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The Effects of Sitting in a Crossed Legs Posture on the Vertebral Angle, Chest Wall Mobility, Pulmonary Function, and Respiratory Muscle Activity: A Preliminary Study
J Korean Soc Phys Med 2019;14(3):13-20
Published online August 31, 2019;
© 2019 Journal of The Korean Society of Physical Medicine.

Hee-Eun Ahn, MSc, PT⋅Tae-Lim Yoon, PhD, PT1†

Department of Rehabilitation Medicine, Cheongju Samsung Rehabilitation Hospital
1Department of Physical Therapy, College of Health and Medical Science, Cheongju University
Received April 3, 2019; Revised April 15, 2019; Accepted May 31, 2019.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
PURPOSE: Sitting with crossed legs may have an effect on maintaining a healthy body posture and proper functioning of the respiratory system. Thus, this study’s objective was to identify whether or not sitting with crossed legs affects the vertebral angle, chest wall mobility, the pulmonary function, and the activity of the respiratory muscles.
METHODS: Thirty healthy subjects were recruited for this study (16 males and 14 females). The vertebral angle, chest wall mobility, pulmonary function, and the activity of the respiratory muscle were measured while the subjects sat in the correct posture and these factors were again measured with the subjects seated with their legs crossed. Three-dimensional motion analysis was used to determine the trunk and lumbar vertebral angles. Surface electromyography was employed to measure the sternocleidomastoid, the rectus abdominis, and the external and internal oblique abdominis muscles. A tapeline was utilized to evaluate the subjects’ chest wall mobility. Spirometry was assessed to determine the forced vital capacity and forced expiratory volume in one second. Paired t-tests were then performed (p<.05).
RESULTS: There were significant differences in the trunk and lumbar flexion angles, the chest wall mobility, the activity of the right external oblique muscle, and the left internal oblique abdominis muscle. However, the difference in pulmonary function did not reach statistical significance.
CONCLUSION: A crossed leg posture caused slight thoracic extension and lumbar flexion, which may lead to a decrease of the chest wall mobility and also to an imbalance of the abdominal muscles. Therefore, sitting with a crossed leg posture should be avoided. Yet a crossed leg posture did not have any clinical effect on the pulmonary function of healthy people. It may be necessary to study the effects of sitting with crossed legs over an extended period of time for patients suffering with impaired respiratory function.
Keywords : Chest mobility, Crossed legs, Muscle activity, Respiration

August 2019, 14 (3)
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