Hi Roland,
As Bill said, performing half or empty lung dives will help you improve the chest stiffness. Personally, I don't believe in lung volumes. That will not affect your depth. The blood-shift is an adaptation to achieve deeper depths. When you are going down there is a lot of pressure around you and the whole body is affected (mainly the air cavities as lungs, sinuses, stomach, etc) but the rib cage is rigid and at some depht the thoracic cage can get more compressed, from that moment the thorax became "more negative" than the rest of the body and the blood flow is re-directed to the pulmonary circulation. The pulmonary circulation is made of capacitance vessel (arteries that can hold a lot of blood) and the thorax is now more "liquid" so less compressible, thats why the feared lung colapse is just an anecdotal thing. Besides the vasoconstriction (narrowing of arteries) product of the diving reflex, sends the blood flow centrally (heart and brain) improving also the bloodshift.
If you are nearby the sea and have a good freediving parter you can practice at actual depth (is more fun), and you can try some hangins (more dangerous) with a good safety freediver with you.
The empty lung practices work well too, and are less extrenous than a dive to actual depth so you can practice it before trying a deep freedive mainly to get expertise with equalizing techniques.
Thats what I do, but when I was living near the sea I always practice within. The sea is our porpose, so make use of it.
|
