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Physical Stress Theory
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Physical Stress Theory - June 3, 2004 5:22:00 AM
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Jon Newman
Posts: 1697
Joined: April 24, 2004
From: Amherst, WI
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I debated where to post this thread. I guess I am after people's opinions but hope for evidence to support those opinions where needed. This forum supposedly encourages that.
Anyway, I'm interested in your ideas regarding the following the following article:
Physical Therapy Volume 82 · Number 4 · April 2002
Tissue Adaptation to Physical Stress: A Proposed "Physical Stress Theory" to Guide Physical Therapist Practice, Education, and Research
Michael J Mueller and Katrina S Maluf
Here is the basic premise:
Fundamental Principle A—Changes in the relative level of physical stress cause a predictable response in all biological tissues. Physical stress is the force, or load, acting on a given area of tissue.
Fundamental Principle B—Biological tissues exhibit 5 characteristic responses to physical stress. Each response is predicted to occur within a defined range along a continuum of stress levels. The 5 qualitative responses to physical stress are decreased stress tolerance (eg, atrophy), maintenance, increased stress tolerance (eg, hypertrophy), injury, and death.
Fundamental Principle C—Physical stress levels that are lower than the maintenance range result in decreased tolerance of tissues to subsequent stresses.
Fundamental Principle D—Physical stress levels that are in the maintenance range result in no apparent tissue change.
Fundamental Principle E—Physical stress levels that exceed the maintenance range (ie, overload) result in increased tolerance of tissues to subsequent stresses.
Fundamental Principle F—Excessively high levels of physical stress result in tissue injury.
Fundamental Principle G—Extreme deviations from the maintenance stress range that exceed the adaptive capacity of tissue result in tissue death.
Fundamental Principle H—The level of exposure to physical stress is a composite value, defined by the magnitude, time, and direction of stress application.
Fundamental Principle I—Individual stresses combine in complex ways to contribute to the overall level of stress exposure.
Fundamental Principle J—Excessive physical stress that causes injury can occur through 1 or more of the following 3 mechanisms: (1) a high-magnitude stress applied for a brief duration, (2) a low-magnitude stress applied for a long duration, and (3) a moderate-magnitude stress applied to the tissue many times.
Fundamental Principle K—Regardless of the mechanism of injury, inflammation occurs immediately following tissue injury and renders the injured tissue less tolerant of stress than it was prior to injury.
Fundamental Principle L—The stress thresholds required to achieve a given tissue response may vary among individuals depending on the presence or absence of several modulating variables.
Is this the unification theory to PT practice? Does this describe our practice at an elemental level adequately? Is there anything missing? Thoughts and opinions welcome, while kudos given to those providing evidence.
jon
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[URL=http://www.sonymusic.com/clips/selection/30/064887/064887_03_03_30.wav]Evidence[/URL]
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Re: Physical Stress Theory - June 3, 2004 6:48:00 AM
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Shill
Posts: 1056
Joined: February 13, 2003
From: Madison WI USA
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Jon,
This article is a great way to describe what we do, or at least what I feel we should do, that is to say how we should practice. It makes the most sense. There are those who will say "its too simple". I say "no it isnt." Not the most eloquent rebuttal, but I strongly feel that the article is the best way to bring together into logical thought processes, our treatment approaches. It deals with physical stressors. We are physical therapists. Our skill is needed to determine how that patient moves in ways that perpetuate abnormal stressors, and how to modify those movements to decrease the stress, allow for healing, than adding stress back to the tissue in an incremental fashion. I love it.(the article that is)
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Steve Hill PT
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Re: Physical Stress Theory - June 5, 2004 8:42:00 AM
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Barrett
Posts: 967
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From: Cuyahoga Falls, Ohio
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Jon,
I've read through the principles several times but fail to see how they might make me feel any better about the treatment I might employ or how they might unify the physical principles already well known about tissue modification. I will certainly admit that some of this is over my head.
I think Principle A is true of connective tissue but not nervous tissue. If I'm right, trying to sort out the patient's complaint of pain in light of the principles is a waste of time.
_____________________________
Barrett L. Dorko P.T.
http://barrettdorko.com
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Re: Physical Stress Theory - June 8, 2004 5:19:00 PM
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Jon Newman
Posts: 1697
Joined: April 24, 2004
From: Amherst, WI
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I sense that this post may be long, but I'll strive for brevity.
The principles that I posted were mostly intendend as an abstract. The full article does address a bit more and strives to be more comprehensive. I feel the theory is a general reflection of our profession (not of an individual within the profession). I had read this article when it first appeared and thought it to be an interesting if not accurate perspective. A re-read of it suprised me with some of the bits I missed that I often see being addressed on this site. While not offering anything new per se, it seemed to be a reasonable attempt to pull together the different aspects of PT into a "deliberately broad theroy". Following, I'll post some bits from the main article in an attempt to better summarize the article and to highlight points I found salient.
"The basic premise of the PST is that changes in the relative level of physical stress cause a predictable adaptive response in all biological tissue"
--The "predictable adaptive response" seems a bit over confident to me. What I interpret this to mean is that for a given tissue there will be a response to stress that may take on the shape of a normal distribution, such that at the extreme ends, the tissue health is poor. The area under the curve could be large or small for any given stressor/tissue combination. They go on to admit:
"Because of the complex interaction among variables, it is not yet possible to determine the absolute value of the thresholds for tissue adaptation proposed within this theory." And this..."In its current form, however, the PST does not define absolute thershold values for tissue adaptation and injury."
--I interpret that to mean that while the theory may be accurate it is not specifically clincially useful. Perhaps it has more didatic utility than anything else.
The following is where I found the theory an interesting reflection of how we (don't) practice PT.
"Psycosocial factors can have a profound influence on tissue adaptation, especially as related to tissue injury." They then give a cursory treatment of the subject and end with "Although we recognize that psychosocial factors can play an important role in a person's response to physical stress, this role is not developed extensively in this perspective. We encourage others to develop the psychosocial componenet of the PST."
Next,
"We predict that the fundamental principles outlined in the PST can be used to describe neural adaptations following central or peripheral nervous system injury, and we encourage others to investigate this prediction"
--I believe that certain nervous system adaptations have been predicted and references are given. However, our whole organism response to those specific tissue adaptations (any tissue adaption for that matter) may not be predictable. I beleive this is one of your points Barrett.
In one of the last sections, there is a slight departure from some theories of PT practice.
"In our view, appropriate treatment, therefore, does not always require accurate identification of the injured structure."
I feel that this perspective tries to integrate and acknowledge the different aspects of PT practice. However, it is schizophrenic in its message. It acknowledges that identifying specific tissue injury may not be that important (to treat pain) and then focues on tissue response to stress. It then notes that psychosocial/neural factors have a profound effect on tissue health but leaves that for others to figure out. Clearly, both are important.
I may expand on some of my thoughts but I'm still interested in what other's think. Thanks to those who responded.
jon
_____________________________
[URL=http://www.sonymusic.com/clips/selection/30/064887/064887_03_03_30.wav]Evidence[/URL]
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Re: Physical Stress Theory - June 9, 2004 3:02:00 AM
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Barrett
Posts: 967
Joined: July 28, 1999
From: Cuyahoga Falls, Ohio
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Jon,
That line; "In our view, appropriate treatment, therefore, does not always require accurate identification of the injured structure." reminded me that I had actually read the article when it first came out and was struck especially by this conclusion. I agree, and I think that imagining we can know which structure is injured is a conceit peculiar to orthopedics.
However, PTs often deal with problems that contain no injury and require instead that we attend to the processes that accompany painful response to movement. I don't think that the application of stress plays much of a role here.
_____________________________
Barrett L. Dorko P.T.
http://barrettdorko.com
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Re: Physical Stress Theory - June 9, 2004 5:23:00 AM
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Jon Newman
Posts: 1697
Joined: April 24, 2004
From: Amherst, WI
Status: offline
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Barrett, I agree. I think the theory helps teach how modifying the magnitude, time and direction of stress may alter tissue health. However, many health care workers (perhaps not enough) realize that tissue health and pain exist on orthogonal scales.
Certainly having healthy tissues is optimal and our profession ought to assist people to obtain healthy tissues in my opinion. However, most people are coming to PT for pain problems that are more complex than simple tissue health problems. Failure to recognize this may lead to frustration and burn out. Far better would be to work on both.
The authors of the article state: "Physiologic factors assume a less important role in physical therapy treatment compared with the factors described previously because physical therapists usually can not modify or treat physiological factors directly. Physical therapists should be aware of the influence of physiological factors, however, because these factors will affect the prognosis of tissue adaptation and recovery from injury."
--This statement is both prophetic and goofy. It would seem to me that our profession centers on (indirectly) influencing physiologic processes to obtain an optimal outcome. It is the physiologic response that we seek, so how can that be "less important" when it is the goal? That was the goofy part. The prophetic part is that a more extensive knowledge of pain physiology is necessary to effectively change it toward a desired outcome. Only then will technique selection begin to actually make sense in my opinion.
jon
_____________________________
[URL=http://www.sonymusic.com/clips/selection/30/064887/064887_03_03_30.wav]Evidence[/URL]
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