Effects of Changing Hip Position on Scapular Kinematics

Area of Science:

• Biomechanics
• Kinesiology
• Orthopedics

Background:

• Scapular kinematics are crucial for shoulder function.
• The influence of hip position on scapular movement is not well understood.
• Understanding these relationships can inform rehabilitation and performance.

Purpose of the Study:

• To investigate the impact of different hip positions on scapular kinematics.
• To quantify changes in scapular upward rotation, posterior tilt (PT), and external rotation during arm elevation.
• To establish baseline data for healthy scapular movement across various postures.

Main Methods:

• Twenty-four subjects performed dominant arm elevation to 120° in the scapular plane.
• Measurements were taken in four randomized conditions: standing, seated, seated with ipsilateral hip flexion, and seated with contralateral hip flexion.
• Two-way ANOVAs analyzed the effects of shoulder elevation and hip position on scapular kinematics.

Main Results:

• Posterior tilt (PT) showed significant main effects for both elevation and hip condition (P < .001), with the greatest PT observed in the standing position.
• Scapular external rotation and upward rotation did not show significant effects related to hip position (P > .390).
• While PT was affected by hip position, the clinical significance may be limited.

Conclusions:

• Hip position influences scapular posterior tilt, particularly in the standing posture.
• Scapular external rotation and upward rotation are not significantly affected by hip position during this specific arm movement.
• These findings provide baseline data on healthy scapular kinematics concerning hip positioning.