The purpose of this study was to investigate whether body positioning would bring about any change in inspiratory and expiratory muscle strength expressed in terms of maximal negative inspiratory pressure (P _Imax) and maximal positive expiratory pressure (P_Emax). The P_Imax and P_Emax measurements were carried out on 20 participants in sitting, half lying, `slumped' half lying, supine lying, right side lying, and left side lying. The one-way analysis of variance showed that P_Imax and P_Emax values were within normal range for all positions. It was hypothesized that a significant change in P_Imax and P_Emax would occur with alteration of the body position in healthy persons, but this was proven negative. The findings were similar to those found for people with chest pathologies; that is, the highest P_Imax and P_Emax values were evident in the more erect positions than recumbent positions. Possible reasons and implications for such findings are discussed in terms of the force of gravity acting on the thoracic cage in various body positions and the length-tension relationship of both the inspiratory and expiratory muscles.