"so when one applies force, even if the intent is for a linearly increasing manifestation then naturally there are too many factors and we have a convergence of curves, our convergence of potentials."
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convergence of curves = all of the inputs to the system in question are not linear inputs - so think of a muscle's range, its efficiency and power output vary at different stages of the motion, ergo, differing amounts of force at differing times of the motion would be required for the motion to manifest "linearly." so think of how to try to "curve a curve so that its straight"
back years ago when I brought my son to the children's science museum, there was a squid exhibit, and a little game to play where you set the various strengths of the squid's muscular force, then hit a button and it executed the input, and based on the overall coherence, it went however far. it took me a dozen tries or so to configure the muscular input so that the squid would go all the way to the other side - so I related that to breathing in that you have different strengths and different distances to cover...so by doing anapana breathwork and smoothing out the motion, making the motion more coherent, you are necessarily working on timings, and when the timings are most coherent then that is when the energetics of the breathwork are prime.
so to relate that to a stretch, we're involving partially the other physical structures that assist the body to move into the position to stretch the desired structure, and by making the movements good and coherent, one can more thoroughly focus the awareness on the structure being stretched. if 100% is failure/injury, then 70% is enough to get the stretch in without getting close to the point of failure. but when one is in very good health, stretching can be taken more closely to 100% without there being quite so much potential for injury.
there's a difference between 'good pain' and 'bad pain' - the bad being more strikingly acute, that's what we wish to avoid in stretching, yet still be able to stretch to a point where the muscle fibers are getting close to their maximal extent, but not so much that it begins compromising tendon and ligament - ligaments especially, for they heal much more slowly than muscle does.
Even in mildly complex systems, any outcome is the wrong thing to target, with the process being where the focus should be.