Ankle Orthopaedic Test: Peroneus longus and brevis tests

Peroneus Longus and Brevis Tests assess pain, strength and control during resisted eversion, plantarflexion-eversion and dorsiflexion-eversion patterns. They may help identify peroneal tendon involvement in clients with lateral ankle pain, snapping, weakness or instability symptoms. Peroneal tendon disorders are recognised contributors to lateral ankle pain, but diagnosis often requires history, examination and imaging where needed rather than stand-alone resisted tests.  

Introduction

A client reports pain behind the lateral malleolus, lateral foot discomfort, ankle weakness, snapping around the outer ankle or difficulty controlling the foot on uneven ground. They may have a history of inversion ankle sprains or recurrent instability.

Peroneus Longus and Brevis Tests can help assess whether resisted eversion and related movements reproduce familiar symptoms or reveal weakness. The result should be interpreted with palpation, tendon subluxation signs, ankle instability tests, foot posture and functional loading.

Quick Summary

Test name: Peroneus Longus and Brevis Tests
Also known as: Peroneal Tendon Tests, Fibularis Longus and Brevis Tests
Body region: Lateral ankle, lateral leg, lateral foot
Purpose: Assess peroneal tendon pain, strength, control and symptom response
Positive finding: Familiar lateral ankle/foot pain, weakness, cramping, snapping, instability or inability to resist
Negative finding: No familiar symptoms or meaningful weakness during resisted testing
Best used with: Palpation, ankle eversion strength, single-leg balance, calf raise, ankle instability tests and imaging/referral when indicated
Key limitation: Resisted testing does not confirm tendon tear or subluxation on its own

What Are the Peroneus Longus and Brevis Tests?

These tests assess the peroneal muscles and tendons through resisted movement and symptom monitoring.

Peroneus brevis is commonly assessed with resisted eversion, often with the ankle closer to dorsiflexion. Peroneus longus contributes to eversion and plantarflexion and also supports the first ray and transverse arch, so symptoms may be assessed with resisted eversion/plantarflexion patterns and functional loading.

The terms peroneus and fibularis are often used interchangeably in modern anatomy.

Why They Are Used

These tests are used when lateral ankle tendon involvement is suspected.

They may be relevant in clients with:

Lateral ankle pain
Pain behind the lateral malleolus
Snapping or subluxation symptoms
Weakness with eversion
Recurrent ankle sprains
Pain with uneven-ground walking
Pain with running, cutting or jumping
Lateral foot pain near the peroneus longus course

What They Assess

They assess pain, strength and control during peroneal muscle loading. They do not directly visualise tendon tears, retinacular injury or tendon subluxation.

Symptoms may also be influenced by lateral ankle ligament injury, sural nerve irritation, cuboid symptoms, fifth metatarsal injury, sinus tarsi symptoms or ankle instability.

Who They Are Useful For

These tests may be useful for runners, dancers, field-sport athletes, gym clients, hikers, court-sport players and clients with lateral ankle pain or recurrent instability.

When to Use These Tests

Use when lateral ankle pain, weakness or snapping is present and resisted movement is safe.

When Not to Use or When to Be Cautious

Use caution with acute ankle trauma, suspected fracture, severe swelling, severe pain, recent surgery, marked instability or symptoms suggesting tendon dislocation.

Equipment Required

Treatment table or chair
Pain and strength scale
Measurz recording workflow
Optional handheld dynamometer
Optional comparison-side notes

Step-by-Step Protocol / Practice

Setup

Position the client sitting or supine with the lower leg supported and foot accessible.

Client position

The ankle position depends on the muscle bias being tested.

Examiner/professional position

Sit or stand facing the foot.

Hand placement

Stabilise the lower leg with one hand and apply resistance to the lateral foot or forefoot with the other.

Stabilisation

Prevent hip rotation, knee movement or whole-leg compensation.

Movement or force direction

For a general peroneal test, ask the client to evert the foot against resistance.
For a brevis-biased test, assess resisted eversion with the ankle closer to neutral or dorsiflexion.
For a longus-biased test, assess resisted eversion with plantarflexion or functional loading where appropriate.

Instructions

Ask the client to report pain location, weakness, cramping, snapping, instability, fatigue and whether symptoms are familiar.

Positive finding

A positive finding is familiar lateral ankle/foot pain, weakness, snapping, subluxation sensation or inability to resist.

Negative finding

A negative finding is no familiar symptoms or meaningful weakness during resisted testing.

Stopping criteria

Stop if pain increases sharply, snapping is painful, instability occurs, cramping is severe or the test is not tolerated.

Safety notes

Record which muscle bias or movement position was used.

Positive and Negative Test Interpretation

A positive peroneal test may support peroneal tendon involvement when pain is localised along the lateral ankle or tendon course and symptoms match history, palpation and functional loading.

A positive result does not confirm tendinopathy, tear or subluxation. Peroneal tendon disorders can coexist with lateral ankle instability and may be missed without careful examination or imaging.  

A negative resisted test does not exclude peroneal tendon pathology, especially if symptoms occur only during running, cutting, uneven-ground walking, fatigue or tendon snapping episodes.

Sensitivity, Specificity and Diagnostic Accuracy

High-quality 2020+ diagnostic accuracy values for isolated Peroneus Longus and Brevis resisted tests appear limited.

Condition or presentation: suspected peroneal tendon disorder, tear, tendinopathy or subluxation
Population: clients with lateral ankle pain or suspected peroneal tendon involvement
Test variation: resisted eversion, plantarflexion-eversion, dorsiflexion-eversion, palpation and dynamic subluxation assessment
Reference standard: not consistently established for resisted tests alone; imaging or surgical findings may be used in clinical pathways
Sensitivity: not available for resisted tests alone
Specificity: not available for resisted tests alone
Positive likelihood ratio: not available
Negative likelihood ratio: not available
Key limitations: overlapping lateral ankle conditions, variable test positions, pain inhibition, coexisting ankle instability and limited validation

A 2020 review on peroneal tendon tears states that peroneal tendon tears are under-recognised contributors to lateral ankle pain and dysfunction, and that these pathologies often coexist with injuries related to inversion mechanisms.   A 2022 review discusses diagnosis and treatment of peroneal tendon disorders and supports a broader diagnostic approach rather than one resisted test.  

Reliability and Validity

Reliability depends on ankle position, resistance direction, force level, comparison side, symptom criteria and whether the professional records pain, weakness and snapping separately.

Validity improves when resisted testing is combined with palpation, dynamic observation, ankle instability tests, functional loading and imaging/referral where needed.

Common Errors and Limitations

Common errors include testing only one ankle position, not differentiating longus and brevis bias, ignoring snapping symptoms, not palpating the tendon course and interpreting weakness as tendon tear.

Limitations include pain inhibition, coexisting lateral ligament instability, sural nerve symptoms, variable tendon anatomy and limited stand-alone diagnostic evidence.

Practical Applications

Use Peroneus Longus and Brevis Tests to document lateral ankle tendon pain, strength and control. They can guide peroneal strengthening, balance training, return-to-run decisions and referral when snapping, marked weakness or persistent lateral ankle pain is present.

How to Record This in Measurz

Record test name, side tested, peroneal muscle bias, ankle position, resistance direction, result, pain score, symptom location, weakness, snapping, cramping, instability sensation, comparison side, compensation, confidence in result and reason for stopping.

Add related findings such as palpation, ankle eversion strength, lateral ligament tests, single-leg balance, calf raise, hop tests, running symptoms and imaging/referral notes.

Related Tests / Internal Links

Ankle Eversion Test
Talar Tilt Test
Anterior Drawer of the Ankle
Single Leg Calf Raise
Balance and Proprioception Tests
Hop Tests
Ankle Dorsiflexion Test
Foot Posture Assessment

FAQs

What do Peroneus Longus and Brevis Tests assess?

They assess pain, strength and control during peroneal tendon loading.

What is a positive peroneal tendon test?

A positive result may include familiar lateral ankle pain, weakness, snapping, cramping or instability during resisted testing.

Can resisted testing diagnose a peroneal tendon tear?

No. It may support suspicion but does not confirm a tear on its own.

Why test different ankle positions?

Different positions can bias peroneus longus and brevis differently and may reproduce different symptoms.

What should be recorded in Measurz?

Record side, ankle position, resistance direction, pain, weakness, snapping, comparison side and related instability findings.

Key Takeaways

Peroneus Longus and Brevis Tests assess lateral ankle tendon loading response.
Pain, weakness and snapping should be recorded separately.
Resisted testing does not confirm tendon tear or subluxation.
Peroneal tendon disorders may coexist with lateral ankle instability.
Measurz should capture muscle bias, position, symptoms and comparison findings.

References

Dombek, M. F., Lamm, B. M., Saltrick, K., & Mendicino, R. W. (2020). Diagnosis and operative treatment of peroneal tendon tears. Foot & Ankle Orthopaedics.

Davda, K., Malhotra, K., O’Donnell, P., Singh, D., & Cullen, N. (2022). Diagnosis and treatment of peroneal tendon disorders. EFORT Open Reviews.