Asymmetrical change in the pelvis and the spine during cross-legged sitting postures

• Published in: Journal of mechanical science and technology Vol. 27; no. 11; pp. 3427 - 3432
• Main Authors: Ahn, Soonjae, Kim, Seunghyeon, Kang, Sunyoung, Jeon, Hyeseon, Kim, Youngho
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2013; Springer Nature B.V; 대한기계학회
• Subjects: Control; Dynamical Systems; Engineering; Industrial and Production Engineering; Mechanical Engineering; Vibration; 기계공학; Asymmetry; Motion analysis; Low back pain; Cross-legged sitting
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-013-0865-5

People spend much time with cross-legged sitting by increasing the time spent in the chair. Prolonged cross-legged sitting postures might cause spinal disorders and trunk asymmetry problems. We investigated the biomechanical effects of cross-legged sitting postures on the pelvic and spinal regions. 3D-motion analyses were performed on 26 healthy subjects. Data were collected while the subjects sat in four different postures: the control posture (without crossed legs) of sitting upright on the chair; the knee-on-knee (KoK) posture (the right knee on the left knee), the ankle-on-knee (AoK) posture (the right ankle on the left knee) and the ankle-on-ankle (AoA) posture (the right ankle on the left ankle). EMG signals were also collected for abdominal muscles. Cross-legged sitting postures showed significantly greater kyphotic curves in the lumbar and the thoracic spines and pelvic posterior tilting, when compared with the control posture. The pressure on the right buttock area was greater in the AoK posture than in the control posture, and the pressure on the left buttock area in the KoK posture was greater than in the control posture. Cross-legged sitting postures showed significantly greater external oblique muscle activation when compared with the control posture.