Objective evaluation of bilateral scapulothoracic movement asymmetry: Normative data for scapular dyskinesis risk assessment
Description
Scapular dyskinesis (SD) is quantified as asymmetrical abnormal movement of the scapulae in relation to the thorax. While SD is commonly observed in the general population, especially in overhead athletes, objective measures to evaluate pathology risk are not currently available. The existing methods to measure SD dyskinesis include the lateral scapular slide test, four-category method, and scapular dyskinesis test, all lack objectivity necessary to help quantify the risk of developing pathology. Data from 15 right-handed male subjects without pathology were gathered and processed measuring bilateral scapulothoracic motion during shoulder flexion, abduction and scaption. Data was obtained utilizing 3D motion capture technology. The bilateral scapulothoracic (ST) motions assessed were scapular upward rotation, posterior tilt, and internal rotation. Comparing dominant vs non-dominant arm, the dominant side showed significantly higher upward and internal rotation in the scapular plane, higher upward rotation in the coronal and higher upward rotation, internal rotation and anterior tilt in the sagittal plane. The overall mean (95% CI), normative / non-pathological bilateral asymmetry found was 9.3% (3.2 – 15.5), with consistently higher asymmetry observed in all ST movements during arm elevations on the sagittal plane. Asymmetries beyond this normative range can be indicative of shoulder pathological risk.
Citation Information
Krieg, Garret and Vardaxis, Vassilios, "Objective evaluation of bilateral scapulothoracic movement asymmetry: Normative data for scapular dyskinesis risk assessment" (2026). Office of Research DMU Research Symposium. 19.
https://digitalcommons.dmu.edu/researchsymposium/2025rs/2025abstracts/19
Objective evaluation of bilateral scapulothoracic movement asymmetry: Normative data for scapular dyskinesis risk assessment
Scapular dyskinesis (SD) is quantified as asymmetrical abnormal movement of the scapulae in relation to the thorax. While SD is commonly observed in the general population, especially in overhead athletes, objective measures to evaluate pathology risk are not currently available. The existing methods to measure SD dyskinesis include the lateral scapular slide test, four-category method, and scapular dyskinesis test, all lack objectivity necessary to help quantify the risk of developing pathology. Data from 15 right-handed male subjects without pathology were gathered and processed measuring bilateral scapulothoracic motion during shoulder flexion, abduction and scaption. Data was obtained utilizing 3D motion capture technology. The bilateral scapulothoracic (ST) motions assessed were scapular upward rotation, posterior tilt, and internal rotation. Comparing dominant vs non-dominant arm, the dominant side showed significantly higher upward and internal rotation in the scapular plane, higher upward rotation in the coronal and higher upward rotation, internal rotation and anterior tilt in the sagittal plane. The overall mean (95% CI), normative / non-pathological bilateral asymmetry found was 9.3% (3.2 – 15.5), with consistently higher asymmetry observed in all ST movements during arm elevations on the sagittal plane. Asymmetries beyond this normative range can be indicative of shoulder pathological risk.
