RESUMO
Previous studies have proposed only one prediction equation for respiratory muscle strength without taking into consideration differences between ages in pediatric population. In addition, those researches were single-center studies. The objective of this study was to establish reference equations for maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax) in children and teenagers. In a multicenter study, 450 healthy volunteers were evaluated (aged 6-18yrs). There were included volunteers with normal lung function. We excluded volunteers who could not perform the tests; participated in physical activity more than twice a week; were born prematurely; smokers; chronic respiratory, cardiologic, and/or neurologic diseases; had acute respiratory disease during the prior three weeks. The volunteers were divided into two groups: Group 6-11 (6-11yrs) and Group 12-18 (12-18yrs). PImax and PEmax were measured according to statement. The mean PImax value was 85.6 (95%IC 83.6-87.6 cmH2O), and PEmax 84.6 (95%IC 85.5-86.2 cmH2O). The prediction equations for PImax and PEmax for Group 6-11 were 37.458-0.559 + (age * 3.253) + (BMI * 0.843) + (age * gender * 0.985); and 38.556 + 15.892 + (age * 3.023) + (BMI * 0.579) + (age * gender * 0.881), respectively (R2 = 0.34 and 0.31, P<0.001). The equations for Group 12-18 were 92.472 + (gender * 9.894) + 7.103, (R2 = 0.27, P = 0.006) for PImax; and 68.113 + (gender * 17.022) + 6.46 + (BMI * 0.927), (R2 = 0.34, P<0.0001) for PEmax. This multicenter study determined the respiratory muscle strength prediction equations for children and teenagers.