Effects of Changing Hip Position on Scapular Kinematics

The effects of hip position and posture on scapular kinematics have yet to be explored. The purpose of this study was to measure differences in scapular kinematics with changing hip position. Scapular kinematics were measured during scapular plane humeral elevation. Twenty-four subjects were required to elevate the dominant arm up to 120° in the following randomized conditions: standing, seated, seated ipsilateral hip flexion, and seated contralateral hip flexion. Two-way analyses of variance were used to evaluate effects of shoulder elevation and hip position on scapular upward rotation, posterior tilt (PT), and external rotation. For external rotation, there was no significant interaction (P = .714) and no main effect of elevation (P = .618) or condition (P = .390). For PT, there was no significant interaction (P = .693) but significant main effects of elevation (P < .001) and condition (P < .001), with the greatest PT in standing. For upward rotation, there was no significant interaction (P = .698), a significant main effect of elevation (P < .001), and no significant effect of condition (P = .726). The effect on PT may not be clinically significant. These results may serve as a baseline measurement of healthy scapular kinematics across hip positions.