The Stork Test, also commonly referred to as the Gillet Test in sacroiliac assessment, is a standing palpatory movement test used to observe relative motion of the posterior superior iliac spine during single-leg hip flexion. The professional palpates the PSIS and sacral base while the client lifts one knee toward the chest. A positive finding is usually described as reduced, absent or altered inferior movement of the PSIS on the tested side. However, the test has important reliability and validity limitations, so it should not be used alone to diagnose sacroiliac dysfunction.
The Stork Test is commonly used in manual therapy, orthopaedic education and lumbopelvic assessment to observe movement around the sacroiliac region. It is typically performed in standing while the client lifts one hip and knee into flexion. The professional palpates the PSIS and sacrum to observe whether expected relative movement occurs.
Although the test is often taught as an SIJ mobility test, interpretation should be cautious. Sacroiliac joint movement is small, palpation can be difficult, and single-leg stance involves balance, hip control, lumbar motion, pelvic rotation and muscular coordination. These factors can influence what the professional feels under their thumbs.
For this reason, the Stork Test should be used as a movement observation and education tool within a broader assessment. A positive finding may suggest the need for further lumbopelvic, hip or functional assessment, but it does not confirm SIJ dysfunction, hypomobility or a pain source.
Test name: Stork Test
Also known as: Gillet Test, Marching Test, SIJ Stork Test
Body region: Lumbopelvic region, sacroiliac region and posterior pelvis
Purpose: Observe relative PSIS movement during active single-leg hip flexion
Commonly associated with: SIJ mobility assessment and lumbopelvic movement asymmetry screening
Positive finding: Reduced, absent, asymmetrical or altered PSIS movement during hip flexion
Negative finding: Expected or symmetrical PSIS movement with no meaningful symptom reproduction
Best used with: Standing Flexion Test, Seated Flexion Test, SIJ provocation tests, lumbar ROM, hip ROM and functional movement assessment
Key limitation: A positive result does not confirm SIJ dysfunction.
The Stork Test is a palpatory movement assessment performed in standing. The client stands on one leg while lifting the opposite knee toward the chest. The professional palpates the PSIS and sacral base to observe relative motion.
In a commonly described interpretation, the PSIS on the side of hip flexion is expected to move inferiorly relative to the sacrum. If this movement appears absent, reduced or altered, the test may be recorded as positive or abnormal. However, this interpretation should be used cautiously because palpated movement may not accurately represent SIJ motion.
The Stork Test is used to observe lumbopelvic movement during single-leg stance and active hip flexion. It may help professionals decide whether to explore pelvic control, hip mobility, lumbar movement, balance, single-leg loading or SIJ-region symptoms in more detail.
It may also be used as a teaching tool for landmark palpation and movement observation. The value of the test is greatest when the result is recorded in detail and used to guide further assessment rather than to label a diagnosis.
The Stork Test assesses:
Palpated PSIS movement during active hip flexion
Lumbopelvic control during single-leg stance
Side-to-side movement differences
Balance strategy and pelvic control
Symptom response during active hip flexion
Possible movement asymmetry around the sacroiliac region
Examiner ability to locate and track posterior pelvic landmarks
It does not reliably confirm sacroiliac joint dysfunction, hypomobility, positional fault, instability or pain source.
The Stork Test may be useful for adults with low back, posterior pelvic, hip-region or single-leg loading symptoms when the professional wants to observe lumbopelvic movement and pelvic control.
It may also be useful in education and training settings for teaching palpation and movement observation. It should be modified or avoided if the client cannot stand safely on one leg, has acute pain, balance difficulty, neurological symptoms, high irritability or cannot lift the hip without symptom aggravation.
Use the Stork Test when:
The client can stand safely on one leg
You want to observe lumbopelvic movement during active hip flexion
You want to compare PSIS movement between sides
You are using it as part of a broader assessment
You can record symptom behaviour and movement quality
You will interpret the finding cautiously with other tests
Use caution or avoid the test when the client has poor balance, acute pain, recent trauma, suspected fracture, severe hip pain, severe low back irritability, worsening neurological symptoms, dizziness, inability to stand safely, or symptoms requiring urgent medical review.
The test should also be interpreted cautiously when landmark palpation is difficult, the client shifts weight excessively, or movement is limited by hip range, pain, guarding or balance confidence.
The Stork Test requires minimal equipment:
Safe standing space
Optional wall, plinth or rail for balance support
Pain rating scale
Symptom-location recording method
Measurz app for structured documentation
Optional video for movement review
Optional MAT notes for related lumbopelvic and functional tests
Within Measurz, the Stork Test can be recorded alongside Standing Flexion, Seated Flexion, lumbar ROM, hip ROM, balance tests, SIJ provocation tests and functional movement assessments. Measurz can also support video capture, movement notes, symptom tracking and comparison over time.
Explain the test and gain consent before palpating the posterior pelvis. Tell the client they will lift one knee toward the chest while standing, and that you will monitor pelvic movement and symptom response.
Record baseline symptoms before testing, including pain score, symptom location and any current low back, pelvic or hip symptoms.
The client stands upright with feet approximately hip-width apart. A wall, rail or plinth may be nearby for balance support if required. Any support used should be documented.
Stand behind the client. Position yourself so you can palpate the PSIS and sacrum while also monitoring balance and safety.
Place one thumb on the PSIS of the tested side and the other thumb on the sacral base or adjacent sacral landmark. Some variations compare both PSIS landmarks. Use a consistent method and document the variation used.
The client should remain upright and balanced. Avoid excessive trunk lean, pelvic rotation or foot movement. Support may be used if needed for safety, but it should be recorded.
Ask the client to slowly lift the tested-side knee toward the chest, flexing the hip and knee. Observe whether the PSIS on that side appears to move inferiorly relative to the sacrum.
Then ask the client to lower the leg and repeat on the opposite side if safe.
Ask:
“Stand tall and slowly lift this knee toward your chest.”
“Move only as far as comfortable.”
“Tell me if you feel pain, pulling, instability or familiar symptoms.”
“Lower the leg slowly.”
“Let me know if symptoms change or spread.”
A positive Stork Test is commonly described as reduced, absent, asymmetrical or altered inferior movement of the PSIS on the tested side during active hip flexion. Symptom reproduction may also be recorded, but pain alone should not be treated as proof of SIJ dysfunction.
A negative finding is expected or symmetrical PSIS movement during hip flexion, with no meaningful familiar symptom reproduction or movement concern.
Stop if pain increases sharply, symptoms spread, neurological symptoms worsen, balance is compromised, the client cannot safely lift the leg, dizziness occurs, or the client asks to stop.
Prioritise balance and comfort. Avoid overinterpreting small palpatory differences. Record uncertainty when the finding is unclear.
A positive Stork Test may suggest altered lumbopelvic movement during active hip flexion. It may indicate that further assessment of pelvic control, hip mobility, lumbar movement, balance, SIJ provocation response or functional single-leg tasks is appropriate.
A positive result does not confirm sacroiliac joint dysfunction, hypomobility, positional fault, instability or the source of pain. The finding can be influenced by balance, hip range, trunk lean, muscular control, guarding, anatomical variation, foot position and examiner palpation accuracy.
A negative result means expected or symmetrical movement was observed under the test conditions. This does not exclude sacroiliac-region involvement, lumbar involvement, hip contribution or movement-related symptoms. It simply means this specific palpatory movement test did not show a clear abnormal finding.
At the time of writing, high-quality diagnostic accuracy evidence reporting sensitivity, specificity, likelihood ratios or diagnostic odds ratios for the Stork/Gillet Test as a stand-alone test for painful SIJ involvement appears limited.
The Stork Test is a mobility palpation test rather than a pain provocation test. It attempts to assess relative movement, not whether a specific load reproduces familiar pain. Because of this, it should not be interpreted in the same way as SIJ pain provocation tests such as distraction, compression, thigh thrust or sacral thrust.
Recent systematic review evidence on palpatory SIJ mobility tests suggests that validity remains limited. Ribeiro et al. reported moderate intra-examiner reliability for the Gillet test, with pooled kappa around 0.46, but the review concluded that further studies are needed to evaluate reliability and validity. This means a professional may sometimes reproduce their own finding, but it does not prove that the test accurately identifies SIJ dysfunction or pain source.
The Stork Test should therefore be interpreted as a movement observation finding rather than a diagnostic accuracy test.
Reliability and validity are important limitations of the Stork Test. The test relies on palpating small movements in a region where motion is subtle and difficult to feel accurately. It is also performed during single-leg stance, which introduces balance, hip control, lumbar movement and weight-shift variables.
Moderate intra-examiner reliability has been reported for the Gillet test in pooled analysis, but this does not guarantee strong inter-examiner agreement or diagnostic validity. In practical terms, two professionals may not always agree on the result, and a positive test does not necessarily mean the SIJ is restricted.
To improve consistency, professionals should standardise foot position, hip flexion instruction, palpation landmarks, movement speed, balance support and documentation. Unclear findings should be recorded as unclear rather than forced into a positive or negative result.
Common errors include:
Misidentifying the PSIS or sacral landmark
Pressing too hard or sliding the thumbs
Allowing excessive trunk lean or pelvic rotation
Ignoring balance strategy
Not documenting whether support was used
Assuming altered movement confirms SIJ dysfunction
Treating pain alone as a positive mobility finding
Failing to compare sides
Not recording symptom response
Ignoring hip, lumbar or balance contributors
Limitations include small SIJ motion, palpation difficulty, limited validity evidence, variable reliability, influence from balance and hip control, and dependence on examiner skill.
The Stork Test can be useful as part of a broader lumbopelvic movement assessment. It may help professionals observe single-leg control, hip flexion strategy, pelvic movement and symptom behaviour.
It may also be useful for education because it teaches careful landmarking, movement observation and cautious interpretation. In practice, the most useful result is often the detailed record of movement quality, symptom response and confidence rather than a simple positive or negative label.
In Measurz, record:
Test name: Stork Test or Gillet Test
Side tested
Starting stance position
Whether support was used
Hip flexion range or movement quality
Observed PSIS movement
Result: positive, negative, unclear or unable to test
Pain score before, during and after
Symptom location
Symptom quality
Whether symptoms were familiar
Balance strategy
Trunk lean or pelvic rotation
Guarding or compensations
Landmarking confidence
Examiner confidence in result
Comparison side
Related Standing Flexion, Seated Flexion, lumbar, hip and SIJ provocation findings
Reason for stopping if applicable
Retest date if relevant
Recording these details improves repeatability, communication, professional education, reassessment quality, team consistency and reporting quality.
Standing Flexion Test
Seated Flexion Test
Sacroiliac Distraction Test
Sacroiliac Compression Test
Sacral Thrust Test
Thigh Thrust Test
Gaenslen Test
Lumbar Flexion Test
Hip ROM Assessment
Balance Assessment
Functional Movement Assessment
It is used to observe lumbopelvic movement and palpated PSIS motion during active single-leg hip flexion.
In sacroiliac mobility assessment, the Stork Test is often used interchangeably with the Gillet Test or Marching Test.
No. It does not diagnose or confirm SIJ dysfunction. Reliability and validity limitations mean it should not be used as a stand-alone diagnostic test.
A positive finding is usually described as reduced, absent, asymmetrical or altered PSIS movement during active hip flexion.
A negative result means expected or symmetrical PSIS movement was observed, with no meaningful symptom reproduction or movement concern.
The test is influenced by balance, hip mobility, trunk movement, pelvic control, examiner palpation accuracy and small SIJ motion.
Record side, support used, movement quality, PSIS response, pain score, symptom location, balance strategy, confidence and related findings.
The Stork Test is a palpatory lumbopelvic movement assessment.
A positive result suggests altered observed PSIS movement, not a confirmed diagnosis.
Reliability and validity limitations should be clearly acknowledged.
The test is best used as part of a broader assessment, not in isolation.
Measurz should capture movement quality, symptom response, side-to-side findings, balance strategy, confidence and related tests.
Klerx, S. P., Pool, J. J. M., Coppieters, M. W., Mollema, E. J., & Pool-Goudzwaard, A. L. (2020). Clinimetric properties of sacroiliac joint mobility tests: A systematic review. Musculoskeletal Science and Practice, 48, 102090. https://doi.org/10.1016/j.msksp.2019.102090
Ribeiro, R. P., Guerrero, F. G., Camargo, E. N., Beraldo, L. M., Pivotto, L. R., Candotti, C. T., & Loss, J. F. (2021). Validity and reliability of palpatory clinical tests of sacroiliac joint mobility: A systematic review and meta-analysis. Journal of Manipulative and Physiological Therapeutics, 44(4), 307–318. https://doi.org/10.1016/j.jmpt.2021.01.001
Ribeiro, R. P., Guerrero, F. G., Camargo, E. N., Pivotto, L. R., Aimi, M. A., Loss, J. F., & Candotti, C. T. (2021). Construct validity and reliability of tests for sacroiliac dysfunction: Standing flexion test and sitting flexion test. Journal of Osteopathic Medicine, 121(11), 849–856. https://doi.org/10.1515/jom-2021-0025
Saueressig, T., Owen, P. J., Diemer, F., Zebisch, J., & Belavy, D. L. (2021). Diagnostic accuracy of clusters of pain provocation tests for detecting sacroiliac joint pain: Systematic review with meta-analysis. Journal of Orthopaedic & Sports Physical Therapy, 51(9), 422–431. https://doi.org/10.2519/jospt.2021.10469
