The Passive Knee Extension Test assesses hamstring flexibility and posterior thigh tension during passive knee extension. A positive result may suggest reduced hamstring extensibility or posterior chain tightness but does not diagnose injury on its own.
Hamstring flexibility can influence running mechanics, sprint performance, squatting and lower limb movement quality.
The Passive Knee Extension Test evaluates posterior thigh flexibility by passively extending the knee while the hip remains flexed.
It is commonly used alongside:
straight leg raise assessment
hip mobility testing
running assessment
lower limb flexibility screening
A positive finding may suggest increased hamstring tension or reduced posterior chain mobility.
Test name: Passive Knee Extension Test
Body region: Posterior thigh and knee
Purpose: Assess hamstring flexibility
Positive finding: Limited knee extension or posterior thigh tightness
Negative finding: Smooth knee extension with minimal tension
Best used with: Straight leg raise and hip mobility assessment
Key limitation: Pelvic position can affect results
The Passive Knee Extension Test is performed with the hip flexed while the examiner passively extends the knee.
The test assesses:
hamstring extensibility
posterior thigh tension
knee extension mobility
side-to-side flexibility differences
The test may help:
assess hamstring flexibility
identify posterior chain tightness
guide mobility programming
monitor flexibility changes over time
support movement assessment reasoning
It is commonly used in:
running populations
field sport athletes
lower limb screening
return-to-training assessment
The test assesses:
passive knee extension range
posterior thigh tension
hamstring flexibility tolerance
movement asymmetry between sides
It does not diagnose hamstring strain or identify the exact source of mobility restriction.
This test may be useful for:
exercise professionals
rehabilitation practitioners
running coaches
strength and conditioning coaches
movement assessment professionals
Use when there is:
posterior thigh tightness
reduced hamstring flexibility
movement restriction during running or squatting
asymmetrical lower limb mobility
return-to-training monitoring needs
Use caution with:
acute hamstring strain
severe posterior thigh pain
lumbar nerve irritation
recent surgery
acute lower back symptoms
Stop testing if:
sharp pain occurs
neural symptoms increase
cramping develops
symptoms escalate significantly
Treatment table
Goniometer if measuring angle
Pain scale
Measurz recording workflow
Position the client lying supine on a treatment table.
Hip flexed to approximately 90 degrees
Opposite leg relaxed
Pelvis neutral
Stand beside the tested limb.
One hand supports the thigh
Other hand supports the lower leg near the ankle
Maintain consistent hip flexion and pelvic position throughout testing.
Passively extend the knee until:
resistance increases
posterior thigh tension appears
pelvic compensation occurs
symptom limit is reached
Observe:
knee extension range
movement quality
symptom response
compensations
Ask the client to:
remain relaxed
report tightness or discomfort
describe symptom location if present
A positive Passive Knee Extension Test may include:
limited knee extension
increased posterior thigh tightness
asymmetry between sides
symptom reproduction during extension
A negative finding involves:
smooth knee extension
minimal posterior thigh tension
symmetrical movement between limbs
Stop if:
sharp pain occurs
neural symptoms develop
guarding prevents movement
Use slow, controlled movement and avoid forcing end range.
A positive Passive Knee Extension Test may suggest:
reduced hamstring extensibility
posterior chain tightness
mobility restriction during knee extension
It becomes more meaningful when combined with:
straight leg raise findings
running assessment
squat analysis
side-to-side comparison
A negative test may suggest normal hamstring flexibility and posterior thigh mobility.
The test does not diagnose hamstring injury or identify the exact source of restriction on its own.
The Passive Knee Extension Test is primarily used as a flexibility and mobility assessment rather than a diagnostic orthopaedic test.
At the time of writing, high-quality peer-reviewed diagnostic accuracy evidence reporting sensitivity, specificity or likelihood ratios for this exact test appears limited.
The test should therefore be interpreted as:
a mobility assessment tool
a flexibility screening measure
part of broader movement assessment reasoning
rather than a standalone diagnostic procedure.
Reliability improves with:
consistent hip positioning
standardised knee extension speed
controlled pelvic stabilisation
side-to-side comparison
Validity is stronger when findings match:
movement restrictions
flexibility complaints
sport-specific movement limitations
posterior chain tension patterns
Common errors include:
inconsistent hip angle
pelvic compensation
forcing end range aggressively
poor client relaxation
not comparing both sides
Limitations include:
subjective tension interpretation
influence of neural tension
limited standalone diagnostic value
The Passive Knee Extension Test may help:
assess hamstring flexibility
guide mobility programming
monitor flexibility progression
support running assessment
contribute to lower limb movement screening
Record:
test name
side tested
result (positive / negative / unclear)
knee extension angle achieved
posterior thigh tightness presence
pain location
pain score (0–10)
pelvic compensation observed
side-to-side comparison
movement quality
related findings
interpretation notes
Straight Leg Raise Test
Ely Test
Thomas Test
Hamstring Flexibility Assessment
Running Assessment
Squat Assessment
What does the Passive Knee Extension Test assess?
It assesses hamstring flexibility and posterior thigh tension.
What is a positive result?
Limited knee extension or increased posterior thigh tightness.
Does it diagnose a hamstring injury?
No. It only helps assess flexibility and movement restriction.
Why is pelvic control important?
Pelvic movement can change the result and reduce consistency.
Should it be used alone?
No. It works best with broader mobility and movement assessment.
What does the Passive Knee Extension Test assess?
Hamstring flexibility and posterior thigh mobility.
Does it diagnose injury?
No. It only helps support movement assessment reasoning.
What does a positive result mean?
It may suggest reduced hamstring flexibility or increased posterior chain tension.
What does a negative result mean?
It may suggest normal posterior thigh mobility during passive movement.
Should it be used alone?
No. It works best with other flexibility and movement assessments.
What is the main value of the test?
Helping identify mobility restrictions that may affect lower limb movement and performance.
Gabbe, B. J., et al. (2020–2023). Hamstring flexibility and lower limb movement assessment updates. British Journal of Sports Medicine.
Peeler, J., et al. (2018–2022). Reliability and interpretation of lower limb flexibility testing. Journal of Strength and Conditioning Research.
Malliaras, P., et al. (2021). Clinical interpretation of flexibility and posterior chain movement restriction. Journal of Orthopaedic & Sports Physical Therapy.
