Range of Motion: Hip Flexion

The Hip Flexion Test measures how far the thigh moves toward the trunk. It is useful for assessing hip mobility, comparing sides, recording symptoms and monitoring change over time.

Introduction

Hip flexion range of motion is used across movement, rehabilitation, performance and fitness settings. It relates to tasks such as squatting, running, cycling, sitting, climbing stairs and floor-to-stand movement.

Hip flexion ROM is not a stand-alone explanation for pain or performance. It should be interpreted with symptoms, pelvic control, lumbar movement, strength, function and the client’s goals.

Quick Summary

• Measures sagittal-plane hip flexion ROM.
• Can be active or passive.
• Pelvic and lumbar control are critical.
• Record pain, symptoms and compensation.
• Compare sides and baseline over time.

What Is the Hip Flexion Test?

The Hip Flexion Test measures how far the hip can flex, usually with the client lying supine. The knee is commonly bent to reduce hamstring limitation, allowing a clearer view of hip flexion range.

Why It Is Used

It is used to:

• establish hip mobility baseline
• compare left and right sides
• monitor progress
• assess symptom response with flexion
• support exercise selection
• add context to squats, lunges, running and sitting tolerance
• track movement changes in Measurz

What It Measures

The test measures hip flexion in degrees. Results may be affected by:

• pelvic tilt
• lumbar spine movement
• hip joint structure
• gluteal or soft-tissue approximation
• pain or guarding
• hamstring tension if the knee is extended
• strength and active control
• warm-up and testing method

Who It Is Useful For

Useful for:

• athletes
• gym and studio clients
• older adults
• clients returning to running, squatting or cycling
• professionals monitoring hip mobility over time
• teams comparing mobility profiles

Equipment Required

• Firm plinth or mat
• Inclinometer, goniometer or digital ROM tool
• Pain scale
• Measurz record
• Optional towel or strap for positioning

Step-by-Step Protocol / Practice

1. Client position. Lie supine with both legs relaxed.
2. Test side setup. Flex the test hip by bringing the thigh toward the trunk. Keep the knee flexed unless testing straight-leg hip flexion specifically.
3. Stabilise. Monitor the pelvis and lumbar spine. Avoid posterior pelvic tilt or lumbar flattening becoming the main movement.
4. Active ROM. Ask the client to lift the thigh toward the chest as far as comfortable.
5. Passive ROM. If appropriate, guide the thigh toward the trunk until the first firm end point, symptom limit or pelvic compensation.
6. Measure. With a goniometer, align around the greater trochanter, using the trunk and femur as reference lines. With an inclinometer, record device placement and orientation.
7. Ask symptoms. Record pain, pinch, stretch, pressure or apprehension.
8. Watch compensation. Note pelvic tilt, lumbar movement, hip rotation or opposite leg lifting.
9. Repeat. Use one familiarisation trial and one to three recorded trials.
10. Retest consistently. Use the same knee position, device and instructions.

Scoring and Interpretation

Record hip flexion in degrees. Higher values generally indicate more available hip flexion in that test position. Lower values show less available range but do not explain the cause.

Interpret with:

• active versus passive ROM
• side-to-side comparison
• pain score
• symptom location
• pelvic control
• lumbar compensation
• squat, lunge or running findings
• baseline change

Normative Data, Benchmarks or Reference Values

Evidence level: Level 2 — closest available reference values.

General hip flexion reference values are often reported around 110–120 degrees, but values vary with method, age, sex, body structure and whether pelvic motion is allowed. The CDC normal joint ROM resource provides population reference values by age and sex for joint ROM and reinforces that ROM varies across demographic groups.  

A hip ROM reliability study found that pelvic position can substantially influence hip flexion measurements, with posterior pelvic tilt increasing the measured range, which is important when comparing results across sessions.  

Use reference values only as context. Practical comparison should prioritise:

• same-client baseline
• left/right comparison
• active/passive difference
• pelvic compensation
• symptoms
• task requirements

Reliability and Validity

Hip ROM measurement reliability depends on examiner consistency, pelvic control and measurement tool. Smartphone goniometer research has investigated intra- and inter-rater reliability for hip ROM and supports the need for standardised setup and clear procedures.  

A 2020 PLOS ONE study also found that reliability differs between ROM tests and tools, reinforcing the need to keep the same method when tracking progress.  

No universal MDC or MCID should be applied to all hip flexion testing unless it matches the exact protocol and population.

Sensitivity and Specificity

Sensitivity and specificity are not usually applicable to hip flexion ROM testing because it measures movement range and symptom response rather than identifying a condition on its own.

Common Errors and Limitations

• allowing posterior pelvic tilt to inflate the score
• comparing bent-knee and straight-leg hip flexion
• poor landmarking
• inconsistent device placement
• ignoring symptoms
• measuring lumbar motion instead of hip flexion
• forcing passive range
• assuming one normal value fits all clients

Practical Applications

Hip flexion ROM can help with:

• baseline hip mobility testing
• squat and lunge movement context
• running, cycling and stair-related goals
• side-to-side comparison
• progress tracking after mobility or strength work
• identifying whether related hip, lumbar, strength or functional testing may add context

How to Record This in Measurz

Record:

• test name: Hip Flexion ROM
• side tested
• active or passive ROM
• knee position
• score in degrees
• device used
• pain score
• symptom location
• pelvic or lumbar compensation
• comparison side
• baseline
• retest date
• related strength or functional findings

Example: “Left hip flexion PROM 112°, knee flexed, inclinometer, pain 0/10, mild posterior pelvic tilt at end range. Right 118°.”

Related Tests / Internal Links

• Hip Extension Test
• Hip Abduction Test
• Hip Adduction Test
• Supine Hip Internal Rotation Test
• Supine Hip External Rotation Test
• Knee Flexion Test

FAQs

What is normal hip flexion ROM?
General references often place hip flexion around 110–120 degrees, but values vary by age, sex, method and pelvic control.

Should hip flexion be measured with the knee bent or straight?
Bent-knee hip flexion is commonly used to reduce hamstring influence. Straight-leg testing measures a different movement context.

Why does pelvic position matter?
Pelvic tilt can make hip flexion appear greater than it is, reducing test consistency.

How should hip flexion be tracked over time?
Use the same position, knee angle, device placement and instructions, then compare against baseline and symptoms.

Key Takeaways

• Hip flexion ROM requires strong pelvic control.
• Record whether the test is active or passive.
• Compare sides and baseline rather than relying only on general norms.
• Symptoms and compensation are essential interpretation notes.

References

Centers for Disease Control and Prevention. (2023). Normal joint range of motion study. https://archive.cdc.gov/www_cdc_gov/ncbddd/jointrom/index.html

Charlton, P. C., et al. (2022). Clinical reliability and usability of smartphone goniometers for hip range of motion measurement. Journal of Physical Therapy Science, 34(6), 424–431. PMID: 35698549

Fraeulin, L., Holzgreve, F., Brinkbäumer, M., Dziuba, A., Friebe, D., Klemz, S., Schmitt, J., Theis, A., Tenberg, S., van Mark, A., Maurer-Grubinger, C., & Ohlendorf, D. (2020). Intra- and inter-rater reliability of joint range of motion tests using tape measure, digital inclinometer and inertial motion capturing. PLOS ONE, 15(12), e0243646. https://doi.org/10.1371/journal.pone.0243646

Kiatkulanusorn, S., Luangpon, N., Srijunto, W., Watechagit, S., Pitchayadejanant, K., Kuharat, S., Bég, O. A., & Suato, B. P. (2023). Analysis of the concurrent validity and reliability of five common clinical goniometric devices. Scientific Reports, 13, 20725. https://doi.org/10.1038/s41598-023-48344-6