Changes in Acromiohumeral Distance with Clinician-Applied and Self-Applied Inferior Glenohumeral Joint Mobilizations Measured Using Ultrasound Imaging

OBJECTIVE: To measure the change in acromiohumeral distance during clinician-applied and self-applied manual shoulder joint mobilization. We hypothesized that the acromiohumeral distance would be significantly greater with clinician-applied manual joint mobilizations (MJM) than with self-applied joint mobilization (SJM). DESIGN: Within-subject, repeated-measures design. METHODS: Nineteen healthy adults (mean age: 22.9 ± 1.2 years) participated. A traction force of 15% body weight was applied during MJM and SJM. Acromiohumeral distance was measured via ultrasound imaging at rest (baseline) and during the 2 test conditions (2 trials each) to quantify inferior accessory motion. The transducer was placed at the anterolateral border of the acromion, and the subacromial space was clearly visualized for acromiohumeral distance measurements. RESULTS: The ICC for acromiohumeral distance measurements ranged from 0.876 to 0.963. Changes in acromiohumeral distance during MJM (3.90 ± 0.51 mm) were significantly greater than SJM (1.68 ± 0.49 mm, P <.001). Acromiohumeral distance changes between sexes: MJM (female: 3.16 ± 0.58 mm, male: 5.15 ± 0.90 mm, P = .060), SJM (female: 0.88 ± 0.51 mm, male 3.05 ± 0.90 mm, P = .029). CONCLUSIONS: Our acromiohumeral distance measurement methodology had excellent test-retest reliability. There was significantly more inferior humeral accessory motion with MJM than SJM. The acromiohumeral distance was 132% greater during MJM and was unchanged or less than resting baseline measurements in almost a third of participants during SJM. JOSPT Open 2025;3(2):114-120. Epub 5 November 2024. doi:10.2519/josptopen.2024.0079