A client reports pain over the top of the shoulder when pressing, reaching across the body, pushing through the arm, lying on the shoulder or returning to gym-based upper-limb loading. The Resisted AC Joint Extension Test may reproduce familiar localised AC joint pain by loading the shoulder into resisted extension.

The test should not be explained as confirming an AC joint sprain, arthritis or separation on its own. A better interpretation is that it documents whether a specific resisted shoulder position reproduces familiar pain over the AC joint region.

 What Is the Resisted AC Joint Extension Test?

The Resisted AC Joint Extension Test is a shoulder pain provocation test used when AC joint involvement is suspected. The client’s shoulder is positioned in flexion, then the examiner applies resistance as the client attempts to extend the arm.

The test is considered meaningful when it reproduces the client’s familiar localised pain over the AC joint region. General shoulder discomfort, posterior shoulder pain, muscular effort or vague upper-limb discomfort should not automatically be recorded as a positive AC joint result.

Why It Is Used

The test is used when the clinical question involves possible AC joint contribution to shoulder pain.

It may be useful when the client reports symptoms during:

Horizontal pressing
Bench press
Push-ups
Dips
Cross-body movements
Reaching across the body
Lying on the affected shoulder
Contact or impact to the shoulder
Upper-limb loading tasks

The test may help document pain behaviour and guide further assessment of AC joint tenderness, cross-body loading, pressing tolerance, shoulder ROM, strength and functional loading.

What It Assesses

The test assesses pain response over the AC joint during resisted shoulder extension.

It does not isolate one structure. A positive result may reflect AC joint sensitivity or load intolerance, but it does not confirm a specific tissue source, grade of injury, degenerative change or structural diagnosis.

Who It Is Useful For

This test may be useful for clients with pain at the top of the shoulder during pressing, pushing, cross-body movements, overhead loading, contact sport, gym training or work tasks involving upper-limb loading.

It may also be useful when the professional wants to compare AC joint provocation tests with broader shoulder findings such as ROM, strength, functional tolerance and symptom location.

When to Use This Test

Use this test when resisted shoulder extension can be performed safely and the clinical question involves AC joint pain provocation.

It is most useful when the client’s symptoms are localised around the AC joint and the professional wants to determine whether a resisted extension position reproduces familiar pain.

When Not to Use or When to Be Cautious

Use caution with acute trauma, suspected fracture, high-grade AC joint injury, severe pain, visible deformity, recent surgery, instability, high irritability or inability to tolerate resisted shoulder movement.

Avoid forcing the test if the client guards, reports sharp escalation of pain, cannot position the arm safely or has symptoms that suggest the test is not appropriate at that time.

Equipment Required

Chair or standing assessment space
Pain and symptom scale
Measurz recording workflow
Optional comparison side notes
Optional video if movement quality or compensation needs to be reviewed

Step-by-Step Protocol / Practice

Setup

Position the client sitting or standing with the trunk upright.

Client position

The tested arm is raised forward to approximately 90 degrees of shoulder flexion, depending on the protocol used and client tolerance.

Examiner position

Stand beside or slightly behind the client so you can control the arm position and apply resistance safely.

Hand placement

Support or guide the distal humerus, forearm or wrist depending on the setup. The other hand may stabilise the shoulder girdle or trunk if required.

Stabilisation

Control the trunk and scapular region as needed so the client does not rotate, lean or compensate during the resisted movement.

Movement or force direction

Ask the client to push the arm backwards into shoulder extension while you resist the movement. The resistance should be controlled and strong enough to provoke the test position without forcing or overpowering the client.

Instructions

Ask the client to report pain location, intensity, quality and whether the symptoms are familiar.

Positive finding

A positive finding is reproduction of familiar localised pain over the AC joint region during resisted shoulder extension.

Negative finding

A negative finding is no familiar AC joint pain during the resisted movement.

Stopping criteria

Stop if pain increases sharply, guarding occurs, the client cannot maintain the position, symptoms become unacceptable or the test cannot be performed with control.

Safety notes

Do not force the shoulder into position or apply sudden resistance. Record whether pain is localised to the AC joint or whether symptoms are more general, posterior, muscular or non-familiar.

Positive and Negative Test Interpretation

A positive Resisted AC Joint Extension Test may support AC joint pain provocation reasoning when it reproduces familiar, localised pain over the AC joint.

It does not confirm a specific AC joint diagnosis by itself. Pain may relate to AC joint sensitivity, previous trauma, degenerative change, local tissue irritation, load intolerance or other shoulder contributors.

A negative test does not exclude AC joint involvement, especially if symptoms only occur under heavier loads, fatigue, sport-specific positions or cross-body loading.

Sensitivity, Specificity and Diagnostic Accuracy

The Resisted AC Joint Extension Test has been studied as part of AC joint physical examination research. Reported diagnostic values have included:

Sensitivity: 72%
Specificity: 85%

These values suggest the test may provide useful information when AC joint involvement is suspected, but it should not be used in isolation. It is best interpreted with other AC joint tests, symptom location, palpation, history, comparison side and functional loading.

A cluster of AC joint tests may improve interpretation, but even test clusters should be interpreted cautiously and matched to the client’s full presentation.

Reliability and Validity

Reliability depends on consistent shoulder position, resistance direction, resistance intensity, symptom criteria and examiner handling.

The test is more meaningful when the positive finding is defined clearly as familiar, localised AC joint pain rather than general shoulder discomfort. Validity is limited when the test is used as a stand-alone diagnostic tool or when any pain is treated as positive.

Common Errors and Limitations

Common errors include applying sudden resistance, failing to stabilise the trunk, recording general shoulder discomfort as positive, ignoring pain location, failing to compare sides and using the test to diagnose AC joint pathology on its own.

Limitations include variable resistance force, symptom overlap with other shoulder conditions, pain irritability, examiner technique differences and limited single-test certainty.

Practical Applications

Use the Resisted AC Joint Extension Test to document whether resisted shoulder extension reproduces familiar AC joint pain.

It is most useful when combined with AC joint palpation, Cross-Body Adduction Test, O’Brien’s Active Compression Test, shoulder ROM, pressing tolerance, push-up or bench press symptoms and upper-limb strength testing.

How to Record This in Measurz

Record test name, side tested, result, pain score, symptom location, symptom quality, shoulder position, resistance direction, comparison side, guarding, compensation, confidence in result and reason for stopping.

Useful notes include whether pain was localised to the AC joint, whether symptoms were familiar, whether pain was muscular or general, whether the client compensated through trunk movement and whether the result matched other AC joint findings.

Add related findings such as AC joint palpation, Cross-Body Adduction Test, O’Brien’s Active Compression Test, shoulder ROM, bench press tolerance, push-up tolerance and overhead symptoms.

Related Tests / Internal Links

Cross-Body Adduction Test
O’Brien’s Active Compression Test
AC Joint Palpation
Paxinos Test
Shoulder ROM Tests
Shoulder Strength Testing
Bench Press Repetition Maximum Test
Push-Up Assessment
Hawkins-Kennedy Test
Neer’s Test

FAQs

What does the Resisted AC Joint Extension Test assess?

It assesses whether resisted shoulder extension reproduces familiar localised pain over the AC joint region.

What is a positive Resisted AC Joint Extension Test?

A positive finding is reproduction of the client’s familiar localised AC joint pain during resisted shoulder extension.

Does it diagnose an AC joint injury?

No. It may support AC joint pain provocation reasoning, but it does not diagnose a specific AC joint condition on its own.

Should general shoulder discomfort count as positive?

No. The result is more meaningful when pain is familiar and localised to the AC joint region.

Should the test be forced?

No. The resistance should be controlled and stopped if symptoms escalate or the client cannot tolerate the position.

What should be recorded?

Record side, pain score, symptom location, shoulder position, resistance direction, comparison side, compensation and whether symptoms were familiar.

Key Takeaways

The Resisted AC Joint Extension Test is an AC joint pain provocation test.
A meaningful positive result should reproduce familiar localised AC joint pain.
It does not diagnose a specific AC joint condition on its own.
Interpret it with AC joint palpation, cross-body loading, O’Brien’s test, ROM, strength and functional findings.
Measurz should capture side, pain score, symptom location, test position, resistance direction and test tolerance.

References

Chronopoulos, E., Kim, T. K., Park, H. B., Ashenbrenner, D., & McFarland, E. G. (2004). Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. The American Journal of Sports Medicine, 32(3), 655–661. https://doi.org/10.1177/0363546503261723

Gismervik, S. Ø., Drogset, J. O., Granviken, F., Rø, M., & Leivseth, G. (2017). Physical examination tests of the shoulder: A systematic review and meta-analysis of diagnostic test performance. BMC Musculoskeletal Disorders, 18, 41. https://doi.org/10.1186/s12891-017-1400-0

Zhang, A. L., et al. (2024). Evidence-based approach to the shoulder examination for subacromial bursitis and rotator cuff tears: A systematic review and meta-analysis. BMC Musculoskeletal Disorders, 25, Article 911.