I have addressed this topic, but not at Thunder’s. Elasticity is caused by a substance called elastin - a very springy molecule, as one would expect. It causes the connective tissue matrix of your skin to recoil after it has stretched. Plasticity is the ability of the connective tissue matrix to undergo a permanent change, and involves changes to collagen, principally.
I floated a hypothesis several years ago: in order for collagen ‘damage’ to occur, one would have to load the elastin network until it had reached maximal extension (hanging is a perfect example of how to achieve this), but I have since backed off from this extreme view. I think that plasticity can occur under lighter loads, and not necessarily from damaging collagen at all.
The matrices of the penile fascia (Buck’s, tunicas, et cetera) are composed of, on average, 5% elastin. This allows the penis to have a passive recoil as the volume (not pressure) of blood in the corpora decreases. Guys with more elastin (like me, unfortunately), will have a more substantial recoil, leading to a smaller flaccid, whereas guys with less elastin have less passive recoil and stay fluffed. The smooth muscle layer under the skin and the smooth muscles within the corpus cavernosa also play a role in penile recoil, the former via temperature and stress cues, while the latter is under control of the erection chemicals (prostaglandins and NO) and other homeostatic cues.
Gee, thanks Mr. Wizard, but WTF does that mean for me?
A couple of things: if you have high elastin, stiff collagen, poor blood flow, and repressive homeostatic cues (as from high blood pressure)… you may be an difficult gainer or never gain at all. Whereas, if you have low elastin, non-oxidized collagen, arteries like garden hoses, and your vascular system is blissful… you are probably one of those smug bastards who can gain multiple inches per year.
Since we all want to be smug bastards, here are some suggestions: 1) if you smoke, eat charred meat or nitrate preserved meat… stop. These are pro-oxidants, and they are ruining your collagen (not to mention your health). 2) consume anti-oxidants (foods or pharmaceuticals), they can reverse some of the damage to your collagen. 3) if you have high blood pressure, get it fixed! 4) if you have small or atrophied penile arteries, work them out by bringing yourself to erection several times a day. Only increased blood flow, volume over time, will cause positive remodelling of arteries. 5) exercise the rest of your body, since your overall health has a huge bearing on your penile health. 6) if you have a higher than average amount of elastin (there is no way to really know, other than how springy your flaccid dick is), you can probably still gain. I have have gained and other ‘growers’ here have reported gains.
Hanging may ultimately prove to be the best method for overcoming elastin, but a dedicated P.E.er, using his hands and a progressively intense stretching and jelqing routine should be able to beat it into submission. Happy pulling!