may suggest that athletes might be unable to maximally harness caffeine's ergogenic effects during the competition period. One way to potentially mitigate these effects is to avoid caffeine use during In their recent paper, Stellingwerff and colleagues [10] developed a framework for the periodization of nutrition, in which nutritional interventions are utilised to support the bridging of performance gaps in athletes across macro-, meso-, and microcycles in a strategic manner. As an example, for an elite middle distance athlete preparing for the Olympic Games, the training year could (very broadly) be broken up into an accumulation phase, in which the athlete accumulates lower-intensity aerobic training volumes interspersed with less frequent high-intensity anaerobic training sessions, followed by an intensification phase, in which the relative volume of low intensity training decreases, and high intensity training increases, followed by the competition phrase. ...
Article
Caffeine is a well-established ergogenic aid, with its performance-enhancing effects demonstrated across a variety of sports and exercise types. As a result of caffeine's ergogenic properties, it is widely utilised by athletes at all levels around both competition and training. Caffeine exerts its performance benefits through a variety of mechanisms, each of which may be of increased importance at a given stage of training or competition. In addition, regular caffeine use may diminish the performance enhancing effects of a subsequent dose of caffeine. Recently, interest in the concept of nutritional periodization has grown; here we propose a framework for the periodization of caffeine through the sporting year, balancing its training and competition performance-enhancing effects, along with the need to mitigate any negative effects of habituation. Furthermore, the regular use of caffeine within training may support the development of positive beliefs towards caffeine by athletes—potentially serving to enhance future performance through placebo and expectancy mechanisms—as well as allowing for the optimisation of individual athlete caffeine strategies. Whilst future work is required to validate some of the suggestions made, the framework proposed here represents a starting point for athletes to maximise caffeine's performance benefits across the sporting year.
... While the concept of nutrient timing has previously been reviewed [1,[20][21][22][23][24][25][26], this has often been done by focusing on singular time periods within the paradigm or organized based on macronutrient impacts rather than holistically as timing. As timing does not occur in isolation, coupled with the fact that the pre-, intra-, and post-training periods interact and influence each other, it is important to consider the concept of nutrient timing across a continuum. ...
... Recently, the concept of periodized nutrition has been promoted. Using this model, dietary intake is altered throughout training micro-, meso-, and macrocycles [25]. This model helps bridge the gap between acute performance and chronic adaptations. ...
... This involves intentionally training in a state of low CHO availability and glycogen levels. Though this may attenuate performance within the acute training bout, it has been shown to potentially bolster long-term adaptations [25,131]. Such adaptations include mitochondrial biogenesis, increased capillarization, and increased capacity for lipid oxidation [25], all of which may contribute to improved endurance performance. ...
Article
Full-text available
Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability.
... Possibly, the amount of a negative energy balance needs to be adapted in the case of Paralympic athletes with already reduced energy needs. As suggested by several different authors [70], a periodized nutrition approach might help achieve this aim in athletes with a disability. It is suggested to plan the nutrition around the training schedule and to fuel the athletes with energy when needed to ensure optimal training conditions and adaptations as well as to enhance recovery [70]. ...
... As suggested by several different authors [70], a periodized nutrition approach might help achieve this aim in athletes with a disability. It is suggested to plan the nutrition around the training schedule and to fuel the athletes with energy when needed to ensure optimal training conditions and adaptations as well as to enhance recovery [70]. ...
... Together with data from the training sessions and existing literature ( Table 2) on energy expenditure during training [9], energy needs might be estimated in order to plan the nutritional intervention. A periodized nutrition approach [70] might further help to fuel for the specific training to enhance performance and optimize recovery without an excessive energy intake leading to weight gain. Before, during, and after high intensity or long endurance rides, athletes should make sure that they consume enough CHO in order to meet their requirements (Table 4). ...
Article
Full-text available
Para-cycling is a sport including athletes with different disabilities competing on the track and on the roads using bicycles, tandems, tricycles, and handbikes. Scientific literature in this special population is scarce, especially in the field of sports nutrition. This review summarizes the physiological aspects and demands of para-cycling. This information together with the existing literature on nutritional interventions in this population, helps to discuss the nutritional considerations. To date, only a limited amount of recommendations are available for this population. In most para-cycling athletes, a reduction in active muscle mass and consequently a reduction in resting energy expenditure occurs, except for visually impaired athletes. Furthermore, carbohydrate and protein intake and hydration, supplementation, heat, and weight loss need to be tailored to the disability-specific adaptations such as the reduced active muscle mass, neurogenic bladder, and bowel, a reduced metabolic cost during exercise, and a higher risk of micronutrient deficiency.
... To address these fluctuations, practitioners in the sports medicine field have long recommended periodizing training [11][12][13] and more recently nutritional training. [14][15][16][17][18] Periodization is an organized approach to training that involves progressive cycling of various aspects of a training program during a specific period of time. 16 Periodization involves division of training cycles throughout the course of the year, where volume, frequency, intensity, time, and type of training are manipulated to meet the demands of the sport. ...
... This gap exists despite several prior investigators 9,15,17 consistently stating that nutrition can be a limiting factor in athletes when training for strength, power, and endurance gains and is sometimes overlooked, as it pertains to the inclusion to the annual training plan. 18,28 Overall, dancers' energy demands fluctuate across the season. Accordingly, dancers should adapt their nutrition to match their training or performance schedule. ...
Article
Dancers' energy demands fluctuate across the season. Accordingly, dancers should adapt their training and nutrition. Still, how to periodize nutrition in dancers remains unclear. This article aims to (1) introduce nutrition periodization and (2) provide recommendations for nutrition periodization in dancers. During preseason, dancers design, rehearse, and train. During in-season, dancers have one or more daily performances. During postseason, dancers rest and prepare for the next season. Nutrition periodization is the strategic and timed nutrient intake to meet varying seasonal energy demands. Overall, nutrition periodization can support dancers' training goals, enhance their performance, and support optimal recovery.
... However, strategies altering nutrient availability before and during exercise can also impact training adaptations by modulating the exercise stimulus and/or cellular responses to the exercise-induced perturbations [2]. Specific strategies to alter nutrient availability can include exercising in the overnight-fasted state, restricting carbohydrate (CHO) ingestion between training sessions, and increasing CHO ingestion before or during exercise [3]. Although performance may be improved following pre-exercise CHO ingestion [4,5], exercise undertaken with reduced availability of CHO can increase the activation of key signaling proteins compared with exercise performed with high CHO availability [6], potentially influencing longer-term training adaptations. ...
... In an attempt to optimize both training adaptations and acute performance during key training sessions, current sport nutrition guidelines suggest training be performed both with high CHO availability, in order to enhance glycolytic and CHO oxidation pathways, and low CHO availability to increase the activation of acute cell signaling pathways related to mitochondrial biogenesis and fat oxidation [3]. Despite the rationale for a periodized approach to nutrition, whereby CHO availability for each workout is varied according to the type of session and its goals within a periodized training cycle [161], many athletes are not following these recommendations and/or are unclear on the current best-practice guidelines. ...
Article
Full-text available
The primary variables influencing the adaptive response to a bout of endurance training are exercise duration and exercise intensity. However, altering the availability of nutrients before and during exercise can also impact the training response by modulating the exercise stimulus and/or the physiological and molecular responses to the exercise-induced perturbations. The purpose of this review is to highlight the current knowledge of the influence of pre-exercise nutrition ingestion on the metabolic, physiological, and performance responses to endurance training and suggest directions for future research. Acutely, carbohydrate ingestion reduces fat oxidation, but there is little evidence showing enhanced fat burning capacity following long-term fasted-state training. Performance is improved following pre-exercise carbohydrate ingestion for longer but not shorter duration exercise, while training-induced performance improvements following nutrition strategies that modulate carbohydrate availability vary based on the type of nutrition protocol used. Contrasting findings related to the influence of acute carbohydrate ingestion on mitochondrial signaling may be related to the amount of carbohydrate consumed and the intensity of exercise. This review can help to guide athletes, coaches, and nutritionists in personalizing pre-exercise nutrition strategies, and for designing research studies to further elucidate the role of nutrition in endurance training adaptations.
... The evaluation of association between nutrition knowledge and diet quality is also complex due to a plethora of inadequately or partially validated instruments to assess nutrition knowledge [12,13] and inappropriate tools to quantify dietary intake [13], such as 24-h dietary recalls and three-day self-reported food diaries, which have both been shown to poorly estimate micronutrient intake [16,17]. Athletes energy requirements are also highly variable throughout macro-, meso-and microcycles, as many adopt a periodised training approach [18,19] complicating the assessment process [20]. Despite only a weak association between an athlete's nutrition knowledge and their diet quality, nutrition education interventions have been shown to increase athlete's nutrition knowledge and lead to greater dietary behaviours [21], optimising physical performance [22]. ...
... Players' dietary intakes should also be quantified alongside training loads, as reported in other high intensity intermittent sports [84,85]. This would give an insight into whether players' dietary intake is optimal in relation to their training load [18,19]. Food consumption frequency questionnaires, as reported by Venutra-Comes et al., (2019) [11] have been shown to display poor validity and reliability [86] in comparison to other methods such as weighed food diaries, snap 'N' send and 24-h dietary recall [17,87]. ...
Article
Full-text available
Background There is a reported mismatch between macronutrient consumption and contemporary macronutrient guidelines in elite standard squash players. Suboptimal dietary practices could be due to a lack of nutrition knowledge among players. Subsequently, the purpose of this study was to assess the sports nutrition knowledge of elite squash players through the Nutrition for Sport Knowledge Questionnaire (NSKQ) and provide an indication of whether players require nutrition support to increase their nutrition knowledge. Methods This cross-sectional study assessed the nutrition knowledge of 77 elite squash players via the NSKQ over the period of June 2020 to August 2020. Results Players conveyed average nutrition knowledge with a mean NSKQ score of 48.78 ± 10.06 (56.07% ± 11.56%). There were no significant differences in NSKQ score between male and female players ( p = .532). There was found to be a weak positive association between world ranking and NSKQ score ( r = .208) and age and NSKQ score ( r = .281). Players who had a relevant undergraduate degree (e.g. BSc Sport & Exercise Science) had significantly greater NSKQ score than players with no relevant qualifications ( p = .022). Players who consulted a sports nutritionist to obtain their main source of nutrition information were shown to have significantly greater knowledge than those who acquired knowledge from a sports scientist ( p = .01) or the internet / social media ( p = .007). Conclusions Players should consult with a sports nutritionist to increase their sport nutrition knowledge. Future research should quantify the effectiveness of a nutritional education intervention at increasing nutrition knowledge in players.
... Within the former aspect, value should be attached to a balanced nutritional approach. The paradigm of periodized nutrition [5,55,95,96] may represent a guide for athletes with an SCI to base their fueling needs on training duration, intensity, and total volume [31,96]. In view of their reduced energy expenditure, such a periodized approach could enable these athletes to ensure optimal training adaptations and recovery without restricting their diet and thus, support maximal performance capacity [31]. ...
... Within the former aspect, value should be attached to a balanced nutritional approach. The paradigm of periodized nutrition [5,55,95,96] may represent a guide for athletes with an SCI to base their fueling needs on training duration, intensity, and total volume [31,96]. In view of their reduced energy expenditure, such a periodized approach could enable these athletes to ensure optimal training adaptations and recovery without restricting their diet and thus, support maximal performance capacity [31]. ...
Article
Full-text available
The Paralympic movement is growing in popularity, resulting in increased numbers of athletes with a spinal cord injury (SCI) competing in various sport disciplines. Athletes with an SCI require specialized recommendations to promote health and to maximize performance, as evidenced by their metabolic and physiological adaptations. Nutrition is a key factor for optimal performance; however, scientifically supported nutritional recommendations are limited. This review summarizes the current knowledge regarding the importance of carbohydrates (CHO) for health and performance in athletes with an SCI. Factors possibly affecting CHO needs, such as muscle atrophy, reduced energy expenditure, and secondary complications are analyzed comprehensively. Furthermore, a model calculation for CHO requirements during an endurance event is provided. Along with assessing the effectiveness of CHO supplementation in the athletic population with SCI, the evaluation of their CHO intake from the available research supplies background to current practices. Finally, future directions are identified. In conclusion, the direct transfer of CHO guidelines from able-bodied (AB) athletes to athletes with an SCI does not seem to be reasonable. Based on the critical role of CHOs in exercise performance, establishing recommendations for athletes with an SCI should be the overall objective for prospective research.
... Next, in this study, the SNs emphasized training or sports periodization plan. The athletes had speci c and individual training periodization programs which integrate different types of training activities, speci cally following their training calendars (25). Nutritional periodization was then used to support training periodization. ...
... Nutrition periodization is de ned as "the planned, purposeful, and strategic use of speci c nutritional interventions to enhance the adaptations targeted by individual exercise sessions or periodic training" (26). Thus, understanding the athletes' training periodization plans provides SNs with an overview or framework to match the nutrition strategies with training outcomes (25). ...
Preprint
Full-text available
Background: It is considered that the implementation of nutrition care process (NCP) leads to more efficient and effective care, as well as enhancing the roles of dietetics and nutrition professionals in the clinical setting. However, little is known about the NCP being implemented in the sports nutrition setting to deliver nutrition care, especially in meal planning. Therefore, this study aims to identify the process that sports nutritionists (SNs) practise in meal planning to plan meals for athletes and identify the application of NCP. Methods: In-depth interviews, using semi-structured interview questions, were conducted with SNs employed at the National Sports Institute of Malaysia. Five SNs who managed different types of sports were recruited. The interviews were audio-recorded and transcribed verbatim. Data were entered into ATLAS.ti 8 and analyzed using thematic analysis. Results: The following processes were identified: (i) collecting pertinent data; (ii) analyzing the collected data; (iii) determining nutrition prescriptions; (iv) formulating goals and determining actions; (v) implementing actions and recommendations; and (vi) monitoring. Conclusions: This study identified 6 general processes practiced by sports nutritionists in meal planning that comprised of the NCP’s interrelated steps, except nutrition diagnosis statement from the Nutrition Diagnosis step of the NCP. A comprehensive process and workflow can help sports dietitians or nutritionists to develop individualized meal plans that can improve athletes’ nutritional status, adherence, health and sports performance.
... In the athletic population, a reduced EA is acceptable for a short-term duration and might be required to reach optimal body composition before a major competition (e.g., the last few weeks) [9]. Therefore, periodization of nutritional approaches (e.g., increase in fat oxidation, training with high or low carbohydrate (CHO) availability, weight loss/gain at different training phases) is as important as training periodization [15][16][17]. Therefore, it would be useful to study a microcycle of seven consecutive days to investigate the nutritional intake on days with different training loads. ...
... The positive correlations between EEE and EI, as well as EA, protein, fat and CHO intake, indicates that during days with a higher EEE a higher EI followed. In a proposed periodized nutrition approach, fueling CHO before a very intensive session might positively influence the quality and overall intensity of the session [17]. Carbohydrate as a fuel after the session would depend on the next session and whether periodized CHO intake was chosen. ...
Article
Full-text available
Background: Low energy availability (LEA) is a major problem as athletes often restrict their energy intake. It has been shown that LEA occurs often in female and endurance athletes and in athletes from weight-sensitive or aesthetic sports. The purpose of this study was to investigate energy availability (EA) in elite wheelchair athletes. Methods: Fourteen elite wheelchair athletes (8 males; 6 females) participated. Data were collected using a weighed seven-day food and training diary to estimate energy intake and exercise energy expenditure. Resting energy expenditure and body composition were measured, whereas energy balance (EB) was calculated. Results: Measured over 7 days, EA was significantly different (36.1 ± 6.7 kcal kg-1 FFM day-1) in male compared to female (25.1 ± 7.1 kcal kg-1 FFM day-1) athletes (p < 0.001). From all analyzed days, LEA occurred in 73% of the days in female athletes and in 30% of the days in male athletes. EB was positive in male athletes (+169.1 ± 304.5 kcal) and negative (-288.9 ± 304.8 kcal) in female athletes. Conclusions: A higher prevalence of LEA was found in female compared to male athletes. A higher energy intake would be recommended to meet energy needs and to maximize training adaptation.
... A transitory increase in performance capacity in response to LEA could make sense from a survival perspective if it facilitates the catching or finding of needed calories. It has also been suggested that transient exposure to LEA within a periodized training and nutritional program may be desirable to drive certain phenotypic adaptations, such as body composition changes or increased efficiency of specific bioenergetic pathways [101]. ...
... Unsubstantiated assumptions that all trade-offs are negative should be avoided, as should over-extrapolation of mechanistic findings. Indeed, there may be situations where transient exposure to LEA within a periodized nutritional cycle may be desirable to drive certain phenotypic outcomes, [101] while more moderate energy restriction throughout the life-course is hypothesized to increase longevity and health-span [127]. The topic of LEA in athletes is both complex and nuanced, and embracing these characteristics of the research topic may be key to the development of appropriate guidelines to support at-risk athletes. ...
Article
Full-text available
The energy costs of athletic training can be substantial, and deficits arising from costs unmet by adequate energy intake, leading to a state of low energy availability, may adversely impact athlete health and performance. Life history theory is a branch of evolutionary theory that recognizes that the way the body uses energy-and responds to low energy availability-is an evolved trait. Energy is a finite resource that must be distributed throughout the body to simultaneously fuel all biological processes. When energy availability is low, insufficient energy may be available to equally support all processes. As energy used for one function cannot be used for others, energetic "trade-offs" will arise. Biological processes offering the greatest immediate survival value will be protected, even if this results in energy being diverted away from others, potentially leading to their downregulation. Athletes with low energy availability provide a useful model for anthropologists investigating the biological trade-offs that occur when energy is scarce, while the broader conceptual framework provided by life history theory may be useful to sport and exercise researchers who investigate the influence of low energy availability on athlete health and performance. The goals of this review are: (1) to describe the core tenets of life history theory; (2) consider trade-offs that might occur in athletes with low energy availability in the context of four broad biological areas: reproduction, somatic maintenance , growth, and immunity; and (3) use this evolutionary perspective to consider potential directions for future research.
... The concept of deliberately promoting reduced carbohydrate (CHO) availability to enhance endurance training induced adaptations of skeletal muscle (i.e. the 'train-low' paradigm) is gaining increased acceptance amongst athletic populations (Bartlett et al. 2015;Marquet et al. 2016;Burke et al. 2018;Stellingwerff et al. 2019). Over the last decade, a multitude of research designs examining the train-low approach (e.g. ...
... This point is especially relevant given that many endurance athletes present daily with transient periods of both CHO and calorie restriction due to multiple training sessions per day as well as longer term periods (i.e. weeks) of sub-optimal energy availability (Vogt et al. 2005;Fudge et al. 2006;Stellingwerff et al. 2019). ...
Article
Full-text available
Key points: Reduced carbohydrate (CHO) availability before and after exercise may augment endurance training-induced adaptations of human skeletal muscle, as mediated via modulation of cell signalling pathways. However, it is not known whether such responses are mediated by CHO restriction, energy restriction or a combination of both. In recovery from a twice per day training protocol where muscle glycogen concentration is maintained within 200-350 mmol.kg-1 dw, we demonstrate acute post-exercise CHO and energy restriction (i.e. <24 hours) does not potentiate potent cell signalling pathways that regulate hallmark adaptations associated with endurance training. In contrast, consuming CHO before, during and after an acute training session attenuated markers of bone resorption, effects that are independent of energy availability. Whilst the enhanced muscle adaptations associated with CHO restriction may be regulated by absolute muscle glycogen concentration, the acute within day fluctuations in CHO availability inherent to twice per day training may have chronic implications for bone turnover. Abstract: We examined the effects of post-exercise carbohydrate (CHO) and energy availability (EA) on potent skeletal muscle cell signalling pathways (regulating mitochondrial biogenesis and lipid metabolism) and indicators of bone metabolism. In a repeated measures design, nine males completed a morning (AM) and afternoon (PM) high-intensity interval (HIT) (8 × 5-min at 85% VO2peak ) running protocol (interspersed by 3.5 hours) under dietary conditions of 1) high CHO availability (HCHO: CHO ∼12 g.kg-1 , EA∼ 60 kcal.kg-1 FFM), 2) reduced CHO but high fat availability (LCHF: CHO ∼3 g.kg-1 , EA∼ 60 kcal.kg-1 FFM) or 3), reduced CHO and reduced energy availability (LCAL: CHO ∼3 g.kg-1 , EA∼ 20 kcal.kg-1 FFM). Muscle glycogen was reduced to ∼200 mmol.kg-1 dw in all trials immediately post PM-HIT (P < 0.01) and remained lower at 17-h (171, 194 and 316 mmol.kg-1 dw) post PM-HIT in LCHF and LCAL (P < 0.001) compared to HCHO. Exercise induced comparable p38MAPK phosphorylation (P < 0.05) immediately-post PM-HIT and similar mRNA expression (all P < 0.05) of PGC-1α, p53 and CPT1 mRNA in HCHO, LCHF and LCAL. Post-exercise circulating βCTX was lower in HCHO (P < 0.05) compared to LCHF and LCAL, whereas exercise-induced increases in IL-6 were larger in LCAL (P < 0.05) compared to LCHF and HCHO. In conditions where glycogen concentration is maintained within 200-350 mmol.kg-1 dw, we conclude post-exercise CHO and energy restriction (i.e. < 24 hours) does not potentiate cell signalling pathways that regulate hallmark adaptations associated with endurance training. In contrast, consuming CHO before, during and after HIT running attenuates bone resorption, effects that are independent of energy availability and circulating IL-6. This article is protected by copyright. All rights reserved.
... Consensus meetings and subsequent statements are fundamental in the generation of expert driven guidelines. Over the past 5 years, consensus statements in Sports Nutrition ranged between 0.3 and 0.5% (Williams and Rollo, 2015;Jeukendrup, 2017;Pitsiladis et al., 2017;Sutehall et al., 2018;Burke et al., 2019;Stellingwerff et al., 2019;Baker et al., 2020;Muniz-Pardos et al., 2021) of the published articles. Historically, consensus statements, such as the International Olympic Committee (IOC) consensus on sports supplements (Maughan et al., 2018) are drafted following in-person meetings of leading medical and scientific content experts. ...
... This results in studies with limited ecological validity. In order to establish the efficacy of nutrition parameters for performance enhancement for all relevant populations, we need to better understand the competition demands of sport (Stellingwerff et al., 2019). Recent advances in wearable technologies and real-time monitoring have accelerated the shift in research from the laboratory to the field in order to enhance ecological validity. ...
Article
Full-text available
Sports nutrition is a relatively new discipline; with ~100 published papers/year in the 1990s to ~3,500+ papers/year today. Historically, sports nutrition research was primarily initiated by university-based exercise physiologists who developed new methodologies that could be impacted by nutrition interventions (e.g., carbohydrate/fat oxidation by whole body calorimetry and muscle glycogen by muscle biopsies). Application of these methods in seminal studies helped develop current sports nutrition guidelines as compiled in several expert consensus statements. Despite this wealth of knowledge, a limitation of the current evidence is the lack of appropriate intervention studies (e.g., randomized controlled clinical trials) in elite athlete populations that are ecologically valid (e.g., in real-life training and competition settings). Over the last decade, there has been an explosion of sports science technologies, methodologies, and innovations. Some of these recent advances are field-based, thus, providing the opportunity to accelerate the application of ecologically valid personalized sports nutrition interventions. Conversely, the acceleration of novel technologies and commercial solutions, especially in the field of biotechnology and software/app development, has far outstripped the scientific communities' ability to validate the effectiveness and utility of the vast majority of these new commercial technologies. This mini-review will highlight historical and present innovations with particular focus on technological innovations in sports nutrition that are expected to advance the field into the future. Indeed, the development and sharing of more “big data,” integrating field-based measurements, resulting in more ecologically valid evidence for efficacy and personalized prescriptions, are all future key opportunities to further advance the field of sports nutrition.
... The diet of athletes was not analyzed in this review as there is an extremely wide range of specific diet approaches among different sports, countries, coaching teams and individuals even in one sports discipline. In addition, the periodized nutrition regime is widespread among athletes and each nutrition macro-, meso-and microcycle affects lipid metabolism in a unique way [40,41]. The same is for supplements or medicine. ...
Article
Regular physical activity significantly affects lipid status. In this literature review, the specific features of athletes blood lipid profiles were analysed. Professional athletes blood lipid status was found considerably preferable compared to sex- and age-matched sedentary population. Regardless of endurance or power type of sports activities, athletes perform lower levels of TC, LDL-C and TG and comparable or higher blood levels of HDL-C. The differences in blood lipids levels and sports disciplines were introduced. Although there are much more factors as diet, place of origin, training regime and even genetic predisposition that should be taken into consideration for future research.
... Jika keunikan tersebut mendapat perhatian khusus, maka atlet akan dapat memanfaatkan potensi-potensi yang dimilikinya secara maksimal (E. E. Smith & Allen, 2019;Stellingwerff, Morton, & Burke, 2019). ...
Article
Full-text available
p> The development of the world is now complex, problems are diverse, including in sports settings. The problem of athletes is more complex, not a few athletes who do not compete because of low self-management, unstable emotional control and even motivation and performance that are not optimal. Not to mention the condition of the relationship between athletes and athletes, athletes with coaches and even family problems that are Carrie away and affect psychological conditions during sparring in the field. The condition requires the existence of a special psychological companion for athletes, this condition makes the background of the need for sports counseling, a sports counselor can accompany the need for special personnel skilled and mastering the psychological concepts of athletes. This has become a new alternative for counselors in performing. Script will present the background of the need for sports counseling services, athlete’s problems, direction of sports counseling services and opportunities and challenges. </p
... Overall, protein recommendation for physically active adults are likely more nuanced whereby the "optimal" amount of protein to consume needs to take into account exercise mode, intensity, duration, and/or health/performance goals within the recommendation. This notion is consistent with periodized nutrition frameworks for carbohydrates commonly advocated to optimize training prescriptions and adaptations, especially for athletes (94). ...
Article
Full-text available
A healthy eating pattern, regardless of age, should consist of ingesting high quality protein preferably in adequate amounts across all meals throughout the day. Of particular relevance to overall health is the growth, development, and maintenance of skeletal muscle tissue. Skeletal muscle not only contributes to physical strength and performance, but also contributes to efficient macronutrient utilization and storage. Achieving an optimal amount of muscle mass begins early in life with transitions to “steady-state” maintenance as an adult, and then safeguarding against ultimate decline of muscle mass with age, all of which are influenced by physical activity and dietary (e.g., protein) factors. Current protein recommendations, as defined by recommended dietary allowances (RDA) for the US population or the population reference intakes (PRI) in Europe, are set to cover basic needs; however, it is thought that a higher protein intake might be necessary for optimizing muscle mass, especially for adults and individuals with an active lifestyle. It is necessary to balance the accurate assessment of protein quality (e.g., digestible indispensable amino acid score; DIAAS) with methods that provide a physiological correlate (e.g., established measures of protein synthesis, substrate oxidation, lean mass retention, or accrual, etc.) in order to accurately define protein requirements for these physiological outcomes. Moreover, current recommendations need to shift from single nutrient guidelines to whole food based guidelines in order to practically acknowledge food matrix interactions and other required nutrients for potentially optimizing the health effects of food. The aim of this paper is to discuss protein quality and amount that should be consumed with consideration to the presence of non-protein constituents within a food matrix and potential interactions with physical activity to maximize muscle mass throughout life.
... The aforementioned changes in self-reported dietary intake in TRE led to a 14% and 11% reduction in carbohydrate intake at MID and POST, respectively. The manipulation of carbohydrate intake is a common nutritional strategy among endurance athletes with the aim of improving metabolic flexibility and augmenting mitochondrial biogenesis but requires careful planning and consideration of the energy requirements for exercise training (30). The observed decline in energy and carbohydrate intake appears to be spontaneous in nature rather than a conscious or intentional reduction and, therefore, if prolonged may lead to a state of low energy availability in the absence of a decline in training load. ...
Article
Purpose: Eight weeks of time-restricted eating (TRE) in concert with habitual exercise training was investigated for effects on body composition, energy and macronutrient intakes, indices of endurance running performance, and markers of metabolic health in endurance athletes. Methods: Male middle and long distance runners (n=23) were randomly assigned to TRE (n=12), or habitual dietary intake (CON; n=11). TRE required participants to consume all of their dietary intake within an 8 h eating window (so-called "16:8" TRE), but dietary patterns, food choices, and energy intake were ad libitum during this window. Participants continued their habitual training during the intervention period. Participants completed an incremental exercise test before (PRE) and after (POST) the 8 week intervention for assessment of blood lactate concentrations, running economy and maximal oxygen uptake. Fasted blood samples were analysed for glucose, insulin and triglyceride concentrations. Dietary intake was assessed at PRE, MID (week 4), and POST using a four-day semi-weighed food diary. Results: Seventeen participants (TRE, n=10; CON, n=7) completed the intervention. Training load did not differ between groups for the duration of the intervention period. TRE resulted in a reduction in body mass (mean difference of -1.92 (95% CI, -3.52 to -0.32) kg, P=0.022). Self-reported daily energy intake was lower in TRE at MID and POST (group*time interaction, P=0.049). No effect of TRE was observed for oxygen consumption, respiratory exchange ratio, running economy, blood lactate concentrations or heart rate during exercise, nor were any effects on glucose, insulin or triglyceride concentrations observed. Conclusion: Eight weeks of 16:8 TRE in middle and long distance runners resulted in a decrease in body mass commensurate with a reduction in daily energy intake, but did not alter indices of endurance running performance or metabolic health.
... In an attempt to optimize both training adaptations and acute performance during key training sessions, current sport nutrition guidelines suggest adjusting energy and CHO intake in response to an athlete's training schedule (6). This can allow some training to be performed with high-CHO availability in order to enhance glycolytic and CHO-oxidation pathways and some training to be performed with low-CHO availability to increase the activation of acute cell signaling pathways related to mitochondrial biogenesis and lipid oxidation (7). ...
Article
Objective: The purpose of this study was to determine the self-reported beliefs and practices relating to pre-exercise nutrition intake among endurance athletes of varying ages and competitive levels and examine differences based on sex, competitive level, and habitual dietary pattern. Method: An anonymous online survey was circulated internationally in English and completed by 1950 athletes of varying competitive levels (51.0% female, mean age 40.9 years [range 18:78]). Survey questions included training background, determinants of pre-exercise nutrition intake and composition, and timing relative to exercise. Results: Prior to morning exercise, 36.4%, 36.0%, and 27.6% of athletes consumed carbohydrate-containing food/drinks before almost every workout, some of the time, and never/rarely, respectively, with significant effects of sex (p < 0.001, Cramer's V (ϕc) = 0.15) and competitive level (p < 0.001, ϕc = 0.09). Nutritional intake before exercise varied based on workout duration for 47.6% of athletes, with significant effects of sex (ϕc = 0.15) and habitual diet (ϕc = 0.19), and based on workout intensity for 39.1% of athletes, with significant effects of sex (ϕc = 0.13) and habitual diet (ϕc = 0.17, all p < 0.001). Additionally, 89.0% of athletes reported using at least some type of dietary supplement (including caffeine from coffee/tea) within 1 hour before exercise. Conclusions: Overall, nearly all factors measured relating to pre-exercise nutrition intake varied by sex, competitive level, habitual dietary pattern, and/or intensity/duration of the training session and suggest a large number of athletes may not be following current recommendations for optimizing endurance training adaptations.
... when athletes undergo strenuous meso-and macrocycle training (38). ...
Article
Full-text available
Cyclists often apply block periodization to high training volumes in meso-and macrocycles to optimize training adaptation and to prepare for competition. Body mass influences performance in many sports, including endurance disciplines, and conditions related to the syndrome Relative Energy Deficiency in Sports (RED-S) such as metabolic adaptations and premature osteoporosis have also been reported in male cyclists. This study aimed to determine how a 4-week mesocycle of intensified endurance training designed to increase performance, would affect markers of REDS in well-trained male cyclists. Twenty-two participants (age: 33.5 ± 6.6 years, height: 181.4 ± 5.2 cm, weight: 76.5 ± 7.4 kg, peak oxygen uptake (VO 2peak): 63.5 ± 6.6 mL·kg −1 ·min −1) were recruited and instructed to maintain their background training load and to follow a supervised training protocol consisting of three high-intensity interval training sessions per week with a work duration of 32 min per session. Protocols included pre-and postintervention assessment of resting metabolic rate (RMR) using a ventilated hood, body composition and bone health by dual-energy X-ray absorptiometry (DXA), blood samples, energy intake, and aerobic performance. The interval training increased participants' aerobic performance-peak power output [4.8%, p < 0.001], VO 2peak [2.4%, p = 0.005], and functional threshold power [6.5%, p < 0.001] as well as total testosterone levels [8.1%, p = 0.011]-while no changes were observed in free testosterone [4.1%, p = 0.326]. Bodyweight, body composition, and energy intake were unchanged from pre-to post-test. Triiodothyronine (T 3) [4.8%, p = 0.008], absolute RMR [3.0%, p = 0.010], relative RMR [2.6%, p = 0.013], and RMR ratio [3.3%, p = 0.011] decreased, and cortisol levels increased [12.9%, p = 0.021], while no change were observed in the total testosterone:cortisol ratio [1.6%, p = 0.789] or the free testosterone:cortisol (fT:cor) ratio [3.2%, p = 0.556]. A subgroup analysis of the five participants with the largest increase Stenqvist et al. Hormonal Response in Male Cyclists in fT:cor ratio, revealed a greater improvement in functional threshold power (9.5 vs. 2.5%, p = 0.037), and higher relative RMR (0.6 vs. −4.2% p = 0.039, respectively). In conclusion, 4 weeks of intensified endurance interval training increased the athletes' aerobic performance and testosterone levels. However, negative changes in markers related to REDS , such as a reduction in RMR and T 3 , and an increase in cortisol were observed. These results indicate the complexity involved, and that male athletes are at risk of developing clinical indications of REDS even during a short 4-week endurance training mesocycle.
... Additionally, muscle glycogen acts as a regulatory molecule (32) that is able to modulate cell signaling and transcriptional responses to exercise and subsequently augment selected skeletal muscle markers of training adaptation [e.g., succinate dehydrogenase (29), citrate synthase (12), and ␤-hydroxyacyl-CoA dehydrogenase (18) enzyme activity and cytochrome-c oxidase subunit IV content (47)]. Most notably, exercise commenced with reduced muscle glycogen [as defined as a "train-low" session (40)] augments the AMP-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor ␥ coactivator-1␣ (PGC-1␣) signaling axis (3,35,39,46) and results in the augmented expression of target genes with putative roles in the regulation of mitochondrial biogenesis and substrate utilization (3,25,33). Although a multitude of research designs have been used to study the physiological and molecular responses to train-low exercise, the recently developed "sleep-low, train-low" model [which requires athletes to perform an evening training session, restrict carbohydrate (CHO) during overnight recovery, and then complete a fasted training session the subsequent morning] provides a potent strategy to augment mitochondria-related cell signaling (3,5,25). ...
... Theme 1. Periodization of Nutrition Strategies in the Yearly Training Plan (Stellingwerff et al., 2019b) Periodization is a cornerstone concept in training for Athletics whereby the exercise load (mode, frequency, intensity, and duration) is strategically manipulated within a sequence of cycles to gradually achieve the physical, biomechanical, physiological, neuromuscular, and psychological attributes needed for success at chosen competition(s). It is self-evident therefore that the Athlete's dietary intake and nutrition strategies should be continually changing to optimize the adaptive effects from the ever changing training program. ...
Article
Full-text available
The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete's well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a "food first" policy should underpin an Athlete's nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.
... Programs of Distance Athletes "Periodized nutrition," the strategic combination of nutrition and exercise to optimize training adaptations and competition performance (Jeukendrup, 2017a), is explained in relation to Athletics by Stellingwerff et al. (2019). In distance events, a variety of strategies, often in apparent conflict with each other but nevertheless targeted at enhancing the specific session or training phase, should be integrated into the annual, meso, and microcycles of training according to the athletes' individualized and changing goals. ...
Article
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.
... It should be noted that adaptations, initiated by exercise, can be amplified or reduced by nutrition. A well-balanced diet plays a key role in proper recovery and enhancing performance, but so too do changes in nutritional intake in response to certain periods of training, so-called nutrition periodization [4]. Periodized nutrition supports training levels and requirements for energy and macronutrients demands throughout a season and/or training period [5]. ...
Article
Full-text available
A well-balanced diet is one of the main factors that may play a supportive role in enhancing acute training stimuli in optimal training adaptation. The aim of the present study was to examine the energy and macro-and micronutrient intake including and excluding supplements among top-level Polish football players during one week of the general preparatory period. In addition, the study looked at whether athletes consume carbohydrates in recommended amounts, depending on the completed training sessions. A total of 26 professional football players were included in the study. The preseason dietary intake was assessed using a 7-day estimated food record. The energy value of the diet and the amounts of the dietary ingredients were assessed using the software Dieta 6.0. The average consumption of energy, vitamin B 2 , vitamin C, vitamin E, folate, and calcium was lower than recommendations, and average intake of sodium and potassium was higher than the norm in the diets of the athletes. The results of this study do not confirm the justification for adding protein preparations to diets of the studied players. Furthermore, football players dietary carbohydrate intake was relatively low in comparison to requirements based on training loads. Based on our results we conclude that further work is necessary to reinforce education about nutritional habits and adjust nutritional strategies to individual needs to enhance athletic performance.
... Ancak sporcuların spor performansını artırmak için basit şeker içeren besinleri sıklıkla tükettikleri ve bu nedenle sporcularda diş çürüğünün yaygın olarak görüldüğü bildirilmektedir. 25,26 Ağız ve diş sağlığı ile ilgili hastalıklar sporcularda yaygın olarak görülen kronik hastalıklar olup, ağız hastalıklarının sistemik hastalıklar ile olan ilişkisi yapılan çalışmalar ile gösterilmiştir. 27,28 Bu nedenle sporcularda var olabilecek diş çürüklerinin spor performansını negatif etkileyebileceği unutulmamalı ve basit şeker tüketim miktarının artmasının ağız diş sağlığını negatif etkileyerek bu döngüde olumsuz rol alabileceği göz önünde bulundurulmalıdır. ...
Article
Full-text available
Sporcular, yüksek şiddette ve/veya uzun süreli antrenman yaptıkları dönemde, sağlıklarını korumak ve antrenmanın etkilerini maksimum düzeye çıkar-mak için diyetleri ile yeterli miktarda enerji almalı-dır. 1 Karbonhidratlar sporcular için temel enerji kaynağıdır. 2 Spor beslenmesinde, müsabaka veya an-trenman sırasında glikojen depolarının optimal dü-zeyde korunması ve antrenman sonrasında toparlan-manın optimal düzeyde sağlanması için karbonhidrat içeren besin tüketimine önem verilmelidir. 3 Karbon-hidratlar spor beslenmesi için temel makro besin öge-sidir ve içerdikleri şeker molekülü sayısına göre basit ORİJİNAL ARAŞTIRMA ÖZET Amaç: Çalışmamızın amacı sporcularda basit şeker tüketiminin ağız ve diş sağlığı üzerine olan etkisini incelemektir. Gereç ve Yön-temler: Çalışmaya, yaşları 15,8±2,6 yıl olan toplam 64 sporcu (43 erkek, 21 kadın) dâhil edildi. Sporcular, basit şeker tüketimi %10'un altında (basit şeker tüketimi az) olanlar ile %10 ve üzerinde (basit şeker tüketimi fazla) olanlar olmak üzere 2 gruba ayrıldı. Sporcuların çürük, kayıp ve dolgulu diş sayıları diş hekimi tarafından klinik muayene ile belirlendi. İki grubun çürük, kayıp ve dolgulu diş sayıları toplamı alı-narak çürük, kayıp, dolgulu diş sayısı toplamı (DMFT) indeksleri he-saplandı. İstatistiksel anlamlılık düzeyi p<0,05 olarak kabul edildi. Bulgular: Basit şeker tüketimi fazla olan sporcuların çürük diş sayısı-nın daha fazla olduğu belirlenirken (p<0,05), kayıp ve dolgulu diş sa-yıları arasında ise istatistiksel olarak anlamlı bir farklılık olmadığı belirlendi (p>0,05). Basit şeker tüketimi fazla olan sporcuların vücut ağırlığı ve beden kitle indeksi ile günlük enerji alımı ve karbonhidrat tü-ketiminin daha fazla olduğu belirlendi (p<0,05). Ayrıca basit şeker tü-ketimi fazla olan sporcuların yağsız vücut kütlesi ve kas kütlelerinin de daha fazla olduğu belirlendi (p<0,05). Sonuç: Enerjinin basit şekerden gelen yüzdesinin yüksek olması, sporcularda ağız ve diş sağlığını kötü etkilemektedir. Basit şeker tüketiminin sporcuların sağlık durumlarını ve vücut kompozisyonlarını etkileyebileceği düşünülmektedir. Anah tar Ke li me ler: Sporcu; beslenme; DMFT; karbonhidrat ABS TRACT Objective: The aim of our study is to show the effect of free sugar consumption and oral-dental health in athletes. Material and Methods: Sixty-four athletes (43 males, 21 females) with a mean age of 15,8±2,6 years who participated in competitions in different sports were included. The athletes were divided into two groups: those with a free sugar consumption of less than 10% (less than free sugar consumption) and those with 10% or more (more than free sugar consumption). Clinical examinations were performed by the dentist in order to determine the number of teeth affected by the caries and their results. Decay, missing and filled teeth with the total number of decay, missing, total number of filled teeth (DMFT) index were calculated. Statistical significance was accepted as p<0.05. Results: Body weight and body mass index, daily energy intake and carbohydrate consumption of athletes who had free sugar consumption were higher (p<0.05). In addition, it was determined that the fat free mass and muscle mass of the athletes who had free sugar consumption were higher (p<0.05). Conclusion: The high percentage of energy from free sugar affects the oral and dental health in athletes. The athletes of the free sugar consumption is thought to affect health status and body composition.
... A Framework for Periodized Nutrition for Athletics by Stellingwerf et al. divides training into macro, meso, and micro cycles depending on the athlete's goals [32]. Utilizing this concept, training the different skill levels is covered below. ...
Article
Full-text available
Nutritional guidance for competitive golfers to improve performance is limited. Recommendations and study conclusions from older research used smaller golf courses compared to today and require a reevaluation of energy expenditure. This review identifies aerobic fitness, in addition to strength, as a key determinant of success. A novel nutritional approach that incorporates carbohydrate supplementation to support aerobic fitness without sacrificing the ability to build strength is presented since longer courses require more stamina. Strategies for training, competition, and recovery are outlined based on different skill levels. American College of Sports Medicine (ACSM) guidelines for carbohydrates, protein, and hydration intake are tailored specifically for competitive golf based on this approach. Putting requires precise movement and can be affected by fatigue. Nutritional studies in golf and similar sports that require focused movements are presented, exhibiting an improvement with adequate hydration and carbohydrate status and caffeine use. Competitive golf poses unique challenges to an athlete and commonly used ergogenic supplements that can improve performance in a variety of circumstances during training, competition, and while traveling are reviewed.
... Nutritional periodisation is nutritional planning based on a training program to enhance its effects [203]. This periodisation means that the optimisation of nutritional strategies for performance consists not only on specifying which substance, but also adjusting the dosage and timing [87]. ...
Article
This article aims to describe the evolution of the use of supplements in sports, based on the reasoning and motivations of use. The consumption of substances, to boost sensory and physical qualities, has been a constant issue throughout human history. Sports competition, as social interaction, began to use sports supplements (SS), that are outside the doping list, to enhance the modifiable pillars of performance such as health, training, and competition. The initial categorisation of SS was chemical however, this coexists with a new classification based on functional aspects. SS use evolved from an intuitive-unproved period to a scientific approach. Nowadays, the focus of the SS is centred on efficiency, the search for new functions of classic SS and combinations, the search for new chemicals of a natural origin, and the effect of pre-pro-post-biotics as ergogenic agents. SS differs from nutritional supplements in the magnitude of the statistical differences in health and performance effects. The use of supplements is spreading from athletes to the general population looking to preventing health and antiaging issues, both with a relevant boost from the food industry, which generates a massive market for food and supplement companies. This new market requires new regulations.
... Short-distance running, jumping, throwing, and combined track and field events (e.g., heptathlon, decathlon) have demonstrated some performance enhancements with creatine use (63)(64)(65), although no benefit has been shown in middle distance (66), long distance (67), ultradistance, and mountain running events (68). Similarly, performance benefits have been seen in short distance swimming, there does not appear to be any effect on longer distance swimmers. ...
Article
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.
... This framework postulates that the provision of nutrition, with a focus on carbohydrate, should be tailored to the individual based on the exercise they undertake, and the time available for recovery, to optimize the desired training or performance response. This has since been recognized and accepted as an applied intervention strategy in the field of sports nutrition [5][6][7][8]. Yet, despite athletes knowing how to periodize carbohydrate and energy intake, they do not systematically follow current sports nutrition guidelines [9,10]. Heikura et al. [9] report that athletes struggled to stick to this dietary periodization behavior and highlight that the support required from a practitioner is highly personalized, and as a result time-consuming. ...
Article
Full-text available
Background It has recently been identified that manipulating carbohydrate availability around exercise activity can enhance training-induced metabolic adaptations. Despite this approach being accepted in the athletic populations, athletes do not systematically follow the guidelines. Digital environments appear to allow nutritionists to deliver this intervention at scale, reducing expensive human coaching time. Yet, digitally delivered dietary behavior change interventions for athletes and the coaching strategy to support them are still novel concepts within sports nutrition. Methods/design We aim to recruit 900 athletes across the UK. 500 athletes will be recruited to test the feasibility of a novel menu planner mobile application with coaching for 6 weeks. 250 athletes with pre-existing nutritionist support will also be recruited as control. We will then conduct a 4-week pilot sequential multiple assignment randomized trial (SMART) with an additional 150 athletes. In the SMART, athletes will be given the application and additional coaching according to their engagement responses. The primary outcomes are the mobile application and coach uptake, retention, engagement, and success in attaining carbohydrate periodization behavior. Secondary outcomes are changes in goal, weight, carbohydrate periodization self-efficacy, and beliefs about consequences. Due to the high attrition nature of digital interventions, all quantitative analyses will be carried out based on both the intention-to-treat and per-protocol principles. Discussion This study will be the first to investigate improving carbohydrate periodization using a digital approach and tailored coaching strategies under this context. Foundational evidence from this study will provide insights into the feasibility of the digital approach.
... In the context of nutrition and exercise prescription for athletes, an amalgamation of multiple "train low" strategies appears optimal as it can be tailored to individual requirements throughout a training cycle [28,29]. A popular example of this approach is the so called "sleep low-train low" strategy, which includes three different training-nutrition interventions: high-intensity training (HIT) in the evening to deplete glycogen stores, followed by low CHO availability overnight (i.e., sleeping low), and low-intensity training (LIT) the next morning under conditions of low muscle glycogen/CHO availability. ...
Article
Full-text available
Background"Sleep Low-Train Low" is a training-nutrition strategy intended to purposefully reduce muscle glycogen availability around specific exercise sessions, potentially amplifying the training stimulus via augmented cell signalling. The aim of this study was to assess the feasibility of a 3-week home-based "sleep low-train low" programme and its effects on cycling performance in trained athletes.Methods Fifty-five trained athletes (Functional Threshold Power [FTP]: 258 ± 52W) completed a home-based cycling training program consisting of evening high-intensity training (6 × 5 min at 105% FTP), followed by low-intensity training (1 hr at 75% FTP) the next morning, three times weekly for three consecutive weeks. Participant's daily carbohydrate (CHO) intake (6 g·kg-1·d-1) was matched but timed differently to manipulate CHO availability around exercise: no CHO consumption post- HIT until post-LIT sessions [Sleep Low (SL), n = 28] or CHO consumption evenly distributed throughout the day [Control (CON), n = 27]. Sessions were monitored remotely via power data uploaded to an online training platform, with performance tests conducted pre-, post-intervention.ResultsLIT exercise intensity reduced by 3% across week 1, 3 and 2% in week 2 (P < 0.01) with elevated RPE in SL vs. CON (P < 0.01). SL enhanced FTP by +5.5% vs. +1.2% in CON (P < 0.01). Comparable increases in 5-min peak power output (PPO) were observed between groups (P < 0.01) with +2.3% and +2.7% in SL and CON, respectively (P = 0.77). SL 1-min PPO was unchanged (+0.8%) whilst CON improved by +3.9% (P = 0.0144).Conclusion Despite reduced relative training intensity, our data demonstrate short-term "sleep low-train low" intervention improves FTP compared with typically "normal" CHO availability during exercise. Importantly, training was completed unsupervised at home (during the COVID-19 pandemic), thus demonstrating the feasibility of completing a "sleep low-train low" protocol under non-laboratory conditions.
... Robust evidence in the field of sports nutrition is found, e.g., carbohydrates in endurance sports and proteins in strength sports [1][2][3]. In addition to the amount and quality of macronutrients, aspects such as timing and periodization of proteins and carbohydrates are increasingly being researched [4][5][6][7]. One aspect of maximizing physical performance relative to body weight is improving body composition. ...
Article
Full-text available
Bioactive peptides are physiologically active peptides mostly derived from proteins following gastrointestinal digestion, fermentation or hydrolysis by proteolytic enzymes. It has been shown that bioactive peptides can be resorbed in their intact form and have repeatedly been shown to have a positive effect on health-related parameters such as hypertension, dyslipoproteinemia, inflammation and oxidative stress. In recent years, there has been increasing evidence that biologically active peptides could also play an important role in sports nutrition. Current studies have shown that bioactive peptides could have a positive impact on changes in body composition and muscular performance, reduce muscle damage following exercise and induce beneficial adaptions within the connective tissue. In the following overview, potential mechanisms as well as possible limitations regarding the sports-related effect of bioactive peptides and their potential mechanisms are presented and discussed. In addition, practical applications will be discussed on how bioactive peptides can be integrated into a nutritional approach in sports to enhance athletic performance as well as prevent injuries and improve the rehabilitation process.
... From a practical perspective, this so-called "trainlow" paradigm has been translated as "fuelling for the work required" whereby daily CHO intake is adjusted day-by-day and meal-by-meal according to the upcoming activity and the desired outcome of the exercise session i.e., promoting exercise intensity versus stimulating metabolic adaptations (Impey et al., 2018). Although such models of nutritional periodization are gaining increased recognition amongst endurance sports (Burke et al., 2018;Impey et al., 2018;Stellingwerff et al., 2019), no such models have yet been developed for the professional soccer player. ...
Article
Full-text available
Despite more than four decades of research examining the physical demands of match-play, quantification of the customary training loads of adult male professional soccer players is comparatively recent. The training loads experienced by players during weekly micro-cycles are influenced by phase of season, player position, frequency of games, player starting status, player-specific training goals and club coaching philosophy. From a macronutrient perspective, the periodization of physical loading within (i.e., match versus training days) and between contrasting micro-cycles (e.g., 1, 2 or 3 games per week schedules) has implications for daily carbohydrate (CHO) requirements. Indeed, aside from the well-recognised role of muscle glycogen as the predominant energy source during match-play, it is now recognised that the glycogen granule may exert regulatory roles in activating or attenuating the molecular machinery that modulate skeletal muscle adaptations to training. With this in mind, the concept of CHO periodization is gaining in popularity, whereby CHO intake is adjusted day-by-day and meal-by-meal according to the fuelling demands and specific goals of the upcoming session. On this basis, the present paper provides a contemporary overview and theoretical framework for which to periodize CHO availability for the professional soccer player according to the "fuel for the work" paradigm.
... However, athletes may deviate from this recommendation and use other nutritional strategies depending on the goals of the training block and the desired training adaptation. For example, in an effort to decrease body fat, improve fat utilization, and stimulate mitochondrial biogenesis, a lower carbohydrate diet or fasted exercise might be utilized during the off-season when exercise intensity is low [2,3]. However, longer durations of adherence to a low-carbohydrate diet may impair sport performance by limiting the body's sources of fuel and suppressing activation of glycolytic enzymes necessary for high intensity exercise [4,5]. ...
Article
Full-text available
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.
... Athletes need adequate energy and nutrition as fuel to sustain their long training hours and maintain their health [1]. Understanding an athlete's training periodization plan would give an idea or guideline for dietitians or nutritionists to match the nutrition strategies to support the training outcome [2]. Athlete training is divided into different cycles throughout the years and each of the cycles consists of different volume, frequencies and intensity of training sessions. ...
Article
Full-text available
—Individualized meal planning is a nutrition counseling strategy that focuses on improving food behavior changes. In the sports setting, the number of experts who are sports dietitians or nutritionists (SD/SN) is small in number, and yet the demand for creating meal planning for a vast number of athletes often cannot be met. Although some food recommender system had been proposed to provide healthy menu planning for the general population, no similar solution focused on the athlete's needs. In this study, the iDietScoreTM architecture was proposed to give athletes and active individuals virtual individualized meal planning based on their profile, includes energy and macronutrients requirement, sports category, age group, training cycles, training time and individual food preferences. Knowledge acquisition on the expert domain (the SN) was conducted prior to the system design through a semi-structured interview to understand meal planning activities' workflow. The architecture comprises: (1) iDietScoreTM web for SN/SD, (2) mobile application for athletes and active individuals and (3) expert system. SN/SD used the iDietScoreTM web to develop a meal plan and initiate the compilation meal plan database for further use in the expert system. The user used iDietScoreTM mobile app to receive the virtual individualized meal plan. An inference-based expert system was applied in the current study to generate the meal plan recommendation and meal reconstruction for the user. Further research is necessary to evaluate the prototype's usability by the target user (athletes and active individuals). © 2020 Science and Information Organization. All rights reserved.
... Although a lack of data is available for comparison, the diet of elite paracyclists and paratriathletes may be affected to a lesser degree than other populations due to their experience in modulating their dietary intake based on their current goals and exercise demands. 17 We also found no differences in alcohol intake which is in contrast to the findings of Ammar et al., 11 who found decreased alcohol binge drinking in the general population which they speculated may be related to younger individuals not being surrounded by their drinking peers. As nutrient requirements are not known for this diverse group of athletes, determination of inadequacy is not possible. ...
Article
Background With the declaration of the COVID-19 pandemic the 2020 Paralympic Games were postponed, impacting the athletes’ competition schedule for the year. Due to the interrupted competition schedule and potentially decreased motivation, Paralympic athletes may be at risk for a highly disrupted training schedule, impacting their ability to prepare for the 2021 Games. Objective Our purpose was to investigate the impact of the COVID-19 pandemic on the training, diet, and fitness of Paralympic cyclists and triathletes. Methods Twenty-four paracyclists and one paratriathlete (15 females and 10 males; age 37.6±9.3 years) completed two incremental exercise tests to assess sport-specific fitness and reported their training volume and intensity for a specified week prior to the pandemic (February) and again in March, April, and May (during pandemic). Participants also reported their dietary intake and sedentary screen time prior to and during the pandemic. Results The amount of time spent engaging in sedentary screen time increased from 4.5 to 6.1 hours (p<.001). No effect of the pandemic was found for training volume (14.2 vs 12.5 hours; p=.18), intensity (678 vs 650; p=.36), or dietary intake (p>.05). While fitness test duration was nominally increased for the second test (27.3 vs 27.9 minutes; p=.02), no difference was seen in fitness (average power output: 201W vs 204W; p=.5). Conclusion Time spent engaging in sedentary screen time activities increased during the COVID-19 pandemic, but there were no differences in training, fitness, or dietary intake over a short-term (3 months), demonstrating the resilience of these athletes.
Chapter
Contemporary sports nutrition guidelines recommend that each athlete develop a personalised, periodised and practical approach to eating that allows him or her to train hard, recover and adapt optimally, stay free of illness and injury and compete at their best at peak races. Competitive triathletes undertake a heavy training programme to prepare for three different sports while undertaking races varying in duration from 20 min to 10 h. The everyday diet should be adequate in energy availability, provide CHO in varying amounts and timing around workouts according to the benefits of training with low or high CHO availability and spread high-quality protein over the day to maximise the adaptive response to each session. Race nutrition requires a targeted and well-practised plan that maintains fuel and hydration goals over the duration of the specific event, according to the opportunities provided by the race and other challenges, such as a hot environment. Supplements and sports foods can make a small contribution to a sports nutrition plan, when medical supplements are used under supervision to prevent/treat nutrient deficiencies (e.g. iron or vitamin D) or when sports foods provide a convenient source of nutrients when it is impractical to eat whole foods. Finally, a few evidence-based performance supplements may contribute to optimal race performance when used according to best practice protocols to suit the triathlete’s goals and individual responsiveness.
Book
Full-text available
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.
Article
Full-text available
The aim is to form a balanced position regarding the ergogenic characteristics of new sports food products in the modern prac�tice of training highly qualified athletes on the basis of clinical-experimental evaluation of the effectiveness of special purpose real food additives. Materials and methods. Studies were carried out on laboratory animals (36 Wistar rats at the age of 3 months weighing 150–200 g and 16 Svetlogorsk mini-pigs) as well as on 102 high-qualified representatives of cyclic sports (all men aged 19–26) − members of national teams such as swimming (25), cross-country athletics (53), and skiing (24). As a control group, we studied 25 athletes of the same gender (all men), age and qualifications who received a placebo (starch capsules) for a long time during exercise. Placebo-con�trolled studies have been conducted on laboratory animals and athletes in compliance with the principles of bioethics. Results. It has been established that in the experiment the application of a new specialized food product MioActiv has a positive ef�fect on the physical performance of animals and delays the onset of fatigue, which significantly exceeds the corresponding character�istics in the placebo group. Athletes also showed an increase in speed when passing competitive distances by 18.7–21.4% (p < 0,05), as well as a significant increase in mental endurance indicators (p < 0,05). The approbation of the innovative pre-workout pharma�cological nutrient complex Pre-Fuse also showed the high efficacy and safety of this product with a positive effect of increasing the performance and endurance of animals, as well as the parameters of mental performance of athletes in the main groups, in contrast to the data in the placebo control groups. Conclusions. An analysis of the prescription components of new types of ergogenic sports nutrition and the presented results of preclinical and clinical studies conducted on the basis of the evidence-based medicine paradigm regarding the effectiveness of spe�cialized products indicate the complex action of these funds on various aspects of both physical and mental performance. From the materials presented in the article, it can be seen that specialized sports nutrition products of an ergogenic orientation can provide significant assistance in increasing sports results
Article
Cycling is predominantly an endurance sport in which fuel utilization for energy production relies on the availability and delivery of oxygen to exercising muscle. Nutrition and training interventions to improve endurance performance are continually evolving, but ultimately, prescription should aim to generate improvements in cycling power and velocity while prioritizing athlete health and well-being. The wide range of cycling events and the different environments in which events take place pose a variety of nutrition-related challenges for cyclists. This review addresses some of these challenges and highlights recent advancements in nutrition for cycling performance.
Article
Purpose of review: The present review summarized evidence on the role of carbohydrates in recovery from exercise within the context of acute and chronic effects on metabolism and performance. Recent findings: Recent studies demonstrate that, in contrast to recovery of muscle glycogen stores, the recovery of liver glycogen stores can be accelerated by the co-ingestion of fructose with glucose-based carbohydrates. Three recent studies suggest this can extend time-to-exhaustion during endurance exercise tests. However, periodically restricting carbohydrate intakes during recovery from some training sessions to slow the recovery of liver and muscle glycogen stores may, over time, result in a modest increase in the ability to oxidize fat during exercise in a fasted state. Whether this periodized strategy translates into a performance advantage in the fed state remains to be clearly demonstrated. Summary: To maximize recovery of glycogen stores and the capacity to perform in subsequent endurance exercise, athletes should consider ingesting at least 1.2 g carbohydrate per kilogram body mass per hour - for the first few hours of recovery - as a mixture of fructose and glucose-based carbohydrates. However, if a goal is increased capacity for fat oxidation, athletes should consider restricting carbohydrate intakes during recovery from some key training sessions. Video abstract: http://links.lww.com/COCN/A15.
Article
Optimising nutrition intake is a key component for supporting athletic performance and supporting adaption to training. Athletes often use micronutrient supplements in order to correct vitamin and mineral deficiencies, improve immune function, enhance recovery and or to optimise their performance. The aim of this review was to investigate the recent literature regarding micronutrients (specifically iron, vitamin C, vitamin E, vitamin D, calcium) and their effects on physical performance. Over the past ten years, several studies have investigated the impacts of these micronutrients on aspects of athletic performance, and several reviews have aimed to provide an overview of current use and effectiveness. Currently the balance of the literature suggests that micronutrient supplementation in well-nourished athletes does not enhance physical performance. Excessive intake of dietary supplements may impair the body's physiological responses to exercise that supports adaptation to training stress. In some cases, micronutrient supplementation is warranted, for example, with a diagnosed deficiency, when energy intake is compromised, or when training and competing at altitude, however these micronutrients should be prescribed by a medical professional. Athletes are encouraged to obtain adequate micronutrients from a wellbalanced and varied dietary intake.
Article
Hilkens et al. (1) raise an interesting question - should low bone mass in elite road-cyclists be treated? We believe the extent of low bone mass should determine if direct treatment is warranted. Although cyclists may have lower bone mass than other groups (1), their T-scores generally reside toward the lower end of population norms and many don’t present with clinical issues per se. Leaner individuals might have some advantage in road cycling, so it is unsurprising that cyclists reside toward the lower end of reference ranges, given that bone mass relates to body mass. The more relevant question may be whether cyclists have compromised bone strength, and whether this increases fracture risk. The most pertinent issue may be how to prevent further bone loss from occurring. The studies cited by Hilkens et al. (1) are on competitive cyclists, but the long-term consequences of cycling for bone are unclear. Bone mass decreases as we age and elite cyclists face several challenges that may, alongside low initial bone mass, create a “perfect storm” for bone (Figure 1). Reduced energy availability (EA) (a consequence of high training expenditure, with or without restricted intake) is arguably the greatest challenge for cyclists’ bone (3). Maintaining adequate EA throughout the season may be unrealistic, particularly when aiming for “race-weight”, but periodization of nutritional practices (4) may reduce the extent and severity of low EA, thus protecting bone. High-impact exercise may be a useful adjunct to training (2), given that cycling is largely unloaded and unlikely to be osteogenic.
Article
Sportler, die ihre Ernährung an das Training anpassen, können ihre Leistungsfähigkeit erhöhen und die Regeneration verbessern. Eine Ernährungsperiodisierung wie das Intervallfasten oder der vorübergehende Verzicht auf eine energetisch ausreichende Nahrungsaufnahme, kann die Reizwirksamkeit des Trainings erhöhen. Davon profitieren insbesondere Sportler, die eine Veränderung der Körperzusammensetzung bewirken wollen.
Article
Sportler, die ihre Ernährung an das Training anpassen, können ihre Leistungsfähigkeit erhöhen und die Regeneration verbessern. Eine Ernährungsperiodisierung, wie das Intervallfasten oder der vorübergehende Verzicht auf eine energetisch ausreichende Nahrungsaufnahme, kann die Reizwirksamkeit des Trainings erhöhen. Davon profitieren insbesondere Sportler, die eine Veränderung der Körperzusammensetzung bewirken wollen.
Chapter
This chapter discusses the uses of biologically active peptides in sports nutrition and their potential mechanisms. In the beginning, it presents physiological parameters that determine athletic performance and how they may be positively influenced by nutrition and potentially the intake of bioactive peptides. It then discusses the potential effects of bioactive peptides on first body composition and muscular performance, second muscle damage, and lastly adaptions of connective tissue. The following section outlines the limitations of previous research about bioactive peptides and their potential mechanisms. By the end of the chapter, it presents practical applications that may help athletes to integrate bioactive peptides into sports nutrition to improve athletic performance as well as injury prevention and rehabilitation.
Article
Though genetics account for up to 50% of our bone health, it is the lifestyle factors (nutritional, physical activity and hormonal status) that determine the difference between a healthy skeleton and frail fracture-prone bones (1). Osteoporosis, a systemic skeletal disorder associated with reduced bone mineral density and increased risk for fracture, is a serious public health problem globally (2) costing about $75 billion for the treatment in the US alone. Mortality rates due to osteoporotic fracture range from 10% to 45% in the first year and is noted following spine and hip fractures (3). There are several types of osteoporosis; postmenopausal osteoporosis, senile osteoporosis (both of which categorized as primary osteoporosis) and secondary osteoporosis. The causes of secondary osteoporosis are many, ranging from low calcium intake, Klinefelter’s syndromes, to inflammatory digestive diseases and low impact activities such as cycling.
Article
Full-text available
When the amount of physical activity increases due to sports, it is necessary to consider the appropriate amountof energy and intake of each nutrient commensurate with the amount of activity. In addition, elite athletes withrigorous training need to be aware of their excess or deficiency of certain nutrients to prevent injuries and illnesses.In particular, the chronic lack of energy intake of athletes has been clearly shown to be related to future diseases,which is a major problem. On the other hand, research is progressing on how to devise nutrient intake accordingto training and game schedules, and supplements for the purpose of improving performance are also being actively developed. There are many problems with the use of supplements, such as the relationship with doping controland a lack of education for junior athletes. In the future, nutrition at sports sites will require more personalizedsupport, and it is hoped that a large amount of evidence will be accumulated.
Article
Full-text available
While athletes’ nutrient intakes have been widely reported, few studies have assessed the diet quality of athletes. This is the first study to evaluate the diet quality of athletes using the purpose-built Athlete Diet Index (ADI). A convenience sample of 165 elite athletes from Australian sporting institutions completed the ADI online, with subsequent automated results provided to their respective accredited sports dietitians (ASDs). At the completion of athlete participation, ASDs (n = 12) responded to a range of survey items using a Likert scale (i.e., 1 = strongly agree to 5 = strongly disagree) to determine the suitability of the ADI in practice. Differences in ADI scores for demographics and sport-specific variables were investigated using independent t-tests, analysis of variance (ANOVA) and Bonferroni multiple comparisons. Spearman’s rank correlation was used to assess the association between total scores and demographics. The mean total ADI score was 91.4 ± 12.2 (range 53–117, out of a possible 125). While there was no difference in total scores based on demographics or sport-specific variables; team sport athletes scored higher than individual sport athletes (92.7 vs. 88.5, P < 0.05). Athletes training fewer hours (i.e., 0–11 h/week) scored higher on Dietary Habits sub-scores compared with athletes training more hours (> 12 h/week; P < 0.05), suggesting that athletes who train longer may be at risk of a compromised dietary pattern or less than optimal nutrition practices that support training. Most (75%) ASDs surveyed strongly agreed with the perceived utility of the ADI for screening athletes and identifying areas for nutrition support, confirming its suitability for use in practice.
Article
Full-text available
Athletes participating in the athletics (track and field) events of jumps, throws, and combined events (CEs; seven-event heptathlon and 10-event decathlon) engage in training and competition that emphasize speed and explosive movements, requiring optimal power-weight ratios. While these athletes represent a wide range of somatotypes, they share an emphasis on Type IIa and IIx muscle fiber typing. In general, athletes competing in jumps tend to have a lower body mass and may benefit from a higher protein (1.5-1.8 g PRO·kg-1·day-1) and lower carbohydrate (3-6 g CHO·kg-1·day-1) diet. Throwers tend to have a higher body mass, but with considerable differences between events. Their intense, whole-body training program suggests higher PRO requirements (1.5-2.2 g PRO·kg-1·day-1), while CHO needs (per kg) are similar to jumpers. The CE athletes must strike a balance between strength and muscle mass for throws and sprints, while maintaining a low enough body mass to maximize performance in jumps and middle-distance events. CE athletes may benefit from a higher PRO (1.5-2 g PRO·kg-1·day-1) and moderate CHO (5-8 g CHO·kg-1·day-1) diet with good energy availability to support multiple daily training sessions. Since they compete over 2 days, well-rehearsed competition-day fueling and recovery strategies are imperative for CE athletes. Depending on their events' bioenergetic demands, athletes in throws, jumps, and CE may benefit from the periodized use of ergogenic aids, including creatine, caffeine, and/or beta-alanine. The diverse training demands, physiques, and competitive environments of jumpers, throwers, and CE athletes necessitate nutrition interventions that are periodized throughout the season and tailored to the individual needs of the athlete.
Article
Full-text available
Middle-distance runners utilize the full continuum of energy systems throughout training, and given the infinite competition tactical scenarios, this event group is highly complex from a performance intervention point of view. However, this complexity results in numerous potential periodized nutrition interventions to optimize middle-distance training adaptation and competition performance. Middle-distance race intensity is extreme, with 800m to 5,000m races being at ~95 to 130% of VO2max. Accordingly, elite middle-distance runners have primarily Type IIa / IIx fiber morphology and rely almost exclusively on carbohydrate (primarily muscle glycogen) metabolic pathways for producing ATP. Consequently, the principle nutritional interventions that should be emphasized are those that optimize muscle glycogen contents to support high glycolytic flux (resulting in very high lactate values, of >20mmol/L in some athletes) with appropriate buffering capabilities, while optimizing power to weight ratios, all in a macro and micro-periodized manner. From youth to elite level, middle-distance athletes have arduous racing schedules (10-25 races/year), coupled with excessive global travel, which can take a physical and emotional toll. Accordingly, proactive and integrated nutrition planning can have a profound recovery effect over a long race season, as well as optimizing recovery during rounds of championship racing. Finally, with evidence-based implementation, and an appropriate risk/reward assessment, several ergogenic aids may have an adaptive and/or performance-enhancing effect in the middle-distance athlete. Given that elite middle-distance athletes undertake ~400 to 800 training sessions with 10 to 25 races/year, there are countless opportunities to implement various periodized acute and chronic nutrition-based interventions to optimize performance.
Article
Full-text available
Background: Skeletal muscle glycogen is an important energy source for muscle contraction and a key regulator of metabolic responses to exercise. Manipulation of muscle glycogen is therefore a strategy to improve performance in competitions and potentially adaptation to training. However, assessing muscle glycogen in the field is impractical, and there are no normative values for glycogen concentration at rest and during exercise. Objective: The objective of this study was to meta-analyse the effects of fitness, acute dietary carbohydrate (CHO) availability and other factors on muscle glycogen concentration at rest and during exercise of different durations and intensities. Data source and study selection: PubMed was used to search for original articles in English published up until February 2018. Search terms included muscle glycogen and exercise, filtered for humans. The analysis incorporated 181 studies of continuous or intermittent cycling and running by healthy participants, with muscle glycogen at rest and during exercise determined by biochemical analysis of biopsies. Data analysis: Resting muscle glycogen was determined with a meta-regression mixed model that included fixed effects for fitness status [linear, as maximal oxygen uptake ([Formula: see text]O2max) in mL·kg-1·min-1] and CHO availability (three levels: high, ≥ 6 g·kg-1 of CHO per day for ≥ 3 days or ≥ 7 g·kg-1 CHO per day for ≥ 2 days; low, glycogen depletion and low-CHO diet; and normal, neither high nor low, or not specified in study). Muscle glycogen during exercise was determined with a meta-regression mixed model that included fixed effects for fitness status, resting glycogen [linear, in mmol·kg-1 of dry mass (DM)], exercise duration (five levels, with means of 5, 23, 53 and 116 min, and time to fatigue), and exercise intensity (linear, as percentage of [Formula: see text]O2max); intensity, fitness and resting glycogen were interacted with duration, and there were also fixed effects for exercise modes, CHO ingestion, sex and muscle type. Random effects in both models accounted for between-study variance and within-study repeated measurement. Inferences about differences and changes in glycogen were based on acceptable uncertainty in standardised magnitudes, with thresholds for small, moderate, large and very large of 25, 75, 150 and 250 mmol·kg-1 of DM, respectively. Results: The resting glycogen concentration in the vastus lateralis of males with normal CHO availability and [Formula: see text]O2max (mean ± standard deviation, 53 ± 8 mL·kg-1·min-1) was 462 ± 132 mmol·kg-1. High CHO availability was associated with a moderate increase in resting glycogen (102, ± 47 mmol·kg-1; mean ± 90% confidence limits), whereas low availability was associated with a very large decrease (- 253, ± 30 mmol·kg-1). An increase in [Formula: see text]O2max of 10 mL·kg-1·min-1 had small effects with low and normal CHO availability (29, ± 44 and 67, ± 15 mmol·kg-1, respectively) and a moderate effect with high CHO availability (80, ± 40 mmol·kg-1). There were small clear increases in females and the gastrocnemius muscle. Clear modifying effects on glycogen utilisation during exercise were as follows: a 30% [Formula: see text]O2max increase in intensity, small (41, ± 20 mmol·kg-1) at 5 min and moderate (87-134 mmol·kg-1) at all other timepoints; an increase in baseline glycogen of 200 mmol·kg-1, small at 5-23 min (28-59 mmol·kg-1), moderate at 116 min (104, ± 15 mmol·kg-1) and moderate at fatigue (143, ± 33 mmol·kg-1); an increase in [Formula: see text]O2max of 10 mL·kg-1·min-1, mainly clear trivial effects; exercise mode (intermittent vs. continuous) and CHO ingestion, clear trivial effects. Small decreases in utilisation were observed in females (vs. males: - 30, ± 29 mmol·kg-1), gastrocnemius muscle (vs. vastus lateralis: - 31, ± 46 mmol·kg-1) and running (vs. cycling: - 70, ± 32 mmol·kg-1). Conclusion: Dietary CHO availability and fitness are important factors for resting muscle glycogen. Exercise intensity and baseline muscle glycogen are important factors determining glycogen use during exercise, especially with longer exercise duration. The meta-analysed effects may be useful normative values for prescription of endurance exercise.
Article
Full-text available
Since the introduction of the muscle biopsy technique in the late 1960s, our understanding of the regulation of muscle glycogen storage and metabolism has advanced considerably. Muscle glycogenolysis and rates of carbohydrate (CHO) oxidation are affected by factors such as exercise intensity, duration, training status and substrate availability. Such changes to the global exercise stimulus exert regulatory effects on key enzymes and transport proteins via both hormonal control and local allosteric regulation. Given the well-documented effects of high CHO availability on promoting exercise performance, elite endurance athletes are typically advised to ensure high CHO availability before, during and after high-intensity training sessions or competition. Nonetheless, in recognition that the glycogen granule is more than a simple fuel store, it is now also accepted that glycogen is a potent regulator of the molecular cell signaling pathways that regulate the oxidative phenotype. Accordingly, the concept of deliberately training with low CHO availability has now gained increased popularity amongst athletic circles. In this review, we present an overview of the regulatory control of CHO metabolism during exercise (with a specific emphasis on muscle glycogen utilization) in order to discuss the effects of both high and low CHO availability on modulating exercise performance and training adaptations, respectively.
Article
Full-text available
Deliberately training with reduced carbohydrate (CHO) availability to enhance endurance-training-induced metabolic adaptations of skeletal muscle (i.e. the ‘train low, compete high’ paradigm) is a hot topic within sport nutrition. Train-low studies involve periodically training (e.g., 30–50% of training sessions) with reduced CHO availability, where train-low models include twice per day training, fasted training, post-exercise CHO restriction and ‘sleep low, train low’. When compared with high CHO availability, data suggest that augmented cell signalling (73% of 11 studies), gene expression (75% of 12 studies) and training-induced increases in oxidative enzyme activity/protein content (78% of 9 studies) associated with ‘train low’ are especially apparent when training sessions are commenced within a specific range of muscle glycogen concentrations. Nonetheless, such muscle adaptations do not always translate to improved exercise performance (e.g. 37 and 63% of 11 studies show improvements or no change, respectively). Herein, we present our rationale for the glycogen threshold hypothesis, a window of muscle glycogen concentrations that simultaneously permits completion of required training workloads and activation of the molecular machinery regulating training adaptations. We also present the ‘fuel for the work required’ paradigm (representative of an amalgamation of train-low models) whereby CHO availability is adjusted in accordance with the demands of the upcoming training session(s). In order to strategically implement train-low sessions, our challenge now is to quantify the glycogen cost of habitual training sessions (so as to inform the attainment of any potential threshold) and ensure absolute training intensity is not compromised, while also creating a metabolic milieu conducive to facilitating the endurance phenotype.
Article
Full-text available
Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance (WDEB) in male athletes with suppressed and normal resting metabolic rate (RMR) and explore if within-day energy deficiency (WDED) is associated with endocrine markers of energy deficiency. Thirty-one male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included. The protocol comprised measurements of RMR by ventilated hood, and energy intake and energy expenditure to predict RMRratio (measured RMR/predicted RMR), energy availability (EA), 24-hour energy balance (EB) and WDEB in 1-hour intervals, assessment of body-composition by dual-energy X-ray absorptiometry, and blood plasma analysis. Subjects were categorized as having suppressed (RMRratio < 0.90, n=20) or normal RMR (RMRratio > 0.90, n=11). Despite no observed differences in 24-hour EB or EA between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8 - 21.8] hours vs. 10.8 [2.5 - 16.4], P=0.023), and had larger single-hour energy deficits compared to subjects with normal RMR (3265 ± 1963 kcal vs. -1340 ± 2439, P=0.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -0.499, P=0.004) and a lower testosterone:cortisol ratio (r = 0.431, P=0.015), but no associations with T3 or fasting blood glucose were observed. In conclusion, WDED was associated with suppressed RMR and catabolic markers in male endurance athletes.
Article
Full-text available
We aimed to (1) report energy availability (EA), metabolic/reproductive function, bone mineral density (BMD) and injury/illness rates in national/world-class female and male distance-athletes; and (2) investigate the robustness of various diagnostic criteria from the Female Athlete Triad (Triad), Low Energy Availability in Females Questionnaire (LEAF-Q) and Relative Energy Deficiency in Sport (RED-S) tools to identify risks associated with low EA. Athletes were distinguished according to benchmarks of reproductive function (amenorrheic [n=13] vs eumenorrheic [n=22]; low [lowest quartile of reference range, n=10] vs normal testosterone [n=14]) and EA calculated from 7-day food and training diaries (< or >30 kcal.kg-1FFM). Sex hormones (p<0.001), triiodothyronine (p<0.05) and BMD (females, p<0.05) were significantly lower in amenorrheic (37%) and low testosterone (40%; 15.1±3.0 nmol/L-1) athletes and bone injuries were ~4.5-fold more prevalent in amenorrheic (ES=0.85; large) and low testosterone (ES=0.52; moderate) groups compared to others. Categorization of females and males using Triad or RED-S tools revealed that higher risk groups had significantly lower T3 (female and male Triad and RED-S:p<0.05) and higher number of all-time fractures (male Triad:p<0.001; male RED-S and female Triad:p<0.01) as well as non-significant but markedly (up to 10-fold) higher number of training days lost to bone injuries during the preceding year. Based on the cross-sectional analysis, current reproductive function (questionnaires/blood hormone concentrations) appears to provide a more objective and accurate marker of optimal energy for health than the more error-prone and time-consuming dietary and training estimation of EA. This study also offers novel findings that athlete health is associated with EA indices.
Article
Full-text available
Periodization theory has, over the past seven decades, emerged as the preeminent training planning paradigm. The philosophical underpinnings of periodiza- tion theory can be traced back to the integration of diverse shaping influences, whereby coaching beliefs and traditions were blended with historically available scientific insights and contextualized against pervading social planning models. Since then, many dimensions of elite preparation have evolved significantly, as driven by a combination of coaching innovations and science-led advances in training theory, techniques, and technologies. These advances have been incorporated into the fabric of the pre-existing peri- odization planning framework, yet the philosophical assumptions underpinning periodization remain largely unchallenged and unchanged. One particularly influential academic sphere of study, the science of stress, particularly the work of Hans Selye, is repeatedly cited by theorists as a central pillar upon which periodization theory is founded. A fundamental assumption emanating from the early stress research is that physical stress is primarily a biologically mediated phenomenon: a presumption translated to athletic performance contexts as evidence that mechanical training stress directly regulates the magnitude of subsequent ‘fit- ness’ adaptations. Interestingly, however, since periodiza- tion theory first emerged, the science of stress has evolved extensively from its historical roots. This raises a funda- mental question: if the original scientific platform upon which periodization theory was founded has disintegrated, should we critically re-evaluate conventional perspectives through an updated conceptual lens? Realigning peri- odization philosophy with contemporary stress theory thus presents us with an opportunity to recalibrate training planning models with both contemporary scientific insight and progressive coaching practice.
Article
Full-text available
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.
Article
Full-text available
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.
Article
Full-text available
Background Endurance athletes perform periodized training in order to prepare for main competitions and maximize performance. However, the coupling between alterations of total energy expenditure (TEE), energy intake, and body composition during different seasonal training phases is unclear. So far, no systematic review has assessed fluctuations in TEE, energy intake, and/or body composition in endurance athletes across the training season.The purpose of this study was to (1) systematically analyze TEE, energy intake, and body composition in highly trained athletes of various endurance disciplines and of both sexes and (2) analyze fluctuations in these parameters across the training season. Methods An electronic database search was conducted on the SPORTDiscus and MEDLINE (January 1990–31 January 2015) databases using a combination of relevant keywords.Two independent reviewers identified potentially relevant studies. Where a consensus was not reached, a third reviewer was consulted. Original research articles that examined TEE, energy intake, and/or body composition in 18–40-year-old endurance athletes and reported the seasonal training phases of data assessment were included in the review. Articles were excluded if body composition was assessed by skinfold measurements, TEE was assessed by questionnaires, or data could not be split between the sexes.Two reviewers assessed the quality of studies independently. Data on subject characteristics, TEE, energy intake, and/or body composition were extracted from the included studies. Subjects were categorized according to their sex and endurance discipline and each study allocated a weight within categories based on the number of subjects assessed. Extracted data were used to calculate weighted means and standard deviations for parameters of TEE, energy intake, and/or body composition. ResultsFrom 3589 citations, 321 articles were identified as potentially relevant, with 82 meeting all of the inclusion criteria. TEE of endurance athletes was significantly higher during the competition phase than during the preparation phase (p < 0.001) and significantly higher than energy intake in both phases (p < 0.001). During the competition phase, both body mass and fat-free mass were significantly higher compared to other seasonal training phases (p < 0.05). Conclusions Limitations of the present study included insufficient data being available for all seasonal training phases and thus low explanatory power of single parameters. Additionally, the classification of the different seasonal training phases has to be discussed.Male and female endurance athletes show important training seasonal fluctuations in TEE, energy intake, and body composition. Therefore, dietary intake recommendations should take into consideration other factors including the actual training load, TEE, and body composition goals of the athlete.
Article
Full-text available
Accurate estimation of energy expenditure is a key element in determining the relationships between aspects of human behavior , physical activity, and overall health. 1,2 Although wear-able devices for estimating energy expenditure are becoming increasingly popular, there is little evidence regarding their validity. 3,4 This study was performed to examine the validity of total energy expenditure estimates made by several wearable devices compared with gold standard measurements for a standardized day (metabolic chamber method) and free-living days (doubly labeled water [DLW] method).
Article
Full-text available
A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.
Article
Full-text available
During the period 1985-2005, studies examined the proposal that adaptation to a low-carbohydrate (<25 % energy), high-fat (>60 % energy) diet (LCHF) to increase muscle fat utilization during exercise could enhance performance in trained individuals by reducing reliance on muscle glycogen. As little as 5 days of training with LCHF retools the muscle to enhance fat-burning capacity with robust changes that persist despite acute strategies to restore carbohydrate availability (e.g., glycogen supercompensation, carbohydrate intake during exercise). Furthermore, a 2- to 3-week exposure to minimal carbohydrate (<20 g/day) intake achieves adaptation to high blood ketone concentrations. However, the failure to detect clear performance benefits during endurance/ultra-endurance protocols, combined with evidence of impaired performance of high-intensity exercise via a down-regulation of carbohydrate metabolism led this author to dismiss the use of such fat-adaptation strategies by competitive athletes in conventional sports. Recent re-emergence of interest in LCHF diets, coupled with anecdotes of improved performance by sportspeople who follow them, has created a need to re-examine the potential benefits of this eating style. Unfortunately, the absence of new data prevents a different conclusion from being made. Notwithstanding the outcomes of future research, there is a need for better recognition of current sports nutrition guidelines that promote an individualized and periodized approach to fuel availability during training, allowing the athlete to prepare for competition performance with metabolic flexibility and optimal utilization of all muscle substrates. Nevertheless, there may be a few scenarios where LCHF diets are of benefit, or at least are not detrimental, for sports performance.
Article
Full-text available
Bone resorption is increased following running, with no change in bone formation. Feeding during exercise might attenuate this increase, preventing associated problems for bone. To investigate the immediate and short-term bone metabolic responses to carbohydrate (CHO) feeding during treadmill running. Ten men completed two 7 d trials, once being fed CHO (8% glucose immediately before, every 20 min during and immediately after exercise at a rate of 0.7 gCHO·kg(-1)BM·h(-1)) and once placebo (PBO). On day 4 of each trial, participants completed a 120 min treadmill run at 70% VO2max. Blood was taken at baseline (BASE) immediately after exercise (EE), after 60 (R1) and 120 (R2) min of recovery and on 3 follow-up days (FU1-FU3). Markers of bone resorption (β-CTX) and formation (P1NP) were measured, along with OC, PTH, ACa, PO4, GLP-2, IL-6, insulin, cortisol, leptin and OPG. Area under the curve was calculated in terms of the immediate (BASE, EE, R1 and R2) and short-term (BASE, FU1, FU2 and FU3) responses to exercise. β-CTX, P1NP and IL-6 responses to exercise were significantly lower in the immediate post-exercise period with CHO feeding (β-CTX: P=0.028; P1NP: P=0.021; IL-6: P=0.036), although there was no difference in the short-term response (β-CTX: P=0.856; P1NP: P=0.721; IL-6: P=0.327). No other variable was significantly affected by CHO feeding during exercise. CHO feeding during exercise attenuated the β-CTX and P1NP responses in the hours but not days following exercise, indicating an acute effect of CHO feeding on bone turnover. Copyright © 2015, Journal of Applied Physiology.
Article
Full-text available
Abstract A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body's ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes.
Article
Full-text available
Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR) coactivator-1α (PGC-1α) and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4): control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]). Gastrocnemius (GTN) muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP) assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E) finished with higher AMPK-α2 activity (147%, p<0.05), nuclear AMPK-α2 and PGC-1α, but no difference in AMPK-α1 activity compared to CON. In addition, PPAR-∂ binding to the CPT1 promoter was significantly increased only in the LG-E group. Finally, cell reporter studies in contracting C2C12 myotubes indicated that PPAR-∂ activity following contraction is sensitive to glucose availability, providing mechanistic insight into the association between PPAR-∂ and glycogen content/substrate availability. The present study is the first to examine PPAR-∂ activity in skeletal muscle in response to an acute bout of endurance exercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal muscle in response to exercise.
Article
Full-text available
The mechanisms that regulate the enhanced skeletal muscle oxidative capacity observed when training with reduced carbohydrate (CHO) availability are currently unknown. The aim of the present study was to test the hypothesis that reduced CHO availability enhances p53 signalling and expression of genes associated with regulation of mitochondrial biogenesis and substrate utilisation in human skeletal muscle. In a repeated measures design, muscle biopsies (vastus lateralis) were obtained from eight active males before and after performing an acute bout of high-intensity interval running with either high (HIGH) or low CHO availability (LOW). Resting muscle glycogen (HIGH, 467 ± 19; LOW, 103 ± 9 mmol.kg(-1) dw) was greater in HIGH compared with LOW (P<0.05). Phosphorylation (P-) of ACC(Ser79) (HIGH, 1.4 ± 0.4; LOW, 2.9 ± 0.9) and p53(Ser15) (HIGH, 0.9 ± 0.4; LOW, 2.6 ± 0.8) was higher in LOW immediately post- and 3 h post-exercise, respectively (P<0.05). Before and 3 h post-exercise, mRNA content of PDK4, Tfam, COXIV and PGC-1α were greater in LOW compared with HIGH (P<0.05) whereas CPT1 showed trend towards significance (P=0.09). However, only PGC-1α expression was increased by exercise (P<0.05) where 3-fold increases occurred independent of CHO availability. We conclude that the exercise-induced increase in p53 phosphorylation is enhanced in conditions of reduced CHO availability which may be related to upstream signalling through AMPK. Given the emergence of p53 as a molecular regulator of mitochondrial biogenesis, such nutritional modulation of contraction-induced p53 activation has implications for both athletic and clinical populations.
Article
Full-text available
Effective coaching is a mixture of pedagogy and principles of sciences, e.g., motor skill acquisition, sociology, and physiology, often referred to as the science of coaching. Instinctive or intuitive coaching has often been incorrectly viewed as the art of coaching. More important should be how coaches develop knowledge, how they access that knowledge at the appropriate times and how this affects their decision-making process. The study of expert coaches should allow inferences to be drawn from their development and applied to coach education. This article intends to clarify coaching expertise and examine the role of tacit knowledge within coaching. The lack of a clear development pathway for aspiring expert coaches is a clear indicator that the current coach education system needs review. Any effective education system should be based on knowledge and understanding rather than mimicry and the implications for the future of coach education are considered. (Contains 2 figures.)
Article
Full-text available
Recent studies suggest that carbohydrate restriction can improve the training-induced adaptation of muscle oxidative capacity. However, the importance of low muscle glycogen on the molecular signaling of mitochondrial biogenesis remains unclear. Here, we compare the effects of exercise with low (LG) and normal (NG) glycogen on different molecular factors involved in the regulation of mitochondrial biogenesis. Ten highly trained cyclists (VO2max 65 ± 1 ml/kg/min, W max 387 ± 8 W) exercised for 60 min at approximately 64 % VO2max with either low [166 ± 21 mmol/kg dry weight (dw)] or normal (478 ± 33 mmol/kg dw) muscle glycogen levels achieved by prior exercise/diet intervention. Muscle biopsies were taken before, and 3 h after, exercise. The mRNA of peroxisome proliferator-activated receptor-γ coactivator-1 was enhanced to a greater extent when exercise was performed with low compared with normal glycogen levels (8.1-fold vs. 2.5-fold increase). Cytochrome c oxidase subunit I and pyruvate dehydrogenase kinase isozyme 4 mRNA were increased after LG (1.3- and 114-fold increase, respectively), but not after NG. Phosphorylation of AMP-activated protein kinase, p38 mitogen-activated protein kinases and acetyl-CoA carboxylase was not changed 3 h post-exercise. Mitochondrial reactive oxygen species production and glutathione oxidative status tended to be reduced 3 h post-exercise. We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity.
Article
Full-text available
The planning and organization of athletic training have historically been much discussed and debated in the coaching and sports science literature. Various influential periodization theorists have devised, promoted, and substantiated particular training-planning models based on interpretation of the scientific evidence and individual beliefs and experiences. Superficially, these proposed planning models appear to differ substantially. However, at a deeper level, it can be suggested that such models share a deep-rooted cultural heritage underpinned by a common set of historically pervasive planning beliefs and assumptions. A concern with certain of these formative assumptions is that, although no longer scientifically justifiable, their shaping influence remains deeply embedded. In recent years substantial evidence has emerged demonstrating that training responses vary extensively, depending upon multiple underlying factors. Such findings challenge the appropriateness of applying generic methodologies, founded in overly simplistic rule-based decision making, to the planning problems posed by inherently complex biological systems. The purpose of this review is not to suggest a whole-scale rejection of periodization theories but to promote a refined awareness of their various strengths and weaknesses. Eminent periodization theorists-and their variously proposed periodization models-have contributed substantially to the evolution of training-planning practice. However, there is a logical line of reasoning suggesting an urgent need for periodization theories to be realigned with contemporary elite practice and modern scientific conceptual models. In concluding, it is recommended that increased emphasis be placed on the design and implementation of sensitive and responsive training systems that facilitate the guided emergence of customized context-specific training-planning solutions.
Article
Full-text available
Middle-distance athletes implement a dynamic continuum in training volume, duration, and intensity that utilizes all energy-producing pathways and muscle fibre types. At the centre of this periodized training regimen should be a periodized nutritional approach that takes into account acute and seasonal nutritional needs induced by specific training and competition loads. The majority of a middle-distance athlete's training and racing is dependant upon carbohydrate-derived energy provision. Thus, to support this training and racing intensity, a high carbohydrate intake should be targeted. The required energy expenditure throughout each training phase varies significantly, and thus the total energy intake should also vary accordingly to better maintain an ideal body composition. Optimizing acute recovery is highly dependant upon the immediate consumption of carbohydrate to maximize glycogen resynthesis rates. To optimize longer-term recovery, protein in conjunction with carbohydrate should be consumed. Supplementation of beta-alanine or sodium bicarbonate has been shown to augment intra- and extracellular buffering capacities, which may lead to a small performance increase. Future studies should aim to alter specific exercise (resistance vs. endurance) and/or nutrition stimuli and measure downstream effects at multiple levels that include gene and molecular signalling pathways, leading to muscle protein synthesis, that result in optimized phenotypic adaptation and performance.
Article
Full-text available
Nutrition is an important co-factor in exercise-induced training adaptations in muscle. We compared the effect of 6 weeks endurance training (3 days/week, 1-2 h at 75% VO(2peak)) in either the fasted state (F; n = 10) or in the high carbohydrate state (CHO, n = 10), on Ca(2+)-dependent intramyocellular signalling in young male volunteers. Subjects in CHO received a carbohydrate-rich breakfast before each training session, as well as ingested carbohydrates during exercise. Before (pretest) and after (posttest) the training period, subjects performed a 2 h constant-load exercise bout (~70% of pretest VO(2peak)) while ingesting carbohydrates (1 g/kg h(-1)). A muscle biopsy was taken from m. vastus lateralis immediately before and after the test, and after 4 h of recovery. Compared with pretest, in the posttest basal eukaryotic elongation factor 2 (eEF2) phosphorylation was elevated in CHO (P < 0.05), but not in F. In the pretest, exercise increased the degree of eEF2 phosphorylation about twofold (P < 0.05), and values returned to baseline within the 4 h recovery period in each group. However, in the posttest dephosphorylation of eEF2 was negated after recovery in CHO, but not in F. Independent of the dietary condition training enhanced the basal phosphorylation status of Phospholamban at Thr(17), 5'-AMP-activated protein kinase α (AMPKα), and Acetyl CoA carboxylase β (ACCβ), and abolished the exercise-induced increase of AMPKα and ACCβ (P < 0.05). In conclusion, training in the fasted state, compared with identical training with ample carbohydrate intake, facilitates post-exercise dephosphorylation of eEF2. This may contribute to rapid re-activation of muscle protein translation following endurance exercise.
Article
Full-text available
We determined the effects of varying daily carbohydrate intake by providing or withholding carbohydrate during daily tra