I’ve continued to read and consider the information at hand. In the scientific text it is stated that cellular damage can “begin” to be seen, under an electron microscope, at strains of 2.5%.
Also, the threshold of 5.14% is called the yield point. The fact that it is called the yield point, and that cellular damage can be seen at lower levels of strain made gave me reason to believe that permanent gains may be made at less than 5.14%. So, I continued to look for more information about the “plastic range”.
When a material reaches its yield point it begins to yield to the force and give to it slightly easier. Yes, permanent elongation does occur at this point, probably all of the elongation becomes permanent here. I did mention that no one should strive for an elongation of 5.14% in one session as other much damage could result.
I presumed that adding at least 5.14% to your BPFSL over many days should be the point at which gains become permanent. I still believe that this is likely to be true.
Still, the routines of successful PE’ers vary, as we know. I began to believe that that a lower strain than 5.14% could be identified as the threshold for entering the plastic range. Also, I believe that this lower strain could be a goal for us to strive for within one PE session, or day of PE (including ADS’ing, or am & pm sessions).
So, I continued to search for more information. Luckily, I have found some.
Here, in this first quote, we see evidence that stretching of the connective tissues needs to go beyond the elastic range, and into the plastic range.
The physiologic loading region of the stress-strain curve shown in Figure 5 represents the range of forces that usually act on CT in vivo and implies that primarily elastic deformation occurs at these loads. The region of microfailure overlaps the end of the physiologic loading zone. Microfailure represents the breakage of the individual collagen fibers and fiber bundles that are placed under the greatest tension during progressive deformation. The remaining intact fibers and bundles that may have not been directly aligned with the force or those that had more intrinsic length absorb a greater proportion of the load. The result is progressive, permanent (plastic) deformation of the CT structure. If the force is released, the broken fibers will not contribute to the recoil of the tissue. A new length of the CT structure is established that reflects the balance between the elastic recoil of the remaining intact collagen and the resistance of the intrinsic tissue water and glycosaminoglycans to compression. Microfailure is a desired outcome of some manual stretching techniques that are intended to produce permanent elongation of CT structures. It is important to note that a low level of CT damage must occur in order to produce permanent elongation. The collagen breakage will be followed by a classical cycle of tissue inflammation, repair, and remodeling that should be therapeutically managed in order to maintain the desired tissue elongation. The use of modalities, compression, elevation, and directed—but limited—application of force may improve the final results through modulation of the inflammatory cycle.
OK, now that we see that the plastic range needs to be entered, lets find out what amount of strain is required to enter the plastic range.
The mechanical behavior of ligaments and tendons can be considered to be representative of idealized periarticular CT placed under loading. The ultimate strengths of other common CT structures are listed in the Table. The ultimate strength of spinal ligaments has been less systematically studied. Panjabi and White indicate that the ultimate strength of spinal ligaments ranges from 35 to 450 N. Within a region of the spine, the strongest ligament is generally the anterior longitudinal ligament and the weakest ligament is the interspinous ligament, with the strength of the capsular ligaments, the posterior longitudinal ligament, and the ligamentum flavum falling in between estimated that macrofailure of CT occurs at approximately 8% elongation of the CT structure but that microfailure begins at approximately 3% elongation. If I make the simplifying assumption that the stress-strain curve is linear and use the elongation estimates of Noyes and colleagues for microfailure and macrofailure, CT would begin to experience microfailure at around 224 to 1,136 N (24-115 kg). This gross approximation of the load necessary to cause microfailure (some permanent elongation) can be used to make some educated guesses about how effective the typical forces encountered in manual therapy will be in stretching CT.
The important information here is that “microfailure begins at approximately 3% elongation”.
I will also display a graph that shows microfailure occurring at 3%. I did not create this graph. I found it on the Internet with information about plastic deformation of ligaments/tendons.
Finally, this is both an update and a clarification to this thread. My hypothesis is that we should aim for a strain (additional stretch in BPFSL) of about 3% in one day. Also, that increasing your BPFSL by just over 5%, over the course of several PE days, should make the gains permanent. I believe that in order to cement gains, it is likely that they have to be sufficient enough gains, such as an increase of 5% or more. If this is the case, dragging out extra days of PE may not be what causes the cementing.
Again, this is all just theory, but it is derived from scientific research about connective tissue, which I believe is the ultimate limiting factor in developing a larger penis.
It is certainly open for debate.