The Hip Internal Rotation Strength Test measures the maximum isometric force produced during hip internal rotation with the hip flexed to 90 degrees. Using the Anker, the assessment provides an objective measure of hip internal 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 internal rotator strength contributes to lower-limb stability, running mechanics, cutting, landing, squatting and rotational control during athletic and everyday movements.
When used with Measurz, the Anker records peak force and can also calculate 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 always be interpreted alongside movement quality, symptoms and functional performance.
The Hip Internal Rotation Strength Test is an isometric assessment where the client attempts to rotate the hip inward while the hip and knee remain flexed to 90 degrees.
Primary muscles assessed include:
Gluteus medius (anterior fibres)
Gluteus minimus (anterior fibres)
Tensor fasciae latae
Adductor longus
Adductor brevis
Pectineus
The fixed design of the Anker allows consistent testing when the same positioning, contact points and instructions are maintained during every assessment.
Explain that the assessment measures how strongly they can rotate their hip inward 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.
Seat the client with:
hips flexed to 90°
knees flexed to 90°
pelvis against the backrest
trunk upright
thighs fully supported
feet clear of the floor if required
Maintain the same seated position for every reassessment.
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 lateral aspect of the distal tibia, approximately 2–3 cm superior to the lateral malleolus.
Avoid placing the load cell directly over the lateral malleolus or the fibular head.
Record the contact point to ensure consistency during future testing.
Prevent movement of:
pelvis
trunk
testing thigh
opposite limb
Only the hip should generate force throughout the assessment.
Use consistent verbal cues.
"Push your leg outwards."
"Build the pressure smoothly."
"Push as hard as you can."
"Hold."
"Keep breathing."
Use the same instructions during every reassessment.
Use:
1–2 practice trials
2–3 maximal trials
3–5 second contractions
30–60 seconds rest between trials
Record either:
the highest trial, or
the average of the recorded trials
Apply the same scoring method during future testing.
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
The Hip Internal Rotation Strength Test may be useful for:
establishing baseline hip strength
comparing left and right limbs
monitoring strength over time
lower-limb performance assessment
athlete profiling
monitoring response to exercise
objective progress tracking
client education
The assessment should support assessment reasoning and should not be used as a stand-alone diagnostic or return-to-sport assessment.
The primary outcome is peak isometric hip internal 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
hip joint pathology
movement quality
running mechanics
balance
readiness for sport or work
Higher force values generally indicate greater hip internal rotation strength in the testing position.
Lower force values may be influenced by:
pain
fatigue
reduced effort
previous injury
poor familiarisation
inconsistent positioning
Interpret the assessment by:
comparing with previous assessments
comparing left and right limbs
considering symptoms during testing
reviewing movement compensations
relating findings to functional demands
Published Anker-specific normative values are currently unavailable.
Studies using handheld dynamometry have demonstrated excellent reliability for hip rotational strength testing when protocols are standardised. Healthy adults generally demonstrate less than a 10% side-to-side difference. Larger asymmetries should be interpreted alongside symptoms, injury history and functional performance rather than used in isolation.
Youth
Provide additional practice trials and interpret findings relative to age, growth and activity level.
Adults
Useful for baseline assessment and long-term strength monitoring.
Older adults
Interpret alongside mobility, balance and functional capacity.
Athletes
Useful for assessing rotational hip strength as part of a comprehensive lower-limb performance profile.
Clients with persistent symptoms
Interpret results alongside pain, confidence and movement quality rather than strength alone.
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
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
It measures maximal isometric hip internal rotation strength with the hip flexed to 90 degrees.
Peak force is the primary outcome measure.
Yes. Bilateral testing allows meaningful side-to-side comparison.
No. It measures muscle strength only and should be interpreted alongside other assessment findings.
Pelvic movement changes the direction of force and reduces the repeatability of the assessment.
Measures maximal isometric hip internal 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 and load cell placement improve repeatability.
Compare results with previous assessments and the opposite limb rather than relying solely on published reference values.
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.
