Validação de equações e construção de tabelas para avaliação da aptidão cardiorrespiratória em escolares por meio do shuttle and run 20m

Abstract

The development of cardiovascular disease risk factors (CDRF) starts and establish in school ages. Risk factors can be easily idenfied by assessing the functional components (VO2max), anthropometrics (BMI, waist circumference, and body fat), as well as hemodynamic (Blood Pressure) even in children and adolescents. However, studies proved that low level of cardiorespiratory fitness (CRF) is an independent risk factor of cardiovascular diseases (CVDs). The Shuttle Run 20 meters (SR20m) test is a field test that is apt to the Brazilian schools circumstance once it requires a minimum equipment and space. Though, so important than measure the VO2max is classified precisely it. In this way, the above the present study had the following aims: 1) To validate the mains VO2max prediction equations by SR20m in Brazilian schoolchildren; 2) To propose cutoff points for VO2max classification through SR20m in Brazilian schoolchildren; 3) To correlate these VO2max cut-off points to the anthropometric and hemodynamic variables. A sample of 824 school children, 485 (59%) male and 339 (41%) females aged between 11 and 18 years (14.38 ± 2.04; 15.15 ± 2.23 years, respectively) both from private schools as public schools in the Federal District. Descriptive statistics, paired t test, analysis of Bland Altman agreement, Anova Two way and Pearson correlation were applied and adopted the significance level of á 0.05 in all comparisons. The results showed that both Kuipers (49.94 ± 4.47 ml.kg-1.min-1) and Barnett (52.19 ± 3.57 ml.kg-1.min-1) equations estimated VO2max precisely compared to the gold standard (50.75 ± 7.83 ml.kg-1.min-1) in boys, but Kuipers showed the best agreement, while only Leger equation (40.34 ± 5.10 ml.kg-1.min-1) was equal than Ergo (39.36 ± 4.85 ml.kg-1.min-1) in girls. As results there were made two reference tables. One for each gender, grouped by two years (11-12; 13-14; 15-16; 17-18), with three levels of classification (poor, good, excellent). Differences were observed in all the anthropometric variables only among the group classified as "bad" for CF compared to other groups (good and excellent), as well as between males and females comparing the bad group (p = 0.0001). In addition, significant negative correlations (p = 0.001) between the anthropometric variables and ACR were observed. Regarding hemodynamic variables both SBP and DBP were higher in boys compared to girls only between the "bad" group (p = 0.001). Therefore, we recommend the use of specific equations for predicting the VO2max in Brazilian schoolchildren. Finally, we conclude that the suggested cutting points were significantly correlated with the anthropometric variables, however the same can t be observe for the hemodynamic parameters.