Prone Instability Test

Purpose[edit | edit source]

To test for the likelihood of a patient with low back pain responding to a stabilization exercise program[1].

Technique[edit | edit source]

The patient lies prone with the body on the examining table and legs over the edge and feet resting on the floor. While the patient rests in this position with the trunk muscles relaxed, the examiner applies posterior to anterior pressure to an individual spinous process of the lumbar spine. Any provocation of pain is reported. Then the patient lifts the legs off the floor (the patient may hold table to maintain position) and posterior to anterior compression is applied again to the lumbar spine while the trunk musculature is contracted.[1][2]


The test is considered positive if pain is present in the resting position but subsides in the second position, suggesting lumbo-pelvic instability. The muscle activation is capable of stabilizing the spinal segment.

Evidence[edit | edit source]

Reference standard success with stabilization exercise program[3].

Sensitivity = .72 - LR = .48

Specificity = .58 + LR = 1.7

This test should be used in conjunction with other tests to confirm the signs and symptoms of lumbar instability. This test also was included in the clinical prediction rule developed by Hicks for patients with favorable responses to spinal stabilization exercise. Therefore, positive test results were correlated with patients with favorable responses, and negative test results were correlated with patients without favorable responses to spinal stabilization exercise programs. This test was one of four variables identified and reported in CPR for lumbar spinal stabilization exercise program success and failure.[4]


Resources[edit | edit source]

Interrater Reliability of Clinical Examination Measures for Identification of Lumbar Segmental Instability

Spinal palpation for lumbar segmental mobility and pain provocation: an interexaminer reliability study.

References[edit | edit source]

  1. 1.0 1.1 Flynn T, Cleland J, Whitman J. User's Guide to the Musculoskeletal Examination: Fundamentals for the Evidence-based Clinician. Buckner, Kentucky: Evidence in Motion; 2008.
  2. Dutton, M. Orthopaedic Examination, Evaluation, and Intervention. New York: The McGraw-Hill Companies, Inc.; 2008.
  3. Hicks G, FritzJ, Delitto A, McGill S. Preliminary development of a clinical prediction rule for determining which patients with low back pain will respond to a stabilization exercise program. Arch Phys Med Rehabil 2005;86:1753-1762.
  4. Fritz JM, Piva SR, Childs JD. Accuracy of the clinical examination to predict radiographic instability of the lumbar spine. Eur Spine J. 2005;14(8):743–50.