ABSTRACT
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.
Subject(s)
Humans , Male , Young Adult , Cardiovascular Physiological Phenomena , Oxygen Consumption/genetics , Peptidyl-Dipeptidase A/genetics , Physical Fitness/physiology , Running/physiology , Epidemiologic Methods , Exercise Test , Genotype , Polymorphism, Genetic/genetics , Sex FactorsABSTRACT
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.
ABSTRACT
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.