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Hi, I have a question about hands free equalization, it's to see if I'm doing it right or getting the physical part down. When I do hands free I close the throat and have the back of my tongue pushing the back roof of my mouth and release the tongue and throat and repeat. Is this correct? Can anyone who can do hands free equalization inform me on how the body should operate with it?
I think you have the names confused. The Valsalva maneuver is closing the nostrils and is the most common method used by Scuba Divers. The Frenzel maneuver was developed by Hermann Frenzel, a Nazi Luftwaffe commander and ENT. They needed a hands free equalizing method of diver bomber pilots who needed both hands to fly the plane.
"The trapped air inside the mouth and nasal cavities is compressed by the movement of the tongue or larynx while doing Frenzel maneuver. The air is forced into the nasal cavity by the pressure and tries to exit by the nose, but the nostrils are squeezed shut. Because the glottis is closed, air cannot return to the lungs. The tongue creates an airtight seal against the upper teeth or in the rear of the mouth, preventing air from escaping. Because there is nowhere else for the air to go, it enters the eustachian tubes and the middle ear, equalizing the pressure"
The air is forced into the nasal cavity by the pressure and tries to exit by the nose, but the nostrils are squeezed shut. Because the glottis is closed, air cannot return to the lungs.
It pains me to debate with such a respected member but I may have found the source of our different interpretations. I think is is fair to say that most divers in English speaking countries think of the word "nostrils" as the external nostrils like the image below:
This is news to me but there are also "integral nostrils" which may also be called:
Internal Nares
Posterior Nostrils
Posterior Nares
Posterior Nasal Aperture
Note the image below with particular attention to the names in red rectangles.
The Frenzel maneuver is performed by raising the soft palate to block the internal nares (nostrils) and the oral cavity. This creates a closed cavity labeled nasopharynx in the above illustration. Note that the eustachian tube opening is inside this cavity. Raising the soft pallet further causes the gas in this cavity to slightly compress and force gas into the eustachian tube to equalize the inner ear.
Apparently there are a small number of people who cannot block their internal nares with their soft palate so must resort to manually pinching their external nares/nostrils. Unfortunately this is much less effective because the higher volume of the nasopharynx plus the nasal cavity results in lower pressure because of the limited movement of the soft palate. Of course there is no reason for Scuba divers with this condition to use Frenzel instead of just using the Valsalva maneuver.
The reason that freedivers use the Frenzel maneuver instead of the Valsalva maneuver is because the lungs are compressed enough at around the 3 ATA/20m/66' that they can no longer generate enough pressure to equalize. The Frenzel maneuver is comparatively depth independent. There is a misnomer that freedivers swallow air performing the Frenzel maneuver but that is not the optimal technique.
I learned the Frenzel maneuver as a hands-free equalizing method from Kirk Krack in Performance Freediving International's Intermediate Freediving class (now part of TDI). Optimally, competitive apnea divers want to be more streamlined and use the absolute minimum energy to equalize.
I think it is fair to say that Hermann Frenzel intended the maneuver to be hands-free so that pilots in unpressurized cabins could use both hands to fly the plane and manage weapons.
For other readers
Valsalva maneuver blocks the exterior nostrils, or nares in the above image, while the lungs (diaphragm and chest mussels) raise the pressure in the oral and nasal cavities to force air into the eustachian tubes. It is most commonly done by manually pinching the external nostrils closed but can also be done by forcing something, like an oval mask without a nose pocket, up against the external nostril openings.
Photo used by permission, Cameron Donaldson,@northernone
The Valsalva maneuver (pinch your hose and blow) is the most common method in Scuba diving because it is so easy to teach and can produce a little higher pressure in most people than the Frenzel maneuver.
Related note
A very common question is how do divers in heavy gear equalize their ears (using the Valsalva maneuver)? This is a little unsanitary but they raises their shoulders so their upper lip can press against the rim/ledge of the bayonet flange and press up to block their exterior nostrils. Here are some other references on equalizing:
It pains me to debate with such a respected member but I may have found the source of our different interpretations. I think is is fair to say that most divers in English speaking countries think of the word "nostrils" as the external nostrils like the image below:
This is news to me but there are also "integral nostrils" which may also be called:
Internal Nares
Posterior Nostrils
Posterior Nares
Posterior Nasal Aperture
View attachment 734210
Note the image below with particular attention to the names in red rectangles.View attachment 734209
The Frenzel maneuver is performed by raising the soft palate to block the internal nares (nostrils) and the oral cavity. This creates a closed cavity labeled nasopharynx in the above illustration. Note that the eustachian tube opening is inside this cavity. Raising the soft pallet further causes the gas in this cavity to slightly compress and force gas into the eustachian tube to equalize the inner ear. View attachment 734219 Apparently there are a small number of people who cannot block their internal nares with their soft palate so must resort to manually pinching their external nares/nostrils. Unfortunately this is much less effective because the higher volume of the nasopharynx plus the nasal cavity results in lower pressure because of the limited movement of the soft palate. Of course there is no reason for Scuba diver with this condition to use Frenzel instead of just using the Valsalva maneuver.
The reason that freedivers use the Frenzel maneuver instead of the Valsalva maneuver is because the lungs are compressed enough at around the 3 ATA/20m/66' that they can no longer generate enough pressure to equalize. The Frenzel maneuver is comparatively depth independent. There is a misnomer that freedivers swallow air performing the Frenzel maneuver but that is not the optimal technique.
I learned the Frenzel maneuver as a hands-free equalizing method from Kirk Krack in Performance Freediving International's Intermediate Freediving class (now part of TDI). Optimally, competitive apnea divers want to be more streamlined and use the absolute minimum energy to equalize.
I think it is fair to say that Hermann Frenzel intended the maneuver to be hands-free so that pilots in unpressurized cabins could use both hands to fly the plane and manage weapons.
For other readers
Valsalva maneuver blocks the exterior nostrils, or nares in the above image, while the lungs (diaphragm and chest mussels) raise the pressure in the oral and nasal cavities to force air into the eustachian tubes. It is most commonly done by manually pinching the external nostrils closed but can also be done by forcing something, like an oval mask without a nose pocket, up against the external nostril openings.
The Valsalva maneuver (pinch your hose and blow) is the most common method in Scuba diving because it is so easy to teach and can produce a little higher pressure in most people than the Frenzel maneuver.
Related note
View attachment 734231A very common question is how do divers in heavy gear equalize their ears (using the Valsalva maneuver)? This is a little unsanitary but they raises their shoulders so their upper lip can press against the rim/ledge of the bayonet flange and press up to block their exterior nostrils. Here are some other references on equalizing:
This all very interesting.
Some background first.
Here in Italy we have developed an equalization technique where pressure is generated by closing the soft palate and raising it, but also pinching the external nostril with fingers, like in Valsalva. This method is named Marcante-Odaglia and was first published in Italian medical journals around 1950.
Years later, when the method was proposed internationally within the CMAS community, we were told that the method was basically the same as Frenzel.
Only difference is that Frenzel is practiced with the mouth closed, not breathing, whilst Marcante-Odaglia was developed for scuba divers using the ARO (CC pure oxygen rebreather) so the device cannot be removed easily from mouth, which stays open, and you can breath while equalising, as mouth and epiglottis are left open.
But in both cases the noise is pinched and the soft palate raised.
Most web sites describing Frenzel also say to pinch nostrils:
For most people raising (closing) the soft palate is easy (for example when filling a rubber balloon with the mouth).
But such a valve is BELOW the Eustachian tubes (as also shown in your figures).
So you need to trap air inside the nasal cavity for exerting pressure inside it, closing also the nostrils.
I suppose from what you write that there should be another valve closer to the nostrils, so that air can be trapped between the two valves (soft palate and these "internal nostrils").
It is a fascinating theory, and I do not have enough anatomical knowledge for confirming or rebutting it.
What I can say is that in most freediving courses Frenzel is taught to be practiced with the mouth closed and pinching the external nostrils.
Here in Italy, good instructors also know of the Marcante-Odaglia method and of his small difference between it and Frenzel (mouth open vs mouth closed), but, as said, always pinching the nostrils.
Outside Italy Marcante-Odaglia is unknown and most instructors only teach the crap Valsalva method.
It would be interesting here the opinion of some ENT.
And, from an historical point of view, also to find the original writings of Frenzel, which should not be classified anymore.
I always had the impression that, while diving on a Stuka, a pilot was not easily pinching his nose.
So I agree with you that initially the Frenzel method was probably hands free, and possibly much more similar to BTV (which was invented, or, better, discovered later, in the eighties, in France - but I was slready using BTV dince my childhood, in the sixties, making me eondering why most other free divets were pinching their nose, as I wasn't needing to do it for equalising).
So perhaps all the history of equalization methods should be rewritten.
I hope that others more aknowledged than me can contribute.
This topic of hands-free equalization is really nice!
@Akimbo thanks for posting that. I've struggled with the full Frenzel method for a while now. I can't seem to consistently generate enough pressure, even while pinching my nose. I figured out a shortcut, which is to first pinch my nose and hum. That pre-pressurizes the nasal cavity a bit, after which the small motion of the tongue and soft palate is more than enough to equalize. It works great, but I've been wanting to figure out how do it without humming.
After reading your post, I think my humming trick is necessary for me when the internal nares are open. In that case you have to pressurize the entire nasal cavity, not just the small section behind the internal nares.
Frenzel is with pinched notrils. Free divers and Stuka pilots use nose clip if they need hands free with Frenzel. This is also in wikipedia article.
Please watch from 5:00 onward, describing all different handsfree equalization techniques as well as Frenzel:
@daviesrye if you are humming, this means you are using your vocal chords, so, your glottis is open. That cannot be Frenzel. So, if you pinch your nose and hum and equalize this is basically some type of valsalva, because you create the pressure through lungs.
Notice this guy (below) is humming when inflating the balloon, he is using hum/lungs to inflate it, he, then closes his glottis and pushes the air back and forth into his nasal cavity without leaks and using the tongue to push it (Frenzel).
The key for hands free equalization is the larynx muscle control and separating/isolating it from the tongue. You can see it in a mirror how your throat will lift, you need to practice with a mirror and have more faith on what you see instead of what you feel.
@Ucarkus thanks for your contribution.
It corresponds with my previous knowledge on the topic, albeit there is always something new to learn...
But the first of your posted videos says "the video is unavailable" from here...
Regarding those "internal nostrils", I have fund no evidence of a way of closing the nostrils without pinching them (this supposed "internal nostrils" valve)
This web page seems to provide a clear explanation of the Frenzel method (with pinched nostrils):
The Frenzel equalisation technique greatly increases the ability of a freediver to descend deeper, more safely and in comfort. Read this article, containing a video of Emma explaining more about this technique and why it is so effective for divers, to learn more.
gofreediving.co.uk
Here the picture showing the position of the Eustachian tubes entrance (above the soft palate valve):
And here a figure, also from the the web site linked above, showing as air trapped in the nasal cavity, above the soft palate kept NEUTRAL and with nostrils pinched, is compressed by raising and pushing back the tongue for forcing equalization with the traditional Frenzel method for free divers (epiglottis closed, no breathing):
Here instead you see our Italian variant, named Marcante-Odaglia, which is most suitable for scuba divers, as it allows to keep the mouth open and to breath, while compressing air trapped above the CLOSED soft palate, simply by pushing it up (again with pinched nostrils):
I continue not understanding how one could close his nostrils from inside, without pinching them...
@Angelo Farina , I have fixed the link, hope you can see it and you will like it. Its a long one but 5:00 is the point where difference of vto techniques explained (based on mri) as well as Frenzel.
@daviesrye if you are humming, this means you are using your vocal chords, so, your glottis is open. That cannot be Frenzel. So, if you pinch your nose and hum and equalize this is basically some type of valsalva, because you create the pressure through lungs.
I'm only humming for a fraction of a second to pre-pressurize the nasal cavity. Then I close the glottis and perform a normal Frenzel. I can do it without the humming step, it's just not as reliable.
edit: although I can do it with my mouth open, so I guess it's actually Marcante-Odaglia.
Being more precise, during a Marcante-Odaglia you can breath, hence not only the mouth is open, but also the epiglottis.
Marcante-Odaglia is less powerful than a pure Frenzel, as in the first pressure comes only by raising the soft palate, thanks to a muscle called tensor palati, whilst in Frenzel the tongue is used, which is a far more powerful muscle.
The fact that your Frenzel is not very powerful can be an indication that you are actually using the Marcante-Odaglia version...
Frenzel is typically emplyed by free divers, who are trained to keep their epiglottis closed.
Marcante-Odaglia is used by scuba divers, who instead are thaught to always keep their epiglottis open.
I personally have no idea what M-O is. I google translated the Italian article and it does sound like Frenzel. But reading @Angelo Farina's description, it does sound like a form of VTO.
I also am not sure you can keep the vocal fold open when doing Frenzel or VTO, when I lift back of my tongue, mine closes automatically and I suspect this is a reflex for protecting the airways during eating or swallowing. Same goes even for Toynbee, the fold will close momentarily. @daviesrye my take on humming exercise is that while humming and trying to lift the back of your tongue, you are trying to find the spot where ET is opened. When ET is open, you will hear it because of hum and once you learn the correct spot, there is no need for humming. But again, there is no right or wrong on this, if it helps by no means do it. VTO is not as strong as valsalva or Frenzel, so, you have to do it more frequently, this is expected.
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