Evaluation of general and sports nutritional knowledge of recreational athletes

Background: Nutritional knowledge is one of the factors that can lead to adopting healthy eating habits and, consequently, favoring sports performance. Aim: The study aimed to assess the nutritional knowledge and its subsections general and sports nutritional knowledge of recreational athletes. Methods: A validated, translated, and adapted 35-item questionnaire was used to assess total (TNK), general-GNK (11 questions), and sports-SNK (24 questions) nutritional knowledge. The Abridged Nutrition for Sport Knowledge Questionnaire (ANSKQ) was provided online using Google Forms. Four hundred and nine recreational athletes (male: 173, female: 236, age  =  32.4  ±  9.6 years) completed the questionnaire. Results: The mean TNK (50.7%) and GNK (62.7%) scores were classified as "average" and higher than SNK (45.2%), which was classified as "poor." Male participants had SNK and TNK scores higher than females, but not for GNK. The youngest participants (18-24 years) had TNK, SNK, and GNK scores higher than other age groups (p < 0.05). Participants who reported previous nutritional appointments with a nutritionist had higher TNK, SNK, and GNK scores than those without it (p < 0.05). Those with "advanced" formal nutrition education (university students, graduate, or postgraduate in Nutrition) scored higher than those of groups "none" and "intermediate," for TNK (advanced  =  69.9%, intermediate  =  52.9%, and none  =  45.0%, p < 0.0001), GNK (advanced  =  74.7%, intermediate  =  63.8%, and none  =  59.2%, p < 0.0001), and SNK, (advanced  =  67.5%, intermediate  =  48.0%, and none  =  38.5%, p < 0.0001). Conclusion: Results suggest a lack of nutritional knowledge in recreational athletes, mainly those without an appointment with a registered nutritionist and formal nutritional education.

Dietary-nutritional needs in tennis: A narrative review

Introduction: Tennis is characterized by a large number of competitions and little recovery time between them. Thus, tennis players and coaching staff have become interested in the role that nutrition can play in maximizing sports performance. The scientific literature does not have recent narrative and/or systematic reviews about to nutrition in tennis. The aim of this study is to map, describe and discuss the state of the science of nutrition and dietetic practices for tennis players from a theoretical and contextual point of view, to enable focused future systematic reviews.Material and methods: A narrative review through the Dialnet, Elsevier, Medline, Pubmed and Web of Science databases, through a search strategy based on keywords separated by Boolean connectors. A series of inclusion / exclusion criteria were applied to select those investigations that responded to the aim of the work.Results: Nutritional recommendations on carbohydrate intake depend on the training load, 5-7 g/kg/day g/kg/day for normal training and 7-10 g/kg/day for competitive periods or high training load. The recommended protein intake is 1.8 g/kg/day and 1 g/kg/day of lipids. The supplements that can optimize tennis performance are caffeine, sodium bicarbonate, creatine and β-alanine. Beetroot juice can be a possible aid to consider in dietetic-nutritional planning in tennis players.Conclusions: Performance and health of tennis player can be optimized, as well as adequate periodization of nutrients and supplements, meeting to the physiological demands of tennis.

Actividad electromiográfica de los músculos del cuádriceps asociado a las diferentes posiciones del pie: un estudio piloto

El fortalecimiento de los músculos del cuádriceps femoral (CF) es importante debido a su función en el movimiento. La posición de la articulación puede generar cambios en el reclutamiento muscular. De esa forma el presente estudio tiene como objetivo verificar si variaciones en las posiciones del pie durante la extensión de las rodillas son eficaces para la selección específica de los músculos recto femoral, vasto lateral y vasto medial, que componen el CF. Once mujeres universitarias (edad 22.36 ± 3.56 años) participaron del estudio. Fue evaluada la activación de los músculos a través de la electromiografía de superficie, con una configuración bipolar, en 3 series de 10 repeticiones máximas (RM) de extensión bilateral de rodilla, en tres posiciones de los pies: neutra, rotación interna y rotación externa. Los resultados no presentaron diferencias significativas entre los músculos del CF en todas las posiciones del pie. En conclusión, los resultados del presente estudio sugieren que las variaciones en los grados de rotación de los pies durante la extensión de las rodillas no son eficaces para la selección específica de los músculos que componen el CF.

Atividade eletromiográfica da musculatura do quadríceps associado às diferentes posições do pé: um estudo piloto

O fortalecimento do grupo muscular quadríceps femoral (QF) é muito importante devido sua função para o movimento. Mudanças na posição do pé, podem gerar alterações no recrutamento muscular, desta forma o presente estudo objetivou verificar se as variações nas posições dos pés, durante a extensão de joelhos, são eficazes para a seleção específica dos músculos reto femoral, vasto lateral e vasto medial, que compõem o QF. Onze mulheres universitárias (idade 22,36 ± 3,56 anos) participaram do estudo. Foi avaliada a ativação dos músculos através da eletromiografia de superfície, com configuração bipolar, em 3 séries de 10 repetições máximas (RM) de extensão de joelhos bilateral, em três posições dos pés: posição neutra, rotação interna e rotação externa. Os resultados não apontam diferenças significativas entre os músculos do QF superficial em todas as posições dos pés. Em conclusão, os resultados do presente estudo sugerem que as variações nos graus de rotação dos pés durante a extensão de joelhos, não são eficazes para a seleção específica dos músculos que compõem o QF.

Effects of Beetroot Juice Supplementation on Performance and Fatigue in a 30-s All-Out Sprint Exercise: A Randomized, Double-Blind Cross-Over Study

As a nitric oxide precursor, beetroot juice (BJ) is known to enhance high-intensity exercise performance (80⁻100% VO2max) yet its impacts on higher intensity sprint exercise (>100% VO2max) remain to be established. This study sought to examine the effects of BJ supplementation on performance and subsequent fatigue during an all-out sprint exercise. Using a randomized cross-over, double-blind, placebo-controlled design, 15 healthy resistance-trained men (22.4 ± 1.6 years) ingested 70 mL of either BJ or placebo. Three hours later, participants undertook a 30-s all-out Wingate test. Before and after the sprint exercise and at 30 s and 180 s post-exercise, three countermovement jumps (CMJ) were performed and blood lactate samples were obtained. Compared to placebo, BJ consumption improved peak (placebo vs. BJ, 848 ± 134 vs. 881 ± 135 W; p = 0.049) and mean (641 ± 91 vs. 666 ± 100 W; p = 0.023) power output and also reduced the time taken to reach Wpeak in the Wingate test (8.9 ± 1.4 vs. 7.3 ± 0.9 s; p = 0.003). No differences were detected in the fatigue index. In addition, while over time CMJ height and power diminished (ANOVA p < 0.001) and blood lactate levels increased (ANOVA p < 0.001), no supplementation effect was observed. Our findings indicate that while BJ supplementation improved performance at the 30-s cycling sprint, this improvement was not accompanied by differences in fatigue during or after this type of exercise.

Effects of beetroot juice supplementation on intermittent high-intensity exercise efforts

Beetroot juice contains high levels of inorganic nitrate (NO3-) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we review the few studies that have addressed this issue. The databases Dialnet, Elsevier, Medline, Pubmed and Web of Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or "sport nutrition" and exercise or sport or "physical activity" or effort or athlete. Nine articles fulfilling the inclusion criteria were identified. Results indicate that beetroot juice given as a single dose or over a few days may improve performance at intermittent, high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect remains unclear.

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.

O USO DE BARRA OU HALTERE NÃO ALTERA A ATIVAÇÃO MUSCULAR DURANTE O EXERCÍCIO PULLOVER

RESUMO Introdução: Inúmeras variações de exercícios têm sido aplicadas nas rotinas de treinamento de força, com o objetivo de otimizar os ganhos de força e hipertrofia e, entre os exercícios usados, podemos destacar o pullover. Objetivo: Comparar a atividade eletromiográfica da parte clavicular do músculo peitoral maior (PMC), parte esternocostal do peitoral maior (PME), cabeça longa do tríceps braquial (TBL), do deltoide anterior (DA), deltoide posterior (DP), latíssimo do dorso (LD) e serrátil anterior (SA) entre os exercícios pullover barra (PB) e pullover haltere (PH). Método: Participaram do estudo 11 homens treinados (idade, 24,50 ± 4,34 anos; percentual de gordura = 13,63 ± 1,94; estatura = 1,76 ± 0,04 m; massa corporal total = 73,12 ± 6,10 kg). A primeira fase do estudo consistiu em avaliações antropométricas e teste e re-teste de 10 repetições máximas (RM). A segunda fase do estudo foi composta pela coleta dos sinais eletromiográficos nos exercícios propostos. Para tal, foi realizada uma série com cargas ajustadas a 90% de 10 RM. Para verificar as diferenças na ativação dos respectivos músculos estudados entre os exercícios PB e PH adotou-se o teste t de Student pareado para amostras dependentes. Resultados: Não foram observadas mudanças na ativação de nenhum dos músculos analisados nos exercícios propostos (P > 0,05). Conclusão: Concluiu-se que a realização do exercício pullover com barra ou com o haltere não altera a participação/ativação dos músculos envolvidos.

Comparison of electromyographic activity during the bench press and barbell pulloverexercises

The aim of the study was to compare the electromyographic (EMG) activity of the following muscles: clavicular portion of pectoralis major, sternal portion of pectoralis major, long portion of triceps brachii, anterior deltoid, posterior deltoid and latissimus dorsi during dynamic contractions between flat horizontal bench press and barbell pulloverexercises. The sample comprised 12 males individuals experienced in resistance training. The volunteers made three visits to the laboratory. The first one consisted of 12 repetitions of the exercises for the electromyographic data collection. The results showed a higher EMG activation of the pectoralis major and anterior deltoid muscles in the flat horizontal bench press in comparison with the barbell pullover. The triceps brachii and latissimus dorsi muscles were more activated in the barbell pullover.

Pontos de transição da frequência cardíaca em teste progressivo máximo

Foi realizada análise do comportamento da frequência cardíaca (FC) e identificação dos pontos de inflexão (PIFC) e de deflexão da FC (PDFC) em teste progressivo máximo, em sujeitos do sexo feminino e masculino. Vinte universitários foram submetidos ao teste em cicloergômetro. A FC foi monitorada para posterior análise e identificação dos pontos de transição (PT). A FC apresentou comportamento sigmóide, com identificação de PT em todos os sujeitos, sendo: a) em 65% PIFC (64 ± 27W; 29 ± 9%Pmáx e 126 ± 12bpm; 66 ± 5%FCmáx) e PDFC (177 ± 45W; 81 ± 10%Pmáx e 178 ± 8bpm; 93 ± 4%FCmáx); b) em 30% apenas PIFC (80 ± 32W; 36 ± 14%Pmáx e 125 ± 13bpm; 66 ± 5%FCmáx) e c) em 5% o PDFC isolado (103W; 57%Pmáx e 150bpm; 82%FCmáx). O PIFC foi encontrado em carga significativamente inferior ao PDFC, sem diferenças na carga e FC relativas entre os sexos.