Several studies have been published assessing the accuracy and association of pain with PA segmental motion testing (manual and algometry). An in vivo assessment in MRI in 2007 concluded lumbar-segmental hypermobility was likely associated with LBP. A PT study by Blinkley et al assessed inter-tester reliability of P-A testing and concluded; “there is poor inter-tester agreement reliability of P-A testing. Caution should be exercised when using P-A testing to assess segmental motion”. In 2005 (Beneck et al J Ortho Sport PT) examined the association between painful segment with P-A testing vs. hyper/hypo mobility with MRI utilized to determine actual motion. L5 was the most painful segment in nearly half the subjects with L4/L5 the least mobile. Their conclusions: “Assumptions of segmental motion cannot be inferred from pain associated with P-A pressure testing”.
Dr. Kennedy comment: These studies can be instructive for our clinical examination of motion disorders as well as re-assessing the accuracy of our palpation. The Mcgill shear instability test affords us the ability to add muscle-contraction (force-closure) to assess the effects of contraction on segmental pain and motion. Where P-A testing alone may afford inaccurate information adding “force-closure” can add substantial reliability and possible validity.