Range of Motion: Ankle Inversion

The Ankle Inversion Test measures how far the sole of the foot turns inward. It can be measured actively or passively, but the result is influenced by subtalar, midfoot and forefoot movement. Recording the method, side, pain, symptoms and compensation helps make the result useful for movement comparison and progress tracking.

Introduction

A client may show limited foot control during balance tasks, feel restricted when changing direction or have a visible side-to-side difference in foot movement. Ankle inversion ROM testing helps quantify this movement.

Because inversion is not a pure single-joint motion, interpretation should be practical. The result is best used to compare sides, monitor change and add context to strength, balance, gait, running or hopping findings.

Quick Summary

Test name: Ankle Inversion Test
Purpose: Measure ankle/foot inversion range of motion
Movement: Sole of the foot turns inward
Joint/body region: Ankle, subtalar joint and foot
Plane: Frontal plane with coupled foot motion
ROM type: Active ROM, passive ROM or both
Score: Degrees of inversion
Equipment: Goniometer, inclinometer or Measurz ROM workflow
Best used with: Ankle eversion, balance, hop tests, foot strength, ankle strength and gait assessment
Key limitation: Inversion includes motion from multiple foot joints, not one isolated joint

What Is the Ankle Inversion Test?

The Ankle Inversion Test measures the inward turning movement of the foot. The movement is often described as subtalar inversion, but in practical testing it may include motion from the subtalar joint, midfoot and forefoot.

Why It Is Used

The test is used to establish baseline movement, compare sides and monitor change.

It may help inform:

Balance programming
Foot and ankle strengthening
Change-of-direction preparation
Ankle mobility monitoring
Side-to-side comparison
Progress tracking after changes in symptoms or loading

What It Measures

The test measures inversion ROM in degrees.

It may be influenced by:

Subtalar joint motion
Midfoot mobility
Foot posture
Pain or stiffness
Strength and motor control
Professional stabilisation
Measurement landmarks
Device placement
Warm-up and previous activity

It does not explain why the movement is reduced or increased.

Active vs Passive Range of Motion

Active inversion measures how far the client can turn the sole inward using their own control.

Passive inversion measures the available movement when the professional guides the foot.

Active and passive values should be recorded separately because they provide different information.

Who It Is Useful For

This test may be useful for runners, field sport athletes, balance clients, gym clients, court sport athletes, dancers and anyone where side-to-side ankle/foot movement comparison is useful.

Equipment Required

Goniometer or inclinometer
Treatment table or chair
Pain scale
Measurz for recording ROM
Optional towel roll
Optional comparison side notes

Step-by-Step Protocol or How to Apply This in Practice

Starting position

Position the client sitting or lying with the lower leg supported and foot free to move.

Client position

Keep the knee and hip relaxed. Record whether the knee is flexed or extended.

Professional position

Sit or stand at the foot end so the heel and lower leg can be stabilised.

Body/joint setup

Start with the ankle near neutral.

Stabilisation

Stabilise the distal tibia and fibula. Minimise whole-leg rotation.

Movement instruction

For active ROM, ask the client to turn the sole of the foot inward.

For passive ROM, guide the foot into inversion gently until the first firm endpoint, symptom limit or agreed end range.

Measurement landmarks

Goniometry methods vary. A common approach is to align the axis near the anterior ankle or between the malleoli, with reference to the tibia and foot. Use the same landmarks each time.

Inclinometer or device placement

If using an inclinometer, place it consistently on the plantar or dorsal aspect of the foot according to your method. Record placement.

What to ask

Ask about pain, stretch, stiffness, symptom location and whether movement feels familiar.

Stopping rules

Stop if pain increases, the client guards, the lower leg rotates or the movement cannot be measured consistently.

What to record

Record active/passive ROM, side, degrees, device, pain score, symptoms, position and compensation.

Number of trials

Use one to three trials and record the selected scoring method.

Retest consistency

Keep device placement, landmarks, stabilisation and position consistent.

Scoring and Interpretation

The score is recorded in degrees.

A higher inversion value indicates more inward foot movement under the tested setup. A lower value indicates less inversion ROM compared with the other side, baseline or selected benchmark.

Interpretation is stronger when paired with:

Eversion ROM
Pain score
Side-to-side comparison
Foot strength
Balance testing
Hop testing
Running or cutting tasks
Movement quality

The result does not explain the cause of movement difference on its own.

Normative Data, Benchmarks or Reference Values

Evidence level: Level 3 — limited exact protocol-matched norms; use practical comparison guidance.

Common teaching references often describe ankle/foot inversion around 30–35 degrees, but values vary depending on whether the measurement captures subtalar-only motion or combined foot motion.

Practical benchmarks:

Compare both sides
Track baseline to retest
Compare active and passive ROM
Record pain at end range
Track movement quality
Interpret with eversion, balance and strength findings

Reliability and Validity

Lower-limb ROM reliability varies depending on joint, device, landmarks, examiner and movement measured. A recent systematic review reported that goniometry, photogrammetry and smartphone methods can be reliable when standardised, but reliability is not automatic across all lower-limb movements.  

For ankle inversion specifically, repeatability depends heavily on stabilising the lower leg and using the same foot landmarks. Small changes should be interpreted cautiously unless repeated and supported by related findings.

Common Errors and Testing Limitations

Common errors include measuring whole-leg rotation, poor lower-leg stabilisation, inconsistent landmarks, changing active and passive methods, over-forcing passive ROM, not recording pain and assuming broad norms apply to every client.

Limitations include multi-joint foot motion, measurement variability, foot structure differences and inconsistent endpoint definitions.

Practical Applications

Use ankle inversion ROM to track side-to-side movement, monitor foot and ankle change, inform balance or strength programming and decide whether further strength, balance or functional tests are useful.

How to Record This in Measurz

In Measurz, record baseline inversion ROM in degrees using the inclinometer or chosen device. Record whether the result is active or passive, side tested, pain score, symptom location, movement direction, test position, device used and compensation notes.

Compare both sides and track progress across sessions. Add related strength, balance, hop or functional findings.

Related Tests or Internal Linking Suggestions

Ankle Eversion Test
Ankle Dorsiflexion Test
Ankle Plantarflexion Test
Single-Leg Balance Test
Y-Balance Test
Hop Tests
Ankle Strength Testing

FAQs

What is normal ankle inversion ROM?

Common references often describe around 30–35 degrees, but values vary by protocol, device, foot structure and measurement method.

How do you measure ankle inversion?

Measure the inward turning movement of the foot using a goniometer or inclinometer while stabilising the lower leg.

Should inversion be measured actively or passively?

Both can be useful. Active ROM shows controlled movement, while passive ROM shows available movement when guided.

What does reduced ankle inversion mean?

It means less inward foot movement under the tested setup. It does not explain the cause by itself.

How should ankle inversion be tracked?

Use the same position, device, landmarks and active/passive method each session.

Key Takeaways

Ankle inversion measures inward foot movement.
The result includes subtalar and foot contribution.
Active and passive values should be recorded separately.
Side-to-side comparison is often more useful than broad norms.
Measurz should capture degrees, pain, side, device and compensation.

References

Clarkson, H. M. (2020). Musculoskeletal assessment: Joint range of motion, muscle testing, and function (4th ed.). Wolters Kluwer.

Milanese, S., et al. (2025). Reliability of range of motion measurements obtained by goniometry, photogrammetry and smartphone applications in lower limb joints: A systematic review. Musculoskeletal Science and Practice. Needs verification.

Norkin, C. C., & White, D. J. (2016). Measurement of joint motion: A guide to goniometry (5th ed.). F. A. Davis.