Depth simulation calculation on empty

[Simos]

Anyone has a good estimate on what depths you can simulate in a 4m deep pool by diving on FRC / empty / unpack? I am not too good with lung volumes so wondering if my estimates are off and particularly, how much these estimates can vary from individual to individual - I've no idea about my lung volume... :head

Just curious as I haven't dived to any depth for a very long time and this morning I did some FRC and empties in a 4m and 'felt' them a bit, so curious to see how careful I should be when I start proper freediving training again

 

[efattah]

The depth you can simulate depends on your RV and TLC.

Assume you have RV=2L and VC=7L, then TLC=RV+VC=9L.

At 4m depth, at full exhale (2L), your lung volume is 2L/1.4 = 1.43L.

To reach this volume on a full inhale (9L TLC), you would need to dive to
9L / P0 = 1.43L
P0 = 6.293 ATM = 52.93m

So you would need to dive to 53m to reach the same lung collapse.

The numbers are different depending on TLC and RV.

 

[Simos]

Thanks Eric - looks like there is a high sensitivity based on lung volumes. When I was trying to calculate I wasn't getting anything bigger than 14m which was worrying me so i thought I was making a mistake but I think I had used something like 5L and 3L for lung volumes.

Do you think exhale dives to a shallow depth are a reasonably realistic simulation to a full lung deeper dive in terms of what happens to the lungs? The pressure gradient is obviously steeper than what it would be on an equivalent deeper dive, wonder if that makes a significant difference.

 

[Simos]

Quick question Eric - I am assuming that by just exhaling as much as I naturally can (without any more though if that makes sense i.e. no unpacking, no further expelling of air etc) I wouldn't be able to reach RV? Or could I?

 

[trux]

Well, the RV is by definition exactly that what you tell - the volume of air remaining in the lungs after you exhale as much as you can, so of course you can and must reach it by exhaling.

 

[Simos]

Well, the RV is by definition exactly that what you tell - the volume of air remaining in the lungs after you exhale as much as you can, so of course you can and must reach it by exhaling.

Yes so we are talking a 'natural' exhale Trux? ie passive exhale? As opposed to exhaling and then say 'muttering your address' etc that basically let's more air out. Bit fuzzy with FRC?

Not that terms matter that much but I am only asking because I never measured my lung volume so just curious to see what volumes I'm likely to have when exhaling fully, when doing a passive exhale, let a 'sigh' out etc. I suppose I could measure it in the pool?

 

[trux]

RV is after a forced exhale. I recommend having a look for example at Wikipedia: File:Lungvolumes.svg - Wikipedia, the free ncyclopedia

 

[Simos]

Yes thanks Trux my lung volumes are a bit rusty.

So basically if I was at 4m blowing as many bubble rings as I could and exhaling the last bit of air I could, then surfacing and exhaling again to RV and measuring the air that comes out and divide that volume by 0.4 it should in theory give me my RV right?

 

[Bill]

Enjoy the discussion but it leaves out one important factor. There seems to be a big difference in the numbers between in and out of the water, sitting, standing or lying down and biggest of all, head down and head up.

P.S. I agree with your theory Simos

 

[cdavis]

Simos,

Full exhales in a 4 m pool don't fully replicate the calculated depth. In the real world of depth, other things are going on that, at least in my case, substantially reduce the actual depth I can dive vs the simulated depth. Its good practice, just be careful to not get squeezed, its easy to do.
I think doing reverse pack negatives in that depth helped my FRC performance considerably. The depth I can do FRC has reduced a lot since I lost access to 4 m.

Connor

 

[Simos]

Thanks for the advice Connor, wish I had easy access to a 4m pool too. I had to get a boat to get to this one lol but since I was there I thought I'd try to see how they felt compared to a couple of years ago when I used to do these regularly in a 3m pool.

I didn't go as far as unpacking or full empty as I 'felt' the pressure when I was on passive exhale. Moral of the story is that I have lost significant flexibility due to lack of training so need to take things slowly...

 

[baiyoke]

Interesting thread.

I've asked similar questions before in another thread ( http://forums.deeperblue.com/general-freediving/95059-lung-stretching.html )

a) My question is: Could I do the excercise on land, getting the same stretch, in a much safer enviroment - and being able to do it more often. Or do you think the extra pressure at 4 meters does something extra...?

Simos,

I think doing reverse pack negatives in that depth helped my FRC performance considerably. The depth I can do FRC has reduced a lot since I lost access to 4 m.

Connor

Question to you cdavis: Have you been lungstretching on land, ever since you lost acces to the 4m pool? Is it because you cannot get the same stretch on land, or is it because you haven't really done the stretching dry, done enough etc.?

Btw - nice way of measuring RV Simos

 

[cdavis]

Not sure what you mean by lung stretching. I tried to replace the 4 m exhale practice with exhales and reverse pac exhales in 2 m plus lots of diaphragm stretches on land. Spent lots of time at 2 m full exhale. Did not work. As far as I could tell, it did no good at all. Thinking now about what next.

Connor

 

[baiyoke]

Lungstretching is not the right term, my bad, but you answered perfectly...

A bit disappointing you were not even able to keep the flexibility with your dry and 2m activities... Does not look promising for dry-stretching...

I have wondered myself why I could neg. pack completely until limit on surface, but still go down 4 meters without being hurt (allthoug I was getting close I could feel). That strongly suggests that the power behind neg. pack is perhaps not that great... and not stretching a lot...

 

[Simos]

Not sure what you mean by lung stretching. I tried to replace the 4 m exhale practice with exhales and reverse pac exhales in 2 m plus lots of diaphragm stretches on land. Spent lots of time at 2 m full exhale. Did not work. As far as I could tell, it did no good at all. Thinking now about what next.

Connor

2m is a bit shallow unfortunately Connor but I think there are some additional steps you could take to stretch the diaphragm a bit more while on empty at the bottom (yoga-style). Not sure if it would be enough at 2m though, at 3m you might feel it a bit...

 

[Simos]

Lungstretching is not the right term, my bad, but you answered perfectly...

A bit disappointing you were not even able to keep the flexibility with your dry and 2m activities... Does not look promising for dry-stretching...

I have wondered myself why I could neg. pack completely until limit on surface, but still go down 4 meters without being hurt (allthoug I was getting close I could feel). That strongly suggests that the power behind neg. pack is perhaps not that great... and not stretching a lot...

Not sure about others that are going deeper but at least for myself unpacking and going to 3m is definitely doing something.

One thing to note (I stand to be corrected): I think the less flexible your diaphragm is, the less you feel these exhales working oddly. Once your diaphragm releases, it feels like you are doing more...

Most total beginners seem to complain that they don't 'feel' anything when doing this exercises and after a couple of months they start working more it seems...

On 4m last weekend I could definitely feel it - as Eric's calculations show, it's surprising how much depth you could simulate...

(I can't take credit for that method for measuring RV, I remember seeing something similar some time ago on another thread, I actually think it was Bill that posted something similar but I could be wrong)

PS even if not for lung stretching, going to -4m is also good for EQ practice

 

[cdavis]

"2m is a bit shallow unfortunately Connor but I think there are some additional steps you could take to stretch the diaphragm"

Like what Simos? I'm very open to suggestions.

 

[efattah]

FYI I think reverse packing is the #1 most dangerous technique you can do. Alfredo Romo almost ruined his freediving career (permanently) after injuring himself doing this, and I have also injured myself with reverse packing. *Not* recommended....

 

[Simos]

"2m is a bit shallow unfortunately Connor but I think there are some additional steps you could take to stretch the diaphragm"

Like what Simos? I'm very open to suggestions.

Was a bit reluctant to post Connor because it relates to what Eric said ie I don't know how safe these techniques are and I wouldn't even know how to explain the right way of doing them as I haven't done so myself or was taught how.

I remember seeing one of our instructors do something 'extra' when we were doing exhales in the 3m pool a few years ago and when I asked the purpose he explained it was mostly for diaphragm stretching.

Let me see if I can find out more and if I do I'll PM you (or post here if safe).

 

[baiyoke]

FYI I think reverse packing is the #1 most dangerous technique you can do. Alfredo Romo almost ruined his freediving career (permanently) after injuring himself doing this, and I have also injured myself with reverse packing. *Not* recommended....

Can you elaborate a bit on that?

Do you mean reverse pack + submersion?

Or reverse pack on land, doing stretching ecercises?

Or reverse pack in itself?

Anyone...