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Girth theory: Pumping vs. clamping

I have much more important things to do than to read about penis physiology, yet that is what I have been doing, and I have learned a lot, and I think answered some questions that have been lingering here. To start:

The question about whether or not blood flows during peak erection is not so simple. The answer is actually yes, and no!

As pudendum has pointed out, the ischiocavernosis muscle (ICM) contracts, which raises pressure in the CC’s above normal arterial pressure. This pressure can in fact cause complete stoppage of venous outflow.

However, studies have shown that ICM contraction is intermittant:

Quote

The belt-form cavernosus muscles’ insertion into the CC presumably constricts on contraction the dorsal penile vessels, with a resulting extra blood entrapment in the cavernous tissue. It was shown in this study that the increase of the cavernosus muscles’ EMG was intermittent, which apparently denotes intermittent cavernosus muscle contraction

The intermittant contractions allow maintenance of pressure, as well as some inflow and outflow of blood to prevent the oxygen deprivation that we have been discussing!

Quote
The intermittent cavernosus muscle contraction during rigid erection seems to be advantageous. On cavernosus muscle contraction, the ICP increases to above the systolic pressure and the penile corpora are apparently transmitted into a high-tension closed cavity. Retention of this high-tension closed cavity for long periods during penile thrusting at coitus may lead to cavernosus tissue ischemia. Therefore, the intermissions in cavernosus muscle contractions allow for alterations in the periods of muscle contraction and relaxation during which the cavernous tissue could be well oxygenated, particularly because the periods of cavernosus muscle contraction are relatively short. These factors provide a natural mechanism that keeps the cavernous tissue well oxygenated and prevents its destruction by ischemia

These quotes were taken from the discussion section of this excellent paper:

http://www.andrologyjournal.org/cgi…l/27/5/695#SEC2


Horny Bastard

Pudendum, in our discussion of your balloon model, and my tank model, I now think neither one is correct.

As you pointed out, the hose connected to my tank represents the arterial inflow at normal arterial pressure. Since the tank (CC) pressure is higher than this hose (arterial) pressure, this hose can not fill the tank.

The balloon model is also wrong because it doesn’t allow for inflow or outflow, which we know happens.

However, I think we can modify the tank model to be accurate if we add a linear peristaltic pump between the hose and the tank entrance, which is used as a “second stage” pump to pump at higher pressure. That is how I view the ICM intermittant contractions; a secondary pump that keeps the penis pumped up at higher pressures than the normal arterial pressure.

I think I am coming to a more clear picture of how vacuum pumping and clamping work differently, which I will post later.


Horny Bastard

Originally Posted by ticktickticker
Pudendum, let’s be careful with experts’ opinions.

Experts sometimes make statements which are correct in one context, but not in an other.

Before I buy Dr. XY’s statment regarding anything, I want the study or paper where measurements of - penile blood flow under peak erection conditions in this case - have been performed.

Anyhow, if it is true that the intracavernous pressure is above 200 mmHg which is well beyond arterial blood pressure, then the arteries would be compressed and arterial inflow reduced to zero.

Why then can one have sex for hours without discoloration? Probably because peak erection is not a several hour phenomen but repeatedly interrupted by phases of slightly decreased erection quality IN ORDER to restore the oxygen tanks (if I were a smart dick, that’s how I would proceed.


One man’s expert is another man’s heretic.

If your interested, I have several references that talk about markedly elevated cavernosa pressures resulting from maximally full cavernosa and then the contraction of the paired Ischiocavernosus muscles that surround the cavernosa.

Pressures are as high as 200 - 300 mm HG.

I agree. I too think the reason the guys can marathon without discoloration is because there is some reduction of erection for relaxation of the Ischiocavernosus muscle and some venous outflow leading to new blood in through the arteries to the cavernosa.

In addition, since the pressure in the skin and the tissues under it do not climb above arterial pressure and the main vein does drain, the skin stays nicely colored throughout a gymnastic night. Now stick a clamp on it and stop blood in and out of the skin, that is a different story.


Last edited by pudendum : 01-04-2008 at .

Originally Posted by pudendum
One man’s expert is another man’s heretic.


Yes. Yes he is.

Originally Posted by pudendum
Now stick a clamp on it and stop blood in and out of the skin, that is a different story.


Yes. Yes it is.


Before: I'd like to show you something I'm very proud of, but you'll have to move real close.

After: I\'d like to show you something I\'m very proud of, but you guys in the front row will have to stand back.

God gave men both a penis and a brain, but unfortunately not enough blood supply to run both at the same time. - Robin Williams (:

Originally Posted by mravg
As pudendum has pointed out, the ischiocavernosis muscle (ICM) contracts, which raises pressure in the CC’s above normal arterial pressure. This pressure can in fact cause complete stoppage of venous outflow.

Exactly, the outflow can be stopped, but is the inflow stopped by the same process? My theory is that pumping will “suck” additional blood into the CC as well as some leaks out due to low intensity erection. I believe Pude is saying that the pump simulates the peak erection so the pump could only be pulling lymph fluid into the tube, not additional blood into the CC.

Originally Posted by pudendum

You may but I don’t.

I’ll ask you again. If I apply a positive pressure of 150 mm Hg on the outside of penis that has a chamber pressure 200 - 300 mm Hg, by your logic, the applied pressure should be subtracted from the chamber pressure. You and I know that his makes no sense. Cavernosa pressure will rise, not fall.

So you guys have not explained to me how a negative pressure is added to make a higher chamber pressure. Explain it to me in the peak erect penis with a poorly compliant tunica. The pressure will equalize with the rest of the penis for the reasons I explained before.

It is important to be clear on this point in order to further the discussion about pumping vs. clamping, so I will discuss this a bit more.

I never said that negative pressure outside the penis will increase pressure inside the penis. I was discussing pressure differential between inside and outside. It is the differential that determines how much stress is on the tunica. If you have 1000 psi inside but 1001 psi outside the penis, then the penis is collapsed and you have no tunica stretching, despite the high internal pressure.

Quote

I’ll ask you again. If I apply a positive pressure of 150 mm Hg on the outside of penis that has a chamber pressure 200 - 300 mm Hg, by your logic, the applied pressure should be subtracted from the chamber pressure.

Yes, and I hope now you see that it is true if we are discussing the pressure differential = P inside minus P outside.

So if you have 200mm inside and then you increase your cylinder pressure to 150mm above atmospheric outside, then you have 50 mm Hg differential. The differential is reduced from the original 200, so you have less force from inside stretching the tunica.

Quote

You and I know that his makes no sense. Cavernosa pressure will rise, not fall.

You are right. For your balloon model, which works for this example, positive pressure outside the balloon increases the pressure inside, but decreases, or fails to change, the pressure differential. The rigidity of the balloon wall will determine how much the pressure outside effects the pressure inside.

Quote
So you guys have not explained to me how a negative pressure is added to make a higher chamber pressure. Explain it to me in the peak erect penis with a poorly compliant tunica. The pressure will equalize with the rest of the penis for the reasons I explained before.

I think I know what you are getting at. Let’s look at a condom filled with water and a knot in the end.

There is a pressure on the water. Since there is no external source of pressure or flow, the pressure inside is a function of the elasticity of the condom wall, and the air pressure pushing on the condom wall.

If you put this water balloon in a vacuum cylinder, the pressure inside is still P(elasticity) + P(air pressure). Air pressure decreased so pressure inside decreased!

This example is different than the one where there is an external hose or pump attached. We were envisioning different models, so we came to different conclusions.

If you imagine the model of the tank with the hose and the booster pump (analgous, I hope, to the erect penis with ICM contracting to maintain pressure), then I look at it this way:

The pump maintains a constant pressure. Let”s say in the case of the erect penis it is 200 mm Hg.

Now there is one extra factor in the pressure inside the penis compared to the water balloon above.

Pressure(CC’s)= Pressure (wall elasticity) + Pressure (air pressure) + Pressure (Pump pressure).

Now you put the penis in a cylinder and pull a vacuum. The air pressure part of the equation goes down, but the pressure in the penis probably doesn’t because the pump (ICM contraction) is maintaining pressure.

However, the differential between inside and outside is now greater, because P(inside) is the same, but P (outside) is less.

Again, it is the differential that tells us that the force on the tunica has increased.


Horny Bastard

Originally Posted by SteadyGains

Exactly, the outflow can be stopped, but is the inflow stopped by the same process?

Well, if you imagine the model of a full tank with a hose coming in and a hose going out, if you pinch the exit hose, the incoming flow also stops because there is no where for additional water to go unless the tank stretches from the incoming water pressure.

Quote
My theory is that pumping will “suck” additional blood into the CC as well as some leaks out due to low intensity erection. I believe Pude is saying that the pump simulates the peak erection so the pump could only be pulling lymph fluid into the tube, not additional blood into the CC.

This continues what I was saying in my last post. As I described, the vacuum in the cylinder results in more force pushing out on the tunica. If this force is enough to stretch the tunica (increase the total volume of the penis), then more blood will enter to fill that volume. So in essence, you are right, the vacuum sucks more blood in, but I don’t like using the term “suck”, except with my wife. :)


Horny Bastard

OK, we seem to have that sorted out…how about a monkey wrench tossed in the works.

I have been thinking about how jelquing with seemingly modest pressures can cause increased girth, and the phenomenon of the tissue under the clamp expanding best ( search Elliptical Strain in Aristocanes thread).

What I’ve been thinking is that PERHAPS because the tunica is essentially a wall or cylinder of fibrous tissue, that putting it under full pressure STRENGTHENS the wall and makes it more resistant to deformation.

The example I am thinking of would be imagine a balloon made of Kevlar fibers. If you inflate it to high pressure, trying to puncture it or more precisely, trying to pull apart the fibers with your fingers or a blunt instrument would be far more difficult than if it was un-inflated or at least partially uninflated.

PERHAPS, its the separation of the fibers from each other, or at least expanding the fibers in relation to each other that is the key. When you jelque at partial erectile levels, you are allowing enough “slack” in the fibers to allow you to make changes of the fibrous “mat” or stretch them apart slightly in relation to their normal inter relationship.

When you have a full erection, or beyond full erection, the fibers are pulled tight forming a very tough wall. Then it depends on the total strength as to whether it will deform enough with clamping or pumping to make progress.

I think it may well be that guys with very tough tunica may respond better to jelquing than high pressure clamping, because having part of the tunica unstressed will allow fibers to be moved or “spread apart” far easier in the part that is being stressed.

Just as the Elliptical Stain formed by the clamp, focuses greater stress on the area under the clamp, perhaps by lowering the overall “taughtness” of the tunica mesh, it is easier to make changes to other areas of the tunica.

Originally Posted by ticktickticker
At peak erection there is probably no net influx but as I pointed out above, peak erection is not maintained forever. Many pumpers (as I) experience partial loss of erection at the end of the session even when entering at peak erection. Most likely the intracavernous pressure drops during pumping below arterial pressure so that there is unimpeded arterial influx as long as dictated by the pressure differences. However, as experience shows, as soon as the vacuum is released the excess blood in the cavernosa will leave the penis and so you pull a plumb but only partially erected penis out of the pump.

This consideration may also be relevant when discussing erect vs unerect entry into the tube and might favour to start at low erection level because more blood can be ‘pulled’ in the cavernosa. In contrast, when starting to pump at peak erection the penis root is initially sealed, so that no substantial further expansion might be possible.


I totally agree. This is why I picked a very specific point in the erection process that is reproducible in most guys who have the ability to reach max erection; particularly if you’ve been doing girth PE for a while. If you understand the situation with regards to the effects at this phase of erection, you can better decide when to apply the PE method you are going to use.

I also agree that after this long convoluted and sometimes confusing discussion in this thread, I think that most (but probably not all of us) would agree that a pump should be applied at a lower level of erection than peak. AGAIN, I will repeat that I am not saying that some volume-induced tension to the tunica is not possible at peak erection. I believe it is small. Success by pumpers in my mind proves that there must be.

Originally Posted by SteadyGains
This part of the theory is in error. I find it near impossible to come close to a peak erection inside the tube. At least for any length of time. To say the the pump simulates a peak erection, I would think that would be in error as well. I think you need to buy a pump, it could help your theory and all of us move forward.


You are misunderstanding me. I am talking about placing pump on a rigid max penis to start.

I don’t doubt that you will not bring your semi erect penis to max erection in the pump. If you remember what I have said in previous posts is that the pump probably has its greatest effect at lower levels of erection. This must be true because there are so many guys writing about pump successes and if most guys, like you, “find it near impossible to come close to a peak erection inside a tube.”

Originally Posted by mravg
In engineering terms, you are saying that the tunica has viscoelastic properties. This is the theory behind ADS strategies as well (low stress for long periods of time). A visco elastic material will have low initial elongation when even high force is applied, but, elongation increases with time, even at lower forces. Good point.


Exactly, the tunica is a viscoelastic structure made up of dense connective tissue with a small elastic component. It has two layers, an inner layer with its collagen (and other fibers) arranged in a circular pattern (circumferential) and an outer layer with fibers arranged length-wise (longitudinally)

At peak erection you are extending the fiber lengths to their maximum, most probably in the inner layer though you cannot rule out an effect on the length-wise fibers (which probably explains length growth with pumping), overpowering the elastic component of the tunica. This is why compliance is very low at peak erection.

Originally Posted by SteadyGains
I am not an expert on this, but others have confirmed and I have have some experience in two stage pumping. Starting with a smaller cylinder and then moving to a larger cylinder helps prevent lymph build up.

Pude, I think we still need to look at time as a factor on Tunica expansion rather than just pressure. As in pumping for 20 minutes at 15hg will get you to pack 2” tube, but you will have lymph fluid. But pumping for 1 hour at 5-8hg will get you to pack a 2” tube with much less lymph fluid.

So if your penis increases in size and the lymph build up is minimal, it is Tunica expansion.


I don’t dispute that pumping is a time sensitive method. Again, I don’t dispute that at lower levels of erection this is more than likely very true.

By the way, in my discussion, I believe that I said that the effect of pumping at peak effect would be a volume effect, for the reasons I have expressed ad nauseam (vomit, cough, sputter, dry heaves!! I think I feel better now).

Originally Posted by mravg
I have much more important things to do than to read about penis physiology, yet that is what I have been doing, and I have learned a lot, and I think answered some questions that have been lingering here. To start:

The question about whether or not blood flows during peak erection is not so simple. The answer is actually yes, and no!
As pudendum has pointed out, the ischiocavernosis muscle (ICM) contracts, which raises pressure in the CC’s above normal arterial pressure. This pressure can in fact cause complete stoppage of venous outflow.

However, studies have shown that ICM contraction is intermittant:

The intermittant contractions allow maintenance of pressure, as well as some inflow and outflow of blood to prevent the oxygen deprivation that we have been discussing!


These quotes were taken from the discussion section of this excellent paper:
http://www.andrologyjournal.org/cgi…l/27/5/695#SEC2


Great article, thank you for posting it. Interesting methods. As I told Stage in another thread, no ones going to stick needles in my penis unless I need it. But there are others who are more daring. that leads us to this report.

Great study design (though there are limitations) and amazing they got volunteers. There has always been discussions of cultural differences in pain perception. I’d think you’d be hard presses (hopefully not too hard, that might hurt as well) to get 18 American guys to volunteer unless they were well compensated. Even then I wouldn’t let anyone wave multiple needles around my penis, especially not on more than one day.

There are interesting results that they found in this study.

First, I know you’re going to say that the pressure inside the cavernosa (which they called ICP) was only 90.6 (plus or minus) 10.7 cm H2O (about 66 mm Hg). They used a 28 gauge needle to poke the tunica (ouch!). The dampening effect of this very small gauge needle would abolish the high and low pulsations to the effects of the beating heart (systolic and diastolic pressures), so all they would see is a mean pressure. Their diagram shows this to be the case Their 66 mm Hg pressure at max filling correlates with the mean pressure seen in the arteries of the rest of the body, so this pressure is the point where no further blood enters (because in inlet and cavernosa chamber pressures are equal).

What is interesting is that when the Ischiocavernosus muscle relaxed, the ICP was 86.3 (plus or minus) 8.6 cm H2O. The plus or minus difference that they report is standard deviation. If you have a working understanding of statistics, you will see that there is no statistical difference between the ICP at the point they call maximum filling and the ICP when the Ischiocavernosus muscles were relaxed. They do not report this (interesting). Is there a change in cavernosa volume at these 2 different times? Don’t know. they didn’t measure it. Does new blood come into the penis? It is interesting that they had a needle in the penis and they didn’t draw off any blood to send to look at the oxygen pressure (partial pressure of oxygen or PO2) in the cavernosa and compare it to a PO2 of blood taken from an artery in the wrist. This would have allowed them to say whether or not new blood with oxygen was bathing the inside of the cavernosa.

Their study is also limited because they do not take any measurements which would tell us about whether there was any blood flow out of the penis. A pressure in the cavernosa equaling mean arterial pressure presses on the veins that drain the cavernosa because the walls of the distended blood pools in the erect cavernosa pinch these draining veins (called the emissary veins) shut. So is there any blood in or blood out in their study? Don’t know.

I bring up these questions because older studies differ from this one. The authors write this hypothesis for there study:

Quote
“We hypothesized that cavernosus muscle contraction during the rigid erectile phase is reflexogenic, although the 2 cavernosus muscles are striated. This hypothesis was investigated in the current study”


Their study design allowed them to prove their hypothesis. Nice job.

However, you notice they did not hypothesize that the reflex contractions of the Ischiocavernosus (and Bulbocavernosus) muscles cause a rhythmic changes in pressure leading to blood exchange in the cavernosa and normal levels of oxygen.

I’d be willing to bet they tried when they first submitted this manuscript but the journal reviewers corrected their error. Having been both a writer and reviewer, I know what I can try to get away with as a writer and what I won’t let an author get away with as a reviewer.

Why is this important? They did not design their experiment to answer this extension of the hypothesis that they actually presented. They did not design their study to answer this hypothesis. They did not make measurements to prove this (and disprove older studies). Don’t get me wrong, this is a great study and I applaud the authors and particularly the volunteers for this investigation. But there are limitations

You can say just about anything in a discussion section (within reasons). I think that their suggestions that this may be a mechanism to keep the cavernosa tissues happy during rigid erection is definitely worth investigating and if true, it would change the mainstream urological and physiologic understanding of the penis at peak erection. I think they should proceed to study this further .

It is also interesting that since this was published in Sept/Oct 2006, this article has not been cited by any other articles or textbooks written since then (Web of Science - Science Citation Index; which is up to date to within 2 weeks of today). Unfortunately it may reflect a chauvinism of scientists particularly in the USA) to the work of others outside their country or to who they consider practice inferior science. Unfortunately this is a very common problem in medical research. I think it stinks and I try not to practice it myself. I think that science can be good where ever you do it and whatever language you speak.

mravg, thank you for finding this report. I think it elevates the discussion.

Originally Posted by mravg
Pudendum, in our discussion of your balloon model, and my tank model, I now think neither one is correct.
As you pointed out, the hose connected to my tank represents the arterial inflow at normal arterial pressure. Since the tank (CC) pressure is higher than this hose (arterial) pressure, this hose can not fill the tank.
The balloon model is also wrong because it doesn’t allow for inflow or outflow, which we know happens.


You’ll see in my evaluation of the study that you presented, that it does not prove or disprove whether blood enters or leaves the cavernosa at peak erection. I still am not convinced. We may end up agreeing to disagree on this point. The data just aren’t there to definitely prove or disprove either of our contentions.

Originally Posted by mravg
However, I think we can modify the tank model to be accurate if we add a linear peristaltic pump between the hose and the tank entrance, which is used as a “second stage” pump to pump at higher pressure. That is how I view the ICM intermittant contractions; a secondary pump that keeps the penis pumped up at higher pressures than the normal arterial pressure.

I think I am coming to a more clear picture of how vacuum pumping and clamping work differently, which I will post later.


Interesting thought. However, I don’t believe your model stands up for this reason. You are proposing a secondary pumping action in the inlet line (that being the arteries that feed the cavernosa). At peak erection, when cavernosa and arterial pressures become equal (the valve is now off), the Ischicavenosus muscles compress the cavernosa, not the arteries that feed it.

A more appropriate model would be to put a compressing mess over 1/3 to 1/2 of the tank and begin to compress it after turning off the valve. My alternative surmises that the compressing mesh can affect a change in the tank wall and transmit it to the fluid within (kinetic energy not just potential energy).

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