This functional assessment involves manual muscle tests of the psoas and a resistive test of the piriformis muscle. I use this examination primarily for patients with sacroiliac joint pain and also for hip flexor strain. An imbalance between the psoas and the piriformis muscles is common with these two injuries.

Functionally, the psoas and piriformis muscles work together in a force-couple relationship during sagittal plane movements, such as with gait. On the swinging leg side, the piriformis elongates to allow the hip to move into flexion. Hip flexion is primarily produced by contraction of the psoas muscle. The reciprocal coupled force-tension between these muscles occurs when the hip is extending on the weight-bearing side.

A muscle-tension balance between these two muscles is important in sacroiliac joint function and force closure.


  1. The practitioner tests for a strong psoas muscle.
  2. Practitioner uses an isometric contraction of the piriformis muscle by placing the hip and knee in 70o flexion and the hip in slight abduction and slight external rotation. The practitioner places one palm on the lateral knee and the other palm on SP 6. The practitioner applies a primary pressure on SP 6 to drive the hip into internal rotation while the other hand guides the hip with mild pressure into slight adduction. The practitioner holds the patient’s isometric contraction for 6-8 seconds.
  3. After this piriformis isometric test and within 3-5 seconds, the practitioner re-tests the psoas MMT. Weakness indicates and imbalance between the piriformis and the psoas.

Treatment of Sacroiliac Joint Pain

The piriformis muscle belongs the the UB sinew channel and the psoas muscle belongs to the Kidney sinew channel. Therefore, using the source and luo point combination is useful to add in addition to local points. Treat the same side of the positive manual muscle tests.

Check out the video below for instruction on how to perform this assessment for sacroiliac joint pain and the power of using UB 58 and K3 acupuncture points.

For more great functional exams and acupuncture treatment, check out the upcoming Module II Low Back, Hip and Groin this coming September and November 2022.


About the author(s):

Matt Callison is the president of the Sports Medicine Acupuncture Certification program. He has been combining sports medicine and traditional Chinese medicine (TCM) for over 26 years. He is the author of the Motor Point and Acupuncture Meridians Chart, the Motor Point Index, The Sports Medicine Acupuncture textbook and many articles on the combination of sports medicine and TCM.