A comparison of sitting posture adaptations of pregnant and non-pregnant females

The postural differences between seated pregnant and non-pregnant subjects were studied, and the effects of various sitting workstation designs were assessed. Five pregnant and five non-pregnant subjects participated in this study. The experimental variables were the table-chair-vertical-distance (35cm and 30cm) and the seat-inclination-angle (0°, +10°and +20°). The seated working postures of the last 10 min of a 50-min sitting session were videotaped and analyzed using a 2D motion analysis system. Postural differences were observed between the pregnant and non-pregnant groups which may be attributed to the changes and/or mechanisms associated with pregnancy. The increased size of the abdomen requires more room in front of the body; in the pregnant subjects this was obtained by holding the upper-arm further from the body, inclining the upper trunk more anterior, and extending the hip more. A seat with a sloping angle of 10°was found to reduce the biomechanical loading on the lower back and in subjective ratings from both groups, was preferred over the other seat angles. Relevance to industry. Pregnant women make up a small but significant part of the workforce. Changes in body form and working posture due to pregnancy change the effective working envelope and increase the biomechanical loads on the musculoskeletal system resulting in an increase in the risk of lower-back pain. This study examined the posture adaptations and the effects of workstation design on pregnant and non-pregnant subjects. Copyright (C) 1999 Elsevier Science B.V.