Ankle Orthopaedic Test: Thompson Test

The Thompson Test, also called the Simmonds-Thompson Test or calf squeeze test, assesses Achilles tendon continuity by observing whether calf compression produces passive ankle plantarflexion. A positive test is absence or marked reduction of plantarflexion compared with the other side. It has high reported diagnostic accuracy for complete Achilles tendon rupture, but results should still be interpreted with the full presentation and referred appropriately when rupture is suspected.

Introduction

Suspected Achilles rupture is clinically important because some clients can still walk or actively move the ankle after rupture. The Thompson Test is one of the most widely used clinical tests for assessing Achilles tendon continuity.

Recent Achilles rupture reviews continue to describe diagnosis as primarily clinical, using history and examination findings such as tendon palpation, Thompson Test and Matles Test. Imaging may still be used when confirmation or treatment planning is needed.  

Quick Summary

Test name: Thompson Test
Also known as: Simmonds-Thompson Test, calf squeeze test
Purpose: Assess Achilles tendon continuity
Body region: Achilles tendon/calf/ankle
Commonly associated presentation: Suspected Achilles tendon rupture
Positive finding: Absent or markedly reduced passive ankle plantarflexion when the calf is squeezed
Negative finding: Passive ankle plantarflexion occurs when the calf is squeezed
Best used with: Palpation, Matles Test, resting ankle angle, gait/weight-bearing assessment and urgent referral pathways where appropriate
Key limitation: Partial tears, swelling, pain, guarding and atypical presentations may complicate interpretation

What Is the Thompson Test?

The Thompson Test assesses Achilles tendon continuity by squeezing the calf and observing whether the ankle passively plantarflexes.

If the Achilles tendon is intact, calf compression should tension the tendon and move the foot into plantarflexion. If the tendon is completely ruptured, plantarflexion may be absent or markedly reduced.

Why It Is Used

The test is used when Achilles tendon rupture is suspected. It can help identify clients who require urgent medical assessment, imaging consideration or referral.

It is especially important because active ankle plantarflexion may still be possible through other muscles.

What It Assesses

The test assesses whether calf compression produces passive ankle plantarflexion, which reflects functional continuity of the Achilles tendon-calf complex.

It does not fully grade the tear, determine exact tear location or replace medical imaging and referral when rupture is suspected.

Who It Is Useful For

This test may be useful for clients with sudden posterior ankle or calf pain, a popping sensation, difficulty pushing off, acute weakness, suspected Achilles rupture or significant change in gait after a calf/Achilles injury.

It may not be appropriate when severe pain prevents positioning, open injury is present or urgent referral is clearly required without further testing.

When to Use This Test

Use the Thompson Test when Achilles tendon rupture is suspected based on history, symptoms or observed function.

When Not to Use or When to Be Cautious

Use caution with severe acute pain, suspected fracture, open wound, recent surgery, marked swelling or when the client cannot safely lie prone. If rupture is strongly suspected, do not delay referral.

Equipment Required

Treatment table
Pain scale
Measurz for recording
Optional comparison side notes
Referral notes where appropriate

Step-by-Step Protocol / Practice

Setup

Position the client prone with the feet hanging relaxed over the edge of the table.

Client position

The knees may be extended or slightly flexed depending on setup. The ankles should be relaxed and visible.

Examiner position

Stand beside the lower leg and observe the foot and ankle.

Hand placement

Place both hands around the bulk of the calf muscle.

Stabilisation

Allow the foot to hang freely so passive ankle movement can be observed.

Movement or force direction

Squeeze the calf firmly but controlled.

Instructions

Ask the client to relax and not actively move the ankle.

Positive finding

A positive Thompson Test is absent or markedly reduced passive ankle plantarflexion compared with the other side when the calf is squeezed.

Negative finding

A negative test is visible passive ankle plantarflexion when the calf is squeezed.

Stopping criteria

Stop if pain is severe or the position is not tolerated.

Safety notes

If Achilles rupture is suspected, arrange appropriate medical assessment rather than continuing unnecessary provocative testing.

Positive and Negative Test Interpretation

A positive Thompson Test strongly increases suspicion of complete Achilles tendon rupture, especially when the history includes sudden posterior calf/ankle pain, a pop, loss of push-off or abnormal resting ankle position.

A negative test reduces suspicion of complete rupture but does not fully exclude partial tear or other Achilles/calf injury. Interpret with palpation, resting ankle angle, gait, strength and symptom history.

Sensitivity, Specificity and Diagnostic Accuracy

The strongest commonly cited diagnostic accuracy evidence for the Thompson Test comes from an older systematic review and meta-analysis, which reported pooled sensitivity around 0.96 and specificity around 0.93 for Achilles tendon rupture. Although this exact-test diagnostic evidence is older than 2020, it remains one of the most relevant sources for the test’s diagnostic accuracy.  

Recent reviews and clinical resources still describe Achilles rupture diagnosis as primarily clinical and include the Thompson Test as part of the standard examination, but newer sources do not necessarily replace the older pooled diagnostic accuracy values.  

Because Achilles rupture is a significant injury, a positive test should prompt appropriate medical referral or further assessment.

Reliability and Validity

The Thompson Test is clinically useful because it directly assesses passive plantarflexion response to calf compression. Validity is strongest for complete Achilles tendon rupture.

Reliability depends on correct positioning, client relaxation, comparison with the other side and clear observation of passive plantarflexion.

Common Errors and Limitations

Common errors include asking the client to actively move the ankle, squeezing too low, failing to compare sides, missing subtle plantarflexion differences and assuming active plantarflexion excludes rupture.

Limitations include partial tears, swelling, pain, guarding, anatomical variation and compensation from other plantarflexors.

Practical Applications

Use the Thompson Test as part of suspected Achilles rupture assessment. A positive test should be treated seriously and recorded clearly.

It is most useful when combined with history, palpation, resting ankle angle, Matles Test, gait assessment and referral pathways.

How to Record This in Measurz

Record test name, side tested, result as positive, negative, unclear or unable to test, passive plantarflexion response, comparison side, pain score, symptom location, reported pop, weakness, gait notes, palpable gap if assessed, resting ankle angle, confidence in result, referral recommendation and related findings.

Related Tests / Internal Links

Matles Test
Calf Raise Test
Single-Leg Calf Raise Strength Test
Ankle Plantarflexion Test
Weight-Bearing Lunge Test
Gait Assessment
Lower-Limb Strength Testing

FAQs

What does a positive Thompson Test mean?

It strongly suggests possible complete Achilles tendon rupture when passive plantarflexion is absent or markedly reduced.

Does active ankle movement rule out Achilles rupture?

No. Some clients may still actively move the ankle using other muscles.

How accurate is the Thompson Test?

The most relevant pooled diagnostic accuracy evidence reports high sensitivity and specificity for complete Achilles rupture.

Should both sides be tested?

Yes. Side comparison helps identify reduced or absent passive plantarflexion.

What should happen after a positive test?

A positive test should prompt appropriate medical referral or further assessment.

Key Takeaways

The Thompson Test assesses Achilles tendon continuity.
A positive test is absent or markedly reduced passive plantarflexion with calf squeeze.
Diagnostic accuracy is high for complete Achilles rupture.
A negative test does not fully exclude partial injury.
Record plantarflexion response, comparison side and referral notes in Measurz.

References

Gatz, M., Driessen, A., Eschweiler, J., Tingart, M., & Migliorini, F. (2022). The acute Achilles tendon rupture: An evidence-based approach from the diagnosis to the treatment. Medicina, 58(9), 1195. https://doi.org/10.3390/medicina58091195 

Reiman, M., Burgi, C., Strube, E., Prue, K., Ray, K., Elliott, A., et al. (2014). The utility of clinical measures for the diagnosis of Achilles tendon injuries: A systematic review with meta-analysis. Journal of Athletic Training, 49(6), 820–829.

Stoffel, K., et al. (2024). Acute rupture of the Achilles tendon: Diagnostics, treatment and rehabilitation. Trauma und Berufskrankheit. Advance online publication.