The Hip External Rotation Strength Test measures the maximum isometric force produced during hip external rotation with the hip flexed to 90 degrees. Using the Anker, the assessment provides an objective measure of hip external rotator strength in a fixed and repeatable testing position.

The assessment is commonly used for baseline strength testing, side-to-side comparison and monitoring changes over time. Hip external rotator strength contributes to lower-limb stability during walking, running, jumping, landing and change-of-direction activities.

When used with Measurz, the Anker records peak force and can calculate additional metrics including force relative to body weight, impulse, torque (when the lever arm is entered), rate of force development, time to peak and fatigue index.

The assessment measures muscle strength only and should be interpreted alongside other physical assessments and functional performance.

What Is the Hip External Rotation Strength Test?

The Hip External Rotation Strength Test is an isometric assessment where the client attempts to rotate the hip outward while the hip and knee remain flexed to 90 degrees.

Primary muscles assessed include:

• Gluteus maximus
• Piriformis
• Obturator internus
• Obturator externus
• Superior gemellus
• Inferior gemellus
• Quadratus femoris

The fixed design of the Anker allows consistent testing when the same positioning, contact points and instructions are used during every assessment.

Step-by-Step Protocol

1. Prepare the client

Explain that the assessment measures how strongly they can rotate their hip outward by pushing their lower leg against the Anker.

Record any:

• hip pain
• groin pain
• buttock pain
• recent injury
• previous surgery
• stiffness
• neurological symptoms
• fatigue

Allow one or two submaximal practice contractions before maximal testing.

2. Position the client

Seat the client with:

• hips flexed to 90°
• knees flexed to 90°
• pelvis positioned against the backrest
• trunk upright
• thighs fully supported
• feet clear of the floor if required

The pelvis should remain level throughout the assessment.

3. Position the testing limb

Position the testing limb so that:

• the femur remains parallel with the opposite thigh
• the knee aligns with the centre of the seat
• the tibia remains vertical
• the ankle remains relaxed

Position the Anker load cell against the medial aspect of the distal tibia, approximately 2–3 cm superior to the medial malleolus.

Avoid placing the load cell directly over bony prominences.

Maintain the same contact point during every reassessment.

4. Stabilise the client

Prevent movement of:

• pelvis
• trunk
• testing thigh
• opposite limb

Only the hip should generate force throughout the contraction.

5. Testing instructions

Use consistent verbal cues.

"Push your leg towards the middle."

"Build the pressure smoothly."

"Push as hard as you can."

"Hold."

"Keep breathing."

Repeat the same instructions during every reassessment.

6. Record the assessment

Use:

• 1–2 practice trials
• 2–3 maximal trials
• 3–5 second contractions
• 30–60 seconds rest between trials

Record either:

• highest trial, or
• average of the recorded trials

Apply the same scoring method for future testing.

7. Repeat the trial if

• the pelvis rotates
• the trunk leans
• the thigh lifts
• the knee changes position
• the load cell slips
• pain limits maximal effort
• the client starts before instructed

Why It Is Used

The Hip External Rotation Strength Test may be useful for:

• establishing baseline hip strength
• comparing left and right limbs
• monitoring strength over time
• lower-limb strength profiling
• athlete performance testing
• monitoring response to exercise
• objective progress tracking
• client education

The assessment should not be used as a stand-alone diagnostic test or to determine readiness for sport.

What It Measures

The primary outcome is peak isometric hip external rotation force.

When analysed in Measurz, additional metrics may include:

• Peak force
• Force relative to body weight
• Impulse
• Torque
• Rate of force development
• Time to peak
• Fatigue index

The assessment does not directly measure:

• hip range of motion
• joint pathology
• balance
• movement quality
• running technique
• return-to-sport readiness

Understanding the Result, Reference Values and What to Look For

Higher force values generally indicate greater hip external rotation strength in the testing position.

Lower force values may be influenced by:

• pain
• fatigue
• reduced effort
• previous injury
• poor familiarisation
• inconsistent positioning

Interpret results by:

• comparing with previous assessments
• comparing left and right limbs
• considering symptoms during testing
• identifying movement compensations
• relating findings to functional goals

Published Anker-specific normative values are currently unavailable.

Research has demonstrated excellent reliability for hip strength assessment using handheld and fixed dynamometry when standardised protocols are followed. Healthy adults generally demonstrate less than a 10% side-to-side difference in hip rotational strength. Greater asymmetries should be interpreted alongside symptoms, injury history and functional performance.

Assessing Different Client Populations

Youth

Provide additional familiarisation trials and interpret results relative to growth and physical development.

Adults

Useful for baseline strength assessment and long-term progress monitoring.

Older adults

Interpret alongside mobility, transfers, balance and daily function.

Athletes

Useful for assessing hip strength during performance profiling for running, jumping, cutting and landing sports.

Clients with persistent symptoms

Interpret alongside pain, confidence and functional performance rather than strength alone.

Common Errors and Limitations

Common errors include:

• pelvis rotating
• trunk leaning
• lifting the testing thigh
• changing knee position
• inconsistent load cell placement
• inconsistent verbal instructions

Limitations include:

• results are specific to the testing position
• pain may reduce maximal force production
• strength alone does not determine functional performance
• published Anker-specific normative values remain limited

Practical Applications

The assessment may be useful for:

• establishing baseline strength
• monitoring progress over time
• comparing left and right limbs
• athlete profiling
• lower-limb performance assessment
• objective reporting within Measurz
• educating clients about measurable improvements

FAQs

What does the Hip External Rotation Strength Test measure?

It measures maximal isometric hip external rotation strength with the hip flexed to 90 degrees.

Which metric should be used routinely?

Peak force is the primary outcome measure.

Should both hips be assessed?

Yes. Bilateral testing allows meaningful side-to-side comparison.

Can this assessment diagnose hip pathology?

No. It measures muscle strength only and should be interpreted alongside other assessment findings.

Why is pelvic position important?

Pelvic movement changes the direction of force and reduces the repeatability of the assessment.

Key Takeaways

• Measures maximal isometric hip external rotation strength.
• Performed with the hip and knee flexed to 90°.
• Peak force is the primary outcome measure.
• Measurz provides additional force-time metrics.
• Consistent positioning improves repeatability.
• Compare results with previous assessments and the opposite limb rather than relying solely on published reference values.

References

Bohannon, R. W. (1997). Reference values for extremity muscle strength obtained by hand-held dynamometry from adults aged 20 to 79 years. Archives of Physical Medicine and Rehabilitation, 78(1), 26–32.

Mentiplay, B. F., Perraton, L. G., Bower, K. J., Adair, B., Pua, Y. H., Williams, G. P., McGaw, R., & Clark, R. A. (2015). Assessment of lower limb muscle strength and power using hand-held and fixed dynamometry: A reliability and validity study. PLOS ONE, 10(10), e0140822.

Thorborg, K., Bandholm, T., Schick, M., Jensen, J., & Hölmich, P. (2013). Hip strength assessment using handheld dynamometry is reliable in athletes. Scandinavian Journal of Medicine & Science in Sports, 23(3), e181–e189.