Fig. 3.

Average (±SE) multiunit muscle EMG (%maximum), comparing phasic vs. tonic activation in each breathing task. Phasic activation represents EMG activity during the inspiratory phase of the breath cycle, whereas tonic activation represents EMG activity during the expiratory phase of the breath cycle. In the case of Mueller maneuver, tonic activity was determined from the exhale immediately following the inspiratory maneuver. *P < 0.05, phasic vs. tonic; ^#P < 0.05 relative to rest breathing.