The Standing Flexion Test is a palpatory movement assessment used to observe relative movement of the posterior superior iliac spines during standing forward flexion. It is often taught as a sacroiliac mobility test, but current evidence suggests important limitations in reliability, validity and clinical interpretation. A positive test is usually described as one PSIS moving earlier, higher or further than the other during forward bending. This finding may support further assessment, but it does not confirm sacroiliac dysfunction, hypomobility, positional fault or a pain source.

Introduction

The Standing Flexion Test is commonly used in manual therapy, movement assessment and orthopaedic education to observe lumbopelvic movement during forward bending. The client stands while the professional palpates both posterior superior iliac spines. As the client bends forward, the professional observes whether one PSIS appears to move differently from the other.

Although the test is simple to perform, it is not simple to interpret. Sacroiliac joint motion is small, palpation accuracy can vary, and standing forward flexion is influenced by many factors beyond SIJ movement. Hamstring flexibility, lumbar mobility, hip motion, pelvic control, foot position, balance, guarding and anatomical variation may all affect the observed movement.

For this reason, the Standing Flexion Test should be used as a movement observation tool within a broader assessment. It should not be used alone to diagnose SIJ dysfunction or confirm the source of symptoms.

Quick Summary

Test name: Standing Flexion Test
Also known as: Standing Forward Flexion Test, SFT, STFT
Body region: Lumbopelvic region, sacroiliac region and posterior pelvis
Purpose: Observe relative PSIS movement during standing forward flexion
Commonly associated with: SIJ mobility assessment and pelvic movement asymmetry screening
Positive finding: One PSIS appears to move earlier, higher or further during forward flexion
Negative finding: No obvious asymmetrical PSIS movement or no meaningful side-to-side difference
Best used with: Seated Flexion Test, Stork Test, lumbar ROM, hip ROM, SIJ provocation tests and functional movement assessment
Key limitation: A positive result does not confirm SIJ dysfunction.

What Is the Standing Flexion Test?

The Standing Flexion Test is a palpatory lumbopelvic movement test. The professional palpates the left and right posterior superior iliac spines while the client bends forward from standing. The test aims to observe whether one PSIS moves more, earlier or higher than the other.

Traditionally, asymmetrical PSIS movement has been interpreted as sacroiliac movement restriction or dysfunction. However, this interpretation should be used cautiously because PSIS movement during standing flexion may be influenced by many non-SIJ factors.

Why It Is Used

The Standing Flexion Test is used to observe lumbopelvic movement symmetry during forward bending. It may help professionals decide whether to examine lumbar flexion, hip flexion, hamstring flexibility, pelvic control, balance, SIJ provocation response or functional movement patterns in more detail.

The test can also help students learn posterior pelvic landmarking and the importance of cautious interpretation. Its value is strongest when it is used to guide further assessment rather than to label a condition.

What It Assesses

The Standing Flexion Test assesses:

• Relative PSIS movement during standing forward flexion
• Palpated lumbopelvic movement asymmetry
• Forward bending strategy
• Pelvic control during flexion
• Symptom response to standing flexion
• Balance and movement confidence
• Possible influence of hip, hamstring or lumbar restrictions

It does not reliably confirm sacroiliac joint hypomobility, positional fault, joint dysfunction or pain source.

Who It Is Useful For

This test may be useful for adults with low back, posterior pelvic, hip-region or movement-related symptoms when the professional wants to observe standing forward bending and lumbopelvic movement.

It may also be useful in education and training settings for learning anatomical palpation, movement observation and careful documentation. It should be interpreted cautiously, especially when the client has high symptom irritability, balance issues, marked guarding or difficulty tolerating forward flexion.

When to Use This Test

Use the Standing Flexion Test when:

• The client can stand and bend forward safely
• You want to observe lumbopelvic movement during forward flexion
• You want to compare PSIS movement from left to right
• The result will be interpreted with other findings
• You can record symptom behaviour and movement quality
• You are using it as part of a broader assessment rather than as a stand-alone conclusion

When Not to Use or When to Be Cautious

Use caution or avoid the test when the client cannot stand safely, has severe pain with flexion, reports dizziness, has acute trauma, has suspected fracture, has worsening neurological symptoms, cannot return from flexion safely, or has symptoms requiring urgent medical review.

Also use caution when the result is difficult to palpate or the client’s movement pattern is strongly influenced by hamstring tightness, hip limitation, fear of movement or balance concerns.

Equipment Required

The Standing Flexion Test requires minimal equipment:

• Safe standing space
• Optional plinth, wall or support nearby
• Pain rating scale
• Symptom-location recording method
• Measurz app for structured documentation
• Optional video for movement review
• Optional MAT movement assessment notes for related tests

Within Measurz, the Standing Flexion Test can be recorded alongside Seated Flexion, Stork Test, lumbar ROM, hip ROM, hamstring flexibility, SIJ provocation tests and functional movement assessments. Measurz can also support video capture, inclinometer measurements, movement notes and structured test recording for repeatability.

Step-by-Step Protocol / Practice

Setup

Explain the test and gain consent before palpating the posterior pelvis. Ask the client to report pain, pulling, stiffness, symptom spread or familiar symptoms during the movement.

Record baseline symptoms before testing, including pain score, symptom location and any current low back, pelvic or leg symptoms.

Client position

The client stands upright with feet approximately hip-width apart. Weight should be distributed as evenly as possible. Knees remain relaxed but not deliberately bent unless a modification is required.

Examiner/professional position

Stand behind the client. Position yourself so you can palpate both PSIS landmarks evenly while also monitoring the client’s balance and safety.

Hand placement

Place one thumb or finger pad on each PSIS. Confirm landmark position carefully before movement begins. Avoid pressing excessively or moving the thumbs during the test.

Stabilisation

No external stabilisation is usually applied. The client should move slowly enough that PSIS movement and overall lumbopelvic motion can be observed.

Movement or force direction

Ask the client to bend forward as far as comfortably possible, allowing the trunk and hips to flex naturally. The movement should be slow and controlled. The client then returns to standing.

Instructions

Ask:

“Slowly bend forward as far as comfortable.”
“Tell me if you feel pain, pulling, stiffness or familiar symptoms.”
“Return to standing when ready.”
“Let me know if symptoms change, spread or feel unusual.”

Positive finding

A positive finding is commonly described as one PSIS moving earlier, higher or further than the other during forward flexion. The side with greater superior movement is often interpreted as the side of altered movement, but this should be documented cautiously.

Negative finding

A negative finding is no clear side-to-side PSIS movement difference and no meaningful symptom reproduction during the test.

Stopping criteria

Stop if pain increases sharply, symptoms spread, neurological symptoms worsen, dizziness occurs, balance is compromised, the client cannot return safely to standing or the client asks to stop.

Safety notes

Keep support nearby if balance is uncertain. Avoid overinterpreting small palpatory differences. Record uncertainty when the finding is unclear.

Positive and Negative Test Interpretation

A positive Standing Flexion Test may suggest observed or palpated asymmetry during standing forward bending. It may indicate that further assessment of lumbar mobility, hip mobility, hamstring flexibility, pelvic control, SIJ provocation response or functional movement is appropriate.

A positive result does not confirm sacroiliac joint dysfunction, hypomobility, positional fault or pain source. The finding can be influenced by lower-limb flexibility, foot posture, hip range, lumbar motion, pelvic morphology, soft tissue thickness, examiner landmarking and client guarding.

A negative result means no clear asymmetry was observed under the conditions tested. This does not exclude sacroiliac-region involvement, lumbar involvement or movement-related symptoms. It simply means this specific palpatory movement test did not show a clear side-to-side difference.

Sensitivity, Specificity and Diagnostic Accuracy

At the time of writing, high-quality diagnostic accuracy evidence reporting sensitivity, specificity or likelihood ratios for the Standing Flexion Test as a stand-alone test for painful SIJ involvement appears limited.

The Standing Flexion Test is a mobility palpation test rather than a pain provocation test. It attempts to assess movement asymmetry, 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.

A 2021 systematic review and meta-analysis of palpatory SIJ mobility tests reported no included study verifying concurrent validity for the tests reviewed. The same review reported moderate intra-examiner agreement for the standing flexion test, with pooled kappa around 0.61. This suggests that the same examiner may sometimes reproduce their own findings, but it does not prove that the test accurately identifies SIJ dysfunction.

A separate 2021 construct validity and reliability study found limited validity and reliability for standing and sitting flexion tests in a healthy sample and recommended further research, especially in symptomatic populations.

Reliability and Validity

Reliability and validity are major limitations of the Standing Flexion Test. The test relies on palpation of small posterior pelvic landmark movements during a complex whole-body movement. Even when a professional can reproduce their own finding, different professionals may not agree on the result.

Validity is also uncertain. A visible or palpated PSIS movement difference does not necessarily mean the SIJ is restricted or that symptoms are coming from the SIJ. Standing flexion involves the lumbar spine, hips, pelvis, hamstrings, lower limbs and balance system.

To improve consistency, professionals should standardise foot position, movement speed, landmarking, symptom recording 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 landmarks
• Pressing too hard or sliding the thumbs
• Asking the client to move too quickly
• Ignoring foot position or weight shift
• Assuming asymmetry equals SIJ dysfunction
• Failing to record symptom response
• Not noting uncertainty
• Ignoring hamstring, hip or lumbar contributors
• Comparing results between professionals without considering reliability limitations
• Using the test as a stand-alone diagnostic tool

Limitations include small SIJ motion, palpation difficulty, variable inter-rater reliability, limited validity evidence, and influence from lumbar, hip and lower-limb movement.

Practical Applications

The Standing Flexion Test can be useful as part of a broader lumbopelvic movement assessment. It may help professionals observe how the client bends forward, whether symptoms are reproduced, and whether a side-to-side pelvic movement difference is worth exploring further.

It may also be useful for education because it highlights the importance of landmarking, movement observation and cautious interpretation. The most useful result is often the detailed record of movement quality and symptom behaviour, rather than a simple positive or negative label.

How to Record This in Measurz

In Measurz, record:

• Test name: Standing Flexion Test
• Starting foot position
• Weight distribution
• Side of observed PSIS movement difference
• Result: positive, negative, unclear or unable to test
• Pain score before, during and after
• Symptom location
• Symptom quality
• Whether symptoms were familiar
• Forward flexion range
• Movement quality
• Speed of movement
• Balance or guarding
• Landmarking confidence
• Examiner confidence in result
• Comparison with Seated Flexion or Stork Test
• Related lumbar, hip, hamstring 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

• Seated Flexion Test
• Stork Test
• Sacroiliac Distraction Test
• Sacroiliac Compression Test
• Sacral Thrust Test
• Slump Test
• Straight Leg Raise Test
• Lumbar Flexion Test
• Hip ROM Assessment
• Hamstring Flexibility Assessment
• Functional Movement Assessment

FAQs

What is the Standing Flexion Test used for?

It is used to observe relative PSIS movement and lumbopelvic motion during standing forward flexion.

Does the Standing Flexion 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 Standing Flexion Test?

A positive finding is usually described as one PSIS moving earlier, higher or further than the other during forward flexion.

What is a negative Standing Flexion Test?

A negative result means no clear side-to-side PSIS movement difference was observed during the test.

Why can the test be difficult to interpret?

Standing forward flexion is influenced by lumbar mobility, hip range, hamstring flexibility, balance, pelvic anatomy, symptom irritability and examiner palpation accuracy.

Is the Standing Flexion Test reliable?

Evidence is mixed. Some intra-examiner agreement has been reported, but this does not prove strong validity or reliable agreement between different examiners.

What should be recorded in Measurz?

Record foot position, side observed, movement quality, pain score, symptom location, confidence, uncertainty and related findings.

Key Takeaways

The Standing Flexion Test is a palpatory lumbopelvic movement assessment.
A positive result suggests observed PSIS movement asymmetry, not a confirmed diagnosis.
Reliability and validity limitations should be explained clearly.
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, confidence and related tests.

References

Colonna, S., & Casacci, F. (2025). The standing forward flexion test in manual therapy: A critical review and a functional reinterpretation. Cureus. https://doi.org/10.7759/cureus.101225

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., 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 (STFT) and sitting flexion test (SIFT). Journal of Osteopathic Medicine, 121(11), 849–856. https://doi.org/10.1515/jom-2021-0025

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

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