CHANGE IN THE COORDINATES OF THE CENTER OF PRESSURE DEPENDING ON SITTING POSTURES

Abstract

Aim. The authors aim to determine the coordinates of the center of pressure in various sitting postures. Materials and methods. The study involved 22 persons (11 males and 11 females) ages from 20 to 50 years. The MBN Stabilo force platform was installed on a chair with a rigid metal frame. Eight tests were conducted in various sitting postures 30 seconds each. The averaged data on three indicators were analyzed: X – center of pressure in the frontal plane; Y – center of pressure in the sagittal plane; Z – body weight. Results. The analysis of the averaged coordinates of the center of pressure in the frontal plane (X axis) when sitting straight indicates its displacement to the right. The center of pressure in the sagittal plane (Y axis) depends on a sitting posture: in 5 sitting postures, the center of pressure was characterized by forward displacement, in 3 sitting postures, the center of pressure was characterized by backward displacement (compared to when sitting straight). When sitting legs under the chairthe maximum values of body weight were recorded (increase by 16.2% compared to when sitting straight), when the body was tilted forward body weight decreased by from 57.8% to 74.8% (compared to when sitting straight). Conclusion. The study showed significant differences in the location of the center of pressure in various sitting postures. The center of pressure in the frontal plane (X axis) when sitting straight could be considered as a criterion for early diagnostics of pelvic and spinal displacement. The center of pressure in the sagittal plane (Y axis) combined with body weight (Z axis) could be used as an indicator of sitting posture.