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is head down harder?
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Because the positive boyancy is provided by the neoprene and lungs, and the negative boyancy is provided by the lead and internal organs which move. Thus, you will still experience compression on various organs, and as the body is designed to operate 'head up', strange things happen 'head down'.
Just to explain a bit better 
in my opinion, there are two main reasons:
1. For beginners, the head down position is unfamiliar and uncomfortable and causes mistakes in posture (looking down, arching back etc) and a lot of tension so obviously this prevents the e-tubes from opening properly and equalisation is hard/impossible
2. The other reason is just due to physics - air will move from high pressure to low pressure in water (pressure is force/area so there is more force acting from under than from above so it moves up - if I am correct!) so when you are head down it's harder to move air from your lungs to the head and specifically the e-tubes. When you are descending feet down the pressure difference between your head and lungs is helping you move air up to your ear drum but the opposite is true when you are head down...
There are probably a few other reasons that have to do with the body but I can't think of any right now...
in my opinion, there are two main reasons:1. For beginners, the head down position is unfamiliar and uncomfortable and causes mistakes in posture (looking down, arching back etc) and a lot of tension so obviously this prevents the e-tubes from opening properly and equalisation is hard/impossible
2. The other reason is just due to physics - air will move from high pressure to low pressure in water (pressure is force/area so there is more force acting from under than from above so it moves up - if I am correct!) so when you are head down it's harder to move air from your lungs to the head and specifically the e-tubes. When you are descending feet down the pressure difference between your head and lungs is helping you move air up to your ear drum but the opposite is true when you are head down...
There are probably a few other reasons that have to do with the body but I can't think of any right now...
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I'd agree with point 1, but as for 2..i'd argue it because the air isnt in water (yet..until you breath out). So in terms of pressure, yes it'll always flow from high to low, but if you're exhaling/gurning etc to equalise then it'd work regardless of body position. That said, if you're upside down and your jowels/neck are being compressed due to depth then that'll make it harder to push the air through the e-tubes to equalise.
Maybe it should be on another thread but it is similar. Why is it fairly easy for me (and many others, it appears) to leave the surface with 4 liters of air (Vt) and clear to 30 meters but near impossible to leave with 6 liters and clear to 50 meters? Same time, same position, same methods, same amounts and they don't work the same.
Hi Bill - ok in fairness there many things that come into play with pressure. I was answering assuming relatively shallow dives and trying to point nthe differences between head up and head down.
In extreme depths lots of things happen from what I've read on here eg trachea collapses etc so it becomes impossible to equalise from the lungs for other reasons but this doesn't really have to do with head up or head down. I'm guessing that there are other body structures too that get compressed and make it more difficult in moderate depths too but again, it's not so much a head up and head down position issue.
Also regarding your question, it sounds to me that again it doesn't have to do so much with heads up or down, but mainly with when you reach residual volume - it's not impossible obviously to equalise past this point but the methods you'd probably use at shallower depths than RV won't work as you won't be able to just take out air from the lungs and move it into your mouth as you'd do at shallower depths. Hence the need for mouthfil and other equalisation techniques. Regarding the specifics of the example you gave - how do you know that you are leaving with exactly 4L and 6L?
Chris - it shouldn't matter that the air is not in the water yet, it's still subject to the same pressure as the surrounding water (hence why it decreases in volume as you descend).
If you are just starting in freediving, I know it feels that when you're upside down lots of things around your neck move and block the e-tubes etc and that it's impossible or very hard to equalise head down but I still maintain that in the vast majority of cases, it's just a question of relaxation and body position combined with being able to control the muscles that open the e-tubes in the head down position.
In my case at least I spent quite a lot of time being convinced that there was something wrong with my right ear when head down and that something would move and block it when upside down (I was even feeling the pressure building up in my neck and head) but I don't have that issue anymore and I am sure that it was just because of not being relaxed and also, I had to train my e-tube muscles and find the movements that would open them.
In extreme depths lots of things happen from what I've read on here eg trachea collapses etc so it becomes impossible to equalise from the lungs for other reasons but this doesn't really have to do with head up or head down. I'm guessing that there are other body structures too that get compressed and make it more difficult in moderate depths too but again, it's not so much a head up and head down position issue.
Also regarding your question, it sounds to me that again it doesn't have to do so much with heads up or down, but mainly with when you reach residual volume - it's not impossible obviously to equalise past this point but the methods you'd probably use at shallower depths than RV won't work as you won't be able to just take out air from the lungs and move it into your mouth as you'd do at shallower depths. Hence the need for mouthfil and other equalisation techniques. Regarding the specifics of the example you gave - how do you know that you are leaving with exactly 4L and 6L?
Chris - it shouldn't matter that the air is not in the water yet, it's still subject to the same pressure as the surrounding water (hence why it decreases in volume as you descend).
If you are just starting in freediving, I know it feels that when you're upside down lots of things around your neck move and block the e-tubes etc and that it's impossible or very hard to equalise head down but I still maintain that in the vast majority of cases, it's just a question of relaxation and body position combined with being able to control the muscles that open the e-tubes in the head down position.
In my case at least I spent quite a lot of time being convinced that there was something wrong with my right ear when head down and that something would move and block it when upside down (I was even feeling the pressure building up in my neck and head) but I don't have that issue anymore and I am sure that it was just because of not being relaxed and also, I had to train my e-tube muscles and find the movements that would open them.
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The question made me think a monofin for arms with feets extended in hydrodynamic position, arms above head, equalization/moutfill etc would be much easier but would require hard trainning to bring the body work the opposite. Imagine the classic monofin style in the opposite. Air would be available all the time on the head for equalization.
Just a thought, and who knows it might be the future of freediving CWT style..
Just a thought, and who knows it might be the future of freediving CWT style..
Bill reading your question again it also seems to me that by the numbers you have chosen, you are assuming that your RV is 1L?
To explain what I mean - from the numbers you have chosen, it looks to me that the underlying assumption is that 1L of air should be able to take you 10m further? I am making the assumption here that reaching RV is the equalisation limit using the technique you are using.
If your RV is 1L and assuming you are indeed starting with 4L and 6L of air respectively, then the numbers add up and you should reach RV at 30m with 4L and at 50m with 6L of air.
In practice, I believe that your RV is likely to be more than 1L and I suspect that you are not exactly starting with those exact amounts of air (which would be very hard to measure).
So let's say for argument's sake that your RV is 2L (too much probably in reality) and that you are starting with 4L of air and 6L on the second dive. In this case, if my maths/understanding is right, you will reach RV at 10m with 4L and at 20m with 6L. So 2 extra L of air won't move the point of reaching RV by 20m but by 10m in this case.
So if in reality your RV is somewhere around 1.2L and you are starting with around 5L (instead of 4 you are saying) and 6L in the second dive, this would mean that you'll be able to equailse to a bit more than 30m with 5L and to 40m with 6L. So not being able to make it to 50m in the second dive is not that surprising.
Hope the above makes sense and above all, that it is correct! (apologies if not! please correct)
To explain what I mean - from the numbers you have chosen, it looks to me that the underlying assumption is that 1L of air should be able to take you 10m further? I am making the assumption here that reaching RV is the equalisation limit using the technique you are using.
If your RV is 1L and assuming you are indeed starting with 4L and 6L of air respectively, then the numbers add up and you should reach RV at 30m with 4L and at 50m with 6L of air.
In practice, I believe that your RV is likely to be more than 1L and I suspect that you are not exactly starting with those exact amounts of air (which would be very hard to measure).
So let's say for argument's sake that your RV is 2L (too much probably in reality) and that you are starting with 4L of air and 6L on the second dive. In this case, if my maths/understanding is right, you will reach RV at 10m with 4L and at 20m with 6L. So 2 extra L of air won't move the point of reaching RV by 20m but by 10m in this case.
So if in reality your RV is somewhere around 1.2L and you are starting with around 5L (instead of 4 you are saying) and 6L in the second dive, this would mean that you'll be able to equailse to a bit more than 30m with 5L and to 40m with 6L. So not being able to make it to 50m in the second dive is not that surprising.
Hope the above makes sense and above all, that it is correct! (apologies if not! please correct)
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The question made me think a monofin for arms with feets extended in hydrodynamic position, arms above head, equalization/moutfill etc would be much easier but would require hard trainning to bring the body work the opposite. Imagine the classic monofin style in the opposite. Air would be available all the time on the head for equalization.
Just a thought, and who knows it might be the future of freediving CWT style..
We sometimes do this as a training exercise for monofinning - personally I can't do it because my monofinning technique is terrible but when we tried I saw that those amongst us who are better at monofinning could complete the length going feet first (with no fins on).
In a moment of frustration I put on my fins on my hands and managed to complete a length going backwards too with terrible technique - wouldn't recommend this though as it was quite tough on the shoulders and it's quite easy to get injured if your technique is not good. :crutch
All great fun though :friday
Agree it's mostly air wanting to move up, bit more relaxed position and easier flow between air passages, etubes etc
Bill, are you using mouthfill/frenzel for those depths ?
Is it your ears or sinuses ?
It seems to be much easier to do this at shallower depths with less air. Dive time, relaxation and urge to breathe seem to be factors that effect it. This year I definitely made leap forward in EQ, being able to do 100m+ head down. I seemed to have got the mouthfill working most of the time. In the past though I could nail the mouthfill %100 of the time on an exhale dive yet on deep dives only getting it working some of the time. On exhale it’s a very short time to “hold on” to the mouthfill, compared to deep dives where people need to hold 30 – 90 seconds. Any contractions, urge to swallow, distraction, incorrect head angle and you will lose it.
On an inhale dive + packing sometimes you tend to not EQ as often because you know you have lots of air left. You still have to EQ and “stay ahead” of it, once you are behind the Etubes will be under pressure and becomes harder if not impossible to EQ. One method I use is to continually pressurise with Frenzel most of the way down, moving the ear drums in&out a bit so I know I have equalised.
Cheers,
Wal
Bill, are you using mouthfill/frenzel for those depths ?
Is it your ears or sinuses ?
It seems to be much easier to do this at shallower depths with less air. Dive time, relaxation and urge to breathe seem to be factors that effect it. This year I definitely made leap forward in EQ, being able to do 100m+ head down. I seemed to have got the mouthfill working most of the time. In the past though I could nail the mouthfill %100 of the time on an exhale dive yet on deep dives only getting it working some of the time. On exhale it’s a very short time to “hold on” to the mouthfill, compared to deep dives where people need to hold 30 – 90 seconds. Any contractions, urge to swallow, distraction, incorrect head angle and you will lose it.
On an inhale dive + packing sometimes you tend to not EQ as often because you know you have lots of air left. You still have to EQ and “stay ahead” of it, once you are behind the Etubes will be under pressure and becomes harder if not impossible to EQ. One method I use is to continually pressurise with Frenzel most of the way down, moving the ear drums in&out a bit so I know I have equalised.
Cheers,
Wal
Thanks for the help Wal. I was hoping to get some suggestions. For the last three years, the vog has limited everything. Sticky ears is part of the problem and when the sinuses act up, I'm lucky to get any training in. Lucky if I can even safety.
The one large mouth fill usually induces a contraction so I start filling early and top off often. On a good day I can get some air at 50.
I copied an idea from Leo. Exhale to about 50% capacity at five meters and take one minute to go to 30. How do you do your exhales?
Good to hear from you
The one large mouth fill usually induces a contraction so I start filling early and top off often. On a good day I can get some air at 50.
I copied an idea from Leo. Exhale to about 50% capacity at five meters and take one minute to go to 30. How do you do your exhales?
Good to hear from you
you are not correct! (if i may go beck to the original post subject)
air dose move from high to low pressure but it dose so in order to reach the point of equilibrium. in a confine space (air ways) the air is always at the same pressure. it is true that the lower (deeper in the water) part will be smaller in volume - like squeezing a part of a balloon so that the other part bulges out - but that shouldn't interfere with equalization.
so air dose not go up, it dosnt go anywhere, the body that holds it just change shape due to the water pressure.
more over, (if you think of the balloon example) there are 50(+-)cm from the lowest part of the lungs to the e-tubs. that is 1/20 of an atmosphere(pressure). dont you think thats negligible?
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let me ask this with a different example:
lets take a 10m diameter rubble ball and submerge it in water. what shap will it take?
at its highest part it is 1 atmosphere and at the lowest 2 atmosphere.
lets say that his shape is now of an upside down pear. so air did move up, naturally, but it doesn't anymore and the air pressure is the same all over our ball. even if we take it down to -100m the ratio of pressure will stay the same and thus its shape also stay the same. he will be more compressed, naturally, but with the same shape air did not move anywhere.
am i missing something?
lets take a 10m diameter rubble ball and submerge it in water. what shap will it take?
at its highest part it is 1 atmosphere and at the lowest 2 atmosphere.
lets say that his shape is now of an upside down pear. so air did move up, naturally, but it doesn't anymore and the air pressure is the same all over our ball. even if we take it down to -100m the ratio of pressure will stay the same and thus its shape also stay the same. he will be more compressed, naturally, but with the same shape air did not move anywhere.
am i missing something?
I don't see the direct relevance and don't even know what shape the balloon would really take but your assumption is not right anyway - how is the ratio of pressure staying the same? In your first example (i.e. at 0-10m), the ratio of pressure from top to bottom is 1:2 - when you go to 100m, the ratio of pressure is 11:12 i.e. a lot less. The pressure gradient decreases a lot as the depth increases, so the shape of your balloon would become more round as you go deeper. (you will also get an additional rounding effect from the fact that the whole balloon is compressing in volume, so the top to bottom won't be 10m anymore but a lot less).
So if your body shape is pear-shaped, you can expect to change to an orange as you go deeper lol
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If we forget about the physics of it for a moment and go back to the original question, these are a few things I observed in practice and where I was basing my answer that it must be mainly due to 2 factors: easier to move air up from lungs than it is to move air down and secondly reasons to so with the opening of the e-tubes.
1. Try this: empty your lungs (no need to unpack) and duck dive (head first) to the bottom of the pool. Even if it's just 3m you'll see that it's not easy to get air from your lungs to your ears in order to equalise while you are inverted at 3m. The moment you turn head up, all of a sudden it's a lot easier to bring air up. (or you can just descending feet first and observe that it's easier to bring air up)
2. If you ask someone who's struggling to equalise head down to try it outside the water, chances are that they'll still find it hard (even though there is now no pressure gradient). So from this you can conclude that on the head down position, they're struggling to open their e-tube(s).
1. Try this: empty your lungs (no need to unpack) and duck dive (head first) to the bottom of the pool. Even if it's just 3m you'll see that it's not easy to get air from your lungs to your ears in order to equalise while you are inverted at 3m. The moment you turn head up, all of a sudden it's a lot easier to bring air up. (or you can just descending feet first and observe that it's easier to bring air up)
2. If you ask someone who's struggling to equalise head down to try it outside the water, chances are that they'll still find it hard (even though there is now no pressure gradient). So from this you can conclude that on the head down position, they're struggling to open their e-tube(s).
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Especially when talking about people new to frediving that can't equalise at all head down, there are so many things that come into play when inverted and prevent EQ. A couple of examples:
1. Duck dive too aggressive - forgetting to equalise on surface and during duck dive. This doesn't manifest when descending feet first as you can't have such an aggressive entry.
2. Finning - someone who is not used to big, freediving fins will need a significant amount of effort to use them and this usually leads to tension in the upper body too as they can't keep the upper body/shoulders/neck relaxed while finning. This is particularly a problem with stereo-finning, I suspect that it might have to do with the fact that it's assymettical.
3. Descending head first naturally makes you want to look down to make sure you don't bang your head on anything - looking down closes the e-tube or at least restricts it. Feet first you don't have this issue unless for some reason you are descending while looking up.
There are other reasons too - the only reason I know is because I had to go through a lot of trouble before I could equalise head down :-(