PRI physical therapy is physical therapy built on the methods of the Postural Restoration Institute (PRI), an education and credentialing organization founded by physical therapist Ron Hruska and established in 2000 [1]. It treats common postural problems as predictable left-right patterns run by the nervous system, and it uses breathing-led positional exercises, plus manual techniques in some cases, to shift them. It is not a separate profession. It is a way of working that physical therapists and other clinicians learn through PRI’s courses.
I have a lot of respect for PRI. It saw the nervous system and the diaphragm when much of physical therapy still focused on individual muscles. I also think it stops one layer short. This article covers both: what PRI physical therapy actually is, what the published evidence does and does not show, and where it fits. If you are looking for the exercises themselves, I have written a separate guide to PRI exercises.
The Postural Restoration Institute in brief
PRI was established in 2000 to, in its own words, “explore and explain the science of postural adaptations, asymmetrical patterns and the influence of polyarticular chains of muscles” [1]. It runs primary, secondary and tertiary courses for licensed healthcare and certified fitness professionals, plus credentialing programs [1][2].
PRI publishes its own current counts of certified and trained professionals and of Postural Restoration Centers on its website [1].
The core idea: your body runs a predictable asymmetry
The human body is not symmetrical inside. The liver sits on the right, the heart leans left, and the two halves of the diaphragm are not mirror images. PRI’s central claim is that this creates a default pattern most people share, which it calls the Left AIC (Anterior Interior Chain) pattern, with a related Right BC (Brachial Chain) pattern in the upper body. In that pattern the pelvis and ribcage sit rotated, one side of the diaphragm works at a disadvantage, and the body compensates.
From there, PRI looks for when that normal asymmetry gets stuck, so you can no longer shift fully onto both sides. That loss of alternation is what it aims to restore. PRI’s courses teach a large catalogue of positional, breathing and manual techniques for doing it [1][2].
What a PRI physical therapy session involves
Sessions vary by clinician, but the published case material shows a consistent shape [3][4].
1. Assessment of the pattern, not just the sore spot. A PRI clinician uses specific tests to read the pelvis and ribcage, such as the Ober’s test, the Adduction Drop Test, the Extension Drop Test and the Hruska Adduction Lift Test, alongside hip and shoulder range of motion and how the ribs move when you breathe [3][4].
2. Breathing-led repositioning exercises. The best known is the 90/90 hip lift with balloon: lying on your back with your feet on a wall and your hips and knees at 90 degrees, pulling gently down through the heels, then breathing in through the nose and slowly out into a balloon [5]. The aim is to bring the ribs down and in and restore the Zone of Apposition, so the diaphragm can do its postural job as well as its breathing one [5].
3. Re-testing. The clinician checks the same tests again, often within the session, to see whether the position has shifted [3][4].
4. A home program. You leave with a short list of positions to repeat between visits. In one published case, a college volleyball player with chronic shoulder pain did three PRI exercises (three sets of ten breaths, at least three times a week) for 38 days. Her reported pain fell from 6/10 to 2/10, and the targeted hip and shoulder rotation measures improved [4]. That was one person, with no comparison, so it shows what a program looks like, not how well it works in general.
Some PRI clinicians also bring in vision, dental and orthotic work through PRI’s specialty courses. Not every PRI-trained clinician does.
What the evidence shows
This is where honesty matters, because PRI is easy to oversell.
The theory paper. The 90/90 balloon exercise was laid out in a 2010 clinical commentary by Boyle and colleagues [5]. It explains the rationale and the mechanics. It is not a trial.
Immediate effects. In a 2013 study, 13 people with lumbopelvic pain and a positive Ober’s test did one PRI exercise designed to activate the hamstrings and abdominals. Straight afterwards, hip adduction improved and pain scores dropped [3]. There was no control group and no follow-up.
Randomized trials in low back pain. A 2021 trial put 33 men with chronic low back pain into PRI, NASM corrective exercise, or a combination for eight weeks. There was no significant difference between the groups in pain, disability or movement control [6]. A 2024 trial in 45 women found that six weeks of PRI exercise, with or without added core stability work, beat a no-exercise control group on pain, function and quality of life, with no difference between the two PRI groups [7].
A systematic review. A 2025 systematic review (a University of Tartu master’s thesis) pulled together 10 studies of PRI for low back complaints. It found PRI helped with pain and function compared with counselling or no intervention, but was broadly similar to other active exercise, and it called for more studies with a low risk of bias [8].
Scoliosis. We could not find a completed randomized trial of PRI for scoliosis. The published record is case-level [9], and a 2026 trial protocol comparing Schroth and PRI in adolescents states that no randomized trial has compared the two directly [10].
What that adds up to: In small studies, PRI exercises were followed by measurable short-term changes, and in the trials so far PRI-based programs helped people with back pain more than doing nothing. The trials so far do not show that PRI beats other well-run exercise programs, and the long-term data is thin.
Where PRI stops
None of that is a knock on PRI’s insight. Treating asymmetry as a nervous system pattern, using breathing as the way in, and treating the diaphragm as a postural muscle as well as a breathing one: PRI built on those ideas before most of the field.
My question is about durability. PRI’s exercises are prescriptive: lie here, breathe like this, feel for this landmark. The position changes, sometimes within a single session. My reading, from our framework, is that the nervous system is following instructions rather than updating the model that generated the pattern in the first place, your body schema. That is a proposal, not something the PRI trials tested. In my experience, for many people the pattern returns and the exercise has to be repeated. I go into this in more detail in PRI exercises: where they stop.
If PRI got you part of the way, that is not failure. It may be a ceiling. As we see it, the next layer is safety, pressure organized through the whole trunk (our five-diaphragm model, which extends PRI’s work on the breathing diaphragm and pelvic floor), and letting the system find a new pattern from sensation rather than prescription. DNS positions come at a similar foundation from the developmental side.
Finding a PRI clinician
PRI keeps its own provider search on its website, filterable by profession, location and specialization (including scoliosis) [2]. A few questions worth asking before you book:
- Which credential do you hold? PRC is for licensed clinicians (physical therapists, occupational therapists, chiropractors, athletic trainers and others). PRT is for fitness professionals such as personal trainers and strength coaches. “Postural Restoration Provider” means the person has completed coursework [2].
- How will we know it is working? A good answer names the tests they will re-check and the change you should feel or see.
- What is the plan once the exercises stop? This is the durability question. It is worth asking any clinician, PRI or not.
Frequently Asked Questions
What is PRI physical therapy?
PRI physical therapy is physical therapy that uses the methods of the Postural Restoration Institute, founded by physical therapist Ron Hruska and established in 2000. It treats common postural patterns as predictable left-right asymmetries and uses breathing-led positional exercises, and in some cases manual techniques, to shift them.
Is PRI evidence-based?
Partly. There are small randomized trials in chronic low back pain, an immediate-effect study of a PRI exercise, case reports, and a 2025 systematic review. The trials show PRI exercise helps compared with doing nothing, but not clearly more than other active exercise programs, and the review calls for more low-risk-of-bias studies.
What do PRC and PRT mean?
They are PRI’s credentials. Postural Restoration Certified (PRC) is for licensed clinicians such as physical therapists, occupational therapists, chiropractors and athletic trainers. Postural Restoration Trained (PRT) is for fitness professionals such as personal trainers and strength coaches. PRI also lists Postural Restoration Providers who have completed coursework.
Does PRI work for scoliosis?
We could not find a completed randomized trial of PRI for scoliosis yet. The published record is limited to case-level reports, and a 2026 trial protocol comparing Schroth and PRI in adolescents notes that no randomized trial has compared the two directly.
How is PRI different from regular physical therapy?
Conventional physical therapy usually works on the painful area with stretching, strengthening and mobility work. PRI starts from whole-body asymmetry and breathing mechanics, and often treats the pelvis and ribcage first even when the pain is in the shoulder or the knee.
Sources
- Postural Restoration Institute. About PRI. posturalrestoration.com/about (accessed 20 October 2026). [T3]
Founding year, mission statement, course structure, and PRI’s own counts of PRC/PRT professionals and centers.
- Postural Restoration Institute. Find a Provider and Where to Start. posturalrestoration.com/find-provider and /providers/start (accessed 20 October 2026). [T3]
Credential definitions (PRC, PRT, Provider), provider search filters, course levels.
- Tenney, H.R., Boyle, K.L., & DeBord, A. (2013). Influence of hamstring and abdominal muscle activation on a positive Ober’s test in people with lumbopelvic pain. Physiotherapy Canada, 65(1), 4-11. PMID: 24381375 [T1]
13 participants; immediate improvement in hip adduction and pain after a PRI exercise. No control group.
- Waldron, J.L., McKenney, M.A., Samuel, M.N., Girouard, T.J., Turner, C.L., & Radzak, K.N. (2020). The use of postural restoration for treatment of chronic rotator cuff pathology: a case report. International Journal of Sports Physical Therapy, 15(5), 832-839. PMCID: PMC7575158 [T2]
Single case; PRI assessment tests, a three-exercise home program, outcomes over 38 days.
- Boyle, K.L., Olinick, J., & Lewis, C. (2010). The value of blowing up a balloon. North American Journal of Sports Physical Therapy, 5(3), 179-188. PMID: 21589673 [T2]
Clinical commentary describing the 90/90 bridge with ball and balloon and its rationale.
- Fazel, F., Zolaktaf, V., & Lenjan Nezhadian, S. (2021). The effect of exercise programs on pain management and motor control in patients with nonspecific chronic low back pain: a randomized matched subjects trial. International Journal of Preventive Medicine, 12:164. PMID: 35070197. doi:10.4103/ijpvm.ijpvm_423_20 [T1]
33 men; PRI vs NASM vs combined for 8 weeks; no significant between-group differences.
- Fouladi, N., Minoonejad, H., & Rajabi, R. (2024). Comparing the effects of the postural restoration exercises with and without core stability exercises in patients with non-specific chronic low back pain. Journal of Modern Rehabilitation, 18(1). doi:10.18502/jmr.v18i1.14728 [T1]
45 women; both PRI groups improved vs control over 6 weeks; no difference between PRI groups.
- Peterson, M. (2025). Postural Restoration Instituudi meetodi efektiivsus alaselja piirkonna kaebustega patsientide ravis: süstemaatiline ülevaade [Effectiveness of the PRI method for low back complaints: a systematic review]. Master’s thesis, University of Tartu. hdl.handle.net/10062/116186 [T2]
10 studies; PRI helped vs counselling or no intervention, similar to other active exercise; more low-risk-of-bias studies needed.
- Henning, S. (2014). Case study reflecting principles and treatment techniques of postural restoration. Scoliosis, 9(Suppl 1), P7. doi:10.1186/1748-7161-9-S1-P7 [T2]
Conference case report applying PRI to scoliosis.
- Daneshmandi, H., Khorsandi Kolur, M., & Sayyar, S. (2026). Schroth versus Postural Restoration Institute (PRI) exercise effects in adolescents with idiopathic scoliosis: protocol for a three-arm randomized trial. Research Square preprint. doi:10.21203/rs.3.rs-8758226/v1 [T3]
Trial protocol (no results yet); states no RCT has directly compared Schroth and PRI.