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# Girth theory: Pumping vs. clamping

Originally Posted by mravg
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.

Thank you. We are in agreement. Though others dispute this. To make sure that everyone else understands, we are talking about making the pressure in a pumping tube positive not negative. This does not necessarily apply to clamping where the areas away from the clamp will distend.

Originally Posted by mravg

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.

Thank you again. We are in agreement. However the degree of the pressure equalization depends upon the compliance of the vessel we’re sucking on. I can guaranty that at peak erection, the cavernosa pressure dose not become 50 mm Hg if a -150 mm Hg force is applied with a pump..

Originally Posted by mravg
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.

Thank you again. We are in agreement.

Originally Posted by mravg
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.

And I agree totally with this.

Originally Posted by mravg
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.

We may disagree whether a linear peristaltic pump or a mesh should be used to simulate the system, however I agree with you here.

The extent of the wall tension and response to drawing a negative pressure over the penis will definitely be controlled by the wall elasticity (or distensibility or compliance).

To complete my understanding and application of your system, I envision peak erection (because this is a quasi-stable situation). At this point the tunica is stiff. However the applied negative pressure can more than likely affect a volume-induced tension to cause connective tissue remodeling and increased girth. So even at this very stiff point, I can envision enough distortion to make growth possible

I think we are very close to a meeting of the minds.

Originally Posted by sparkyx
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.

Good question, (I know that really helps).

The tension-induced connective tissue model that I presented (Possible reason for PE induced growth) does tend to agree with your statement regarding further stress beyond max (say the tunica at peak erection, AGAIN) may cause strengthening, not lengthening. A tendon pulled maximally with muscle contraction (muscle loading) shows a predominant increase in collagen fiber diameter making the tendon stronger, not necessarily longer. This keeps it from being ripped from where it inserts into bone.

This may be the analogous situation of attempting to stretch the tunica at peak erection.

The situation appears to be different when a tendon or ligament is stretched when it is not loaded (the muscle is not contracted in the case of the tendon). We know that ligament and tendon stretch and elongation does occur. Stretching is an important part of overall health. Actual collagen fiber (and other fiber) length increases. This is what gives us flexibility.

I think your hypothesis is a good one. This expands (or erects) our understanding beyond the static and very specific case of the peak erect tunica (which I think I have a better handle on now; talc always helps) to a more complex discussion of the effects of PE on a constantly changing penis at different stages of erection and therefore different tunica compliances or levels of loading.

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.

The difference between peek erection and the expansion achieved in the tube is that in the last case the dick is open to the circulation, while - as pudendum described so well, in the case of peak erection the dick is closed by (intermittent => see mrvag’s comment and link) muscular activity.

Later - ttt

During peak erection, do the capillaries have a another way in? As in do they get blood from a different route than the CC?

All capillaries get their blood from the arteries, just as the corpora cavernosa do.

Later - ttt

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.

That is indeed an important comment I was not aware of. Since I have two tubes, which I am using on different days (the smaller one for length, the bigger for girth) I want to give it a try soon.

Thanks for the suggestion.

Later - ttt

Mravg,

I was just going to add that all day compression (ADC?) also proves this theory. I have had a quest to stay “plump” before and after a workout (or just because I like it) and have had varying success. But I know if I spent say 2 to 3 hours in a type of ADC, my clamping or pumping session starts like I have already done a few sets. Thus even a minor stress on the Tunica over a period of time provides for easier expansion. Now add in any negative PI’s and the expansion is not there.

If you practice adc some of the expansion is fluid accumulation under the skin (that’s what I experience), some is tunica expansion. What I like most is the expansion of my glans from adc. It apparently has a quite different dynamic compliance than the tunica.

Later - ttt

Originally Posted by Mr. Happy
This makes sense to me and squares with my experience.

So, what do we think therefore of low force with no erection going into the tube?

Probably no big difference:

If you start unerected the blood will be pulled in until there is pressure equilibrium. If you get in erected the vessels open toward the body and again, blood is shifted until pressure equilibrium.

Later - ttt

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/content/full/27/5/695#SEC2

Considering your lack of interest in penis physiology I would like to compliment you about digging out a very interesting paper with high relevance to our topic.

Btw - I found it fascinating that voluntary contraction of the same muscles does not increase cavernous pressure. Penis physiology IS fascinating, after all - mravg?

Later - ttt

Originally Posted by pudendum
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 think the paper quoted by mrvag says it all: invasive measurement, and yes, due to muscular activity (only involuntary!) cavernous pressure rises above arterial pressure.

And: this effect is intermittent, has to be intermittent, in order to protect the intracavernous structures from ischemic damage.

Later - ttt

Originally Posted by ticktickticker
I think the paper quoted by mrvag says it all: invasive measurement, and yes, due to muscular activity (only involuntary!) cavernous pressure rises above arterial pressure.

And: this effect is intermittent, has to be intermittent, in order to protect the intracavernous structures from ischemic damage.

tt - Invasive measurement is important and this study showed very good design for the hypothesis they asked.

Remember what you said about experts. You must be able to differentiate what they confirmed by their results and what they propose in their discussion. I know this is a fine point, but it is an important one as well.

They show that cavernosa pressure is not always elevated above arterial pressure (supra-arterial as they called it) throughout the peak erection phase with intermittent changes associated with Ischiocavernosus and Bulbocavernosus muscle contraction. This definitely bucks the mainstream thought here. Their data are good. I would have loved to see a trace of the time course of pressure fall off when these muscles relaxed as they nicely showed with pressure rise (call me a skeptic).

This study was preformed in awake individuals with drug induced erection (could you imagine trying to get a spontaneous erection wired up the way they were?). A very important prior study, which they do not quote, was published in the journal Science in 1983. It looked at volunteers at night with spontaneous nocturnal penile tumescence (which we know as “night wood”). These authors chose to study this type of erection because it is spontaneous, normal and reliably repeatable (at least that what PI’s tell us). The authors measured Ischio- and Bulbocavernosa muscle activity (on the skin, not with needles), blood flow with an external monitor around the penis (a validated method), and penis circumference at the base and below the glans. (Note: They too did not look at blood flow in the veins leaving the cavernosa).

This older study also found intermittent contractions of the Ischio- and Bulbocavernosus muscles. But, they found them during the filling phase of the erection (which the present study did not see). They also saw that these contractions were the longest and the strongest at maximum circumference (peak erection). When these contractions abruptly went away, erection starts to soften and go away.

They concluded:

Quote
“The picture suggested by our data is this: Changes in penile blood flow always precede changes in penile circumference. Continuous increased blood flow is the primary determinant of penile expansion and rigidity during erection. Delicate fine-tuning mechanisms, signaled by the oscillations in blood flow during full erection, modulate blood flow to keep the cavernous bodies maximally filled. The mechanisms sometimes involve the bulbocavernosus and ischiocavernosus muscles, which are called into action when pumping of the blood is needed to supplement the flow. Both the vascular system and [these muscles] may have feedback connections [through the nervous system] with cavernosa smooth muscle [in the walls around the blood pools or sinusoids] and maybe the final necessary condition for achievement and maintenance of maximum penile rigidity.”

Karacan I, et al. Erectile mechanism in man. Science 220 (1983) 1080-2.

Note their conclusion is totally different than from the present study. It is more in line with what they measured and studied.

Is there a difference between a spontaneous night erection and one induced by a drug injected into the cavernosa while the penis is wired for sound? Ahh, let me think about that a second…Dah, do you think maybe!. All of the above the shoulder influences (either when awake or asleep) in the erection process are important. Do you think that maybe the guys with needles in there penises were a little distracted and that having an erection was the last thing on their mind? Do the differences in the contraction patterns of these muscle in these two studies differ because of this? I think it it more than likely and might influence pressure measurement results as well. Again, call me a skeptic, but that’s what I am.

However, I agree that absence of pressure rise with kegels is very surprising and may turn our idea that this brings more blood into the erectile chambers on its ear. It is possible that there are volume changes without pressure changes as the penis becomes more erect, but this cannot be the case with peak erection. This the real hot news for us here and we need to reevaluate our methods in light of this.

Originally Posted by sparkyx
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.

I’ve been thinking about this a lot since I first read this. I think that Sparkyx is on to a very important point here. In fact, I think this concept might be so important as to take us further down the road towards the Holy Grail of PE: why and how do we grow.

Yes Sparkyx, wall tension is everything. As I noted in the thread on the connective tissue mechanisms of connective tissue remodeling (Possible reason for PE induced growth), tension is the most important stimulus. The question we all ask is: what type of tension and how intense?

Tension is tension, no matter the cause. But how this tension is generated and when is important.

There is a very important and simple principle known as LaPlaces’s Law that describe wall tension (which tunica stretch is).

OH NO, not another scientific explanation!!! Please bear with me, this is actually simple and important. I’ll make it simple.

If you have a tube (like the cavernosa) with a radius, r, with a wall (like the tunica) with a thickness, M, with an internal pressure, P, then you can describe the tension on the wall (the tunica), T, by the following equation:

T = P * r/M. [Tension on the tunica = (radius of the cavernosa X cavernosa pressure)/tunica thickness]

Let’s assume that tunica thickness does not change, so M is constant (it may not be but for giggles and grins, let’s assume it is). Therefore, tension increases by increased pressure, radius or both.

Sparkyx comments on stretch when the tunica is stiff versus when the tunica is flexible is explained well using this law.

When the tunica is tight, at peak erection, the radius change is very small. Depending upon the method you use, clamping, bending or pumping, the change in pressure is variable. In this case, the tension is bumping up against a tunica that just can’t stretch much more. The tunica does not “want’ to rupture with these kinds of stresses in the future, so the tension-induced stretch (like in the case of the muscle loaded tendon stretch) causes a connective tissue remodeling which increases collagen fiber diameter and not length. The tunica therefore becomes stronger and resists stretch even more.

When the tunica is flexible in the semi erect penis when you jelq, pressure and radius both increase in the power stroke of the jelq. This stretch in a more lax state of the tunica is like the unloaded (muscle relaxed) stretch of tendons and ligaments for flexibility. This could lead to the elongation of circular tunica fibers and cause girth expansion. This is tension generated against a flexible and movable tunica, which is why I think jelqing is so effective.

I would think pumping’s effect in the semi erect penis would be almost entirely through increases in radius, as pressure in the tunica may either stay the same or even drop because of the negative pressure effect on the cavernosa of an incomplete erection.

So PE work on a loaded or unloaded tunica is entirely different and may have a different result. I think this is very important and we need to think about this.

Thank you Sparkyx.

Originally Posted by pudendum
OH NO, not another scientific explanation!!! Please bear with me, this is actually simple and important. I’ll make it simple.

Scientific is fine; simple is fine too. Sensible has to be ubiquitous.

Originally Posted by pudendum
So PE work on a loaded or unloaded tunica is entirely different and may have a different result. I think this is very important and we need to think about this.

Fair enough. I agree with your ultimate idea.

I just have trouble with this:

Originally Posted by pudendum
If you have a tube (like the cavernosa) with a radius, r, with a wall (like the tunica) with a thickness, M, with an internal pressure, P, then you can describe the tension on the wall (the tunica), T, by the following equation:

T = P * r/M. [Tension on the tunica = (radius of the cavernosa X cavernosa pressure)/tunica thickness]

Let’s assume that tunica thickness does not change, so M is constant (it may not be but for giggles and grins, let’s assume it is). Therefore, tension increases by increased pressure, radius or both.

Perhaps I’m nit-picking, but I find this suspect. It may be too simple.

It seems to assume all things are equal (if it doesn’t make that assumption perhaps you could further elaborate). To my way of thinking they aren’t; a wall of steel is different than a wall of clay, as a rule. You would need very different thicknesses of these two materials to have your equation work.

Granted with human physiology there are limited variables, but those variables have to be expressed in a range. My bone density would likely not be identical to a 18-year-old’s or a 70-year-old’s, for example. I would guess there were some variation with each individual tunica as well, which would account for the variations of success or failure to gain from one or the other (or even any) method.

I basically agree that a semi-erect state is where the penis has the best chance of being ‘molded’ and influenced by force. Too much force means shock and recoil and, as you pointed out, and toughening of collagen fibers.

I think I also missed you point about the low level erection pumping. Are you saying the efficacy is made greater or lessened by the more uniform pressure the pump exerts?

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 Mr. Happy
Scientific is fine; simple is fine too. Sensible has to be ubiquitous.

Fair enough. I agree with your ultimate idea.

I just have trouble with this:

Perhaps I’m nit-picking, but I find this suspect. It may be too simple.

It seems to assume all things are equal (if it doesn’t make that assumption perhaps you could further elaborate). To my way of thinking they aren’t; a wall of steel is different than a wall of clay, as a rule. You would need very different thicknesses of these two materials to have your equation work.

Granted with human physiology there are limited variables, but those variables have to be expressed in a range. My bone density would likely not be identical to a 18-year-old’s or a 70-year-old’s, for example. I would guess there were some variation with each individual tunica as well, which would account for the variations of success or failure to gain from one or the other (or even any) method.

I basically agree that a semi-erect state is where the penis has the best chance of being ‘molded’ and influenced by force. Too much force means shock and recoil and, as you pointed out, and toughening of collagen fibers.

I think I also missed you point about the low level erection pumping. Are you saying the efficacy is made greater or lessened by the more uniform pressure the pump exerts?

It is a simple principle. Sometimes the simplest explanation is the best.

It has been used to explain many things in the body. It is an important concept to understanding the stretching of blood vessels when blood volume increases as when you eat too much salt. The vessels (particularly small vessels) distend by pressure, increasing the vessel radius which results in elevated vessel wall tension. Over a short period of time, the smooth muscle of the vessel wall relaxes to relieve the tension. The tension is relieved and pressure is decreased at a larger vessel radius. This is the stress-relaxation process that keeps blood pressure stable over the short term (See Arthur C. Guyton’s Textbook of Medical Physiology).

With the tunica it takes us back to the compliance of the tunica at different phases of erection.

I think the effect of pumping is due to the tension increase by the increased volume in the cavernosa at a lower level of erection that increases cavernosa radius and increasing tunica tension at a higher compliance (more distensible), which equals unloaded stretch.

I think long sustained pumping with a uniformed pressure is the key. You’re holding the wall tension high at an increased radius and stimulating connective tissue lengthening (in the circular fibers of the tunica, lengthening = increased girth).

Last edited by Mr. Happy : 01-05-2008 at . Reason: You're for Your

Originally Posted by pudendum

Is there a difference between a spontaneous night erection and one induced by a drug injected into the cavernosa while the penis is wired for sound? Ahh, let me think about that a second…Dah, do you think maybe!. All of the above the shoulder influences (either when awake or asleep) in the erection process are important. Do you think that maybe the guys with needles in there penises were a little distracted and that having an erection was the last thing on their mind? Do the differences in the contraction patterns of these muscle in these two studies differ because of this? I think it it more than likely and might influence pressure measurement results as well. Again, call me a skeptic, but that’s what I am.

A few observations:

A number of us here at Thunders have commented that our firm, nocturnal erections are very often girthier than our conscious, sexual ones. They feel thicker in the hand; I’ve even gone so far as to measure a few of them in the night and came up with about .25 inch more girth than my measured daytime erections. Also, it’s been noted by others that an eighty or ninety percent conscious erection is often fatter than a totally firm erection.

In the case of nocturnal erections it seems logical that the parasympathic nervous system, which is definitely pro-erection in one of its functions and takes over while we are unconscious, allows for some unusual outward deformation of the tunica than does the sympathetic nervous system. In the case of a conscious erection at, say, 80 percent, the tunica is clearly less rigid and so jelking and modified Ulis are more PE-productive than when we become yet more erect.

The implication here is that my tunica, and maybe yours, is capable right now of expanding to hold more cavernosal volume than it usually does when I have a firm erection.

Trick is, 1) how to get that 1/4th inch, or whatever, all the time :) and 2) how to get the tunica to relax yet further to make girth increase easier. OR, to cause the tunica sheath to grow wider and longer.

_______________

avocet8

Originally Posted by pudendum
I think long sustained pumping with a uniformed pressure is the key. You’re holding the wall tension high at an increased radius and stimulating connective tissue lengthening (in the circular fibers of the tunica, lengthening = increased girth).

I totally agree here—this makes perfect sense.

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