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Girth theory: Pumping vs. clamping

Originally Posted by pudendum
Turn the tables. If instead of using negative pressure in the pump, let say you apply a positive pressure of 6 in Hg (say you have the ability to seal it). If negative pressure is added to cavernosa pressure, than positive pressure must be subtracted. Can you imagine that by adding positive pressure outside the penis that cavernosa pressure would decrease? I can’t.

As in my example of the fluid filled balloon exposed to a negative pressure. The balloon with the fluid will expand and in so doing decrease the pressure of the fluid within. The opposite would occur with positive pressure. Is the cavernosa of the penis different, no matter how small the pressure change might be because of the stiff tunica at peak erection? I don’t think so.

If you add the negative pressure to pressure within the erectile chambers, then instead of inflating a flaccid penis, it would push the blood out. It would have never been a medically approved method for impotence (before Viagra and the other phosphodiesterase-5 inhibitors) if this was the case.

So which way is it? It can’t be both ways. Help me to understand this here.

Pudendum - thanks for the new perspective. I like looking at things from a different angle. I will think about that and answer after a good night’s sleep.


Later - ttt

I too am a little confounded by the idea that an erection means the absolute cessation of any and all in-flow and out-flow.

Isn’t it just a differential, that the outflow is dramatically lessened? Surely there must be an exchange of some level or the penis would go cold.


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 pudendum

It can’t be both ways. Help me to understand this here.

Interesting discussion.

Let me throw in some ideas to help you visualize what happens with pumping and clamping.

First, picture 2 different extremes of cylindrical tubes: One is a metal pipe, the other is a condom. The penis is somewhere in between, in terms of tendency to deform under changes in pressure.

Now, you need to understand the difference between GAUGE pressure and ABSOLUTE pressure.

Put a pressure gauge on the open metal pipe and it will read Zero (psi, mm hg, inches hg or whatever units you want to use.)

However, the pressure in the open pipe is the same as atmospheric pressure, about 14.7 psi or 760 mm hg, or 30 inches hg.

I like to think in terms of psi because it tells you the force applied per unit area (pounds per square inch), but it doesn’t really matter. In engineering we would say the pressure in the open pipe is 0 psig or 14.7 psia (gauge vs. absolute pressure).

Let’s stick with the pipe because it doesn’t change shape so things are easier to visualize.

You talked about reducing pressure outside the pipe, like in vacuum pumping, and if the pressure drop “gets through” to the tunica.

Imagine pumping 200mm Hg into the metal pipe and sealing it off. So the pressure inside the pipe is 200 mm greater than the pressure on the outside wall of the pipe, which is the atmospheric pressure pushing in. So there is a net force pushing outward on the pipe wall.

If you drop the atmospheric pressure around the pipe, by 6 inches Hg which is about 150 mm Hg, (from 760 mm Hg to 610 mm Hg) then the pressure in the pipe does not change!

However, the outward force on the pipe wall has increased from 200 mm Hg to 350 mm Hg.

The thing you need to understand here, is that the gauge pressure will measure the pressure in the pipe without considering the atmospheric pressure. There is atmospheric pressure on our bodies all the time, and it is balanced by the internal pressure in our bodies. We consider that we are not actually under pressure right now, but we are, it is just all balanced.

So the vacuum cylinder creates lower surrounding pressure, so changes the internal/external balance. The result is more force outward, because you have less force pushing inward.

Let’s call that chapter one because this is getting too wordy.


Horny Bastard

A simple way to look at this idea is to imagine an empty aluminum beer can. If you suck the air out of it, the walls collapse. People envision that some “sucking force” is actually pulling the walls inward, but that is incorrect. The atmospheric pressure is crushing the can from the outside! The atmospheric pressure isn’t increasing, it is just not balanced by an internal pressure of atmospheric gas pushing outward to resist.

It’s the same thing with a vacuum cylinder. The force on the tunica can increase without the pressure inside the penis increasing.


Horny Bastard

Hurray!
mravg!
:clap:

I like it when you post. I usually understand everything you say first time through.


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 (:

Thanks man!

I was going to get to your comment below next:

Originally Posted by Mr. Happy

I too am a little confounded by the idea that an erection means the absolute cessation of any and all in-flow and out-flow.

Isn’t it just a differential, that the outflow is dramatically lessened? Surely there must be an exchange of some level or the penis would go cold.

You are right. It is just the differential. Like if you turn on your water hose but the end is blocked off, the hose gets full and rigid. If you poke a nail through the hose, water is leaking out but the hose stays rigid because the pressure coming in is maintained. I was going to look up “high flow priapism” which I don’t understand very well, but it is an example of what you are talking about.


Horny Bastard

:up:


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 (:

tickler,
I believe that it’s not the Bib hanger that causes the base girth, it’s more or less the “tree roots” syndrome. I was not a hanger, but my base girth increased even more than my overall girth. I think that was because of all the vigorous pulling I did.

It seems like some of the “inner penis” gets pulled out. Furthermore, the hairline on my shaft also climbed noticeably (this might further suggest what I just mentioned).

I read through the entire thread and I wanted add to some of the topics brought up in this thread.

Gains under the clamp - I think this has been explained in great detail in the past and it is mainly due to the additional stress right next to the clamp. It was theorized that it may be beneficial to create a set of clamps that placed pressure every .25 inch. I actually built one by gluing several clamps together - remove the ratchet part of the clamp on every other clamp. It was very uncomfortable, but you can clamp at a lower level erection and get the same pressure.

Pressure generated by the clamp vs pump.

I think this is an interesting question. Can it be tested scientifically or by the group here?

I also think that several of the guys that are very experienced at both clamping and pumping could give a relatively good guess. My experience would guess that clamping is a much higher level of pressure than most people pump. I have to say to get any pressure similar to a clamp you have to be over 10 hg closer to 15hg. I know one member here said that after clamping they considered pumping a low level exercise.

Originally Posted by mravg
However, the outward force on the pipe wall has increased from 200 mm Hg to 350 mm Hg.

The thing you need to understand here, is that the gauge pressure will measure the pressure in the pipe without considering the atmospheric pressure. There is atmospheric pressure on our bodies all the time, and it is balanced by the internal pressure in our bodies. We consider that we are not actually under pressure right now, but we are, it is just all balanced.

So the vacuum cylinder creates lower surrounding pressure, so changes the internal/external balance. The result is more force outward, because you have less force pushing inward.

Let’s call that chapter one because this is getting too wordy.


I agree. I have a few points to add.

Most people disregard the concept that you so aptly present. In essence a blood pressure of 120/80 mm Hg is with respect to atmospheric pressure, which is considered to be zero. In reality blood pressure is 880/840 mm Hg (varying with weather and altitude).

The effects of the outward forces generated by pumping that you describe (200 to 350 mm Hg) depends upon the wall of the vessel through which this pressure gradient is “transmitted”. For you example of a pipe, the compliance is zero (or as close to zero as to be negligible). This decrease in external compressing force (below atmospheric) is against an immovable wall. This gradient does not effect a result. Why?

Movement of anything, let’s say water in a pipe, is from areas of high pressure to low pressure. A boulder rolls down hill, not up. This movement decreases the energy of the water as it flows away from its high pressure source. This energy of movement is called kinetic energy.

Let say that the movement from this high energy source (let’s say water in a water tower) is stopped. The energy (in this case a high pressure source) is still there, but it is not relieved. This energy (pressure here) has the potential to flow or move. This energy is known as potential energy.

Returning to your pipe example, there is an increased pressure gradient across the pipe wall as you lower the outside pressure, but there is no relief of this increase because the wall does not distort. (For example there is a lot of potential energy in the water behind a dam.) Therefore the potential energy against the wall of the pipe may be increased over the potential energy when the pressure outside was atmospheric. But the pipe says, “big deal.”

My balloon example is different. The outside pressure drop below atmospheric causes the elastic wall of the balloon to distort and stretch to relieve the potential energy change. What is happening is that the potential energy change (with the increased pressure gradient) in this case is converted to kinetic energy moving the walls of the balloon to attempt to alleviate the pressure change.

The difference in these two situations is the wall of the vessel in the system. The key point is the ability to distend the vessel wall. This is the concept of compliance. The balloon has a very high compliance, the pipe has a compliance of zero.

Again, taking the very isolated situation of the peak erection with Ischiocavernosus muscle contraction with a very rock hard tunica, its compliance is very low, much more like the pipe than the balloon. Therefore the pressure gradient established by the negative pressure generated by the pump represents potential energy. The very stiff, bilayered tunica doesn’t move very much, so kinetic energy is low.

I agreed with Sparxx that this may be just enough to affect some increase wall stress required for tension-induced connective tissue remodeling to explain the successes seen with pumping.

Originally Posted by SteadyGains
My experience would guess that clamping is a much higher level of pressure than most people pump. I have to say to get any pressure similar to a clamp you have to be over 10 hg closer to 15hg. I know one member here said that after clamping they considered pumping a low level exercise.


I’d agree to that.

I think that there is a general idea that higher pressure = greater efficacy and I, for one, am not convinced that this is true. But I also think it has to do with what we mean by effective. Does it mean gaining quickly?

I’m not sure that is unilaterally true.

I would look at safety, and how a practice contributes to the overall health of the organ as well, not simply gains.


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

A simple way to look at this idea is to imagine an empty aluminum beer can. If you suck the air out of it, the walls collapse. People envision that some “sucking force” is actually pulling the walls inward, but that is incorrect. The atmospheric pressure is crushing the can from the outside! The atmospheric pressure isn’t increasing, it is just not balanced by an internal pressure of atmospheric gas pushing outward to resist.

It’s the same thing with a vacuum cylinder. The force on the tunica can increase without the pressure inside the penis increasing.

I agree this is definitely an effect with air. Gases are very compressible. If instead the can is filled with water, the effects would be different, because fluids are far less compressible.

Originally Posted by pudendum
I agree this is definitely an effect with air. Gases are very compressible. If instead the can is filled with water, the effects would be different, because fluids are far less compressible.

I was just about to propose that.

Assuming the penis is full of blood/fluid, then the effect pressure differential would be far, far less than in the case on an empty can.

Also, the empty can is an open system, not closed as would be the case with an unopened can to further illustrate the point.


06/21/07 NBP = 7.75(tape) FSL = 7.875 EG = 5.00 Volume= 15.42

09/13/07 NBP = 8.375 FSL = 8.75 EG = 5.38 Volume = 19.29 (+25%)

12/26/07 NBP = 8.625 FSL = 8.75 EG = 5.50 Volume = 20.82 (+35%)

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