Answer from Leslie Kaminoff (in charge of esutra dialogues)
The easy part of the answer relates to which schools teach the different approaches to breathing.
The only lineage I’m aware of that explicitly teaches the “top to bottom” breath is Krishnamacharya’s. Specifically, Viniyoga, the method taught by his son Desikachar, is the system in which this is found. The Ashtanga yoga of Sri K. Pattabhi Jois (another student of Krishnamacharya’s) teaches the control of the lower abdomen through Mula bandha, so the “top to bottom” breath is somewhat implicit in that approach, although many of K.P.J.'s students have different opinions about breathing methodology (a few of them are on the list, so perhaps they’d like to chime in). Prof. K.'s other famous student, Mr. Iyengar, seems to favor the bottom-to-top pattern (at least that’s what I recall from reading his book “Light on Pranayama”).
It should be pointed out that in Viniyoga, there is no “right” way to breathe; all instruction is given on an individual basis, and “bottom to top” breathing (or any number of other patterns) may be prescribed if it is useful for certain students in certain situations.
All the other schools of yoga that I’m aware of teach some variation of the “bucket breath” (bottom to top) approach that Mukunda describes; which brings me to the second part of my response.
Embedded in Mukunda’s description of these breathing patterns are a few oft-repeated inaccuracies that perpetuate much confusion about breathing (I don’t mean to imply that the well-learned Mukunda is confused – he’s just asking the questions).
Let’s look at: “Some Indian yoga teachers teach how to breathe in three part motion like filling a glass from the bottom upward. In this image one is to inhale expanding the belly first then let the air raise upward into the chest.”
Air never rises upward into the chest Here?s why: A glass or a bucket filling from the bottom upward is a very common image and justification that’s given for this 3-part breathing pattern. The problem with it is that the lungs are not a bucket, and air is not water. Actually, what’s more fundamentally erroneous is the entire notion that the order in which you change the shape of your body cavities during inhalation has something to do with the order in which the different parts of the lungs will fill with air. This is simply not the case, and it comes from the almost universal confusion between muscular movements and air movements.
During breathing, air only goes in and out from the lungs, and it can only move through the lungs by means of the bronchial tree. The inhaled air enters from the top downward, branches left and right, and then fans out from center to periphery. The path of the exhaled air, of course, follows the exact opposite pattern. This pathway remains the same no matter how you manipulate your respiratory muscles.
**A belly breath does NOT bring air into the belly NOR does it cause the lower part of the lungs to fill first. ** Sorry, folks; I know how often this stuff gets repeated, and how attached to our teaching language we can become.
Mukunda’s next statement was: “Some others teach breathing in reverse following the pattern of the diaphragm.”
I don’t really know what Mukunda means by “following the pattern of the diaphragm,” so perhaps he could clarify it for us. I do know that the statement would be more correct if he substituted the phrase “bronchial tree” for diaphragm.
There’s a lot more I could say about this (enough to fill the book I’m working on!), but I’d prefer to continue this dialogue by answering questions about my response, and posting other responses to Mukunda’s question.