The basic premise of the system that is taught by the Postural Restoration Institute is that the body is asymmetrical and, in order to optimize human function, we need to try and restore as much symmetry needed in order to have balanced reciprocal function (while appreciating the asymmetries of the body and acknowledging that we will not change them). Basically, we have a liver on the right side, the crural attachments on the right lumbar vertebrae are thicker than on the left, the right lung has three lobes while the left lung has two, etc (we can go on and on with these sorts of asymmetries), thus we tend to orient ourselves over the right leg which places us in a pattern of right mid stance, referred to as a Left AIC.
The main pattern discussed and the backbone of their system is the Left AIC (short for Anterior Interior Chain). The Anterior Interior Chain is a chain of muscles which connect the torso to the knee and consists of the diaphragm, psoas, iliacus, TFL, vastus lateralis, and biceps femoris. We have two AICs in the body, one on both sides, however the Left AIC tends to be more dysfunctional than the right. Additionally, individuals may find themselves in other patterns but underneath those patterns is always a Left AIC due to the natural asymmetry of the human body as discussed above.
In this Left AIC pattern the main findings include things such as:
- Anterior pelvic rotation on the left
- Increased hamstring length, tension, and tone on the left
- Pelvis rotated to the right side
- Right ischial tuberosity sitting lower than the left
- Left femoral head is not received as well by the acetabulum as the right is
- Right side is more in a position of adduction, internal rotation, and extension
- Left side is more in a position of abduction, external rotation, and flexion
- Decreased trunk rotation to the right side
- Decreased right apical expansion and left diaphragm opposition
- Increased left rib flare (poor left zone of apposition)
- Decreased left mediastinum expansion
All of these things are actually “normal” and are due to the natural asymmetry we all posses; however, some people – with proper training – can control this position better than others and thus perform at a higher level. Other individuals may not control this position well and end up compensating in such a way that they themselves in a position of PEC – short for posterior exterior chain – where they exhibit many of the things above on both sides, bilaterally.
The Posterior Exterior Chain consists of our latissimus dorsi, QL, Posterior Intercostals, Serratus Posterior, and Ilicostalis Lumborum.
Being in a PEC position is characterized by attributes such as:
- Stiff looking gait mechanics
- Bilateral hyperlordosis
- Both hips in a position of flexion, external rotation, and abduction (people tend to walk with their toes out)
- Butt gripping (tight gluteus maximus bilaterally)
- Flat and stiff thoracic spine
- Bilateral compression of the SI-joints
- Sagital plane dominant individuals who have lost optimal function in the frontal and transverse planes
- Pelvic floor in a descended position, bilaterally, causing the muscles of the pelvic outlet to be stiff and inflexible leading to issues with constipation
- Poor zone of apposition bilaterally
- In a state of hyperinflation, lacking the ability to exhale and allow the diaphragm to dome up
Goal of PRI
The goal is to use a battery of tests to determine what sort of position the individual is in and then what type of control they actually have. To do this, the Postural Restoration Institute has a number of tests – some are tests of position while others are tests of function – to help understand the person in front of you and make informed decisions about exercise prescription. To take it a step further, the tests are also used, in an algorithmic sort of way, to differentiate between individuals displaying one of these patterns versus individuals displaying one of these patterns but considered to be “pathological” and displaying a certain amount of ligament laxity – referred to as a Patho Left AIC or Patho PEC. This information further drives exercise choices as those that are pathological may need a different set of exercises or exercise regression to ensure they are performing the movements in the right position and feeling the correct muscles working.
PRI can get extensive with the exercises as they have over 100 in their catalog although there are a few exercises that would be considered “big money” exercises for each of the possible patterns one may be in. If you understand the patterns and use the testing approach effectively you will understand which structures/muscles you are looking to facilitate and which you are looking to inhibit and can pretty much use any permutation of the “big money” exercises as long as they achieve the intended goal and improve the testing when you go to re-test, which should be done frequently to know if what you are doing is working and if you are helping re-position the individual.
Similarities with other Approaches
Whether it is PRI or any other system (DNS, FMS/SFMA, Janda, Osteopathic approaches, etc) there should be some similarities in the message as all of the systems are dealing with the human body. It is the similarities between all these things that I care the most about because it helps me see the big picture and be aware of more things when I look at an individual.
One thing PRI does is go heavy into the anatomy of the body with regard to how muscles function and they do a good job of differentiating between which attachments are moving and which are stable. For example, we can have femoral acetabular rotation (a femur rotating on a pelvis) and we can have acetabular femoral rotation (a pelvis rotating over a femur). This is similar to the idea of punctum fixum and punctum mobile in the DNS methodology. While some may consider looking at things like this as being a bit excessive, I truly believe that understanding these concepts can be extremely helpful to understanding function and programming exercise.
PRI has a large focus on breathing and talks extensively about the “zone of apposition” (ZOA) – the aspect of the diaphragm that apposes the chest wall. The ZOA is influenced by the position of the rib cage. When the rib cage is flared upward, ribs in external rotation, the ZOA is not in a position to function and allow for proper diaphragmatic breathing. In DNS this same position is referred to as on “open scissor position” where the rib cage is angled upward and the pelvis is angled downward (anteriorly tilted), causing increased erector spinae tone and a lengthened abdominal wall which posses a high amount of tension. Individuals with an inefficient ZOA or the open scissor tend to be more upper chest breathers, stuck in a hyperinflated position, and recruit the neck musculature (SCM, Scalenes, Levator, Upper Trap) to assist with respiration.
I see a bit of an Osteopathic influence in the PRI system which is cool because I have read a lot of Osteopathic texts. The whole approach to re-positioning the pelvis in PRI is similar to self Muscle Energy Techniques where the individual is using muscular force to drive the pelvis into a certain position (which is great because you don’t have to put your hands on the person for these techniques to be useful and can allow the client to feel empowered by performing the activities on their own). The interesting thing is that the common pattern in PRI, the Left AIC, is opposite that of the common pattern in Wolf Schamberger’s text, The Malalignment Syndrome, which states that everything is happening on the right side (right pelvis in anterior rotation rather than the left) and this is similar to some of the other Osteopathic things I have read in the past. The instructor gave some answers as to why this is and in the end it comes down to a visualization thing as most of the other approaches were looking at anatomical landmarks with the person either supine or prone on the table and because of this they can be flawed as anatomical landmarks can change when someone lies down on the table (Schamberger does talk about some of these changes in his book on pgs. 43-44). Thus, PRI recommends tests of position and function rather than static tests of anatomical landmarks. The instructor of the course also talked about how the Muscle Energy Techniques used in those Osteopathic approaches achieved a similar result a lot of the time, even though their understanding of the position was incorrect, because they were activating the correct muscles to drive the pelvis into the correction position. Who’s right? Who’s wrong? Does it really matter? At the end of the day the goal is to make a positive improvement and if you did something that had a positive influence, even if your explanation or thought process wasn’t 100% correct, I don’t know if it matters all that much. Another thing that I would add is that the Osteopaths discussed breathing and the autonomic nervous system pretty extensively so perhaps their holistic approach achieved many of the similar results that those using PRI achieve. Regardless, there are a lot of similarities between these two approaches to pelvic movement and correction which is interesting to look at and be aware of. The Osteopathic similarities with PRI also show up with regard to the discussion on the diaphragm and viscera as the Osteopathic techniques on visceral manual therapy/massage discuss similar relationships between the diaphragm and the liver on the right side and the diaphragm and the spleen on the left.
Finally, the PRI patterns, particularly the PEC, is where I see some similarities to Janda and Travell and Simons. This pattern is very similar in appearance and function to the Upper and Lower Crossed Patterns from Janda. Many of the muscles which are discussed as needing inhibition in PRI (and in Janda) are also those that are either needed to keep us upright throughout the day (anti-gravity muscles) or those that help assist with respiration when the diaphragm is not functioning properly. So, it makes sense that things you want to inhibit in some of these patterns are the lumbar erectors (we live in a world of extension) and the glutes (particularly in the PEC pattern). Additionally, the vastus lateralis is a muscle which is part of the Anterior Interior Chain and one that can function significantly in these patterns to help provide stability. It comes as no surprise that this muscle is also one that is frequently riddled with trigger points, particularly in the lateral side under the IT-band (which lies over the vastus lateralis, biceps femoris, and is influenced by the TFL – all three muscles which are part of the Anterior Interior Chain).
Integration & Conclusions
I have enjoyed the courses thus far and look forward to taking more of them. I think that they underpin things I already do in practice very nicely and can fit well within the FMS model as another tool that can positively impact the results in some of the tests. Also, I have found that when there are a number of things going wrong in the FMS using some of the PRI approach can be helpful to reposition the individual and then retest to see what sort of improvements have been made. I have been using some of the exercises in my own warm ups and in the warm ups of a few people I have been working with (based on what we have found in testing) and the results have been very positive.
I don’t think any one system has all the answers and I don’t think any system will ever have all the answers as there are so many things that influence the body and so many things we don’t quite know. What I will say is that I really enjoy when different philosophies line up and share many similarities. The PRI approach is one more tool in the toolbox to help understand human function and their courses are some of the most fun I have had during a con ed course in a pretty long time.