João Carlos Bouzas Marins

Heart Rate Monitoring in Soccer: Interest and Limits During Competitive Match Play and Training, Practical Application.

Abstract Alexandre, D, Da Silva, C, Hill-Haas, S, Wong, DP, Natali, AJ, De Lima, JRP, Filho, MGB, Marins, JCB, Garcia, ES, and Chamari, K. Heart rate monitoring in soccer: Interest and limits during competitive match play and training–Practical application. J Strength Cond Res 26(10): 2890–2906, 2012—The identification of physiological loads imposed by soccer training or match play reveals essential information, which may help improve training and recovery strategies. Until today, the use of heart rate (HR) monitoring is not standardized in soccer. Thus, the aim of this review was to analyze, determine and compare the exercise intensity (EI) monitored by HR in professional, youth, and recreational soccer players during matches and training sessions using a meta-analysis. Heart rate is one of the most common physiological variables used to determine exercise internal training load. The mean EI recorded during competitive matches was described as 70–80% of V[Combining Dot Above]O2max or 80–90% of maximal heart rate (HRmax), independent of the playing level. With respect to HR training zones, approximately 65% of the total match duration is spent at intensity of 70–90% HRmax and rarely below 65% HRmax. However, although HRmax is mostly employed in the literature, monitoring EI should be expressed in relation to reserve heart rate, as it was described as a more reliable indicator of HR, allowing interindividual comparisons. The HR response according to the playing position indicates that midfielders are characterized by the highest EI, followed by forwards and fullbacks. Moreover, in the second half of the match, the EI is lower than that observed during the first half; this reduction could be correlated with the level of the players physical conditioning. Consequently, coaches may favor the use of interval training or small-sided training games because these are shown to improve both aerobic capacity and the ability to repeat high-intensity actions. Small-sided games allow reaching similar HR responses to those found during interval training and match play but with greater heterogeneity values. Future investigations should include a larger sample of players with special reference to playing position and the expression of EI in percentage of the reserve heart rate, analyzing the possible intergender differences in HR response.

Pre-game hydration status, sweat loss, and fluid intake in elite Brazilian young male soccer players during competition

Abstract In this study, we assessed the pre-game hydration status and fluid balance of elite young soccer players competing in a match played in the heat (temperature 31.0 ± 2.0°C, relative humidity 48.0 ± 5.0%) for an official Brazilian soccer competition. Fluid intake was measured during the match, as were urine specific gravity and body mass before and after the game to estimate hydration status. Data were obtained from 15 male players (age 17.0 ± 0.6 years, height 1.78 ± 0.06 m, mass 65.3 ± 3.8 kg); however, data are only analysed for 10 players who completed the full game. The mean (±s) sweat loss of players amounted to 2.24 ± 0.63 L, and mean fluid intake was 1.12 ± 0.39 L. Pre-game urine specific gravity was 1.021 ± 0.004, ranging from 1.010 to 1.025. There was no significant correlation between sweat loss and fluid intake (r = 0.504, P = 0.137) or between urine specific gravity and fluid intake (r = −0.276, P = 0.440). We conclude that young, native tropical soccer players started the match hypohydrated and replaced about 50% of the sweat lost. Thus, effective strategies to improve fluid replacement are needed for players competing in the heat.

Os efeitos do treinamento de força sobre os fatores de risco da síndrome metabólica

INTRODUCAO: Medidas nao-farmacologicas, como a atividade fisica, vem sendo recomendadas para prevencao e tratamento de doencas cronicas nao transmissiveis. OBJETIVO: Realizar revisao da literatura para verificar os mecanismos por meio dos quais o treinamento de forca provoca alteracoes metabolicas e celulares, agindo positivamente sobre os fatores de risco da sindrome metabolica. METODODOLOGIA: Foram utilizadas as bases de dados Medline, Scielo, Science Direct e Capes. A busca foi restrita aos ultimos 10 anos. Os termos utilizados para pesquisa foram: obesity, dislipidemy,hypertension, diabetes mellitus, metabolic syndrome, resistance training, weight lifting, exercise. RESULTADOS: O treinamento de forca atua sobre parâmetros metabolicos e celulares promovendo efeitos positivos no controle e na prevencao dos fatores de risco relacionados a sindrome metabolica, tais como diminuicao do peso corporal, aumento da sensibilidade a insulina, aumento da tolerância a glicose, diminuicao dos niveis pressoricos de repouso e melhoria do perfil lipidico. CONCLUSAO: A revisao dos artigos cientificos apresentados fornece dados que permitem concluir que o treinamento de forca pode contribuir de forma efetiva na diminuicao dos fatores de risco relacionados a sindrome metabolica.

Validity of body adiposity index in predicting body fat in a sample of brazilian women

This study aimed to verify the validity of BAI in predicting %BF in a sample of Brazilian women

Thermal body patterns for healthy Brazilian adults (male and female)

The aim of this study was to establish the skin temperature (Tsk) thermal profile for the Brazilian population and to compare the differences between female and male Brazilian adults. A total of 117 female and 103 male were examined with a thermographic camera. The Tsk of 24 body regions of interest (ROI) were recorded and analyzed. Male Tsk results were compared to female and 10 ROI were evaluated with respect to the opposite side of the body (right vs. left) to identify the existence of significant contralateral Tsk differences (ΔTsk). When compared right to left, the largest contralateral ΔTsk was 0.3°C. The female vs. male analysis yielded significant differences (p<0.05) in 13 of the 24 ROI. Thigh regions, both ventral and dorsal, had the highest ΔTsk by sex (≈1.0°C). Tsk percentile below P5 or P10 and over P90 or P95 may be used to characterize hypothermia and hyperthermia states, respectively. Thermal patterns and Tsk tables were established for Brazilian adult men and women for each ROI. There is a low Tsk variation between sides of the body and gender differences were only significant for some ROIs.

Diagnóstico do estado nutricional dos atletas da Equipe Olímpica Permanente de Levantamento de Peso do Comitê Olímpico Brasileiro (COB)

This study aimed to diagnose the nutritional status of the Weight Lifting Permanent Olympic Team Athletes of the Brazilian Olympic Committee (COB). The sample was composed of 24 athletes, aged 16-23 yr, 12 males (19.7 ± 2.4 yr) and 12 females (19.2 ± 1.8 yr). The following procedure was applied to diagnose the nutritional status: analysis of the adequability of energy and macronutrient intake - carbohydrates (CHO), lipids (LIP) and proteins (PRO) -, through the methods 24-hr diet records and the Food Consumption Frequency Questionnaire, besides anthropometrical profile characterization. The results obtained from the dietary evaluation showed that the energy distribution among the macronutrients was adequate, 54 ± 6.8% (CHO); 28,5 ± 5.9% (LIP); and 14.5 ± 3.4% (PRO) for the male team, and 56.3 ± 4.7% (CHO); 28.6 ± 4.6% (LIP); and 13.7 ± 2.4% (PRO) for the female team. However, regarding total energy intake, 83% of the athletes presented energy intake below the recommended values, considering the high level of physical activity, resulting in daily caloric deficiency. Body fat percentage of the male athletes (3.6 ± 0.7%) indicated that all of them were below the reference standard, while 58% of the female athletes had excess fat (17.9 ± 5.8%). It was concluded that although the athletes showed an adequate caloric distribution of macronutrients, it was still not sufficient to meet the energy requirements of their modality, thus these athletes should seek nutritional orientation.

Associação entre risco cardiovascular e hipertensão arterial em professores universitários

A hipertensao arterial e uma das mais importantes causas modificaveis de morbi-mortalidade cardiovascular precoce na populacao adulta mundial, alem de ser fator de risco independente para doencas cardiovasculares. Assim objetivou-se verificar a associacao entre indicadores de risco cardiovascular e hipertensao arterial em professores universitarios. Foram avaliados 145 professores da Universidade Federal de Vicosa (UFV), no ano de 2009, analisando-se as variaveis: sexo, idade, indice de massa corporal (IMC), relacao cintura/quadril (RCQ), circunferencia abdominal (CA), percentual de gordura (%G), colesterol total (CT), triacilglicerol (TG), glicose, pressao arterial sistolica (PAS) e diastolica (PAD) de repouso e consumo maximo de oxigenio (VO2max). Utilizou-se o teste ANOVA one way para comparacao entre individuos normotensos e pre-hipertensos e hipertensos. Calculou-se a razao de chances de desenvolvimento de quadros de PA elevada entre os individuos que apresentavam niveis indicativos de risco cardiovascular. Todos os tratamentos possuiram nivel de significância de p < 0,05. Os homens apresentaram valores significativamente maiores para idade, peso, estatura, IMC, RCQ, CA, PAS e PAD. Ja as mulheres possuiam um %G significativamente elevado. Os individuos com niveis pressoricos elevados apresentaram valores maiores para todas as variaveis, a excecao do VO2max. Observou-se associacao os fatores de risco e elevacao da PA somente para as variaveis: sexo, idade, IMC, CA, %G e TG. Conclui-se que o genero, a idade, o IMC, a circunferencia abdominal, o percentual de gordura corporal e os triacilglicerois foram considerados indicadores de risco cardiovascular por apresentarem associacao com a hipertensao arterial na amostra de professores avaliados.

Teste de força de preensão manual: análise metodológica e dados normativos em atletas

Abstract Introduction : There are different sports that use the hand as a major body segment involved in performance: judo, tennis, sailing, rowing, boxing, weightlifting and others. Handgrip strength is required in sports where the level of force generated can be the difference in the final performance. Manual dynamometry is a valuable tool that can be used in the detection of sporting talents, training control and in the assessment of injury recov-ery. Objectives : The aim of this study is to review the main methodological aspects involved in the measure-ment of hand grip strength, using the Jamar™ dynamometer and identifying the features of validity, reliability, precision, position for doing the test, handle position, instructions, number of measures, rest period between attempts, duration of contraction, and pre-test heating. Materials and methods : An electronic search of the literature available on the area was carried out, using the databases of MEDLINE, SciELO and LILACS. The key-words used were: handgrip strength, manual dynomometry, hand, grip, strength, dynamometer, Jamar, norms and reference values.

Práticas de redução de massa corporal em judocas nos períodos pré-competitivos

O objetivo deste trabalho foi identificar, em judocas, os procedimentos adotados para a reducao da massa corporal em periodos proximos as competicoes e discuti-los frente a literatura. Participaram deste estudo 105 do sexo masculino pertencentes as classes junior e senior (idade media de 21,5 ± 8,0 anos). De acordo com os resultados, 73,6% dos atletas desenvolveram estrategias de reducao de massa corporal em periodos pre-competitivos, e os metodos mais utilizados por eles foram: aumento do numero de atividades fisicas alem das habituais (76,1%), restricao calorica (59,8%), reducao de carboidratos (32,6%) e restricao de liquidos (20,7%). Em valores absolutos, os judocas masculinos reduzem significativamente mais (p < 0,05) a massa corporal em relacao as mulheres (4,5 ± 3,5 e 1,7 ± 0,8 kg, respectivamente). As mulheres iniciam com maior antecedencia a competicao (p < 0,05) a reducao da massa corporal (14 ± 6 e 19 ± 7 dias, respectivamente). Pode-se inferir que a maioria dos judocas adota estrategias de reducao aguda de massa corporal em periodos que antecedem as competicoes, o que pode resultar na queda do rendimento

Efeito do nível de condicionamento físico e da hidratação oral sobre a homeostase hídrica em exercício aeróbico

The objective was to evaluate the influence of the level of physical conditioning on the hydration status and the efficiency of the intake of 3 mL of water / kg of body weight to maintain the euhydration of athletes or healthy active individuals. Two groups of subjects consisting of 15 male athletes {VO2max 68 ± 5.4 mL (kg.min)-1} and 15 healthy active male subjects {VO2max 50.3 ± 6.3 mL (kg.min)-1} were evaluated. The hydration status was diagnosed through monitoring of body weight, specific gravity of the urine and the hematocrit during 80 minutes of treadmill running. 3 mL of water / kg of body weight were drunk during the activity. The environmental conditions of the test were 21.9 + 1.5 °C and 89.2 ± 5.6 % relative air humidity (RAH) for the athletes and 21.8 ± 1.6°C and 93.2 ± 3.5 % RAH for the active subjects. The average percentage of dehydration and the relative weight loss were significantly greater in the athletes (2.15 ± 0.7 % and 1.3 ± 0.5 kg), compared to the active subjects (1.03 ± 0.7 % and 0.74 ± 0.43 kg), respectively. The specific gravity of the urine increased significantly only in the athletes, while the hematocrit did not vary significantly between groups. Considering the conditions of the test, it was concluded that the higher level of conditioning allowed a lower hydration status and that, although the hydric loss had not reached critical levels, the strategy of hydration utilizing 3 mL of water / kg of body weight was not sufficient to maintain the subjects here completely euhydrated.The objective was to evaluate the influence of the level of physical conditioning on the hydration status and the efficiency of the intake of 3 mL of water / kg of body weight to maintain the euhydration of athletes or healthy active individuals. Two groups of subjects consisting of 15 male athletes {VO2max 68 ± 5.4 mL (kg.min)-1} and 15 healthy active male subjects {VO2max 50.3 ± 6.3 mL (kg.min)-1} were evaluated. The hydration status was diagnosed through monitoring of body weight, specific gravity of the urine and the hematocrit during 80 minutes of treadmill running. 3 mL of water / kg of body weight were drunk during the activity. The environmental conditions of the test were 21.9 + 1.5 °C and 89.2 ± 5.6 % relative air humidity (RAH) for the athletes and 21.8 ± 1.6°C and 93.2 ± 3.5 % RAH for the active subjects. The average percentage of dehydration and the relative weight loss were significantly greater in the athletes (2.15 ± 0.7 % and 1.3 ± 0.5 kg), compared to the active subjects (1.03 ± 0.7 % and 0.74 ± 0.43 kg), respectively. The specific gravity of the urine increased significantly only in the athletes, while the hematocrit did not vary significantly between groups. Considering the conditions of the test, it was concluded that the higher level of conditioning allowed a lower hydration status and that, although the hydric loss had not reached critical levels, the strategy of hydration utilizing 3 mL of water / kg of body weight was not sufficient to maintain the subjects here completely euhydrated.