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Re: Blowing terminology

Author: Tony Pay ★2017
Date: 2008-09-19 10:34

Arnoldstang wrote:

>> I have been reduced to a blethering idiot. >>

It's just that you need to be clearer about what it is that you don't understand.

Which bit of the following gives you a problem?

(0) When you blow, you use your back and abdominal muscles simultaneously.

(1) The combination of back and abdominal muscles working together doesn't bend your body, because the 'bending' force of the abdominal muscles is met with an equal and opposite 'straightening' force of your back muscles.

(2) The combination of back and abdominal muscles working together DOES squeeze your guts inwards.

(3) That inward squeeze creates both an upward and a downward push.

(4) The downward push is resisted in some way (unless you are intending to defaecate).

(4) The upward push encounters the diaphragm, which is a membrane dividing the upper part of your guts from the thorax, which contains the lungs.

(5) The diaphragm is also a muscle, and like all muscles, it is either relaxed or flexed to some degree.

(6) If the diaphragm is relaxed, the upward push MOVES it upwards and expels air from the lungs.

(7) This is normal blowing.

(8) BECAUSE the diaphragm is also a muscle, it has a function when it flexes: and that function is to draw air into the lungs.

(9) If you have no air in your lungs, the diaphragm is dome-shaped: roughly speaking, the (roughly circular) bottom edge of the dome is attached to your body frame, and the middle bit is higher.

(10) The diaphragm draws air into the lungs by flexing. This flexion causes the diaphragm to flatten, so that its dome shape becomes more disc-shaped: the top of the dome gets much closer to the bottom. This increases the volume of the thorax, and air is therefore drawn into the lungs.

(11) You can therefore imagine a normal cycle of breathing in and blowing out to consist of:

IN:
(a) The diaphragm flexes and flattens to draw air into the lungs;
(b) As the diaphragm flattens, it pushes the guts down;
(c) The guts expand outwards, pushing the relaxed abdominal and (perhaps) back muscles outwards.
OUT:
(a) The abdominal and back muscles flex and push the guts inwards;
(b) The diaphragm relaxes and is pushed up by the upward push of the guts:
(c) The thorax is reduced in volume and the air in the lungs is pushed out.

(12) There is however a special case of blowing where the first part of OUT(b) isn't true. In this special case, known as blowing with support, the diaphragm doesn't relax completely.

(13) What that means is that the upward push of the guts is resisted by the diaphragm, which continues to push down to some extent. The 'support' in (12) is this downward push.

(14) Therefore, in this case, the effect of the abdominal and back muscles is lessened; the air in the lungs is pushed against to a smaller extent.

(15) You can get this smaller push on the air in the lungs EITHER by blowing normally, but less; OR by blowing with support, with the amount less being equal to the support.

Tony

Post Edited (2008-09-19 13:38)

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Blowing terminology new

Arnoldstang

2008-09-18 15:10