You raise good points, Dick Builder, I’ll try to answer as I can:
Originally Posted by Dick Builder
I fully understand the difference between static and dynamic tension and agree with your synopsis. However, in order to make my point, would you agree that when the woman in the article forced her knee slightly beyond its normal range of motion, for that five minute interval, do you think that the tissues relaxed entirely? Or, do you believe as I do that there was still some residual tension on the CT when she released the device? The reason I bring up this point is because I believe that when weight is reduced after achieving fatigue, when hanging, the tissues can relax a bit because the force was reduced, resulting in an equilibrium of sorts. In other words, there is no longer sufficient force to overcome the tissues elasticity, creating plastic deformation. The reduction in weight returns the tissues back into or below the elastic range. Granted, the force is not removed entirely. However, I don’t believe it is in the subject’s knee either. But, you are correct, it isn’t exactly static in nature.
I can’t know if, in the experiment we are speaking of, the CT was completely relaxed after 5 minutes; however, the goal of that kind of device was to reach the max relaxed state before stretching a bit more the tissue. According to principles we have seen explained in the studies I posted, the lower the load, and the slower the rate when applying that load, the faster visco-elastic adaptation; so, the CT elongate and the tension on it is reduced.
After a while, the tissue should be mantained at that length with a reduced tension (weight if you are hanging).
But it’s difficulty to reproduce this process with weigths.
The classic "step by step" procedure that hangers advocates is pretty different, to my eyes:
a) they start with, (just to say) 10 lbs, doing (again just to say) 4 sets. When "fatigue" is felt, the weight is reduced. What is this "fatigue"? Only hangers are speaking of that ( if you agree, we will deserve a specific anlasys of fatigue in the coming posts).
b) at this point the weight is reduced because, if don’t, you are not able to hang anymore.
This seems a way to reach microfailures, not viscoelastic deformation, doing cyclical loading with medium weights. It doesn’t seem the best way to reach visco-elastic adaptation.The load is fighting against, both, the elastic (shortening) reaction of CT and the inner strength of fibers (I hope it’s clear).
Hangers could do a better imitation of Static Progressive Stretching process, as I see things, starting with a really low load and sligthly augmenting this load after a given amount of time: if the elastic resistance that CT is opposing is reduced, the tissue can be elongated, safely (avoiding tears and scars), a bit more - and the load applied can be augmented safely as well. So, one is "walking" safely from the viscoelastic (temporary) adaptation to the microfailures region (permanent deformation).
I know it seems to counter-addict the "phylosophy" of SSP, but I don’t think the authors of that case-report are really explaining what happened in the tissue of patient, maybe they aren’t also understanding it; let’s re-read this (#40):
"Taylor et al.4 experimented with rabbit muscle/tendons and felt that the main response to stretch could be explained by viscoelastic properties alone, exclusive of reflex effects. They found that denervated muscles responded similarly to the innervated muscles in flexibility testing. Interestingly, they found that most of the stress relaxation took place within 12 to 18 seconds of stretch and there was insignificant relaxation afterwards. They also found that in static stretching, 80 percent of the stretch occurred after the first four stretches and stretching afterwards improved elongation very little. Of course we are dealing with rabbit tendons — are there any human volunteers in the audience?"
http://www.chir oweb.com/archiv … s/11/04/27.html
I think the authors of the case-study on SSP are excluding creep-elongation withou any reason; the SSP could just be a way to produce creep-elongation (visco-elastic adaptation) in short-term applying low-loads at slow rate, touching microtears-based elongation in the last 5 minutes. The goal of that authors, on the other hand, was not to explain deeply CT adaptation: they wanted to give empirical-scientific basis for an orthopedic device - it’s a mix of advertising and scientific experiment, if you get what I mean.
Originally Posted by Dick Builder
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However, this patient utilized the stress relaxation technique in five minute intervals in a thirty minute set, which is very similar to manual stretching and hanging. Besides, most articles that I have read that utilize the creep deformation you are talking about are dynamic in nature, utilizing a low load over a span of eight to twelve hours.
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A constant, low-load, applied in a continous way for many hour is the best way to reach creep deformation without micro-failures. We want this deformation because we want that most of the load wil be able to cause microfailures in the smarter way: the minimal amount of time and effort, the minimal scar-production, the minimal shortening reaction of collagenous tissue. So, I wrote of the 2-phase PE approach.
But, if one is in a hurry for gains, given that a low-load/slow-rate is the basic principle for best viscoelastic deformation, SSP is kind a "micro-version" of that 2-phase PE approach: in 25 minutes (but I think for TA the time should be slightly longer) you have most of the viscoelastic elongation, in the last 5 minutes you have a small amount of microfailures. Heating and cooling can enhance this approach. That’s it :) .