Examining assessment methods of scapular motion: Comparing results from planar elevations and functional task performance

Background: Scapular kinematics of breast cancer survivors are most often evaluated during arm elevation. However, known compensations exist during functional task performance. The purpose of this study was to determine if scapular kinematics of breast cancer survivors during arm elevation are related to scapular kinematics during functional task performance. Methods: Scapular kinematics of 25 non-cancer controls and 25 breast cancer survivors (split by presence of impingement pain) during arm elevation in 3 planes and 3 reaching and lifting functional tasks were measured. Scapular upward rotation and scapulohumeral rhythm (SHR) at 30 increments of arm elevation were calculated. Between-group differences of upward rotation during arm elevation were evaluated with one-way ANOVAs < 0.05). The association of upward rotation angle and SHR during arm elevation and functional tasks was tested with Pearson correlations (p < 0.05). Findings: Scapular upward rotation was reduced for the breast cancer survivor with pain at lower levels of arm elevation in each plane by up to 7.1 degrees (p =.014 to 0.049). This is inconsistent with functional task results, in which upward rotation decrements occurred at higher levels of arm elevation. Upward rotation angles and SHR during arm elevation had an overall weak-to-moderate relationship (r = 0.003 to 0.970, p = .001 to 0.048) to values from functional tasks. Arm elevation during sagittal plane elevation demonstrated scapular upward rotation that was most closely associated to upward rotation during functional task performance. Interpretation: Inconsistent relationships suggests that clinical evaluations should adopt basic functional movements for scapular motion assessment to complement simple arm elevations.