Efectos de la periodización nutricional en la composición corporal de corredores de media distancia de Djibouti / Efeitos da periodização nutricional na composição corporal em corredores de média distância do Djibutiano / Effects of nutritional periodization on the body composition of middle-distance runners from Djibouti

RESUMEN Introducción: La composición corporal es un indicador fundamental para definir el estado nutricional del corredor. Objetivo: El estudio tuvo como objetivo evaluar los efectos de la intervención de periodización nutricional en la composición corporal de corredores juveniles djiboutianos de élite en distancia media. Materiales y métodos: La muestra fue de 22 corredores masculinos, en edades comprendidas entre 16 y 18 años. Para la valoración, se diseñó un experimento constituido por 11 sujetos en el grupo control y 11 en el experimental. Como mediciones antropométricas se tomaron el peso, estatura y seis panículos adiposos para evaluar el porcentaje de grasa, índices de adiposidad, índice de masa corporal y el de sustancia corporal activa pues, para llevar el seguimiento de la intervención propuesta, se realizó una entrevista de recordatorio 24 horas de siete días. Resultados: Se diseñó una dieta periodizada, con la manipulación de los carbohidratos. La periodización nutricional con alta y baja ingesta de carbohidratos durante 12 semanas disminuyó significativamente (p< 0,05) el porcentaje de grasa, sin alterar el peso corporal ni el índice de sustancia corporal activa en los corredores djiboutianos de media distancia juveniles del grupo experimental. Conclusiones: Los resultados expuestos contribuyen a mejorar el control biomédico del entrenamiento en los corredores de élite juveniles de distancia media en Djibouti, ya que existían limitaciones de datos sobre su composición corporal y el efecto que pudiera tener la nutrición periodizada sobre esos indicadores

SÍNTESE Introdução: A composição corporal é um indicador chave na definição do estado nutricional do corredor. Objetivo: O estudo visava avaliar os efeitos da intervenção de periodização nutricional sobre a composição corporal em corredores de elite júnior djibutianos de meia distância. Materiais e métodos: A amostra consistiu de 22 corredores masculinos, de 16-18 anos de idade. Para a avaliação, foi projetado um experimento com 11 sujeitos no grupo de controle e 11 no grupo experimental. Como medidas antropométricas, foram tomadas medidas de peso, altura e seis panniculi adiposos para avaliar a porcentagem de gordura, índices de adiposidade, índice de massa corporal e índice de substância corporal ativa. Para acompanhar a intervenção proposta, foi realizada uma entrevista de lembrete de sete dias, 24 horas por dia. Resultados: Foi projetada uma dieta periódica, com a manipulação de carboidratos. A periodização nutricional com alta e baixa ingestão de carboidratos por 12 semanas diminuiu significativamente (p<0,05) o percentual de gordura, sem alterar o peso corporal ou o índice de substância corporal ativa em corredores djibutianos juvenis de meia distância no grupo experimental. Conclusões: Os resultados acima contribuem para melhorar o monitoramento biomédico do treinamento em corredores de elite de distância média júnior em Djibuti, já que havia limitações de dados sobre sua composição corporal e o efeito que a nutrição periodizada poderia ter sobre esses indicadores.

ABSTRACT Introduction: Body composition is a fundamental indicator to define the nutritional status of the runner. Objective: The study aimed to evaluate the effects of the nutritional periodization intervention on the body composition of elite junior Djiboutian runners in middle distance. Materials and methods: The sample consisted of 22 male runners, aged between 16 and 18 years. For the assessment, an experiment consisting of 11 subjects in the control group and 11 in the experimental roup was designed. As anthropometric measurements, weight, height and six adipose tissue were taken to evaluate the percentage of fat, adiposity index, body mass index and active body substance index, since, in order to monitor the proposed intervention, an interview of reminder 24 hours seven days. Results: A periodized diet was designed, with the manipulation of carbohydrates. Nutritional periodization with high and low carbohydrate intake for 12 weeks significantly (p<0.05) decreased percentage fat without altering body weight or active body substance index in juvenile middle-distance Djiboutian runners from the experimental group. Conclusions: The exposed results contribute to improve the biomedical control of training in elite junior middle-distance runners in Djibouti, since there were data limitations on their body composition and the effect that periodized nutrition could have on these indicators.

Gênero e distância influenciam preditores de desempenho em nadadores jovens / Género y la distancia de influencia predictores del rendimiento en nadadores jóvenes / Gender and distance influence performance predictors in young swimmers

Predictors of performance in adult swimmers are constantly changing during youth especially because the training routine begins even before puberty in the modality. Therefore this study aimed to determine the group of parameters that best predict short and middle swimming distance performances of young swimmers of both genders. Thirty-three 10-to 16-years-old male and female competitive swimmers participated in the study. Multiple linear regression (MLR) was used considering mean speed of maximum 100, 200 and 400 m efforts as dependent variables, and five parameters groups as possible predictors (anthropometry, body composition, physiological and biomechanical parameters, chronological age/pubic hair). The main results revealed explanatory powers of almost 100% for both genders and all performances, but with different predictors entered in MLR models of each parameter group or all variables. Thus, there are considerable differences in short and middle swimming distance, and males and females predictors that should be considered in training programs.

Preditores de desempenho modificam-se constantemente na juventude devido ao início precoce das rotinas de treinamento sistematizado na natação. Sendo assim, o objetivo do estudo foi determinar o grupo de parâmetros que melhor prediz performances de curta e média distância em nadadores jovens de ambos os gêneros. Trinta e três nadadores competitivos de ambos os gêneros (10 a 16 anos) participaram do estudo. Foi utilizada regressão linear múltipla (RLM) considerando as velocidades médias de 100, 200 e 400m como variáveis dependentes, e cinco grupos de parâmetros como possíveis preditores (antropometria, composição corporal, parâmetros fisiológicos e biomecânicos, idade cronológica/ pilosidade pubiana). Os principais resultados revelaram poder de explicação próximo a 100% para ambos os gêneros em todas as performances, entretanto com diferentes preditores nos modelos de RLM. Logo, há consideráveis diferenças que devem ser consideradas em programas de treinamento entre preditores de performances de curta e média distância, para meninos e meninas.

Predictores de rendimiento en nadadores adultos cambian constantemente en la juventud, especialmente porque la rutina de entrenamiento comienza antes de la pubertad. Por tanto, el objetivo fue determinar el conjunto de parámetros que mejor predice el rendimiento de corta y media distancia de los nadadores de ambos sexos. Participaron 33 nadadores de ambos sexos (edad, 10-16 años). Regresión lineal múltiple fue usada considerando la velocidad promedio de 100, 200 y 400m como variables dependientes, y cinco grupos de parámetros como posibles predictores (antropometría, composición corporal, parámetros fisiológicos y biomecánicos, edad/vello púbico). Los principales resultados revelan explicación cercana al 100% para ambos sexos en todas las distancias, pero con diferentes modelos de predicción para cada grupo de parámetros o con todos los parámetros. Por tanto, existen diferencias considerables entre los predictores de cortas y media distancias en los niños y niñas que deben ser considerados en los programas de entrenamiento.

A influência do genótipo da ECA sobre a aptidão cardiovascular de jovens do sexo masculino moderadamente ativos / The influence of ACE genotype on cardiovascular fitness of moderately active young men

FUNDAMENTO: O gene da enzima conversora de angiotensina (gene ECA) tem sido amplamente estudado em relação a fenótipos de aptidão cardiorrespiratória, contudo a associação do genótipo da ECA com corridas de meia-distância tem sido pouco investigada. OBJETIVO: O presente estudo investigou a possível influência da enzima conversora de angiotensina (ECA) (I/D) sobre a aptidão cardiovascular e o desempenho em corridas de meia-distância por parte de brasileiros jovens do sexo masculino. A validade da previsão de VO2max em relação ao genótipo da ECA também foi analisada. MÉTODOS: Um grupo homogêneo de homens jovens moderadamente ativos foi avaliado em um teste de corrida (V1600 m; m.min-1) e em um teste adicional em esteira ergométrica para a determinação de VO2max. Posteriormente, o [(0,177*V1600m) + 8.101] VO2max real e previsto foi comparado com os genótipos da ECA. RESULTADOS: O VO2max e V1600m registrados para os genótipos DD, ID e II foram 45,6 (1,8); 51,9 (0,8) e 54,4 (1,0) mL.kg-1.min-1 e 211,2 (8,3); 249,1 (4,3) e 258,6 (5,4 ) m.min-1, respectivamente e foram significativamente mais baixos para os genótipos DD (p < 0,05). O VO2max real e previsto não diferiram entre si, apesar do genótipo da ECA, mas o nível de concordância entre os métodos de VO2max real e estimado foi menor para o genótipo DD. CONCLUSÃO: Concluiu-se que existe uma possível associação entre o genótipo da ECA, a aptidão cardiovascular e o desempenho em corridas de média distância de jovens do sexo masculino moderadamente ativos e que a precisão da previsão do VO2max também pode ser dependente do genótipo da ECA dos participantes.

BACKGROUND: The angiotensin I-converting enzyme gene (ACE gene) has been broadly studied as for cardiorespiratory fitness phenotypes, but the association of the ACE genotype to middle-distance running has been poorly investigated. OBJECTIVE: This study investigated the possible influence of Angiotensin-Converting Enzyme (ACE) genotype (I/D) on cardiovascular fitness and middle-distance running performance of Brazilian young males. The validity of VO2max to predict the ACE genotype was also analyzed. METHODS: A homogeneous group of moderately active young males were evaluated in a 1,600 m running track test (V1600m; m.min-1) and in an incremental treadmill test for VO2max determination. Subsequently, the actual and the predicted [(0.177*V1600m) + 8.101] VO2max were compared to ACE genotypes. RESULTS: The VO2max and V1600m recorded for DD, ID and II genotypes were 45.6 (1.8); 51.9 (0.8) and 54.4 (1.0) mL.kg-1.min-1 and 211.2 (8.3); 249.1 (4.3) and 258.6 (5.4) m.min-1 respectively, and were significantly lower for DD carriers (p< 0.05). The actual and predicted VO2max did not differ from each other despite ACE genotype, but the agreement between actual and estimated VO2max methods was lower for the DD genotype. CONCLUSION: It was concluded that there is a possible association between ACE genotype, cardiovascular fitness and middle-distance running performance of moderately active young males and that the accuracy of VO2max prediction may also depend on the ACE genotype of the participants.

Índices fisiológicos e neuromusculares relacionados à performance nas provas de 800 m e 1500 m rasos / Neuromuscular and physiological indices associated with 800- and 1500-m running performance

O objetivo deste estudo foi determinar e correlacionar os índices fisiológicos e neuromusculares com a performance de corredores treinados nas distâncias de 800 m e 1500 m. Onze atletas realizaram os seguintes testes: 1) determinação das performances nos 800 m e 1500 m; 2) determinação do consumo máximo de oxigênio (VO2max), velocidade correspondente ao VO2max (vVO2max) e velocidade correspondente ao onset of blood lactate accumulation; 3) saltos verticais (Counter Movement Jump - CMJ e Continuous Jump - CJ); 4) determinação do tempo de exaustão (Tlim) e 5) testes submáximos para determinação da economia de corrida e teste supra-máximo para cálculo do máximo déficit acumulado de oxigênio. Houve correlação significante da vVO2max e do Tlim com as duas provas. O CJ se correlacionou somente com os 800 m. Conclui-se que a potência aeróbia é a principal determinante da performance nas duas distâncias, destacando-se que os aspectos neuromusculares influenciam os 800 m.

The purpose of this study was to determine and correlate the neuromuscular and physiological indices with the performance of trained runners in distances of 800 m and 1500 m. Eleven athletes were evaluated in the following tests: 1) simulation of performances in 800 m and 1500 m; 2) determination of maximum oxygen consumption-VO2max; velocity at VO2max-vVO2max and of velocity at onset of blood lactate accumulation; 3) vertical jumps (Counter Movement Jump and Continuous Jump); 4) determination of time to exhaustion-Tlim; and 5) submaximal tests for identification of running economy, followed by a supramaximal test for determination of maximum accumulated oxygen deficit. vVO2max and Tlim were correlated with both distances. The CJ was correlated only to 800m. It is concluded that aerobic power is the main determinant of performance for the two distances, emphasizing that neuromuscular aspects influence the 800 m.

RELATIONSHIP BETWEEN MIDDLE-DISTANCE RUNNING PERFORMANCE AND POWERS ESTIMATED FRONT BLOOD LACTATE CONCENTRATION DURING INTERMITTENT RUNNING / 体力科学

This study was conducted to clarify the relationship between power estimated by blood lactate movement during intermittent running test (Maximal Anaerobic Running Test : MART), and velocity of middle distance running (V 800 m, V 1500 m) . The subjects were well-trained male middledistance runners (n=8) .<BR>MART consisted of a variable number of 20 seconds runs on a treadmill with a 100 seconds recovery period between runs. The runs were performed ona a 4° incline. After 40 second recovery, earlobe blood samples were taken and blood lactate concentrations were analyzed. The first run was performed at 250 m/min. Velocity of the treadmill was increased by 25 m/min for each consecutive run until volitional exhaustion.<BR>The power requirement associated with the absolute value of blood lactate (La) and relative value of peak blood lactate (PBLa) was determined from the La or %PBLa vs power curve by linear interpolation from the two consecutive La values which were above and below the desired value.<BR>Results were summarized as follows:<BR>(1) Maximal power (Pmax) for MART was correlated positively with V800m (r=0.880, P<0.01) and V1500m (r=0.948, p<0.001) .<BR>(2) Power estimated at 40% value of PBLa (P40%La) correlated positively with V 1500 m (r=0.903, P<0.01), and at 60% value of PBLa (P60%La) was correlated positively with V800m (r=0.835, P<0.01) and 1500m (r=0.936, p<0.001) .<BR>These results indicate that MART is a valid test for estimating middle distance running performance and P40%La, and P60%La are important indexes with 800-m and 1500-m running.

Effects of middle-distance triathlon race on serum biochemical parameters / 体力科学

For the purpose of examining relative impact of the middle-distance triathlon race (Swim : 2.0 km, Bike : 90.0 km, Run : 21.0 km), blood samples were taken on the day before, immediately after, and the day following the race from triathletes who participated in a middle-distance triathlon race at Tokunoshima, Kagoshima in June 1993. White blood cell count was significantly increased immediately after the race.It was recovered on the next day to the value observed before the race. Serum creatine phosphokinase activity was elevated significantly immediately after the competition. It continued to rise up to the level of about 4 times higher than the pre-race value. In terms of renal function, serum creatinine concentration showed a significant increase immediately after the competition. However, it recovered to normal range by the day after the competition. In addition, serum urea nitrogen concentration was also significantly increased after the competition. It remained at the high level until the day after the competition. In conclusion, it might be suggested that the middle-distance triathlon gives a significant impact on human body, even though it is quntitatively less than the long-distance type (Swim : 3.9 km, Bike : 180.2 km, Run : 42.2 km) .

Quantitative urinal protein increase after middle distance running according to age group / 体力科学

Changes in the amount of urinary protein and β<SUB>2</SUB>-microglobulin (β<SUB>2</SUB>-MG) were observed after middle-distance running in 46 primary school boys, 46 junior high school boys, 74 high school boys and 51 male college students, aged between 6 and 21 years.<BR>The running distance was varied according to age : 800 m for 6- to 7-year-olds, 1, 200 m for 8- to 9-year-olds, 1, 700 m for 10- to 11-year-olds and 1, 500 m for 12- to 21-year-olds.<BR>Urine was collected from each subject before and 30 min after running, and total urinary protein was analyzed by the Lowry method and β<SUB>2</SUB>-MG by the reverse passive hemagglutination method.<BR>For all subjects at rest, total urinary protein was 14.2-19.1 mg/d<I>l</I> on average and increased to 24.6-96.2 mg/d<I>l</I> at 30 min after running, while β<SUB>2</SUB>-MG at rest was 3.10-7.12 μg/d<I>l</I> and increased to 30.53-1202.87 μg/d<I>l</I> at 30 min after running.<BR>Urinary protein originating in blood plasma and that in non-blood plasma was calculated on the basis of the study of Poortmans (1968) . Urinary protein originating in blood plasma after running was 2.54-6.58 times higher than that before running, whereas non-blood plasma after running was 1.04-1.92 times higher than that before running. This suggests that the increased urinary protein after running mainly originates from blood plasma. In terms of age, urinary protein from non-blood plasma in boys aged 6 to 11 years showed a greater increase than that in boys over 12 years old.<BR>The ratio of β<SUB>2</SUB>-MG to urinary protein after running was 7.0-80.6 times higher than that before running. The correlation coefficient between urinary protein and β<SUB>2</SUB>-MG became higher after running than that before running. These findings indicate that low-molecular-weight urinary protein is predominantly reabsorbed in the proximal renal tubule. In terms of age, the increase in the above ratio in 12-14-year-olds was lower than that in 1521-year-olds, suggesting that the reabsorption ability of the proximal renal tubule matures with age.