UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research.

Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts.

Thermoregulation in boys and men exercising at the same heat production per unit body mass.

PURPOSE: Child-adult thermoregulatory comparisons may be biased by differences in metabolic heat production ([Formula: see text]). We compared thermoregulatory responses of boys and men exercising at two intensities prescribed to elicit either a fixed [Formula: see text] per unit body mass (BM) or a fixed absolute [Formula: see text]. METHODS: Ten boys (10-12 years) and 10 men (19-25 years) performed 4 × 20-min cycling at a fixed [Formula: see text] per BM (W kg(-1)) at 35 °C and 35 % relative humidity (MENREL). Men also cycled (MENABS) at the same absolute [Formula: see text] (in W) as the boys. RESULTS: [Formula: see text] was lower in boys compared with MENREL, but similar to MENABS (mean ± SD, 233.6 ± 38.4, 396.5 ± 72.3, 233.6 ± 34.1 W, respectively, P < 0.001). Conversely, [Formula: see text] per unit BM was similar between boys and MENREL, and lower in MENABS (5.7 ± 1.0, 5.6 ± 0.8 and 3.3 ± 0.3 W kg(-1), respectively; P < 0.001). The change in rectal temperature was similar between boys and MENREL (0.6 ± 0.2 vs. 0.7 ± 0.2 °C, P = 0.92) but was lower in MENABS (0.3 ± 0.2 °C, P = 0.004). Sweat volume was lower in boys compared to MENABS (500 ± 173 vs. 710 ± 150 mL; P = 0.041), despite the same evaporative heat balance requirement (E req) (199.1 ± 34.2 vs. 201.0 ± 32.7 W, P = 0.87). CONCLUSION: Boys and men demonstrated similar thermoregulatory responses to 80 min of exercise in the heat performed at a fixed [Formula: see text] per unit BM. Sweat volume was lower in boys compared to men, despite similarities in absolute [Formula: see text] and E req.

Mild to moderate hypohydration reduces boys' high-intensity cycling performance in the heat.

PURPOSE: To evaluate the effect of 1 and 2 % hypohydration on high-intensity cycling performance of 10- to 12-year-old boys in the heat. METHODS: In a counterbalanced order, nine boys attended three sessions in which they cycled intermittently (6 × 10-min bouts at 40-45 % [Formula: see text]) in a climate chamber. During each session, environmental conditions and water intake were individually adjusted to achieve a target hypohydration level of 0, 1 or 2 %, based on change in body weight (BW). Following 45 min of rest in thermoneutral conditions when the target hypohydration was maintained, each boy re-entered the climate chamber (35 °C and 50-55 % RH) to perform the cycling performance test at 90 % [Formula: see text] until exhaustion. Heart rate (HR) and rectal temperature (T re) were recorded continuously throughout each session. Total mechanical work (TMW) was taken as a measure of cycling performance. RESULTS: Actual hypohydration level at the start of the cycling performance test in each session was: 0.1 ± 0.0 %, 1.1 ± 0.1 % and 2.0 ± 0.1 %. With 2 % hypohydration, TMW (35.5 ± 6.8 kJ) was significantly (p < 0.05) lower than with 0 % hypohydration (49.3 ± 9.8 kJ). When expressed as a percentage of TMW with 0 % hypohydration, TMW was reduced by 15.5 and 23.3 % with 1 and 2 % hypohydration, respectively (p < 0.05 for both). At the start of the cycling performance test, HR was 13 and 15 bpm higher, and T re was 0.3 °C higher (p < 0.05 for all) with 1 and 2 % hypohydration, respectively, compared with 0 % hypohydration. CONCLUSION: Mild (~1 %) to moderate (~2 %) hypohydration reduces high-intensity cycling performance of healthy young boys in the heat.

Effects of acute dehydration on neuromuscular responses of exercised and nonexercised muscles after exercise in the heat.

Dehydration can impair aerobic performance, but its effects on muscular strength are still unclear. This study evaluated the effect of dehydration induced by cycling in the heat on exercised (knee extensors) and nonexercised (elbow flexors) muscles' strength and activation. Ten healthy recreationally active and nonacclimatized men (age, 22.71 ± 2.21 years old; body mass (BM), 77.94 ± 7.35 kg; height, 1.76 ± 6.46 m; body fat, 18.93 ± 3.01%) cycled in the heat in 2 separate sessions: dehydrated (DHY) and euhydrated (EUH). Dehydrated session led to a 2% BM loss, and water ingestion prevented the water loss in the euhydrated session. Knee extensor and elbow flexor maximal isometric torques and muscle activation were assessed before and after exercising in both sessions. Knee extensor torque decreased 15.8% (p < 0.001; 294.27 ± 44.82-247.16 ± 40.54) in dehydrated session, whereas no significant reduction (2.98%; p = 0.348; 291.99 ± 48.37-281.74 ± 38.65) was observed in the euhydrated session. No significant session-time interaction (p = 0.098) was observed for elbow flexor responses (DHY, 67.51 ± 14.53-62.95 ± 13.60; EUH, 68.26 ± 13.06-67.87 ± 13.89). Muscle activation capacity was unaffected by the hydration status. Maintenance of euhydration state during cycling in the heat may attenuate strength impairments caused by water loss in exercised muscle groups.

Responses of obese and lean girls exercising under heat and thermoneutral conditions.

OBJECTIVE: To compare thermoregulatory and perceptual responses between lean and obese girls during and after exercise under heat (HC) and thermoneutral (TC) conditions. STUDY DESIGN: In a randomized order, 27 girls (14 lean [16.6 ± 6.7% fat and 9.1 ± 1.3 years] and 13 obese [41.3 ± 6.7% fat and 9.4 ± 1.1 years]) cycled 30 minutes at ~55% peak oxygen uptake in 2 sessions, which only differed in the thermal conditions (35 °C and 40% relative humidity vs 24 °C and 50% relative humidity). RESULTS: Initial rectal temperature (T(re)) was higher in obese versus lean during HC (37.5 ± 0.3 °C vs 37.3 ± 0.3 °C, P = .03) and TC (37.6 ± 0.3 °C vs 37.3 ± 0.2 °C; P = .03) sessions. During cycling, Tre remained higher in the obese, but the rate of increase was greater in the lean. This change occurred mainly in the HC, when final Tre of the lean surpassed that of the obese (37.8 ± 0.2 vs 38.0 ± 0.2 °C, P = .04). Sweat volume (in mL · m(-2)) was similar between lean and obese in the HC (167 ± 119 and 120 ± 145) and TC (200 ± 196 vs 72 ± 20). Heart rate, rate of perceived exertion, and thermal sensation were similar between groups, independent of the thermal condition. Cycling in HC produced decreased thermal comfort (P = .009) and increased irritation (P = .02) within the lean girls. CONCLUSION: Thermoregulatory and perceptual responses of prepubescent obese girls during 30 minutes of cycling at a similar relative intensity do not seem to be impaired when comparing with a lean group either in TC or HC.

Vegan shrimp alternative made with pink oyster and lion's mane mushrooms: Nutritional profiles, presence of conjugated phenolic acids, and prototyping.

The increasing demand for seafood is responsible for many environmental impacts, especially caused by aquaculture. Shrimp accounts for a substantial part of seafood production and therefore also for negative effects associated with it. This work aimed to develop a mushroom-based shrimp analogue with a texture similar to shrimp using the fruiting bodies of pink oyster mushroom (Pleurotus djamor) and lion's mane (Hericium erinaceus). Three flushes of pink oyster mushrooms and a first flush of lion's mane mushroom were analysed regarding their nutritional composition and whether they are suitable shrimp alternatives. The two mushrooms are rich in proteins (∼32% and ∼26% w/w for the first flush of pink oyster and lion's mane, respectively). The protein content of pink oyster mushroom decreased and the dietary fibre content increased across the different flushes. The antioxidants in the mushrooms were extracted using different methods, whereby aqueous extracts mostly excelled in terms of antioxidant activity. Hydrolysis confirmed the presence of conjugated p-coumaric acid in both mushrooms and possibly conjugated caffeic acid in pink oyster. Texture analysis results of the prototypes were close to the values of fried shrimp. However, although the sensory qualities of the final prototypes were perceived as similar to shrimp, further improvements in the recipe are necessary to make the prototypes indistinguishable from shrimp.

Thermoregulatory and perceptual responses of lean and obese fit and unfit girls exercising in the heat.

OBJECTIVE: To verify the thermoregulatory and perceptual responses of obese and lean girls, either fit or unfit, exercising in the heat at a similar rate of metabolic heat production per unit body mass. METHODS: A total of 34 pubescent girls were allocated in four groups: 12 obese fit, 9 obese unfit, 5 lean fit, and 8 lean unfit. The obese groups (13.2±1.4 years, 40.5%±5.8% fat by DXA) differed in their aerobic fitness (V˙O2peak 76.0±8.1 vs. 56.6±5.8mL.kgmusclemass-1.min-1), as well as the lean groups (13.1±1.6 years, 24.0%±4.8% fat) (V˙O2peak 74.5±2.9 vs. 56.2±5.0mL.kgmuscle mass-1min-1). Girls cycled two bouts of 25min with a 10min rest in between, at ∼5.4W.kg-1 in the heat (36°C and 40% relative humidity) and they were kept euhydrated. Rectal and skin temperatures and heart rate were measured every 5min. Perceptual responses were evaluated throughout the exercise. RESULTS: Initial rectal temperature was higher in the obese subjects compared to the lean subjects (37.5±0.3 and 37.2±0.3°C). No difference was observed among the girls whom were obese (eight fit or unfit) and lean (also fit or unfit) throughout the exercise in rectal temperature (37.6±0.2, 37.5±0.3, 37.5±0.3, 37.4±0.3°C, respectively), skin temperature (34.8±0.8, 35.1±1.0, 34.4±0.9, 35.2±0.9°C), and heart rate (128±18; 118±12, 130±16, 119±16beatsmin-1). No differences were observed in perceptual responses among groups. CONCLUSION: Regardless of the adiposity or aerobic fitness, pubescent girls had similar thermoregulatory and perceptual responses while cycling in the heat at similar metabolic heat production.

Energy substrate utilization with and without exogenous carbohydrate intake in boys and men exercising in the heat.

Little is known about energy yield during exercise in the heat in boys compared with men. To investigate substrate utilization with and without exogenous carbohydrate (CHOexo) intake, seven boys [11.2 ± 0.2 (SE) yr] and nine men (24.0 ± 1.1 yr) cycled (4 × 20-min bouts) at a fixed metabolic heat production (Hp) per unit body mass (6 W/kg) in a climate chamber (38°C and 50% relative humidity), on two occasions. Participants consumed a 13C-enriched 8% CHO beverage (CARB) or placebo beverage (CONT) in a double-blinded, counterbalanced manner. Substrate utilization was calculated for the last 60 min of exercise. CHOexo oxidation rate (2.0 ± 0.3 vs. 2.5 ± 0.2 mg·kg fat-free mass-1·min-1, P = 0.02) and CHOexo oxidation efficiency (12.8 ± 0.6 vs. 16.0 ± 0.9%, P = 0.01) were lower in boys compared with men exercising in the heat. Total carbohydrate (CHOtotal), endogenous CHO (CHOendo), and total fat (Fattotal) remained stable in boys and men (P > 0.05) during CARB, whereas CHOtotal oxidation rate decreased (P < 0.001) and Fattotal oxidation rate increased over time similarly in boys and men during CONT (P < 0.001). The relative contribution of CHOexo to total energy yield increased over time in both groups (P < 0.001). In conclusion, endogenous substrate metabolism and the relative contribution of fuels to total energy yield were not different between groups. The ingestion of a CHO beverage during exercise in the heat may be as beneficial for boys as men to spare endogenous substrate.

[Bone mineral density, milk intake and physical activity in boys who suffered forearm fractures]. / Densidade mineral óssea, ingestão de leite e atividade física de meninos que sofreram fraturas no antebraço.

OBJECTIVE: To compare boys with and without forearm fracture in terms of their bone mineral density, intake of milk and dairy products, and physical activity. METHODS: There were 23 boys in each group (aged between 7 and 13 years). They were submitted to bone densitometry with dual-energy x-ray absorptiometry (DEXA) of the forearm (opposite side of the fracture). Participants answered questionnaires about their intake of milk and dairy products, and about their physical activity. RESULTS: The mean+/-SD of the bone mineral density of the radial and ulnar distal diaphysis in the case group (0.430+/-0.038 g.cm(-2)) was significantly lower (p = 0.018) than that of the control group (0.458+/-0.039 g.cm(-2)). Likewise, the mean of the distal metaphysis of the forearm was 0.309+/-0.033 g.cm(-2) in the case group and 0.349+/-0.054 g.cm(-2) in the control group (p = 0.004). Milk intake (1.5+/-1.2 cups a day) was significantly lower in the case group (p = 0.001) than in the control group (2.7+/-1.2 cups a day). The number of boys who practiced after-school physical activity was significantly lower (p = 0.017) in the case group (six boys = 26%) than in the control group (15 boys = 53%). CONCLUSION: Boys who suffered forearm fracture showed lower bone mineral density compared with the control group. In the case group, milk intake and physical activity were lower than in the control group.

Thermoregulatory and perceptual responses of lean and obese fit and unfit girls exercising in the heat / Respostas termorregulatórias e perceptivas de meninas magras e obesas com alta e baixa aptidão aeróbica exercitando-se no calor

Abstract Objective: To verify the thermoregulatory and perceptual responses of obese and lean girls, either fit or unfit, exercising in the heat at a similar rate of metabolic heat production per unit body mass. Methods: A total of 34 pubescent girls were allocated in four groups: 12 obese fit, 9 obese unfit, 5 lean fit, and 8 lean unfit. The obese groups (13.2 ± 1.4 years, 40.5% ± 5.8% fat by DXA) differed in their aerobic fitness (V˙O2peak 76.0 ± 8.1 vs. 56.6 ± 5.8 mL.kg muscle mass-1.min-1), as well as the lean groups (13.1 ± 1.6 years, 24.0% ± 4.8% fat) (V˙O2peak 74.5 ± 2.9 vs. 56.2 ± 5.0 mL.kg muscle mass-1 min-1). Girls cycled two bouts of 25 min with a 10 min rest in between, at ∼5.4 W.kg-1 in the heat (36 °C and 40% relative humidity) and they were kept euhydrated. Rectal and skin temperatures and heart rate were measured every 5 min. Perceptual responses were evaluated throughout the exercise. Results: Initial rectal temperature was higher in the obese subjects compared to the lean subjects (37.5 ± 0.3 and 37.2 ± 0.3 °C). No difference was observed among the girls whom were obese (eight fit or unfit) and lean (also fit or unfit) throughout the exercise in rectal temperature (37.6 ± 0.2, 37.5 ± 0.3, 37.5 ± 0.3, 37.4 ± 0.3 °C, respectively), skin temperature (34.8 ± 0.8, 35.1 ± 1.0, 34.4 ± 0.9, 35.2 ± 0.9 °C), and heart rate (128 ± 18; 118 ± 12, 130 ± 16, 119 ± 16 beats min-1). No differences were observed in perceptual responses among groups. Conclusion: Regardless of the adiposity or aerobic fitness, pubescent girls had similar thermoregulatory and perceptual responses while cycling in the heat at similar metabolic heat production.

Resumo Objetivo: Verificar as respostas termorregulatórias e perceptivas de meninas obesas e magras, com alta e baixa aptidão aeróbica, exercitando-se no calor com produção metabólica de calor similar por massa corporal. Métodos: Um total de 34 meninas púberes foram alocadas em quatro grupos: 12 obesas com alta aptidão aeróbica, 9 obesas com baixa aptidão aeróbica, 5 magras com alta aptidão aeróbica e 8 magras com baixa aptidão aeróbica. Os grupos obesos (13,2 ± 1,4 anos, 40,5% ± 5,8% de gordura por DXA) diferiram em sua aptidão aeróbica (V˙O2peak 76,0 ± 8,1 vs. 56,6 ± 5,8 mL.kg de massa muscular-1.min-1), bem como os grupos magros (13,1 ± 1,6 anos, 24,0% ± 4,8% de gordura) (V˙O2peak 74,5 ± 2,9 vs. 56,2 ± 5,0 mL.kg de massa muscular-1min-1). As meninas pedalaram duas sessões de 25 minutos com descanso de 10 minutos entre as sessões, a ∼5,4 W.kg-1 no calor (36∘C e 40% de umidade relativa) e foram mantidas hidratadas. As temperaturas retal e cutânea e a frequência cardíaca foram medidas a cada 5 minutos. As respostas perceptivas foram avaliadas durante o exercício. Resultados: A temperatura retal inicial foi maior nas meninas obesas em comparação com as magras (37,5 ± 0,3 e 37,2 ± 0,3 °C). Não houve diferença entre as meninas obesas (com alta aptidão aeróbica ou não) e magras (também com alta aptidão aeróbica ou não) durante todo o exercício em relação à temperatura retal (37,6 ± 0,2; 37,5 ± 0,3; 37,5 ± 0,3; 37,4 ± 0,3 °C; respectivamente), temperatura da pele (34,8 ± 0,8; 35,1 ± 1,0; 34,4 ± 0,9; 35,2 ± 0,9 °C), e frequência cardíaca (128 ± 18; 118 ± 12, 130 ± 16, 119 ± 16 batimentos.min-1). Não foram observadas diferenças nas respostas perceptivas entre os grupos. Conclusão: Independentemente da adiposidade ou do condicionamento aeróbico, as meninas púberes tiveram respostas termorregulatórias e perceptivas semelhantes, enquanto pedalavam no calor com uma produção metabólica de calor similar.

[Childhood obesity--towards effectiveness]. / Obesidade infantil: como podemos ser eficazes?

OBJECTIVE: To review therapeutic approaches to childhood obesity and also its diagnosis and prevention. SOURCES OF DATA: Searches were performed of scientific papers held on the MEDLINE, Ovid, Highwire and Scielo databases. Keywords utilized were: "childhood", "obesity" and a variety of combinations of this term with "treatment", "prevention" and "consequence". The search returned papers including review articles, observational studies, clinical trials and consensus statements. Bibliographical references in these articles were also investigated if it was perceived that they were relevant. Data was collected from 1998 to 2003. SUMMARY OF THE FINDINGS: While a number of different Brazilian prevalence studies were found, few gave details of the results of educational programs in our country. CONCLUSIONS: Childhood obesity must be prevented through prescriptive diets from birth throughout childhood. Educational programs that might be applicable to primary health care or schools should receive further study.

[Individual outpatient care versus group education programs. Which leads to greater change in dietary and physical activity habits for obese children?]. / Atendimento ambulatorial individualizado versus programa de educação em grupo: qual oferece mais mudança de hábitos alimentares e de atividade física em crianças obesas?

OBJECTIVE: To compare two strategies for childhood obesity management: ambulatory assistance (individual) and educational program (in group). METHOD: Children and adolescents from 7 to 13 years of age were selected at random. They were divided into two groups: individually assisted or assisted in groups. An educational program about childhood obesity was created, with monthly meetings that consisted of lectures with parents' participation and group work. Simultaneously, children and teenagers of the other group received individual ambulatory assistance. The program took place for six months. Body composition, eating habits and physical activities were assessed before and after interventions. RESULTS: The sample comprised 38 children and adolescents whose mean age was 9.9 years. The program was more effective in increasing physical activity (p = 0.003), specially walking (p = 0.003), as well as in reducing total cholesterol (p = 0.038). Reduction of body mass index, obesity index and caloric intake was similar in both groups. As for food habits, ambulatory assistance increased the intake of fruits (p = 0.033) and vegetables (p = 0.002) and reduced the amount of French fries and crisps (p = 0.041), while children participating in the program reduced the intake of soft drinks (p = 0.022), sandwiches, pizza and fast food (p = 0.006). CONCLUSIONS: Both strategies for handling childhood obesity were favorable to changes in food and physical activity habits. Group assistance was as effective as individual assistance, consolidating it as an alternative for obesity treatment.

Ankle sprain risk factors: a 5-month follow-up study in volley and basketball athletes / Fatores de risco para entorse de tornozelo: estudo de 5 meses de acompanhamento em atletas de vôlei e basquete / Factores de riesgo de esguince del tobillo: estudio de seguimiento de 5 meses en atletas de voleibol y baloncesto

ABSTRACT Introduction Ankle sprain is a frequent sports injury among volley and basketball players, and identifying risk factors is necessary to prevent injuries and prolong their careers. Objective To identify intrinsic and extrinsic factors in basketball and volleyball players related to the risk of ankle sprain injury over a five-month follow-up period. Methods Ninety-four Brazilian young competitive athletes (15.8±1.7 years, 47 basketball and 47 volleyball players) participated in this study. They were evaluated for intrinsic risk factors (previous history of ankle sprain, dominant lower limb, ankle ligament laxity, range of motion of the ankle-foot complex, electromyographic response time of ankle evertors, postural control and muscular torque of ankle invertors and evertors) and extrinsic risk factors (type of shoes worn, use of orthosis, previous injuries while training or competing, and the players' position). Results During the study period, 18 (19%) athletes suffered unilateral sprains. Multivariate logistic regression analysis gave a final regression with four factors: dominant leg (p=0.161), type of shoes worn (p=0.049), player's position (p=0.153), and peroneus brevis muscle reaction time (p=0.045). There was an 86.1% probability of an ankle sprain if the athlete had a left dominant leg, wore shoes without vibration dampeners, or played in the small forward, wing/hitter spiker, middle blocker, or opposite spiker positions, and had a peroneus muscle reaction time longer than 80ms. However, only the player's position was significantly (p=0.046) associated with lesion occurrence. Conclusion The player's position appeared to be a risk factor in both sports, and this result may help professionals to prevent ankle sprains. Level of Evidence I; High quality randomized clinical trial with or without statistically significant difference but with narrow confidence intervals.

RESUMO Introdução A entorse de tornozelo é uma lesão esportiva frequente em jogadores de vôlei e basquete, e a identifica ção dos fatores de risco é necessária para prevenir lesões e prolongar a carreira. Objetivo Identificar fatores intrínsecos e extrínsecos em jogadores de basquetebol e vôlei relacionados com o risco de entorse de tornozelo ao longo de cinco meses de acompanhamento. Métodos Noventa e quatro atletas brasileiros jovens e competitivos (15,8 ± 1,7 anos, 47 jogadores de basquete e 47 de voleibol) participaram do estudo. Foram avaliados os fatores de risco intrínsecos (história prévia de entorse de tornozelo, membro inferior dominante, frouxidão ligamentar do tornozelo, amplitude de movimento do complexo tornozelo-pé, tempo de resposta eletromiográfica dos músculos do tornozelo, controle postural e torques musculares dos inversores e eversores de tornozelo) e os fatores extrínsecos (tipos de calçado, uso de órteses, lesões prévias durante treinamento ou competição e posição dos jogadores). Resultados Durante o período do estudo, 18 (19%) atletas sofreram entorses unilaterais. A análise de regressão logística multivariada forneceu a regressão final com quatro fatores: perna dominante (p = 0,161), tipo de calçado (p = 0,049), posição do jogador (p = 0,153) e tempo de reação do músculo fibular curto (p = 0,045). Constatou-se uma probabilidade de 86,1% de entorse de tornozelo se o membro inferior esquerdo fosse o dominante, se o calçado não tivesse amortecedores ou se a posição de jogo fosse ala, ponta, saída de rede, oposto e tivesse um tempo de reação dos músculos fibulares maior que 80 ms. No entanto, apenas a posição do jogador foi significativamente (p = 0,046) associada à ocorrência de lesão. Conclusão A posição de jogo apareceu como um fator de risco em ambos os esportes e esse resultado pode ajudar os profissionais a prevenir entorses de tornozelo. Nível de evidência I; Estudo clínico randomizado de alta qualidade com ou sem diferença estatisticamente significante, mas com intervalos de confiança estreitos.

RESUMEN Introducción El esguince de tobillo es una lesión deportiva frecuente en los jugadores de voleibol y baloncesto, y la identificación de los factores de riesgo es necesaria para prevenir lesiones y prolongar la carrera. Objetivo Identificar factores intrínsecos y extrínsecos relacionados con el riesgo de esguince de tobillo a lo largo de cinco meses de seguimiento. Métodos Noventa y cuatro atletas brasileños jóvenes y competitivos (15,8 ± 1,7 años, 47 jugadores de baloncesto y 47 de voleibol) participaron del estudio. Se evaluaron los factores de riesgo intrínsecos (historia previa de esguince de tobillo, extremidad inferior dominante, lasitud del ligamento del tobillo, rango de movimiento del complejo tobillo-pie, tiempo de respuesta electromiogr á fica de los músculos del tobillo, control postural y el torque muscular de los inversores y eversores del tobillo) y los factores de riesgo extrínsecos (tipo de zapato, uso de ortesis, lesiones previas durante entrenamiento o competición y posición de los jugadores). Resultados Durante el período del estudio, 18 (19%) atletas sufrieron esguinces unilaterales. El análisis de regresión logística multivariada proporcionó la regresión final con cuatro factores: pierna dominante (p = 0,161), tipo de calzado (p = 0,049), posición del jugador (p = 0,153) y tiempo de reacción del músculo peroneo corto (p = 0,045 ) Se constató una probabilidad de esguince de tobillo de 86,1% si la extremidad inferior izquierda era la dominante, si el zapato no tenía amortiguadores o si la posición de juego fuera alero, punta, delantero de red, opuesto y tuviera un tiempo de reacción de los músculo del peroneo de más de 80 ms. Sin embargo, solo la posición del jugador fue significativamente (p = 0,046) asociada a la ocurrencia de lesión. Conclusión La posición de juego apareció como un factor de riesgo en ambos deportes y este resultado puede ayudar a los profesionales a prevenir esguinces de tobillo. Nivel de evidencia I; Estudio clínico aleatorizado de alta calidad con o sin diferencia estadísticamente significativa, pero con intervalos de confianza estrechos.

Thermoregulation of competitive artistic gymnastic athletes and non-athlete girls exercising in the heat / Termorregulação em atletas de ginástica artística e meninas não-atletas durante exercício no calor

Abstract It’s unclear whether the combination of intense, chronic training and heat exposure during prepubescence improves thermoregulatory responses to exercise in artistic gymnastics athletes. The objective of this study was to compare thermoregulatory and perceptual responses between artistic gymnastics athletes and non-athlete girls while exercising both in heat and thermoneutral conditions. Seven athletes (8.7 ± 1.3 yrs) and 7 nonathletes (9.4 ± 1.5 yrs) cycled for 30 min at load (W) of ~55% VO2peak, on two separate occasions in a randomized order: heat (35˚C, 40% relative humidity) and thermoneutral conditions (24˚C, 50% relative humidity). Rectal temperature, heart rate, rate of perceived exertion, thermal sensation, thermal comfort and irritability were measured throughout the exercise. Initial rectal temperature was similar between athletes and non-athletes in both heat (37.2 ± 0.4 vs. 37.4 ± 0.2˚C, respectively) and thermoneutral conditions (37.3 ± 0.2 vs. 37.3 ± 0.3˚C). Final rectal temperature was similar between groups (38.0 ± 0.2 vs. 38.2 ± 0.2˚C in heat and 37.8 ± 0.2 vs. 37.9 ± 0.2˚C in thermoneutral conditions). Initial heart rate was lower in athletes in the heat (76 ± 7 vs. 91 ± 11 bpm, P = 0.01); however, throughout cycling, it became similar between groups. Athletes reported similar perceptual responses compared to non-athletes, with the exception of higher thermal comfort in the 10th minute of exercise in thermoneutral conditions (P = 0.003). It was concluded that athletes were similar to non-athletes with respect to thermoregulatory and perceptual responses during 30 min of cycling at similar relative intensities.

Resumo Não está claro se a combinação de treinamento crônico intenso e a exposição ao calor durante a pré-adolescência melhoram as respostas termorregulatórias ao exercício em atletas de ginástica artística (GA). Objetivou-se comparar as respostas termorregulatórias e perceptivas entre atletas de GA e não-atletas durante uma sessão de exercício nas condições de calor (CC) e termoneutra (CT). Sete atletas (8,7 ± 1,3 anos) e 7 não-atletas (9,4 ± 1,5 anos) pedalaram por 30 minutos com carga (W) referente ~55% VO2pico, em CC (35˚C e 40% umidade relativa) e CT (24˚C e 50% umidade relativa). A temperatura retal (Tre), frequência cardíaca (FC), taxa de percepção de esforço, sensação e conforto térmico e irritabilidade foram medidas durante o exercício. Tre inicial foi similar entre atletas e não-atletas em CC (37,2 ± 0,4 vs. 37,4 ± 0.2˚C, respectivamente) e CT (37,3 ± 0,2 vs. 37,3 ± 0.3˚C). Tre final foi similar entre os grupos (38,0 ± 0,2 vs. 38,2 ± 0.2˚C na CC; e 37,8 ± 0,2 vs. 37,9 ± 0.2˚C na CT). FC inicial foi menor nas atletas na CC (76 ± 7 vs. 91 ± 11 bpm, P = 0,01). No entanto, ao longo das pedaladas, foi similar em ambos os grupos. As respostas perceptivas foram similares entre os grupos, com exceção ao maior conforto térmico das atletas aos 10 minutos de pedalada (P= 0,003). As atletas de GA apresentaram respostas termorregulatórias similares as não-atletas durante 30 minutos de pedalada em similar intensidade relativa nas CC e CT.

Sweat rate and electrolyte concentration in swimmers, runners, and nonathletes.

UNLABELLED: Because swimmers train in an aquatic environment, they probably do not need to sweat as much as runners who train on land and, therefore, should not develop the same magnitude of sweating adaptations. PURPOSE: To compare sweat rate and electrolyte concentration in swimmers, runners and nonathletes. METHODS: Ten swimmers (22.9 ± 3.1 years old), 10 runners (25 ± 2.9 y) and 10 nonathletes (26.5 ± 2.2 y) cycled in the heat (32 degrees Celsius and 40% relative humidity) for 30 min at similar intensity relative to their maximal cycle test. Sweat volume was calculated from the difference of their body mass before and after cycling, since they were not allowed to drink. Sweat was collected from the scapula using absorbent patch placed on the skin that was cleaned with distilled water. After cycling, the patch was transferred to syringe and the sample was obtained when squeezing it to a tube. Concentration of sodium ([Na+]), chloride ([Cl-]) and potassium ([K+]) were analyzed using an ion selector analyzer. RESULTS: The sweat volume, in liters, of swimmers (0.9 ± 0.3) was lower (P < .05) than that of runners (1.5 ± 0.2) and similar to that of nonathletes (0.6 ± 0.2). [Na+] and [Cl-], in mmol x L(-1), of swimmers (65.4 ± 5.5 and 61.2 ± 81), and nonathletes (67.3 ± 8.5 and 58.3 ± 9.6) were higher (P < .05) than those of runners (45.2 ± 7.5 and 38.9 ± 8.3). [K+] was similar among groups. CONCLUSIONS: The lower sweat volume and higher sweat [Na+] and [Cl-] of swimmers, as compared with runners, indicate that training in the water does not cause the same magnitude of sweating adaptations.

Rehydration during exercise in the heat reduces the physiological strain index in healthy adults / Reidratação durante exercício no calor reduz o índice de esforço fisiológico em adultos saudáveis / Reidratação durante exercício no calor reduz o índice de esforço fisiológico em adultos saudáveis

Exercise in the heat leads to physiological alterations that reflect mainly on the cardiovascular system. The physiological strain index (PSI) uses heart rate (HR) and rectal temperature (Tre) to evaluate the cardiovascular strain and it has been recommended in literature. However, few studies have used PSI to evaluate its response following dehydration and rehydration protocols. Thus, the aim of the present study was to verify the effect of rehydration proportional to fluid losses during prolonged exercise in the heat on hydration status, PSI and rating of perceived exertion (RPE) in healthy subjects. Ten volunteers performed two exercise sessions in the heat. The first with fluid restriction until subjects reached 2% body mass (BM) reduction. The second exercise session had rehydration proportional to fluid losses of the first. HR and Tre were monitored during the entire exercise protocol in order to calculate PSI. Subjects also reported their RPE. BM, urine specific gravity (USG) and urine color (UC) were measured to evaluate hydration status. Results demonstrated greater PSI in the fluid restriction trial compared to the rehydration trial from 45 minutes of exercise (p<0.05), and that differences remain significant until the end of the protocol. RPE also presented significant differences between trials (p<0,001). Rehydration strategy was effective to maintain hydration status and attenuate the increase in PSI and RPE, which has important implications for physical exercises, especially those lasting over 45 minutes. .

O exercício no calor provoca alterações fisiológicas que refletem principalmente no sistema cardiovascular. O índice de esforço fisiológico (IEF), que utiliza o comportamento da temperatura corporal (Tre) e da frequência cardíaca (FC) para avaliar o nível de sobrecarga cardiovascular vem sendo preconizado na literatura. Porém, poucos estudos avaliaram os efeitos da desidratação e reidratação sobre este marcador. Assim, o objetivo foi verificar o efeito de uma estratégia de reidratação proporcional à perda hídrica durante exercício prolongado no calor sobre o estado de hidratação, IEF e taxa de percepção de esforço (TPE) de sujeitos saudáveis. Dez sujeitos realizaram duas sessões de exercício no calor, sendo a primeira sem reidratação (redução de 2% da massa corporal) (MC) e a segunda com reidratação (água mineral) em um volume proporcional à perda da primeira sessão. A FC e a Tre foram monitoradas durante o exercício para o cálculo do IEF. A TPE também foi obtida durante o exercício. A MC, gravidade específica (GEU) e coloração da urina (COR) foram mensuradas antes e após o exercício para avaliação do estado de hidratação. Os resultados demonstraram maior IEF na situação sem reidratação comparada à situação com reidratação a partir de 45 minutos de exercício (p<0,05), mantendo-se significativa até o final do protocolo. A TPE também apresentou diferença significativa entre as situações (p<0,001). A estratégia de reidratação foi efetiva para manter o estado de hidratação, atenuar o IEF e a TPE, trazendo importantes implicações para práticas desportivas, sobretudo àquelas que têm duração superior a 45 minutos.

Sweat electrolyte loss in asthmatic children during exercise in the heat.

This study assessed sweat electrolyte concentration and losses in asthmatic children during exercise in the heat. Eleven asthmatics (AG; 11 +/- 2 years old) and 11 nonasthmatics (CG; 10 +/- 1 year old) underwent a maximal progressive cycleergometer test. During a second session, participants cycled in the heat (35 degrees C, 60% RH) of a climatic chamber for 30 min at 50-60% of maximal workload. Sweat was collected using sweat patches attached to the dorsal region. No differences were observed in sweat [Na+] (AG = 35 +/- 12.9 and CG = 43.4 +/- 18 mmol/L) and [Cl-] (AG = 27.3 +/- 10.4 and CG = 38.5 +/- 19.1 mmol/L). There was no difference in sweat Na+ losses (AG = 0.47 +/- 0.36 and CG = 0.66 +/- 0.68 mmol/kg/h) and Cl- losses (AG = 0.37 +/- 0.29 and CG = 0.59 +/- 0.62 mmol/kg/h) between groups. Asthmatic children did not differ from nonasthmatics in their sweat electrolyte concentrations and electrolyte losses.