Respiratory muscle strength of Brazilian adolescents: obtained and predicted values

Objectives: To compare the obtained values for maximal respiratory pressures of a sample of Brazilian adolescents with the values predicted by Wilson et al. and Domenech-Clar et al. Methods: 156 adolescents (84 boys) aged between 12 and 17 years were assessed. Maximal respiratory pressures were assessed by a digital manometer with the adolescents in the seated position and wearing a nose clip. Maximal inspiratory and expiratory pressures were performed from residual volume and total lung capacity, respectively. Comparison of the values of maximal respiratory pressures obtained in this study with those predicted by the equations proposed by Wilson et al. and Domenech-Clar et al., was performed by the paired Student’s t test. To verify the association between these values, the pearson’s correlation test was used. Results: Mean maximal inspiratory pressure was 74,66 ± 22,95 cm H2O and 103,52 ± 25,67 cm H2O for girls and boys, respectively. Mean maximal expiratory pressure was 86,23 ± 25,92 cm H2O and 120,08 ± 27,37 cm H2O for girls and boys, respectively. The values obtained by this study did not differ and also did not significantly correlate with those predicted by the equations proposed by Wilson et al., e Domenech-Claret al. Conclusions: The equations proposed by Wilson et al. and Domenech-Clar et al. were not successful in predicting the values for maximal respiratory pressures in the population studied, indicating the necessity of using in clinical practice reference values from a healthy population of the same ethnicity.