Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance

Dietary Intakes of Professional and Semi-Professional Team Sport Athletes Do Not Meet Sport Nutrition Recommendations-A Systematic Literature Review

Background: to develop sport-specific and effective dietary advice, it is important to understand the dietary intakes of team sport athletes. This systematic literature review aims to (1) assess the dietary intakes of professional and semi-professional team sport athletes and (2) to identify priority areas for dietetic intervention. Methods: an extensive search of MEDLINE, Sports DISCUS, CINAHL, Web of Science, and Scopus databases in April–May 2018 was conducted and identified 646 studies. Included studies recruited team sport, competitive (i.e., professional or semi-professional) athletes over the age of 18 years. An assessment of dietary intake in studies was required and due to the variability of data (i.e., nutrient and food group data) a meta-analysis was not undertaken. Two independent authors extracted data using a standardised process. Results: 21 (n = 511) studies that assessed dietary intake of team sport athletes met the inclusion criteria. Most reported that professional and semi-professional athletes’ dietary intakes met or exceeded recommendations during training and competition for protein and/or fat, but not energy and carbohydrate. Limitations in articles include small sample sizes, heterogeneity of data and existence of underreporting. Conclusions: this review highlights the need for sport-specific dietary recommendations that focus on energy and carbohydrate intake. Further exploration of factors influencing athletes’ dietary intakes including why athletes’ dietary intakes do not meet energy and/or carbohydrate recommendations is required.

The combination of sport and sport-specific diet is associated with characteristics of gut microbiota: an observational study

Background

Recently, gut microbiota have been studied extensively for health promotion, disease prevention, disease treatment, and exercise performance. It is recommended that athletes avoid dietary fiber and resistant starch to promote gastric emptying and reduce gastrointestinal distress during exercise, but this diet may reduce microbial diversity and compromise the health of the athlete’s gut microbiota.

Objective

This study compared fecal microbiota characteristics using high-throughput sequencing among healthy sedentary men (as controls), bodybuilders, and distance runners, as well as the relationships between microbiota characteristics, body composition, and nutritional status.

Methods

Body composition was measured using DXA, and physical activity level was assessed using IPAQ. Dietary intake was analyzed with the computerized nutritional evaluation program. The DNA of fecal samples was extracted and it was sequenced for the analysis of gut microbial diversity through bioinformatics cloud platform.

Results

We showed that exercise type was associated with athlete diet patterns (bodybuilders: high protein, high fat, low carbohydrate, and low dietary fiber diet; distance runners: low carbohydrate and low dietary fiber diet). However, athlete type did not differ in regard to gut microbiota alpha and beta diversity. Athlete type was significantly associated with the relative abundance of gut microbiota at the genus and species level: Faecalibacterium, Sutterella, Clostridium, Haemophilus, and Eisenbergiella were the highest (p < 0.05) in bodybuilders, while Bifidobacterium and Parasutterella were the lowest (p < 0.05). At the species level, intestinal beneficial bacteria widely used as probiotics (Bifidobacterium adolescentis group, Bifidobacterium longum group, Lactobacillus sakei group) and those producing short chain fatty acids (Blautia wexlerae, Eubacterium hallii) were the lowest in bodybuilders and the highest in controls. In addition, aerobic or resistance exercise training with an unbalanced intake of macronutrients and low intake of dietary fiber led to similar diversity of gut microbiota. Specifically, daily protein intake was negatively correlated with operation taxonomic unit (r = − 0.53, p < 0.05), ACE (r = − 0.51, p < 0.05), and Shannon index (r = − 0.64, p < 0.01) in distance runners..

Conclusion

Results suggest that high-protein diets may have a negative impact on gut microbiota diversity for athletes, while athletes in resistance sports that carry out the high protein low carbohydrates diet demonstrate a decrease in short chain fatty acid-producing commensal bacteria.

Protein Supplements and Their Relation with Nutrition, Microbiota Composition and Health: Is More Protein Always Better for Sportspeople?

Sports nutrition products are developed and targeted mainly for athletes to improve their nutrient intake, performance, and muscle growth. The fastest growing consumer groups for these products are recreational sportspeople and lifestyle users. Although athletes may have elevated physiological protein requirements and they may benefit from dietary supplements, the evidence regarding the role of dietary protein and supplements in the nutrition of recreational sportspeople and sedentary populations is somewhat complex and contradictory. In high-protein diets, more undigested protein-derived constituents end up in the large intestine compared to moderate or low-protein diets, and hence, more bacterial amino acid metabolism takes place in the colon, having both positive and negative systemic and metabolic effects on the host. The aim of the present review is to summarize the impact of the high-protein products and diets on nutrition and health, in sportspeople and in sedentary consumers. We are opening the debate about the current protein intake recommendations, with an emphasis on evidence-based effects on intestinal microbiota and personalized guidelines regarding protein and amino acid supplementation in sportspeople and lifestyle consumers.

Snacking in nutrition and health

Many studies suggest that distributing energy and nutrient intake across 4-5 eating occasions/day (rather than across three standard meals) could favourably affect human health. The inclusion of 1-2 snacks in the daily pattern alleviates the potential digestive and metabolic overload caused by fewer heavier meals and might contribute to meet recommendations for food groups (e.g. fruits, dairy) and nutrients like fibre and vitamins. The snack composition should be evaluated taking into account the whole day's diet. In early and late ages, and for specific population groups, snacking may need to follow particular characteristics in order to be optimal, both in terms of composition and timing. This document, which is the result of a collaboration of experts across several fields of research, intends to provide a review of the current scientific literature on meal frequency and health, highlighting the beneficial effects of correct snack consumption across the human lifespan.

Maximizing the intersection of human health and the health of the environment with regard to the amount and type of protein produced and consumed in the United States

This review utilizes current national dietary guidelines and published databases to evaluate the impacts of reasonable shifts in the amount and type of protein intake in the United States on the intersection of human and environmental health. The established scientific basis and recommendations for protein intake as described in the US Dietary Reference Intakes are reviewed. Data on food availability from both the US Department of Agriculture and the Food and Agriculture Organization of the United Nations and data on consumption from the National Health and Nutrition Examination Survey are used to examine estimates of current US protein consumption. Greenhouse gas (carbon dioxide equivalents, CO2eq) and blue and green water impacts of US protein consumption resulting from US agricultural practices were obtained from previously published meta-analyses. A 25% decrease in protein intake paired with a 25% shift from animal food to plant food protein intake-from an 85:15 ratio to a 60:40 ratio-would best align protein intake with national dietary recommendations while simultaneously resulting in 40% fewer CO2eq emissions and 10% less consumptive water use. The modeling of this strategy suggests a savings of 129 billion kilograms of CO2eq and 3.1 trillion gallons of water relative to current consumption.

Protein supplement consumption is linked to time spent exercising and high-protein content foods: A multicentric observational study

The main aim of this study is to analyze if protein supplement consumption and food patterns vary across three geographical regions and secondly to identify possible factors that increase the likelihood of ingesting protein supplements. A total of 916 responses from gym users of 3 countries (Italy, Turkey and UK) were entered for analysis. Questions were related to supplement consumption (protein and other supplements), food intake and training habits. A descriptive analysis, analysis of variance (ANOVA), and logistic regression were performed. No differences were found across groups regarding: prevalence of protein supplement consumption, typology of other ingested supplement and food intake. No relation was found between level of education (r = .12) or geographical region (r = .16) and protein consumption. The analysis showed that the coach is the main source of suggestion for the intake of protein supplements (52.3%). The logistic regression model highlighted that gym users who exercised more (OR 1.51, p < 0.001) and consumed higher quantities of chicken (OR 1.39, p < 0.001) eggs (OR 1.18, p < 0.001) and canned tuna (OR 1.15, p < 0.05) were more likely to use protein supplements. Geographical area does not seem to influence the supplementation pattern. Time spent exercising and high protein foods are factors associated with protein supplement consumption.

Dietary Intake of Polish Female Soccer Players

The aim of the study was to evaluate the energy expenditure and fulfillment of nutritional needs of female soccer players. Participants in this research were 41 professional soccer players from the three Polish female soccer league levels: Ekstraleague, I League and II League. The participants had their height and body mass measured. Total Energy Expenditure was measured by means of a SenseWear Pro3 Armband device. Data related to the food-intake energy values and the consumption of macro- and micronutrients were obtained through systematic recording of results, which was conducted over a three-day-long period at the start of the competitive season. The average age of the participants was 21 ± 5 years, the average height was 167.5 ± 5 cm, and the average body mass was 62.53 ± 9.8 kg. The average energy expenditure of the participants was 2811 ± 493 kcal/day, and their average energy intake was 1476 ± 434 kcal/day. The average consumption of carbohydrates, fats, and proteins was 199 ± 20.6, 47.3 ± 20.7, and 72.3 ± 24.2 g/day, respectively. There was a prevalence of inadequate intake of potassium, calcium, magnesium, iodine, vitamins D, E and B1, and folate in the diet of the examined group. The remaining micronutrients were consumed in the prescribed amounts by at least 50% of the examined group. The participants demonstrated low energy intakes, and consequently, low consumption of macronutrients and a large number of micronutrients.

Alpine junior world ski championship: nutritional habits and performance in elite skiers

BACKGROUND

Young athletes need to consume an appropriate diet in order to maintain health and optimize growth and athletic performance. We evaluated nutritional habits of junior elite skiers.

METHODS

Alpine junior elite skiers (N.=68; 42 males and 26 females; age range 16-20 years) coming from 20 countries were recruited during the Alpine Junior World Ski Championship, Roccaraso, Italy. Nutritional habits were assessed using a 3-day food record and the NHANES Food Frequency Questionnaire. Data were compared with nutritional recommendations and Recommended Dietary Allowances (RDAs) for athletes.

RESULTS

During the training period, the energy intake in both males and females was significantly lower with respect to estimated energy needs. Carbohydrate intake expressed in terms of grams per kilogram of body weight did not meet the RDAs in both groups (4.19 and 5.15 g/kg in males and females, respectively). Protein and fat consumption exceeded the RDAs with a protein intake of 2.34 g/kg in males and 2.10 g/kg in females, and a fat intake >35% of total daily calories. During competition days, both males and females increased carbohydrate intake to 6.23 and 8.11 g/kg respectively, reaching the RDAs. Protein intake increased to 2.56 and 3.14 g/kg in males and females, respectively, and fat intake slightly decreased, still exceeding the RDAs.

CONCLUSIONS

Junior elite skiers reported a low intake of carbohydrates and a high intake of protein and fat. Nutritional counselling should be given to athletes to maintain their health and improve their physical performance.

Within-Day Amino Acid Intakes and Nitrogen Balance in Male Collegiate Swimmers during the General Preparation Phase

A higher protein intake is recommended for athletes compared to healthy non-exercising individuals. Additionally, the distribution and quality (i.e., leucine content) of the proteins consumed throughout the day should be optimized. This study aimed to determine the nitrogen balance and distribution of protein and amino acid intakes in competitive swimmers during the general preparation phase. Thirteen swimmers (age: 19.7 ± 1.0 years; VO₂max: 63.9 ± 3.7 mL·kg-1·min-1, mean ± standard deviation) participated in a five-day experimental training period. Nutrient intakes were assessed using dietary records. Nitrogen balance was calculated from the daily protein intake and urinary nitrogen excretion. The intake amounts of amino acids and protein at seven eating occasions were determined. The average and population-safe intakes for zero nitrogen balance were estimated at 1.43 and 1.92 g·kg-1·day-1, respectively. The intake amounts of protein and leucine at breakfast, lunch, and dinner satisfied current guidelines for the maximization of muscle protein synthesis, but not in the other four occasions. The population-safe protein intake level in competitive swimmers was in the upper range (i.e., 1.2⁻2.0 g·kg-1·day-1) of the current recommendations for athletes. The protein intake distribution and quality throughout the day may be suboptimal for the maximization of the skeletal muscle adaptive response to training.

Energy Balance Coexists With Disproportionate Macronutrient Consumption Across Pretraining, During Training, and Posttraining Among Indian Junior Soccer Players

PURPOSE

To evaluate energy expenditure, energy intake, and nutrient adequacy of Indian junior soccer players.

METHOD

Forty junior national-level soccer players (Under-12 and Under-16 age groups) were assessed for 3-day weighed food records and 3-day energy expenditure. Energy and nutrient intake was analyzed from food records, and energy expenditure was measured using a portable metabolic analyzer and activity records. Nutrient adequacy was determined by comparing intake with prevailing recommendations.

RESULTS

Players exhibited no significant difference between energy intake (boys = 3062 [340.9] and girls = 2243 [320.3] kcal·d^-1) and expenditure (boys = 2875 [717.3] and girls = 2442 [350.3] kcal·d^-1). Across age groups, the Under-12 boys showed positive energy balance as against energy deficits in Under-16. Girls showed energy deficits, although not significant. There were 58% of girls showing energy availability <30 kcal·kg^-1 fat-free mass, of which 37% were Under-16 players. Carbohydrates contributed to >60% of energy expenditure among 95.2% boys and 73.7% girls. Among 52.4% boys and 47.4% girls, <25% of energy expenditure was contributed by fat. More than 95% players consumed <1 g·kg^-1 carbohydrates pretraining and 100% of them consumed >1.2 g·kg^-1 carbohydrates posttraining.

CONCLUSION

Junior soccer players consumed more than recommended carbohydrates in the diet, although not aligning with the pretraining, during training, and posttraining meal requirements. Considering the energy deficits observed among Under-16 players, a suitable dietary modification is warranted.

Comparison of a sports-hydration drink containing high amylose starch with usual hydration practice in Australian rules footballers during intense summer training

BACKGROUND

Fluid deficits exceeding 1.6% can lead to physical and cognitive impairment in athletes. Sport drinks used by athletes are often hyper-osmolar but this is known to be suboptimal for rehydration in medical settings and does not utilize colonic absorptive capacity. Colonic absorption can be enhanced by fermentative production of short chain fatty acids (SCFA) from substrates such as high amylose maize starch (HAMS). This study therefore compared, in elite Australian Football League (AFL) players at the height of outdoor summer training, a novel dual-action sports oral rehydration strategy that contained HAMS as well as glucose, to their usual rehydration practices (Control). The primary outcome markers of hydration were hematocrit and body weight.

METHODS

A randomized single-blind crossover study was undertaken in thirty-one AFL players; twenty-seven completed the study which was conducted on four days (two days in the Intervention arm and two in Control arm). The Intervention arm was comprised a 50-100 g evening preload of an acetylated HAMS (Ingredion Pty Ltd) followed by consumption of a specially formulated sports oral rehydration solution (SpORS) drink during intense training and recovery. Players followed their usual hydration routine in the Control arm. Quantitative assessments of body weight, hematocrit and urine specific gravity were made at three time-points on each day of training: pre-training, post-training (90 min), and at end of recovery (30-60 min later). GPS tracking monitored player exertion.

RESULTS

Across the three time-points, hematocrit was significantly lower and body weight significantly higher in Intervention compared to Control arms (p < 0.02 and p = 0.001 respectively, mixed effects model). Weights were significantly heavier at all three assessment points for Intervention compared to Control arms (Δ = 0.30 ± 0.13, p = 0.02 pre-training; Δ = 0.43 ± 0.14, p = 0.002 post training; and Δ = 0.68 ± 0.14, p < 0.001 for recovery). Between the pre-training and end-of-recovery assessments, the Control arm lost 0.80 kg overall compared with 0.12 kg in the Intervention arm, an 85% lower reduction of bodyweight across the assessment period.

CONCLUSION

The combination of the significantly lower hematocrit and increased body weight in the Intervention arm represents better hydration not only at the end of training as well as following a recovery period but also at its commencement. The magnitude of the benefit seems sufficient to have an impact on performance and further studies to test this possibility are now indicated.

TRIAL REGISTRATION

Trial is listed on the Australian New Zealand Clinical Trials Registry ( ACTRN 12613001373763 ).

Dietary intake of professional Australian football athletes surrounding body composition assessment

BACKGROUND

Sports Dietitians aim to assist in improving performance by developing nutrition knowledge (NK), enhancing dietary intake and optimising body composition of athletes. In a high-pressure environment, it is important to identify factors that may compromise an athlete's nutrition status. Body composition assessments are regularly undertaken in sport to provide feedback on training adaptions; however, no research has explored the impact of these assessments on the dietary intake of professional athletes.

METHODS

This cross-sectional study assessed dietary intake (7-day food diary), nutrition knowledge (Nutrition for Sport Knowledge Questionnaire) and body composition (Dual-energy X-ray absorptiometry) of 46 professional male Australian football (AFL) athletes during a 2017 pre-season training week (7 days) where body composition assessments were undertaken. Dietary intake was assessed against International Olympic Committee recommendations for professional athletes.

RESULTS

Overall, no athlete met dietary their recommended energy intake (15 ± 1.1 vs. 9.1 ± 1.8 MJ, respectively) or carbohydrate recommendations (6-10 vs. 2.4 ± 0.9 g·kg-1·day-1). Only 54% met protein recommendations. Secondary analyses demonstrated significant associations between education status and energy intake (P < 0.04) and vegetable intake (P < 0.03), with higher levels of education being associated with higher intakes. A moderately positive association was observed between NK scores and meeting estimated energy requirements (r = 0.33, P = 0.03). NK scores were also positively associated with protein (r = 0.35, P = 0.02), fibre (r = 0.51, P = 0.001) and calcium intakes (r = 0.43, P = 0.004).

CONCLUSIONS

This research identified that the dietary intake of professional AFL athletes during a pre-season training week where body composition assessments were undertaken did not meet current recommendations. Several factors may influence the dietary intake of AFL athletes, including lower education levels, poor NK and dietary intake restriction surrounding body composition assessment. Athletes may require support to continue with performance-based nutrition plans in periods surrounding body composition assessment.

Pacing Strategy of a Full Ironman Overall Female Winner on a Course With Major Elevation Changes

Pryor, JL, Adams, WM, Huggins, RA, Belval, LN, Pryor, RR, and Casa, DJ. Pacing strategy of a full Ironman overall female winner on a course with major elevation changes. J Strength Cond Res 32(11): 3080-3087, 2018-The purpose of this study was to use a mixed-methods design to describe the pacing strategy of the overall female winner of a 226.3-km Ironman triathlon. During the race, the triathlete wore a global positioning system and heart rate (HR)-enabled watch and rode a bike outfitted with a power and cadence meter. High-frequency (every km) analyses of mean values, mean absolute percent error (MAPE), and normalized graded running pace and power (accounting for changes in elevation) were calculated. During the bike, velocity, power, cadence, and HR averaged 35.6 km·h, 199 W, 84 rpm, and 155 b·min, respectively, with minimal variation except for velocity (measurement unit variation [MAPE]: 7.4 km·h [20.3%], 11.8 W [7.0%], 3.6 rpm [4.6%], 3 b·min [2.3%], respectively). During the run, velocity and HR averaged 13.8 km·h and 154 b·min, respectively, with velocity varying four-fold more than HR (MAPE: 4.8% vs. 1.2%). Accounting for elevation changes, power and running pace were less variable (raw [MAPE] vs. normalized [MAPE]: 199 [7.0%] vs. 204 W [2.7%]; 4:29 [4.8%] vs. 4:24 min·km [3.6%], respectively). Consistent with her planned pre-race pacing strategy, the triathlete minimized fluctuations in HR and watts during the bike and run, whereas velocity varied with changes in elevation. This case report provides observational evidence supporting the utility of a pacing strategy that allows for an oscillating velocity that sustains a consistent physiological effort in full Ironman races.

ISSN exercise & sports nutrition review update: research & recommendations

Background

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words ‘sport nutrition’. Consequently, staying current with the relevant literature is often difficult.

Methods

This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches.

Conclusions

This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.

Macronutrient Intakes of Male Rugby Union Players: A Review

Rugby is a worldwide intermittent team sport. Players tend to be heavier than the majority of similar team sport athletes on whom the dietary guidelines have been developed. Therefore, the aim of the current review was to describe the intakes of rugby union players. Article databases were searched up to February 2017 and were included if they were published in English and reported dietary intakes of male rugby union players. Of the research articles identified, energy intakes were lower than two of three studies that reported intakes and expenditure, which would suggest the players were losing weight that is somewhat supported by the decreases in skinfolds seen during preseason. However, it should also be noted that there are errors in both the measurement of energy intakes and expenditure. Carbohydrate intakes ranged from 2.6 to 6.5 g·kg^-1·day^-1, which is lower than the current relative to body mass recommendations; however, this would not be classed as a low-carbohydrate diet. The consistently low intakes of carbohydrate suggest that these intake levels maybe sufficient for performance, given the players greater body mass or there are errors in the measurements. However, there is currently no evidence for the carbohydrate needs of rugby union players in terms of performance. The lower intakes than expenditure would suggest the players were losing weight. Previous research shows that rugby union players lose body fat during preseason training.

A Review of Prevention, Diagnosis, and Treatment of Relative Energy Deficiency in Sport in Artistic (Synchronized) Swimming

The syndrome of relative energy deficiency in sport (RED-S) is a clinical entity characterized by low energy availability, which can negatively affect the health and performance of both male and female athletes. The underlying mechanism of RED-S is an inadequacy of dietary energy to support optimal health and performance. This syndrome refers to impaired physiological function, including metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health, with psychological consequences that can either precede (through restrictive dietary habits) or result from RED-S. The term RED-S extends beyond the condition termed the "Female Athlete Triad." Formerly known as synchronized swimming, artistic swimming is an Olympic sport requiring a high level of fitness as well as technical skill and artistry. The risk of RED-S is high in artistic swimming as it is an aesthetic, judged sport with an emphasis on a lean physique. RED-S is of significant concern in the sport of artistic swimming because of the potential negative effects on physical and mental health as well as consequences on athletic performance. This paper reviews health and performance consequences associated with low energy availability resulting in RED-S in artistic swimming. Medical and nutritional considerations specific to artistic swimming are reviewed, and methods to help detect and manage RED-S are discussed. Prevention and management of RED-S in this athlete population should be a priority for coaches, and the sport medicine professionals working with artistic swimming athletes should utilize the RED-S CAT, a Clinical Assessment Tool for screening and managing RED-S.

Risk factors for precompetitive sleep behavior in elite female athletes

BACKGROUND

Sleep is of major importance for the athletes' short and long-term health, performance and recovery; however, published studies on athletes' sleep and even fewer before competition are scarce. This study evaluated the risk factors of sleep in young female gymnasts before an international competition.

METHODS

Sixty-seven rhythmic gymnasts (M=18.7, SD=2.9 years) of high performance (M=36.6, SD=7.6 h/week) were evaluated regarding training and sport practice, body composition, sleep duration, daytime sleepiness by the Epworth Sleepiness Scale, sleep quality by the Pittsburgh Sleep Quality Index, precompetitive anxiety by the Sport Competition Anxiety Test form A, and detailed dietary intake just prior to a world competition.

RESULTS

The majority of the participants (83.6%) presented reduced body fat levels (M=9.1, SD=2.1%) and low energy availability (EA, M=31.5, SD=11.9 kcal/kgFFM/day). They slept 8h10±1h30/night on weekdays and 8h40±00h40/night on weekends, 67% suffered from mild daytime sleepiness and 78% had a reduced sleep quality. Precompetitive anxiety was on average moderate (M=22.7, SD=3.2). The risk factors for short sleep duration were: 1.92 for a training volume>30 hours/week (95% CI 0.84-4.39), 4.57 for menstruation (95% CI 1.17-17.77), 6.62 for bedtime ≥11:00 PM (95% CI 1.74-25.10), 1.40 for BF<12% (95% CI 1.03-1.92), 2.19 for FFM<30 kg (95% IC 0.94-4.94), 2.37 for BMR<1100 kcal/day (95% CI 1.06-5.32), 1.90 for EEE≥700 kcal (95% CI 0.92-3.93) and 3.17 for EA<45 kcal/kg FFM/day (95% CI 0.84-6.59). Age, performance, sleep duration on weekdays and precompetitive stress were also predictors for a reduced sleep quality and/or abnormal daytime sleepiness.

CONCLUSIONS

Age, training regime, menstruation, individual preferences for bedtime, body composition and energy were important predictors of gymnasts' precompetitive sleep with consequences upon their sleep duration, SQ and DS.

Branched-Chain Amino Acids Are the Primary Limiting Amino Acids in the Diets of Endurance-Trained Men after a Bout of Prolonged Exercise

Background

The indicator amino acid oxidation (IAAO) method estimates the protein intake required to maximize whole-body protein synthesis and identify the daily protein requirement in a variety of populations. However, it is unclear whether the greater requirements for endurance athletes previously determined by the IAAO reflect an increased demand for all or only some amino acids.

Objective

The aim of this study was to determine the primary rate-limiting amino acids in endurance-trained athletes after prolonged exercise, by measuring the oxidation of ingested [1-13C]phenylalanine in response to variable amino acid intake.

Methods

Five endurance-trained men (means ± SDs: age, 26 ± 7 y; body weight, 66.9 ± 9.5 kg; maximal oxygen consumption, 63.3 ± 4.3 mL · kg-1 · min-1) performed 5 trials that involved 2 d of controlled diet (1.4 g protein · kg-1 · d-1) and running (10 km on day 1 and 5 km on day 2) prior to performing an acute bout of endurance exercise (20-km treadmill run) on day 3. During recovery on day 3, participants consumed test diets as 8 isocaloric hourly meals providing sufficient energy and carbohydrate but a variable amino acid intake. The test diets, consumed in random order, were deficient (BASE: 0.8 g · kg-1 · d-1) and sufficient (SUF; 1.75 g · kg-1 · d-1) amino acid diets modeled after egg protein, and BASE supplemented with branched-chain amino acids (BCAA diet; 1.03 g · kg-1 · d-1), essential amino acids (EAA diet; 1.23 g · kg-1 · d-1), or nonessential amino acids (NEAA diet; 1.75 g · kg-1 · d-1). Whole-body phenylalanine flux (Q), 13CO2 excretion (F13CO2), and phenylalanine oxidation (OX) were determined according to standard IAAO methodology.

Results

There was no effect of amino acid intake on Q (P = 0.43). F13CO2 was significantly (all P < 0.01) lower than BASE for the BCAA (∼32%), EAA (∼31%), and SUF (∼36%) diet treatments. F13CO2 for the NEAA diet was ∼18% lower than for BASE (P < 0.05) but ∼28% greater than for SUF (P < 0.05). OX was similarly decreased (∼24-41%) in all conditions compared with BASE (all P < 0.05).

Conclusion

Our results suggest that the BCAAs may be the primary rate-liming amino acids in the greater daily protein requirement of endurance trained men. This trial was registered at clinicaltrials.gov as NCT02628249.

Sleep duration, body composition, dietary profile and eating behaviours among children and adolescents: a comparison between Portuguese acrobatic gymnasts

Sleep, body composition and dietary intake are crucial for athletes' health and performance but have never been investigated in acrobatic gymnasts. Thus, this study aimed to evaluate sleep, body composition, dietary intake and eating behaviours of acrobatic gymnasts. Using a cross-sectional study, 82 Portuguese acrobatic gymnasts (12.8 ± 3.1 years, 61 females and 21 males) were evaluated during the competitive period to collect training data, sleep duration, body composition, dietary intake and eating behaviours before, during and after practices. Most of the gymnasts (91.5%) slept less than 8 h/night. Female adolescents slept significantly less on weekdays than female children (P = 0.024). Female adolescents' mean body mass was below the normal and 60.0% showed menstrual irregularities; 4.9% of females bases were overweight and 2.4% obese. Male adolescents slept significantly less on weekdays than male children (P = 0.001); significant differences were shown for fat-free mass (P = 0.014); however, 3.7% were overweight. All daily energy and macronutrient intakes were significantly different according to age and gender, with exception for fibre and energy intake in females (P = 0.057 and P = 0.052, respectively), and for protein in males (P = 0.068). Female and male adolescents demonstrated significant lower energy availability (32.8 ± 9.4 kcal/kg FFM/day and 45.1 ± 14.7 kcal/kg FFM/day) than children (45.8 ± 8.7 kcal/kg FFM/day and 53.8 ± 9.1 kcal/kg FFM/day), respectively. Significant low intakes of important vitamins and minerals were reported. Most of the participants did not eat or drink during or immediately after training sessions.

CONCLUSION

Acrobatic gymnasts revealed low BF, short sleep duration and macro- and micronutrients inadequate intakes. The Female Athlete Triad was demonstrated by female adolescent gymnasts. What is Known: • Adequate dietary intake is an important resource for athletes' short and long-term health and performance. • There are no published studies in acrobatic gymnasts' sleep, body composition or dietary intake. What is New: • This study provides the first data on significant differences in energy intake and availability between acrobatic gymnasts; overweight and obesity were present in females. • Macro and micronutrients were inappropriate. Female Athlete Triad was observed in female adolescent acrobatic gymnasts.

Characterization and Comparison of Nutritional Intake between Preparatory and Competitive Phase of Highly Trained Athletes

Background and objective: For a high level athlete, it is essential to ensure optimal energy as well as macro- and micro-nutrient and fluid intakes, in order to improve their performance during training and competition. Protein intake should be 1.2⁻2.1 g/kg/d, whereas the requirements for carbohydrate and fat intakes should be >5g/kg/d and 20⁻35% of energy, respectively. The micronutrient and fluid intakes in athletes were compared to the Dietary Reference Intake (DRI) and European Food Safety Authority (EFSA) recommendations, respectively. This study aimed to characterize and compare the nutritional habits of athletes at the preparatory and competitive phase, and to test if their nutritional intakes were in accordance with the recommendations. Materials and methods: A total of 276 professional athletes were assessed. To evaluate their nutritional intake, the athletes completed a 7 days food record. Under reporting was defined using a ratio of energy intake to basal metabolic rate (BMR) of 1.1. Body composition was assessed using dual energy X-ray absorptiometry (DXA). Results: Almost half (49%) of the athletes from the final sample reported lower measured intakes of carbohydrates and 27% reported a higher consumption of proteins than what was recommended. In both the preparatory and competitive phases, the micronutrients with a higher mismatch between the actual and recommended intakes were vitamins D and E, magnesium, folate, calcium, and zinc for both sexes, and iron intake for females. A large proportion of athletes reported a lower water intake. Compared to the recommendations, males reported a higher intake of carbohydrates, lipids, vitamins E, calcium, and magnesium (p <0.05) in the competitive phase, while females reported a lower ingestion of water, vitamins A and D, and calcium (p <0.05) in the preparatory phase. Conclusions: Overall, in the preparatory and competitive phases of the season, athletes reported a macro- and micro-nutrient intake below the recommendations, especially in the female athletic population. Dietary intakes in athletes need to be optimized and adjusted to their requirements, according to sex and sport, so as to avoid compromising health and performance.

Brief Education Intervention Increases Nutrition Knowledge and Confidence of Coaches of Junior Australian Football Teams

This study evaluated the impact of a brief (20-min) nutrition education intervention embedded in an existing mandatory coach education course for coaches of junior (8–12 years old) Australian football teams. A total of 284 coaches (68% of 415 coaching course participants) completed a presession questionnaire, and 110 coaches (27% of coaching course participants) completed an identical postsession questionnaire. The responses to the pre- and postsession surveys were matched for 78 coaches. Coaches’ ratings of their own understanding of the nutritional needs of young athletes (6.81, 8.95; p < .001), the importance of young athletes adhering to a healthy diet (9.09, 9.67; p = .001), their confidence in their own nutrition knowledge (7.24, 8.64; p < .001), and their confidence in advising young athletes on nutrition and hydration practices (6.85, 8.62; p < .001), all significantly improved following the education session. Nearly all coaches (>95%) provided a correct response to six of the 15 nutrition and hydration knowledge questions included in the presession questionnaire. Even with this high level of presession knowledge, there was a significant improvement in the coaches’ nutrition and hydration knowledge after the education session across five of the 15 items, compared with before the education session. The results of this study suggest that a simple, short nutrition education intervention, embedded in an existing coach education course, can positively influence the nutrition knowledge and self-efficacy of community-level, volunteer coaches of junior sports participants.

Development and validation of a brief general and sports nutrition knowledge questionnaire and assessment of athletes' nutrition knowledge

Background

The Nutrition for Sport Knowledge Questionnaire (NSKQ) is an 89-item, valid and reliable measure of sports nutrition knowledge (SNK). It takes 25 min to complete and has been subject to low completion and response rates. The aim of this study was to develop an abridged version of the NSKQ (A-NSKQ) and compare response rates, completion rates and NK scores of the NSKQ and A-NSKQ.

Methods

Rasch analysis was used for the questionnaire validation. The sample (n = 181) was the same sample that was used in the validation of the full-length NSKQ. Construct validity was assessed using the known-group comparisons method. Temporal stability was assessed using the test-retest reliability method. NK assessment was cross-sectional; responses were collected electronically from members of one non-elite Australian football (AF) and netball club, using Qualtrics Software (Qualtrics, Provo, UT).

Results

Validation - The A-NSKQ has 37 items that assess general (n = 17) and sports (n = 20) nutrition knowledge (NK). Both sections are unidimensional (Perc5% = 2.84% [general] and 3.41% [sport]). Both sections fit the Rasch Model (overall-interaction statistic mean (SD) = − 0.15 ± 0.96 [general] and 0.22 ± 1.11 [sport]; overall-person interaction statistic mean (SD) = − 0.11 ± 0.61 [general] and 0.08 ± 0.73 [sport]; Chi-Square probability = 0.308 [general] and 0.283 [sport]). Test-retest reliability was confirmed (r = 0.8, P < 0.001 [general] and r = 0.7, P < 0.001 [sport]). Construct validity was demonstrated (nutrition students = 77% versus non-nutrition students = 60%, P < 0.001 [general] and nutrition students = 60% versus non-nutrition students = 40%, P < 0.001 [sport]. Assessment of NK - 177 usable survey responses from were returned. Response rates were low (7%) but completion rates were high (85%). NK scores on the A-NSKQ (46%) are comparable to results obtained in similar cohorts on the NSKQ (49%). The A-NSKQ took on average 12 min to complete, which is around half the time taken to complete the NSKQ (25 min).

Conclusions

The A-NSKQ is a valid and reliable, brief questionnaire designed to assess general NK (GNK) and SNK.

Electronic supplementary material

The online version of this article (10.1186/s12970-018-0223-1) contains supplementary material, which is available to authorized users.

Keto-adaptation enhances exercise performance and body composition responses to training in endurance athletes

BACKGROUND

Low-carbohydrate diets have recently grown in popularity among endurance athletes, yet little is known about the long-term (>4wk) performance implications of consuming a low-carbohydrate high fat ketogenic diet (LCKD) in well-trained athletes.

METHODS

Twenty male endurance-trained athletes (age 33±11y, body mass 80±11kg; BMI 24.7±3.1kg/m²) who habitually consumed a carbohydrate-based diet, self-selected into a high-carbohydrate (HC) group (n=11, %carbohydrate:protein:fat=65:14:20), or a LCKD group (n=9, 6:17:77). Both groups performed the same training intervention (endurance, strength and high intensity interval training (HIIT)). Prior to and following successful completion of 12-weeks of diet and training, participants had their body composition assessed, and completed a 100km time trial (TT), six second (SS) sprint, and a critical power test (CPT). During post-intervention testing the HC group consumed 30-60g/h carbohydrate, whereas the LCKD group consumed water, and electrolytes.

RESULTS

The LCKD group experienced a significantly greater decrease in body mass (HC -0.8kg, LCKD -5.9kg; P=0.006, effect size (ES): 0.338) and percentage body fat percentage (HC -0.7%, LCKD -5.2%; P=0.008, ES: 0.346). Fasting serum beta-hydroxybutyrate (βHB) significantly increased from 0.1 at baseline to 0.5mmol/L in the LCKD group (P=0.011, ES: 0.403) in week 12. There was no significant change in performance of the 100km TT between groups (HC -1.13min·s, LCKD -4.07min·s, P=0.057, ES: 0.196). SS sprint peak power increased by 0.8 watts per kilogram bodyweight (w/kg) in the LCKD group, versus a -0.1w/kg reduction in the HC group (P=0.025, ES: 0.263). CPT peak power decreased by -0.7w/kg in the HC group, and increased by 1.4w/kg in the LCKD group (P=0.047, ES: 0.212). Fat oxidation in the LCKD group was significantly greater throughout the 100km TT.

CONCLUSIONS

Compared to a HC comparison group, a 12-week period of keto-adaptation and exercise training, enhanced body composition, fat oxidation during exercise, and specific measures of performance relevant to competitive endurance athletes.

Nutritional Aspects of the Female Athlete

Athletes have specific needs based on sex, size, sport, exercise intensity, duration of activity, phase of training, and the season in which the sport is played. Nutritionally, the female athlete is unique, with needs that may vary based on hormonal fluctuations related to the menstrual cycle. This article provides an overview of the distinct nutritional needs and concerns of the physically active female, including energy availability, macronutrient needs, micronutrient needs, hydration, supplements, and other nutritional issues. Although there is some research focusing specifically on the female athlete and her exceptional nutritional concerns, further gender-specific exploration is needed in all areas.

Nutritional needs in the professional practice of swimming: a review

[Purpose]

Swimming requires developing a high aerobic and anaerobic capacity for strength and technical efficiency. The purpose of this study was to establish the nutritional requirements and dietary strategies that can optimize swimming performance.

[Methods]

Several related studies retrieved from the databases, Dialnet, Elsevier, Medline, Pubmed, and Web of Science, through keyword search strategies were reviewed.

[Results]

The recommended carbohydrate intake ranges between 6-10-12 g/kg/d, protein 2 g/kg/d, and fat should surpass 20-25% of the daily intake.

[Conclusion]

Performance can be optimized with a hydration plan, as well as adequate periodization of supplements, such as caffeine, creatine, sodium bicarbonate, B-alanine, beetroot juice, Vitamin D, bovine colostrum, and HMB.

Position paper on vegetarian diets from the working group of the Italian Society of Human Nutrition

BACKGROUND

Interest in vegetarian diets is growing in Italy and elsewhere, as government agencies and health/nutrition organizations are emphasizing that regular consumption of plant foods may provide health benefits and help prevent certain diseases.

METHODS AND RESULTS

We conducted a Pubmed search, up to September, 2015, for studies on key nutrients (proteins, vitamin B12, iron, zinc, calcium, vitamin D, and n-3 fatty acids) in vegetarian diets. From 295 eligible publications the following emerged: Vegetarians should be encouraged to supplement their diets with a reliable source of vitamin B12 (vitamin-fortified foods or supplements). Since the plant protein digestibility is lower than that of animal proteins it may be appropriate for vegetarians to consume more proteins than recommended for the general population. Vegetarians should also be encouraged to habitually consume good sources of calcium, iron and zinc - particularly vegetables that are low in oxalate and phytate (e.g. Brassicaceae), nuts and seeds, and calcium-rich mineral water. Calcium, iron, and zinc bioavailability can be improved by soaking, germination, and sour-dough leavening that lower the phytate content of pulses and cereals. Vegetarians can ensure good n-3 fatty acid status by habitually consuming good sources of a-linolenic acid (walnuts, flaxseeds, chia seeds, and their oils) and limiting linoleic acid intake (corn and sunflower oils).

CONCLUSIONS

Well-planned vegetarian diets that include a wide variety of plant foods, and a reliable source of vitamin B12, provide adequate nutrient intake. Government agencies and health/nutrition organizations should provide more educational resources to help Italians consume nutritionally adequate vegetarian diets.

Exposure and perceptions of marketing for caffeinated energy drinks among young Canadians

OBJECTIVE

To examine exposure to energy drink marketing among youth and young adults, and test perceptions of energy drink advertisements (ads) regarding target audience age and promoting energy drink use during sports.

DESIGN

A between-group experiment randomly assigned respondents to view one of four energy drink ads (sport-themed or control) and assessed perceptions of the ad. Regression models examined marketing exposure and perceptions.

SETTING

Online survey (2014).

SUBJECTS

Canadians aged 12-24 years (n 2040) from a commercial panel.

RESULTS

Overall, 83 % reported ever seeing energy drink ads through at least one channel, including on television (60 %), posters/signs in stores (49 %) and online (44 %). Across experimental conditions, most respondents (70·1 %) thought the ad they viewed targeted people their age or younger, including 42·2 % of those aged 12-14 years. Two sport-themed ads were more likely to be perceived as targeting a younger audience (adjusted OR (95 % CI): 'X Games' 36·5 %, 4·16 (3·00, 5·77); 'snowboard' 19·2 %, 1·50 (1·06, 2·13)) v. control (13·3 %). Participants were more likely to believe an ad promoted energy drink use during sports if they viewed any sport-themed ad ('X Games' 69·9 %, 8·29 (6·24, 11·02); 'snowboard' 76·7 %, 11·85 (8·82, 15·92); 'gym' 66·8 %, 7·29 (5·52, 9·64)) v. control (22·0 %). Greater reported exposure to energy drink marketing was associated with perceiving study ads as promoting energy drink use during sports.

CONCLUSIONS

Energy drink marketing has a high reach among young people. Ads for energy drinks were perceived as targeting youth and promoting use during sports. Such ads may be perceived as making physical performance claims, counter to Canadian regulations.

Considerations for Fueling an Endurance Athlete With Home Parenteral Nutrition

The goal of clinicians managing nutrition support for patients with home parenteral nutrition (HPN) is to adapt nutrition needs to best serve the consumers, so they may have the best quality of life despite specialized nutrition needs. Some HPN consumers may desire to participate in endurance athletics, which will require special considerations. This review is intended to outline key nutrition differences in endurance athletes that a nutrition support team should consider when providing HPN.

Exercise and Older Adults

Regular exercise is essential for healthy aging and offers many health benefits, including reduced risk of all-cause mortality, chronic disease, and premature death. Because physical inactivity is prevalent, greater focus is needed on integrating exercise into care plans and counseling, and developing partnerships that support exercise opportunities. Older adults should be as physically active as their abilities and conditions allow. For substantial health benefits, older adults need to do aerobic, muscle-strengthening, and stretching exercises weekly, and balance activities as needed. Appropriate planning must take account of factors such as prescribed medications, nutrition, injuries, hip and knee arthroplasties, and chronic conditions.

Energy and sports drinks in children and adolescents

Sports drinks and caffeinated energy drinks (CEDs) are commonly consumed by youth. Both sports drinks and CEDs pose potential risks for the health of children and adolescents and may contribute to obesity. Sports drinks are generally unnecessary for children engaged in routine or play-based physical activity. CEDs may affect children and adolescents more than adults because they weigh less and thus experience greater exposure to stimulant ingredients per kilogram of body weight. Paediatricians need to recognize and educate patients and families on the differences between sport drinks and CEDs. Screening for the consumption of CEDs, especially when mixed with alcohol, should be done routinely. The combination of CEDs and alcohol may be a marker for higher risk of substance use or abuse and for other health-compromising behaviours.

Promotion of Healthy Weight-Control Practices in Young Athletes

Children and adolescents may participate in sports that favor a particular body type. Some sports, such as gymnastics, dance, and distance running, emphasize a slim or lean physique for aesthetic or performance reasons. Participants in weight-class sports, such as wrestling and martial arts, may attempt weight loss so they can compete at a lower weight class. Other sports, such as football and bodybuilding, highlight a muscular physique; young athletes engaged in these sports may desire to gain weight and muscle mass. This clinical report describes unhealthy methods of weight loss and gain as well as policies and approaches used to curb these practices. The report also reviews healthy strategies for weight loss and weight gain and provides recommendations for pediatricians on how to promote healthy weight control in young athletes.

Somatotype, Level of Competition, and Performance in Attack in Elite Male Volleyball

This study investigated the relationship between somatotype, level of competition, and performance in attack in elite level male volleyball players. The objective was to test for the potential covariation of competition level (Division A1 vs. A2) and playing position (hitters vs. centers vs. opposites) considering performance in attack. Anthropometric, body composition and somatotype variables were measured according to the Heath-Carter method. The attack actions of 144 players from 48 volleyball matches were analyzed and their performance was rated using a 5-point numerical scale. Results showed that players of Division A1 were taller, heavier, more muscular, and less endomorphic compared to those of Division A2. MANOVA and follow-up discriminant function analysis revealed somatotype differences among playing positions with centers and opposites being endomorph-ectomorph and hitters being central. Centers performed constantly better than hitters and opposites regardless of the division and somatotype. Multiple linear regression analysis showed that variables defining ectomorph and endomorph players, centers, and players of Division A1 significantly determined the relative performance superiority and were able to explain the variation in performance by almost 25%. These results could be taken into account by coaches when assigning players to particular playing positions or when designing individualized position-specific training programs.

The nutrition for sport knowledge questionnaire (NSKQ): development and validation using classical test theory and Rasch analysis

BACKGROUND

Appropriate dietary intake can have a significant influence on athletic performance. There is a growing consensus on sports nutrition and professionals working with athletes often provide dietary education. However, due to the limitations of existing sports nutrition knowledge questionnaires, previous reports of athletes' nutrition knowledge may be inaccurate.

METHODS

An updated questionnaire has been developed based on a recent review of sports nutrition guidelines. The tool has been validated using a robust methodology that incorporates relevant techniques from classical test theory (CTT) and Item response theory (IRT), namely, Rasch analysis.

RESULTS

The final questionnaire has 89 questions and six sub-sections (weight management, macronutrients, micronutrients, sports nutrition, supplements, and alcohol). The content and face validity of the tool have been confirmed based on feedback from expert sports dietitians and university sports students, respectively. The internal reliability of the questionnaire as a whole is high (KR = 0.88), and most sub-sections achieved an acceptable internal reliability. Construct validity has been confirmed, with an independent T-test revealing a significant (p < 0.001) difference in knowledge scores of nutrition (64 ± 16%) and non-nutrition students (51 ± 19%). Test-retest reliability has been assured, with a strong correlation (r = 0.92, p < 0.001) between individuals' scores on two attempts of the test, 10 days to 2 weeks apart. Three of the sub-sections fit the Rasch Unidimensional Model.

CONCLUSIONS

The final version of the questionnaire represents a significant improvement over previous tools. Each nutrition sub-section is unidimensional, and therefore researchers and practitioners can use these individually, as required. Use of the questionnaire will allow researchers to draw conclusions about the effectiveness of nutrition education programs, and differences in knowledge across athletes of varying ages, genders, and athletic calibres.

Energy expenditure and nutrition status of ballet, jazz and contemporary dance students

Purpose: To evaluate of the energy expenditure in 3 types of dance classes (ballet, Jazz, and contemporary), as well as of the daily energy balance depending on dance type. Materials and methods: 40 females attending dance classes with a median age of 21.0 (19.0-25.0) and 10 males with a median age of 27.0 (20.0-28.0) participated in this study. The energy cost of each dance class was measured using the BodyMedia SenseWear Sensor and total daily energy expenditure was evaluated using a 3-day recording of physical activity. The dietary intake was evaluated with a 3-day food diary recording. Statistical analysis was performed using the SPSS software. Results: Median energy expenditure varied from 306 (277-328) Kcals/class for contemporary dance to 327 (290-355) Kcals/class for ballet and 369 (333-394) Kcals/class for jazz for females with significant differences between contemporary and jazz classes. For males, energy expenditure was 508 (447-589) Kcals/class and 564 (538-593) Kcals/class for ballet and jazz classes, respectively. Females had lower values for all anthropometric measurements, energy intake, macronutrient intakes, and energy expenditure, compared with males. The anthropometric characteristics did not differ between dance types. Both female and male dance students were in a negative energy balance. Conclusions: The use of sensors such as BodyMedia SenseWear together with keeping daily diaries make measurement of physical activity in dancing reliable and accurate. Exercise expenditure differs across types of dance in females but not in males. Both sexes had inadequate energy and carbohydrate intakes.

Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study

No study has concurrently measured changes in free-living whole body protein metabolism and exercise performance during recovery from an acute bout of resistance exercise. We aimed to determine if whey protein ingestion enhances whole body net protein balance and recovery of exercise performance during overnight (10 h) and 24 h recovery after whole body resistance exercise in trained men. In a double-blind crossover design, 12 trained men (76 ± 8 kg, 24 ± 4 years old, 14% ± 5% body fat; means ± standard deviation (SD)) performed resistance exercise in the evening prior to consuming either 25 g of whey protein (PRO; MuscleTech 100% Whey) or an energy-matched placebo (CHO) immediately post-exercise (0 h), and again the following morning (~10 h of recovery). A third randomized trial, completed by the same participants, involving no exercise and no supplement served as a rested control trial (Rest). Participants ingested [15N]glycine to determine whole body protein kinetics and net protein balance over 10 and 24 h of recovery. Performance was assessed pre-exercise and at 0, 10, and 24 h of recovery using a battery of tests. Net protein balance tended to improve in PRO (P = 0.064; effect size (ES) = 0.61, PRO vs. CHO) during overnight recovery. Over 24 h, net balance was enhanced in PRO (P = 0.036) but not in CHO (P = 0.84; ES = 0.69, PRO vs. CHO), which was mediated primarily by a reduction in protein breakdown (PRO < CHO; P < 0.01. Exercise decreased repetitions to failure (REP), maximal strength (MVC), peak and mean power, and countermovement jump performance (CMJ) at 0 h (all P < 0.05 vs. Pre). At 10 h, there were small-to-moderate effects for enhanced recovery of the MVC (ES = 0.56), mean power (ES = 0.49), and CMJ variables (ES: 0.27-0.49) in PRO. At 24 h, protein supplementation improved MVC (ES = 0.76), REP (ES = 0.44), and peak power (ES = 0.55). In conclusion, whey protein supplementation enhances whole body anabolism, and may improve acute recovery of exercise performance after a strenuous bout of resistance exercise.

International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine

Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).

Effects of short-term plyometric training on physical fitness parameters in female futsal athletes

[Purpose] To verify the effects of short-term plyometric training (PM) on body composition, flexibility and muscle power output in female Futsal athletes. [Subjects and Methods] Twenty female Futsal athletes (19.5 ± 1.29 years) equally and randomly divided into control and experimental groups were submitted to a sit-and-reach flexibility test, body composition measures and horizontal jump, at baseline and one day after the final training session. Both groups retained their training routines while only the experimental group participated in an additional 25 minutes of PM 2 times a week over 4 weeks. [Results] The experimental group showed higher values of flexibility and muscle power and lower body fat after the intervention in comparison to the baseline and control group. In addition, the effect size within-group after intervention indicated a moderate, large and very large effect for body fat, flexibility and muscle power, respectively. [Conclusion] These results show that plyometric training may be effective in reducing body fat and increasing flexibility and muscle power in female Futsal athletes. Thus, it may suggest that PM can be applied in the field of preventive physical therapy.

Comparison of body composition and nutrients' deficiencies between Portuguese rink-hockey players

We evaluated dietary intake and body composition of child and adolescent rink-hockey players and controls. Seventy-two male rink-hockey players (38 children and 34 adolescents) and 79 male controls (43 children and 36 adolescents) were evaluated in order to collect training data, detailed dietary intake and body composition. Rink-hockey players presented significantly lower body fat (BF) and higher fat-free mass (FFM) than controls. Mean intakes of carbohydrate and protein were considered to be adequate, but mean intakes of fat were above the recommended levels in athletes. Significant differences were found for energy intake (EI) and exercise energy expenditure (EEE) between athletes and controls (P < 0.05), resulting in some cases of low energy availability in rink-hockey players. Significant group differences (P < 0.05) were also observed for vitamins and mineral intakes in child and adolescent rink-hockey players due to higher mean intakes in control groups. Low intakes of vitamins D, E and K, calcium, iron, boron and magnesium were reported in athletes, with exception for thiamine (P = 0.449), riboflavin (P = 0.246), pantothenic acid (P = 0.065), magnesium (P = 0.061) and phosphorus (P = 0.051) in children and for niacin (P = 0.652), vitamin D (P = 0.406) and zinc (P = 0.783) in adolescents.

CONCLUSION

Nutritional deficiencies in macronutrients and micronutrients observed in very young rink-hockey players can impair their growth and development with negative consequences upon athletic performance. What is Known: • Adequate dietary intake is an important resource for athletes' short- and long-term health, performance and recovery. • There are no published studies in rink-hockey players' energy availability. What is New: • This study provides the first data on significant differences in energy intake between very young athletes and controls, resulting in low energy availability in rink-hockey players. • Mean intakes of fat were above the recommended levels, and micronutrients intakes were inappropriate in athletes with consequences for their health and performance.

Hydration and Fluid Replacement Knowledge, Attitudes, Barriers, and Behaviors of NCAA Division 1 American Football Players

Judge, LW, Kumley, RF, Bellar, DM, Pike, KL, Pierson, EE, Weidner, T, Pearson, D, and Friesen, CA. Hydration and fluid replacement knowledge, attitudes, barriers, and behaviors of NCAA Division 1 American football players. J Strength Cond Res 30(11): 2972-2978, 2016-Hydration is an important part of athletic performance, and understanding athletes' hydration knowledge, attitudes, barriers, and behaviors is critical for sport practitioners. The aim of this study was to assess National Collegiate Athletic Association (NCAA) Division 1 (D1) American football players, with regard to hydration and fluid intake before, during, and after exercise, and to apply this assessment to their overall hydration practice. The sample consisted of 100 student-athletes from 2 different NCAA D1 universities, who participated in voluntary summer football conditioning. Participants completed a survey to identify the fluid and hydration knowledge, attitudes and behaviors, demographic data, primary football position, previous nutrition education, and barriers to adequate fluid consumption. The average Hydration Knowledge Score (HKS) for the participants in the present study was 11.8 ± 1.9 (69.4% correct), with scores ranging from 42 to 100% correct. Four key misunderstandings regarding hydration, specifically related to intervals of hydration habits among the study subjects, were revealed. Only 24% of the players reported drinking enough fluids before, during, immediately after, and 2 hours after practice. Generalized linear model analysis predicted the outcome variable HKS (χ = 28.001, p = 0.045), with nutrition education (Wald χ = 8.250, p = 0.041) and position on the football team (χ = 9.361, p = 0.025) being significant predictors. "Backs" (e.g., quarterbacks, running backs, and defensive backs) demonstrated significantly higher hydration knowledge than "Linemen" (p = 0.014). Findings indicated that if changes are not made to increase hydration awareness levels among football teams, serious health consequences, including potential fatalities, could occur on the field, especially among heavier linemen.

Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study

In spite of well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance. In this cross-sectional study, we compared elite vegetarian and omnivore adult endurance athletes for maximal oxygen uptake (VO2 max) and strength. Twenty-seven vegetarian (VEG) and 43 omnivore (OMN) athletes were evaluated using VO2 max testing on the treadmill, and strength assessment using a dynamometer to determine peak torque for leg extensions. Dietary data were assessed using detailed seven-day food logs. Although total protein intake was lower among vegetarians in comparison to omnivores, protein intake as a function of body mass did not differ by group (1.2 ± 0.3 and 1.4 ± 0.5 g/kg body mass for VEG and OMN respectively, p = 0.220). VO2 max differed for females by diet group (53.0 ± 6.9 and 47.1 ± 8.6 mL/kg/min for VEG and OMN respectively, p < 0.05) but not for males (62.6 ± 15.4 and 55.7 ± 8.4 mL/kg/min respectively). Peak torque did not differ significantly between diet groups. Results from this study indicate that vegetarian endurance athletes’ cardiorespiratory fitness was greater than that for their omnivorous counterparts, but that peak torque did not differ between diet groups. These data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.

Dietary Intake of Athletes Seeking Nutrition Advice at a Major International Competition

International travel and short-term residence overseas is now a common feature of an elite athlete's competition schedule, however, food choice away from home may be challenging and potentially impact on performance. Guidelines for dietary intake specific to competition exist for athletes, however, there is little evidence available to ascertain if athletes meet these recommendations during competition periods, particularly when food is provided in-house. During the Delhi 2010 Commonwealth Games, dietitians based in the dining hall recorded 24 h dietary recalls with all athletes who visited the nutrition kiosk. Analysis of dietary intake was conducted with FoodWorks (Xyris Pty Ltd., Brisbane, Australia). Overall, athletes reported consuming a median total daily energy intake of 8674 kJ (range 2384-18,009 kJ), with carbohydrate within the range of 1.0-9.0 g per kg of bodyweight (g/kg) (median = 3.8) and contributing to 50% total energy (TE) (range 14%-79%). Protein and fat intake ranged from 0.3-4.0 g/kg (median = 1.7) to 10-138 g (median = 67 g), and contributed to 21% TE (range 8%-48%) and 24% TE (range 8%-44%), respectively. Athletes reported consuming between 4 and 29 different food items (median = 15) in the previous 24 h period, with predominately discretionary, grains/cereals, meats, poultry, fish, eggs, and meat alternative items. This suggests that dairy, fruit, and vegetable intake may be suboptimal and intake of the micronutrients iron, zinc, calcium, and vitamins A and C may be of concern for a number of athletes.

Effects of Almond- and Olive Oil-Based Docosahexaenoic- and Vitamin E-Enriched Beverage Dietary Supplementation on Inflammation Associated to Exercise and Age

n-3-polyunsaturated fatty acids and polyphenols are potential key factors for the treatment and prevention of chronic inflammation associated to ageing and non-communicable diseases. The aim was to analyse effects of an almond and olive oil beverage enriched with α-tocopherol and docosahexaenoic, exercise and age on inflammatory plasma markers, and immune gene expression in peripheral blood mononuclear cells (PBMCs). Five young and five senior athletes who were supplemented for five weeks with a functional beverage performed a stress test under controlled conditions before and after beverage supplementation. Blood samples were taken immediately before and 1 h after each test. Plasma, erythrocytes and PBMCs were isolated. Beverage supplementation increased plasmatic Tumour Necrosis Factor α (TNFα) levels depending on age and exercise. Exercise increased plasma non esterified fatty acids (NEFAs), soluble Intercellular adhesion molecule 3 (sICAM3) and soluble L-selectin (sL-Selectin), and this increase was attenuated by the supplementation. Exercise increased PGE2 plasma levels in supplemented young and in senior placebo athletes. Exercise increased NFkβ-activated levels in PBMCs, which are primed to a pro-inflammatory response increasing pro-inflammatory genes expression after the exercise mainly in the young group after the supplementation. The functional beverage supplementation to young athletes enhances a pro-inflammatory circulating environment in response to the exercise that was less evident in the senior group.

The impact of nutrition education on nutrition knowledge and adherence to the Mediterranean Diet in adolescent competitive swimmers

OBJECTIVES

Nutrition education of adolescent competitive swimmers is under-studied although their diet and nutrition knowledge are generally poor. This study aimed to assess the impact of nutrition education on nutrition knowledge and adherence to the Mediterranean Diet (MD) and explore the effect of parental education on the swimmers' MD adherence.

DESIGN

A pre-post measurement interventional study was carried out.

METHODS

A half-day nutrition education session was delivered for the swimmers and a separate session for their parents. At baseline and 6-weeks post-workshop, a short nutrition knowledge assessment of food sources of nutrients and the MD composition as well as adherence to the MD using the KIDMED Index were undertaken. The swimmers' parents also completed the KIDMED Index to evaluate the swimmers' diet.

RESULTS

Thirty-four competitive swimmers (age: 15.2±1.5 yr, 23 males) and 22 of their parents participated in the study. There was an improvement in MD adherence with 47% having good adherence post-intervention vs 21% at baseline (p<0.01) and an increase in the KIDMED Index score (median [interquartile range]: 5.0 [4.0-7.0] vs 7.0 [7.0-9.0]; p<0.01)). There was also an increase in the swimmers' nutrition knowledge assessment score (median [IQR]: 7.0 [5.0-8.0] vs 7.0 [6.0-8.0], p<0.05)), and a trend for a lower score post-intervention in swimmers whose parents did not participate compared to those whose parents participated (6.0 [6.0-7.8] vs 7.0 [7.0-8.0], p=0.063).

CONCLUSIONS

The intervention improved adherence to the MD and increased nutrition knowledge. The findings support parental participation in nutrition education.

Weight Management for Athletes and Active Individuals: A Brief Review

Weight management for athletes and active individuals is unique because of their high daily energy expenditure; thus, the emphasis is usually placed on changing the diet side of the energy balance equation. When dieting for weight loss, active individuals also want to preserve lean tissue, which means that energy restriction cannot be too severe or lean tissue is lost. First, this brief review addresses the issues of weight management in athletes and active individuals and factors to consider when determining a weight-loss goal. Second, the concept of dynamic energy balance is reviewed, including two mathematical models developed to improve weight-loss predictions based on changes in diet and exercise. These models are now available on the Internet. Finally, dietary strategies for weight loss/maintenance that can be successfully used with active individuals are given. Emphasis is placed on teaching the benefits of consuming a low-ED diet (e.g., high-fiber, high-water, low-fat foods), which allows for the consumption of a greater volume of food to increase satiety while reducing energy intake. Health professionals and sport dietitians need to understand dynamic energy balance and be prepared with effective and evidence-based dietary approaches to help athletes and active individuals achieve their body-weight goals.