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.

Introduction

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.

Quick Summary

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.

What Is the Stork Test?

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.

Why It Is Used

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.

What It Assesses

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.

Who It Is Useful For

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.

When to Use This Test

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

When Not to Use or When to Be Cautious

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.

Equipment Required

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.

Step-by-Step Protocol / Practice

Setup

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.

Client position

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.

Examiner/professional position

Stand behind the client. Position yourself so you can palpate the PSIS and sacrum while also monitoring balance and safety.

Hand placement

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.

Stabilisation

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.

Movement or force direction

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.

Instructions

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.”

Positive finding

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.

Negative finding

A negative finding is expected or symmetrical PSIS movement during hip flexion, with no meaningful familiar symptom reproduction or movement concern.

Stopping criteria

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.

Safety notes

Prioritise balance and comfort. Avoid overinterpreting small palpatory differences. Record uncertainty when the finding is unclear.

Positive and Negative Test Interpretation

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.

Sensitivity, Specificity and Diagnostic Accuracy

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

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 and Limitations

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.

Practical Applications

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.

How to Record This in Measurz

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.

Related Tests / Internal Links

• 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

FAQs

What is the Stork Test used for?

It is used to observe lumbopelvic movement and palpated PSIS motion during active single-leg hip flexion.

Is the Stork Test the same as the Gillet Test?

In sacroiliac mobility assessment, the Stork Test is often used interchangeably with the Gillet Test or Marching Test.

Does the Stork Test diagnose SIJ dysfunction?

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.

What is a positive Stork Test?

A positive finding is usually described as reduced, absent, asymmetrical or altered PSIS movement during active hip flexion.

What is a negative Stork Test?

A negative result means expected or symmetrical PSIS movement was observed, with no meaningful symptom reproduction or movement concern.

Why is the test difficult to interpret?

The test is influenced by balance, hip mobility, trunk movement, pelvic control, examiner palpation accuracy and small SIJ motion.

What should be recorded in Measurz?

Record side, support used, movement quality, PSIS response, pain score, symptom location, balance strategy, confidence and related findings.

Key Takeaways

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.

References

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