Comparison of postures according to sitting time with the leg crossed

[Purpose] The purpose of this study was to identify postural changes in adults who have adopted the habit of sitting with their legs crossed. [Subjects and Methods] The subjects were 232 adults in their 20s and 30s (84 males and 148 females). They were divided into 0-, 1-, 2-, and 3-hour or more groups by observing how much time per day they sat with their legs crossed while sitting on a chair. We measured the postural alignment of all the subjects in the sagittal plane and coronal plane. In the sagittal plane, distances from the line of gravity to the external auditory meatus, the shoulder joints, the knee joints, and the calcaneocuboid joint were measured. In the coronal plane, the shoulder inclination and the pelvic tilt were measured. [Results] The shoulder joints, the knee joints, and the calcaneocuboid joint did not show any significant differences, but the head was aligned further forward in the 3-hour group compared to the other groups. In the coronal plane, the acromion processes and the anterior superior iliac spines of the 3-hour group showed statistically significant differences than those of all of the other groups. [Conclusion] The results indicate that sitting with the legs crossed for longer than three hours per day may cause shoulder inclination, lateral pelvic tilt and forward head posture.