The analysis of the regional distribution of respiratory volumes was done with Optoelectronic plethysmography (BTS Bioengineering, Italy), in which 89 reflective markers were adhered to the skin of volunteers using hypoallergenic adhesives, on particular anatomical points of the chest wall and abdomen (Aliverti and Pedotti 2003). The device emitted an infrared light on the reflective markers which was captured by eight cameras around the room, allowing the spatial determination of each marker. Thus, changes in lung volumes were calculated at each of the three compartments of the rib cage: pulmonary or upper ribcage (Rc, p), abdominal or lower ribcage (Rc, a) and abdomen (Ab). After the first OEP evaluation, a nontoxic, hypoallergenic pen was used to mark the placement of the dorsal reflective markers allowing the patient to lay in supine for the manual technique or the sham. The markers were then placed at the exact same anatomical points for reevaluation.

The maximal inspiratory and expiratory pressures (MIP, MEP) were obtained from the residual volume and total lung capacity, respectively, according to the criteria of the ATS/ERS (ATS/ERS, 2002) and measured using a portable digital manometer, model MVD 300 (® MDI Ltd., Brazil).