Association Between Lateral Pelvic Tilt and Asymmetry in Sitting Pressure Distribution

Physical therapists commonly associate lateral pelvic tilt (LPT) with a variety of musculoskeletal adaptations, syndromes and altered function. Such musculoskeletal adaptations have been suggested in many reports to cause unequal sitting pressure distribution (SPD) at the buttock/chair interface. However, those reports have failed to provide objective evidence to support that hypothesis. This study was conducted to examine the relationship between LPT and SPD in a sample of healthy female volunteers. Subjects were tested for pelvic symmetry using an anthropometric frame, then assigned to two groups: symmetrical (n = 36) and LPT (n = 9). SPD was measured in an upright sitting posture using an interface pressure mat. Although the results indicated that there were no significant differences between the two groups in the magnitude and position of the peak pressure, there was a greater variability among subjects in the LPT group than the symmetrical group. This observation is worth further investigation as it tends to indicate that persons with LPT are less likely able to maintain a steady sitting position.