Autogenic drainage medium lung volume breath (Airway clearance autogenic drainage medium lung volume breath, in sitting; 01)

Sit in a chair or on a bed with a pillow under your legs.
Place one hand on your stomach muscles.
Take a medium breath in through your nose, approximately half of your lung capacity.
Open your mouth wide and keep your throat open.
Breathe all of the air out of your lungs in a long and steady breath, like a forced sigh.
You should feel your abdominal muscles tensing under your hand.