Scapular Assistanse Test

The Scapular Assistance Test (SAT) is a biomechanical and clinical tool used to evaluate the role of scapular movement dysfunction in shoulder pain and impaired function. Coordinated scapular motion is essential for normal shoulder mechanics, particularly during humeral elevation, when the scapula moves in upward rotation, external rotation, and posterior tilt¹.

The SAT is used to:

• Assess whether abnormal scapular kinematics contribute to shoulder symptoms (e.g., pain, motion restriction).

• Determine if manual facilitation of scapular movement reduces symptoms or improves function.

• Guide rehabilitation strategies targeting scapular stability.

It is particularly useful for diagnosing scapular dyskinesis and its contribution to impingement syndrome, rotator cuff pathology, or related shoulder disorders².

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Biomechanical background

The scapula plays a central role in shoulder mechanics, providing a stable base for glenohumeral movement.

• Reduced upward rotation, posterior tilt, or external rotation may lead to subacromial impingement and rotator cuff dysfunction by narrowing the subacromial space.

• The SAT evaluates whether restoring optimal scapular motion (through manual assistance) reduces symptoms, thus clarifying the functional contribution of the scapula.

Test execution

Patient position

• The patient is standing or seated, allowing free arm movement.

Examiner position

• The examiner stands behind the patient to manually control scapular motion.

Procedure

1. Baseline movement

   • The patient actively elevates the arm (in the sagittal or scapular plane) until pain or restriction occurs.

2. Scapular assistance

   • One examiner hand is placed at the inferior angle of the scapula to assist upward rotation.

   • The other hand is placed on the superior scapula to facilitate posterior tilt and external rotation.

   • A controlled force is applied to simulate normal scapular dynamics during arm elevation.

3. Repeat arm elevation

   • The patient elevates the arm again while the examiner assists scapular motion.

Interpretation

• Positive SAT

  • Reduction in pain or increased range of motion with assisted scapular movement.

  • Indicates scapular dyskinesis is a significant contributor to the patient’s shoulder symptoms.

• Negative SAT

  • No improvement in pain or motion.

  • Suggests the problem is primarily glenohumeral or related to other structures.

Rehabilitation implications

A positive SAT indicates that scapular-focused interventions may be beneficial, including:

• Strengthening of the lower trapezius, serratus anterior, and rhomboids.

• Mobility training and motor control exercises to restore scapular stability.

Diagnostic validity and evidence

Clinical reliability

• In the scapular plane: kappa coefficient 0.53, agreement 77%².

• In the sagittal plane: kappa coefficient 0.62, agreement 91%².

• These results indicate good reliability, especially when performed by experienced clinicians.

Biomechanical and EMG support

• Acromiohumeral distance: SAT increases the distance between the acromion and humeral head, reducing subacromial compression⁴.

• Muscle activation: EMG studies show increased activation of serratus anterior and lower trapezius during SAT, which alleviates symptoms and restores scapular kinematics⁴.

Limitations

• Skill-dependent: Accurate execution requires good understanding of scapular biomechanics.

• Subjective interpretation: Relief of pain or improved motion may vary between patients and clinicians.

• Not a stand-alone test: SAT is best used in combination with other assessments, such as the Scapular Dyskinesis Test or Scapular Retraction Test, for comprehensive evaluation.

Conclusion

The Scapular Assistance Test is a valuable clinical tool for identifying the scapular contribution to shoulder dysfunction. A positive SAT indicates that scapular-focused rehabilitation may reduce symptoms, improve function, and restore normal shoulder mechanics.

References

1. Seitz AL, McClure PW, Lynch SS, Ketchum JM, Michener LA. Effects of scapular dyskinesis and scapular assistance test on subacromial space during static arm elevation. Journal of Shoulder and Elbow Surgery. 2012 May 1;21(5):631-40.

2. Rabin A, Irrgang JJ, Fitzgerald GK, Eubanks A. The intertester reliability of the scapular assistance test. Journal of Orthopaedic & Sports Physical Therapy. 2006 Sep;36(9):653-60.

3. Clinical Physio. Scapula Assistance Test | Clinical Physio. Available from: http://www.youtube.com/watch?v=Lj_NoWvpjYA[last accessed 26/6/2024]

4. Ribeiro LP, Barreto RP, Pereira ND, Camargo PR. Comparison of scapular kinematics and muscle strength between those with a positive and a negative Scapular Assistance Test. Clinical Biomechanics. 2020 Mar 1;73:166-71.