Abstract
This study analyzed regional pulmonary ventilation and electromyographic (EMG) activity of the respiratory muscles during an inspiratory muscle endurance (IME) test in 10 young women. Radioaerosol (99mTc-DTPA) was generated using a jet nebulizer connected to a linear inspiratory loading system. The lung scintigraphic analysis showed an increase in the radioaerosol deposition using loads of 20 and 30
cmH
2O (
p
<
0.01). The vertical gradient showed a larger radioaerosol deposition in the medium third of the lungs during the control period (
p
<
0.001). There were larger amounts of radioaerosol deposition in the medium third when compared with the upper and lower third at 30
cmH
2O (
p
<
0.001). The horizontal gradient showed a larger deposition in the intermediate and central segments during all phases (
p
<
0.00). Electromyographic activity from the muscles of the lower rib cage increased with loads of 20 and 30
cmH
2O (
p
<
0.03). There was an increase in deposition of radioaerosol when the load increased (
r
=
0.584,
p
=
0.000 for the left lung and
r
=
0.609,
p
=
0.000 for right lung). These findings suggest that during the IME test, EMG activity in the muscles of the lower rib cage increase during progressive respiratory workloads is associated with a greater radioaerosol deposition in the medium third and intermediate and central segments of the lungs.
