In-vivo measurements of force and humeral movement during inferior glenohumeral mobilizations.

BACKGROUND

Inferior joint mobilization has been proposed as an assessment technique and an intervention for individuals with shoulder dysfunctions. While such techniques are common, few quantitative in vivo measures of manual movement of the humeral head have been reported.

OBJECTIVE

The purpose of this study was to measure in vivo inferior translational movements occurring in the glenohumeral joint during manual mobilization techniques and to determine the intratester reliability of those inferior translational movements.

DESIGN

Cross sectional reliability study.

METHODS

Twenty three healthy volunteers participated. Subjects were positioned supine with the shoulder in 55 degrees of abduction and 30 degrees of horizontal adduction. Visualizing the humeral head and the acromion, ultrasound images of the superior aspect of the glenohumeral joint were taken with the arm at rest and as an examiner applied a grade 1, a grade 2 and a grade 3 inferior mobilization. This process was repeated three times on each shoulder. Humeral head position was measured in reference to the superior aspect of the acromion and the amount of inferior movement determined by the distance the humeral head moved from the rest position.

RESULTS

The mean differences between the rest position and a grade 1, a grade 2 and a grade 3 mobilization were 0.96 mm, 2.44 mm and 3.64 mm respectively. Intraclass correlation coefficients (ICC) for movements were moderate for grade one (ICC = 0.681) and good for grade 2 (0.889) and grade 3(0.898).

CONCLUSIONS

Results support the ability of one examiner to reliably reproduce three different grades of inferior mobilization.