[cebaztian]

This is getting complicated :-)

Please note: My try to define Squeeze was not: "diving under RV", but "diving under RV AND taking the bloodshift reduction of volume into account".

Can you elaborate on why long-term packing might increase RV? I understand you're only citing somebody else's study, but do you have any more details on what their hypotheses might be?

A rumour that T.Sietas had mentioned this.

but if diver suffer shortness of breath and his/her pulse oximetry is lower than normal, the problem has to be in other place than The trachea

My hypothesis is that things break around the trachea area and that fluids goes down into lung and causes near drowning symptoms (described).

Mastering frenzel or mouthfill is definitely not required to get squeezed -- in fact some of the worst squeezes have happened to valsalva divers (i.e. Dieter Baumann).

Hmm, I am getting confused. These examples above RV must be untrained freedivers progressing too fast to depth. I thought that EARDRUMS would fail long before a squeeze if you only have VALSALVA.

Originally Posted by laminar

1. What was your progression to 72m like? What dives preceeded it in terms of depth and difficulty?

To short warm-up period (I must confess). It was a 14 day trip to Dahab. Last deep dive four month earlier. Some negatives to 4 meters three week before. Some negatives on land (reverese packing).
In Dahab: 35x10 (some FRC),46,58,60,66,72.

So by saying that packing is the only way you can get to 70m, it may also be the cause of increased RV and thus make it more likely for you to get squeezed,

Exactly.

5. A proper mouthfill will likely get you deeper than 72m (depending on your physiology).

Ears is not the problem.
I hope I am not totally wrong when I say that mouthfill technique takes care of equalizing, BUT makes you more prone to squeeze, since your ears are not stoping you.

Are you using a mouthfill from a depth shallower than 30m

Once at about 30.

It's frustrating to think that you're being careful and have a "squeeze"

I wasnt careful. I should have had two week more warm-up dives.

Sebastian
Thanks for all input.