Background: In orthopaedic practice, it is well established that weak scapular stabilizers and an unstable scapula is related to shoulder dysfunction. Faulty scapular position has been linked to decreased scapular stability and is thought to be a result of weak or unbalanced timing in the recruitment of scapulothoracic dynamic stabilizing muscles. Kibler has described a four-type classification of scapulothoracic dysfunction. Functional performance testing is used to objectively measure activities that simulate various desired activities. The reliability of assessing the four static scapular positions may be important in diagnosing shoulder dysfunction. An understanding of the scapular position and its relationship to functional performance testing is needed.
Purpose: The purpose of this study was to determine if a static scapular test, the Kibler scapula classification, in healthy participants affects the ability to perform a closed chain functional test that involves the use of the scapula and the upper extremity, the Davies Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST). A secondary analysis was performed to evaluate the reliability of a student physical therapist and an experienced physical therapist to identify scapular type by observation.
Study design: Multicenter, single session descriptive cohort.
Methods: Sixty-one healthy participants (33 males, 28 females; mean age 24.19±2.61) completed testing across two locations in one testing session. Blood pressure and heart rate as well as height and weight were measured for each participant. Participants were classified by visual observation of Kibler scapular classification. The average number of CKUEST touches, a normalized score, and a power score were calculated for each participant. Three trials were performed and participants were required to take a 45-second rest break between each CKCUEST trial.
Results: One way analysis of variance (ANOVA) showed statistically significant differences in Type I and Type IV Kibler scapula classification for the CKCUEST power score, however when an ANCOVA controlled for body mass index, there was no statistically significant difference. A strong correlation r=.94 was observed between student and experienced physical therapist in evaluating all four types of Kibler scapular classification.
Conclusions: Visually observed Kibler scapular position does not affect the ability to perform the Davies CKCUEST in healthy young adults. The ability to identify Kibler scapular position was reliable between student and experienced physical therapists. Additional studies are required to identify the usefulness of the Kibler scapular position classification.
Level of evidence: 2b: Individual Cohort Study.
Keywords: davies closed kinetic chain upper extremity stability test; kibler scapular classifications; movement system; upper extremity performance tests.