I have the benefit of being associated with some outstanding thinkers and PRI practitioners. Whenever and wherever we get together, conversation eventually drifts toward discussion of PRI principles and application. One of our greatest challenges has been to unravel the foundations from which Ron Hruska evolved the Postural Restoration Institute system of evaluation and treatment that we all utilize with such great success.
The following are just a couple of questions that we have posed and our attempts to reach conclusions and greater understanding. If anything it may stimulate some thought and initiate some discussion.
What are we actually measuring when we place a patient on the treatment table and perform our PRI testing algorithm and what is our goal for treatment?
I clearly recall a conversation over lunch between Eric Oetter, Mike Robertson, and myself during the PRI Pelvis Restoration course at the Cantrell Center for Physical Therapy and Wellness. We were discussing the concepts of adaptive capacity, adaptive potential, movement variability, what we are actually measuring when evaluating a patient on the treatment table, and how this affects performance.
Our conclusion was that what we are actually measuring as PRI-educated therapists and coaches is the capacity of our client/athlete to adapt to the ever chaotic nature of the environment they are perceiving. Positive findings during examination such as a positive Adduction Drop Test, limited apical expansion, or loss of shoulder rotation was merely indicative of a human system incapable of demonstrating variability ultimately controlled by the central nervous system. More specifically an autonomic nervous system shift toward sympathetic dominance.
I was reminded of this PRI lunch after reading a blog post recently that referenced the following study:
In essence, what the researchers found in the study was that pain-free subjects demonstrated variability in the muscle activity of the erector spinae during a repetitive lifting task and those with low back pain did not demonstrate this variability as well as experiencing increased pain during the task.
The authors’ conclusion was that reduced variability of muscle activity may have important implications for the provocation and recurrence of LBP due to repetitive tasks.
Needless to say, this study is somewhat validating for our discussion group of PRI faithful.
Truth be told, after searching there are many studies that support our lunchtime conclusion; and movement variability as a favorable concept in human function is not a new concept having its foundations in dynamic systems theory.
From Shumway-Cook and Woollacott’s Motor Control: Translating Research into Clinical Practice:
“… in dynamic systems theory, variability is not considered to be the result of error, but rather as a necessary condition of optimal function. Optimal variability provides for flexible, adaptive strategies, allowing adjustment to environmental change, and as such is a central feature of normal movement.”
What the PRI model provides is a non-invasive real-time measurement of system variability determined by autonomic nervous system tone. While EEG, heart rate variability, or galvanic skin response may be preferred methods to determine autonomic tone, these are not tools commonly used by a practicing physical therapist in a clinical setting or a coach in the training room nor would they be practical.
The goal of treatment then becomes restoring an optimal level of variability to the system to allow for optimization of behavior and maximization of performance.
We came up with a statement that encompassed our entire discussion that included the influence of variability on pain and performance. I still have the notes on my iPhone dated 8/24/13:
"Restoring variability to the human system is the ultimate goal to promote neuroplastic change creating a relatively permanent change in behavior that provides adaptability within the system to cope with variability in the environment."
In PRI terms, our goal is help a patient achieve neutral (restore variability) and then recruit the appropriate PRI planar families (neuroplastic change to remap the three planes in the brain… Thanks to Zac Cupples!) to restore reciprocal and alternating movement (change behavior to cope with the environment).
How did Ron Hruska arrive at the concept of using simple, common orthopedic tests as effective PRI measurement tools?
As mentioned above, as physical therapists our measurement tools are limited by practicality. If we look at PRI from a strictly biomechanical perspective, the PRI methodology provides for a low barrier of entry to a PT who has never been exposed to its concepts before. Myokinematic Restoration looks, sounds, and feels like biomechanical course, but we all know that it is not. This is a brilliant way to provide understanding to a group with more than a few preconceived notions, right?
While I certainly cannot speak for Ron, and I’m willing to be wrong, I believe there is more to this process, and this came from a conversation I had with Eric Oetter over Sunday breakfast.
From our first day in an introductory PRI course we are shown that asymmetry because of in-utero development and positioning, brain hemispheric dominance, asymmetrical vestibular development, and internal anatomical differences is normal, expected, and predictable. Determining patterning that represents discord in the system then seems to be impossible until your realize that the skeletal system, is inherently symmetrical. Therefore there is no better way for a physical therapist to determine the state of the system as a whole than identifying asymmetries or patterns via our typical orthopedic testing.
The brain processes and integrates all sensory inputs, internal and external, and generates behavior, including motor behavior, based on our perceptions with respect to the environment, emotional status, and previous experiences. I don’t think it’s unreasonable to consider that the ability to produce reciprocal and alternating movement is not only an effective measure of autonomic tone but also a key measurement of overall health.
Bill Hartman, PT