The effects of sitting with the right leg crossed on the trunk length and pelvic torsion of healthy individuals

[Purpose] The purpose of this study was to determine the effects on the trunk length and pelvic torsion of healthy individuals that arise from crossing the right leg while sitting. [Subjects and Methods] The subjects in this study were 30 healthy individuals consisting of 18 males and 12 females. The subjects were instructed to sit on a chair, the height of which was adjustable, so that their knee and hip joints were bent at 90°. For the study, they sat stripped to the waist, with the back and hips bare. They were then instructed to perform a one-leg-crossed sitting posture by placing the right leg on the top of the left knee. A spinal posture test was performed to measure the subjects' trunk length and pelvic torsion by using a three-dimensional image-based spinal diagnostic system. [Results] The results of the three-dimensional spine examination showed statistically significant decreases in trunk length and pelvic torsion after the one-leg-crossed sitting posture. [Conclusion] In this study, the right leg-crossed sitting posture led to a decrease in the right trunk length with time and, in terms of pelvic torsion, increased the posterior rotation of the right pelvis when compared with the left pelvis.