Belly pumping is a very stimulating exercise, intensively using the abdominal muscles while retaining the breath.
I start by emptying my lungs and the abdomen as much as I can. I lean forward a few times, in order to “squeeze out” the last bit of air.
While lungs (and “abdomen”) are empty, I use my diaphragm muscles, to push the abdomen in and out. Contrary to the Breath of fire, where on the inhale muscles are relaxed, in Belly pumping diaphragm muscles are used to push the stomach back and forth.
I keep with the back and forth movement as long as I can retain my breath and then inhale.
Comparing: Breath of Fire / Bellows Breathing / Belly Pumping
All three types of breathing are rapid and intensive.
“Breath of fire” is an inhaling and exhaling exercise using the diaphragm to push out the air from the lower part of the lungs (abdomen). It is a stomach breathing, where the diaphragm is use to expel air from the abdomen, exhaling. Inhaling occurs by means of inertia, that is releasing the diaphragm muscle tension.
“Bellows breathing” is an inhaling and exhaling exercise focusing on the upper part of the lungs, avoiding as much as possible movement of the abdomen.
“Belly pumping” is a retention exercise. After maximum air is expelled from the lungs, the diaphragm muscles are used to push the stomach forward and backward rapidly, while holding the breath.