OBJECTIVE: This study compares the respiratory muscle strength (RMS) obtained from analog manometers using different types of mouthpiece and trachea. METHODOLOGY: Fifty healthy sedentary or insufficiently active individuals were evaluated (25 men and 25 women), in age 25 ± 5 years, height of 167 ± 8 cm and weight of 65 ± 12 kg, belonging to the community of São Carlos, SP, and region. For the evaluation of RMS were taken measures of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) according to the method recommended by Black and Hyatt (1969). The volunteers were referred to anamnesis and, later, maximum respiratory pressures were measured in the individuals at standing, using an analog manometers with operational limit of ± 300 cmH2O, with a nose clip, a circular and a rectangular mouthpiece and tracheas with the same length and different internal diameters, which are of 1 cm and 1.5 cm. RESULTS: It was observed that there were no significant differences (Wilcoxon Test: p < 0.05) between the diameters of the trachea, and the values obtained by the MEP with the rectangular mouthpiece were significantly higher in both sexes. CONCLUSION: The results of this study show that there was no interference from the diameters of the trachea in the values obtained from MEP and MIP; however, the types of mouthpiece used in analog manometer interfere in the values obtained from MEP. The anatomical shape of the rectangular mouthpiece cooperated in obtaining the highest values of MEP.
MIP; MEP; Mouthpiece; Trachea
