Scapular Kinematics During Shoulder Elevation Performed With and Without Elastic Resistance in Men Without Shoulder Pathologies

Abstract

STUDY DESIGN: Controlled laboratory study using within-group comparisons. OBJECTIVES: To compare scapular kinematics between active and resisted shoulder elevation performed in the sagittal (flexion), frontal (abduction), and scapular (scapular abduction) planes. BACKGROUND: Several studies have documented scapular kinematics during arm elevation against an external load; however, there is little information on how scapular kinematics change with loading provided by elastic bands, an exercise approach often used in the clinic. METHODS: Thirty-two men without shoulder pathology participated in the study. The level of resistance to be used for each individual was determined prior to data collection and standardized by perceived effort on a Borg scale. Three-dimensional scapular kinematics were recorded with an electromagnetic tracking device in all 3 planes of shoulder elevation for both the unloaded (active) and loaded (resisted) conditions. Data for scapular kinematics were analyzed at 30 degrees, 60 degrees, 90 degrees, and 120 degrees of humerothoracic elevation and lowering. Comparisons between loading conditions were made using analysis-of-variance models. RESULTS: In general, for all 3 planes of movement, the scapula was more downwardly rotated and anteriorly tilted during the elevation phase and more so during the lowering phase of shoulder elevation when performed against elastic resistance. While some of the statistically significant differences might not have been large enough to be considered clinically meaningful, some values were of a magnitude similar to previously reported differences between healthy and symptomatic individuals. CONCLUSION: The changes in scapular motion during the loaded condition were relatively small in this population with normal scapular motion, but they were in a direction that would be-considered to have potential to lead to injuries, suggesting caution when using these exercises in individuals with poor scapular control.