Breath-Stacking
OtherWe used a silicone face mask, connected to a unidirectional valve which allowed only inspiration and is connected to a spirometer showed that the volume inspired by the individual. The face mask was attached to the appraised performed successive breaths until the researcher realized the lack of volume of air being inhaled and this time it was allowed to expire (Baker et al., 1990; Feitosa et al., 2012).