Oral branched-chain amino acids supplementation in athletes: a systematic review

Branched-chain amino acids (BCAAs) are oxidized in the muscle and result in stimulating anabolic signals—which in return may optimize performance, body composition and recovery. Meanwhile, among athletes, the evidence about BCAA supplementation is not clear. The aim of this study was to review the effects of BCAAs in athletic populations. The research was conducted in three databases: Web of Science (all databases), PubMed and Scopus. The inclusion criteria involved participants classified both as athletes and people who train regularly, and who were orally supplemented with BCAAs. The risk of bias was individually assessed for each study using the revised Cochrane risk of bias tool for randomized trials (RoB 2.0). From the 2298 records found, 24 studies met the inclusion criteria. Although BCAAs tended to activate anabolic signals, the benefits on performance and body composition were negligible. On the other hand, studies that included resistance participants showed that BCAAs attenuated muscle soreness after exercise, while in endurance sports the findings were inconsistent. The protocols of BCAA supplements differed considerably between studies. Moreover, most of the studies did not report the total protein intake across the day and, consequently, the benefits of BCAAs should be interpreted with caution

Carbohydrate intake among male soccer players: a systematic review and meta-analysis

INTRODUÇÃO: As diretrizes relativas ao consumo de hidratos de carbono têm sido extensivamente discutidas. Apesar deste macronutriente ser reconhecidamente determinante no rendimento desportivo, escassas revisões sistemáticas e meta-análises foram conduzidas para avaliar a ingestão de hidratos de carbono em futebolistas masculinos. OBJETIVOS: O objetivo desta revisão sistemática, com meta-análise, foi avaliar a ingestão de hidratos de carbono em diferentes períodos da época competitiva. Adicionalmente, foi examinado o consumo de hidratos de carbono por grupo posicional. METODOLOGIA: As bases de dados utilizadas foram PubMed, SPORTDiscus e Web of Science Core Collection. Os estudos incluídos consideraram os seguintes critérios de elegibilidade: jogadores de futebol masculino, idade superior a 18 anos e consumo de hidratos de carbono expresso em g.kg-1.dia-1. RESULTADOS: Inicialmente, foram identificados 1992 artigos. Destes, 11 foram considerados elegíveis para a revisão sistemática e 10 foram incluídos na meta-análise. Os resultados demonstraram que os futebolistas masculinos, consomem em média, 4,3 g.kg-1.dia-1 e 5,0 g.kg-1.dia-1 nos períodos competitivos e preparatórios (pré-época), respetivamente. Não foi encontrado qualquer estudo que reportasse o consumo de hidratos de carbono durante a off-season. Apenas três estudos examinaram a variação do consumo de hidratos de carbono por grupo posicional. Embora as amostras sejam limitadas, os guarda-redes parecem ingerir uma menor quantidade de hidratos de carbono comparativamente a atletas de outras posições em campo. CONCLUSÕES: Considerando as limitações associadas às metodologias utilizadas para aferir o consumo de hidratos de carbono em atletas, a presente revisão sistemática realça a necessidade de desenvolver estratégias nutricionais para o cumprimento das diretrizes deste macronutriente.INTRODUCTION: Guidelines for carbohydrate (CHO) intake have been systematically updated. Although CHO are determinant to soccer performance, few systematic reviews or meta-analyses described the CHO ingestion among male soccer players. OBJECTIVES: This systematic-review, with meta-analyses, examined the CHO intake in male soccer players according to the competitive schedule (preparatory season, season and off-season). Additionally, the variability of CHO intake considering playing position was described. METHODOLOGY: Three databases were consulted: PubMed, SPORTDiscus and Web of Science Core Collection. Studies were included according to the following eligibility criteria: (i) male soccer players, (ii) age ≥ 18.0 years, (iii) CHO intake expressed in g.kg-1.day-1. RESULTS: Initially, 1992 manuscripts were identified. Of those, 11 manuscripts were considered eligible for the systematic review and 10 manuscripts were included in the meta-analyses. The results of the current meta-analysis showed that male soccer players consumed, on average, 4.3 g.kg-1.day-1 and 5.0 g.kg-1.day-1 of CHO during the season and in the preparatory period, respectively. Surprisingly, no studies reported CHO intake during off-season. Only three studies examined CHO ingestion by playing position. Although samples were limited, goalkeepers seemed to ingest less CHO than outfielders. CONCLUSIONS: Considering the limitations associated with CHO intake reporting, nutritional strategies to confirm that athletes meet the intake of this macronutrient are needed.info:eu-repo/semantics/publishedVersio

Characterization of Static Strength, Vertical Jumping, and Isokinetic Strength in Soccer Players According to Age, Competitive Level, and Field Position

: Muscular strength is strongly related to speed and agility tasks, which have been described as the most decisive actions preceding goals in the soccer game. This study aimed to characterize the players’ strength indicators and to analyze the variation associated with age, competition level, and positional role. Eighty-three male soccer players from A team (n = 22), B team (n = 17), U-23 (n = 19), and U-19 (n = 25) participated in this study. Handgrip strength was assessed using a hand dynamometer (Jamar Plus+), countermovement jump (CMJ) and the squat jump (SJ) were evaluated using Optojump Next, and a Biodex System 4 Pro Dynamometer was used to assess the isokinetic strength of knee extension/flexion. Team A players showed increased lower-body strength compared to their peers, mainly through their increased vertical jumping capacity (i.e., CMJ and SJ; ps < 0.019), and superior performance in isokinetic assessments (i.e., peak torque, total work, and average power). Overall, older players outperformed their younger peers regarding vertical jumping, static strength, and average power in isokinetic strength (ps < 0.005). This study emphasizes the superior strength levels of professional soccer players compared with their lower-division peers, even after controlling by age. This information is of great value to sports agents and coaches, underlining the need to design and include strength-specific content during soccer training.info:eu-repo/semantics/publishedVersio

The quantification of physical performance and internal training load in youth male soccer players during preseason

Purpose: The monitoring of training loads and quantification of physical performance are common practices in youth soccer academies to support coaches in prescribing and programming training for individuals. The interaction between training load and physical performance is unknown during a preseason period in youth soccer players. The current study assessed changes in training load and physical assessments across a 4-week preseason period. The relationship between physical performance and match playing time in youth male soccer players was also investigated. Methods: The training loads of 25 professional youth academy male soccer players were monitored throughout a 4-week preseason period. Assessments of power, agility, speed, and aerobic capacity were undertaken in the first training session. Session ratings of perceived exertion (sRPE) and well-being questionnaires were collected during all training sessions and preseason matches. Playing time during subsequent competitive matches was recorded. Results: T test and 30-m-sprint assessments, conducted on the first day of preseason, were predictors of sRPE throughout preseason (t test χ2/df = 2.895, poor adjustment; 30-m sprint χ2/df = 1.608, good adjustment). YoYo Test performance was related with changes in perceived fatigue (χ2/df = 0.534, very good adjustment). Faster players reported higher values of sRPE, and players with higher aerobic capacity reported higher levels of fatigue across preseason. Well-being, perceived fatigue and soreness, and sRPE decreased across preseason. Greater match durations were related to higher levels of fatigue during preseason (P < .05). Conclusion: The current study highlights the relationship between training load, physical assessments, and playing time. Coaches and practitioners can use physical test data at the start of preseason as an indication of players that report higher sRPE, perceived fatigue, and reduced well-being across preseason, supporting decisions around individualized training prescriptions

Dietary intakes and daily distribution patterns of macronutrients in youth soccer players

IntroductionThere has been an abundance of dietary analysis research conducted on adult male soccer players, while studies on youth players are lacking. Furthermore, the daily distribution of energy and macronutrient intake throughout the day has been reported to influence training adaptations, but this is often not considered in the literature. This study aims to quantify daily energy and macronutrient intake and assess their distribution over 5 days, and compare daily energy intakes and predicted daily energy expenditure in under-16 male soccer players.MethodsThe sample included 25 soccer participants aged 14.8–15.7 years. Five-day self-reported food diaries were used to record the food/drink consumption. Intake was analyzed for total daily energy, macronutrient intakes, and distribution among meals (breakfast, lunch, dinner, and snacks). Daily energy expenditure was predicted by resting energy expenditure and physical activity levels developed for youth sports participants.ResultsThe mean total energy intake was 1,928 ± 388 kcal∙day−1, whereas the estimated daily energy expenditure was 3,568 kcal∙day−1. Relative daily protein intakes were lower at breakfast, morning snack, afternoon snack, and night snack compared to lunch and dinner.DiscussionYouth soccer players do not appear to meet energy requirements and daily CHO guidelines. Fluctuations in protein intake throughout the day were noted and may influence training adaptations (i.e., muscle protein synthesis and recovery)

Body composition among long distance runners

OBJECTIVE: The current study aimed to examine the body composition of adult male ultra-trail runners (UTR) according to their level of participation (regional UTR-R, vs. national UTR-N). METHODS: The sample was composed of 44 adult male UTR (aged 36.5±7.2 years; UTR-R: n=25; UTR-N: n=19). Body composition was assessed by air displacement plethysmography, bioelectrical impedance, and dual-energy X-ray absorptiometry. In addition, the Food Frequency Questionnaire (FFQ) was applied. A comparison between the groups was performed using independent samples t-test. RESULTS: Significant differences between groups contrasting in the competitive level were found for chronological age (in years; UTRR: 38.8±8.2 vs. UTR-N: 33.5±4.1); body density (in L.kg-1; UTR-R: 1.062±0.015 vs. UTR-N: 1.074±0.009); and fat mass (in kg; UTR-R: 12.7±6.8 vs. UTR-N: 7.6±2.7). CONCLUSION: UTR-N were younger, presented higher values for body density, and had less fat mass, although no significant differences were found for fat-free mass. The current study evidenced the profile of long-distance runners and the need for weight management programs to regulate body composition.OBJETIVO: O presente estudo objetivou examinar a composição corporal dos corredores de ultra-trail (UTR) e, adicionalmente, comparar dois grupos de acordo com o nível de participação (Regional vs. Nacional, respectivamente UTR-R e UTR-N). MÉTODOS: A amostra foi composta por 44 corredores adultos masculinos (36,5±7,2 anos de idade; UTR-R: n=25; UTR-N: n=19). A composição corporal foi avaliada recorrendo à pletismografia de ar deslocado, bioimpedância elétrica e absorciometria de raios X de dupla energia. Adicionalmente, foi utilizado o Questionário de Frequência Alimentar. A comparação entre grupos foi realizada com base na prova t-student para amostras independentes. RESULTADOS: Foram encontradas diferenças significativas por nível de competição para as seguintes variáveis dependentes: idade cronológica (em anos; UTR-R: 38,8±8,2 vs. UTR-N: 33,5±4,1); densidade corporal (em kg/L; UTR-R: 1,062±0,015 L/kg vs. UTR-N: 1,074±0,009); massa gorda (em kg; UTR-R: 12,7±6,8 kg vs. UTR-N: 7,6±2,7). CONCLUSÃO: Os UTR-N tendem a ser mais jovens e apresentam valores superiores de densidade corporal e, consequentemente, valores menores de massa gorda, sendo a massa isenta de gordura semelhante entre os grupos. O presente estudo determinou o perfil dos corredores adultos masculinos de longa distância (ultra-trail), realçando a importância de uma cuidadosa regulação da massa corporal

A systematic review of the physical, physiological, nutritional and anthropometric profiles of soccer referees

Background: The development of soccer referees has received consideration by international and national refereeing governing bodies. Age and performance are two of the criteria used to nominate international referees. In addition, nutrition, body composition and physiological outputs have received little attention. The aim of this study was to review the information related to match indicators, testing, nutrition, and physiological profiling of soccer referees. Methods: The inclusion criteria of the manuscripts in the present review that the articles included male and/or female soccer referees, relevant data about performance, testing, nutrition, body composition, body size and physiology. Three databases were consulted: Web of Sciences all databases, PubMed and Scopus. The tools developed by the National Institute of Health were used to assess risk-of-bias according to studies design. Results: In total, 110 manuscripts were included in the present review. Match activities of soccer referees and assistant referees are not comparable and are influenced by several factors. Additionally, match performance is often used to validate field protocols. The associations between match indicators and field protocols were not constant across the studies consulted, particularly in short-maximal tests. An age decline in physical performance was not conclusive. Body size did not discriminate referees and assistant referees, as well as referees of different competitive levels. Few studies focused on nutritional guidelines among referees. Conclusions: The current review did not consider studies about decision making, psychological aspects or visual parameters. Age is not a useful criterion to define international level thereby, age specific criteria of fitness assessment, laboratory outputs, mainly aerobic fitness, and body composition should be created for referees and assistant referees. Trial registration: The protocol was published in INPLASY (International Platform of Registered Systematic Review and Meta-Analysis Protocols) with the registration number 202280052 and doi 10.37766/inplasy2022.8.00

A Systematic Review of the Physical, Physiological, Nutritional and Anthropometric Profiles of Soccer Referees

Abstract Background The importance of soccer referees is widely accepted by international soccer organizations and governing bodies, although there is little research summarizing and appraising the literature on soccer referees. The aim of this study was to systematically review the information related to physical demands, nutrition and physiological profiling of soccer referees. Methods Conforming with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, searches of three electronic databases (Web of Sciences, PubMed and Scopus) were conducted on 24 April 2022. The following search terms were used: (Soccer OR football AND refer*) AND (physical OR physiolo* OR load* OR “body composition” OR “fat mass” OR “fat free mass” OR “body size” OR “nutrition*” OR “nutritional assessment” OR “nutritional intake” OR “macronutrient*” OR “micronutrient*”). The inclusion criteria of the manuscripts written in English were that articles with male and/or female soccer referees and included relevant data concerning performance, physical testing, nutrition, body composition, body size and/or physiology of soccer referees. The tools developed by the National Institute of Health were used to assess risk of bias according to the study design. Results In total, 110 manuscripts were included in the present review. Match activities of soccer referees and assistant referees are not comparable. Variation in performance is influenced by competitive level and competitive schedules. Additionally, match performance is often used to validate field protocols. The associations between match indicators and field protocols were not constant across the included studies, particularly in short-maximal tests. An age decline in physical performance was not conclusive. Body size did not discriminate between referees and assistant referees, as well as referees of different competitive levels. Few studies focused on nutritional guidelines among referees, particularly exercise energy expenditure. Energy intake was comparable across studies, but referees did not follow the daily dietary recommendations. Aerobic output was frequently assessed, and it was not comparable to the values for soccer players. Conclusions Although there are decreases in the running profiles of older referees, they maintain the same distances from the ball, and thus, age per se should not be used to define participation at the international level. The assessment of physical fitness warrants future consideration given the levels of fatigue that are apparent at the end of matches. In order to attain ideal levels of body composition, future studies need to provide guidelines for daily energy expenditure and nutritional intake. Trial registration: The protocol was published in INPLASY (International Platform of Registered Systematic Review and Meta-Analysis Protocols) with the registration number 202280052 and https://doi.org/10.37766/inplasy2022.8.005

Predicting resting energy expenditure among athletes:a systematic review

Resting energy expenditure (REE) is often estimated in athletes using equations developed from the general population however, the application in athletic-specific populations is questionable. The aim of this systematic review was to compare measured REE and estimations of REE obtained from non-sport participants and athletes. Inclusion criteria met PICO criteria: population – participantsinvolved in organized sport; intervention – resting energy expenditure was obtained by calorimetry; comparator – equations to estimate REE; outcomes – comparisons between measured REE and predicted REE. The search was conducted in Web of Science all databases, PubMed and Scopus. Comparisons between measured REE and predicted REE as well the potential models to estimate REE developed among athletes were summarized. Allowing for variation among studies, equations developed within general populations were not comparable to REE measured by calorimetry in athletes. Equations across athleticsamples were obtained but, few studiestested their validity acrossindependent samples of sport participants. Nevertheless, equations developed within athlete populations seem to be widely unused in sports nutrition literature and practice. De Lorenzo and ten Haaf equations appear to present an acceptable agreement with measured REE. Finally, equations used among adults should not be generalised for youth sport participants