Abstract
Women experience specific anatomical and physiological changes during pregnancy. These changes cause postural and movement instability and impose excessive strain on body muscles, such as erector spinae, contributing to low back pain (LBP). Sit-to-stand motion includes stretching and bending of the trunk and can potentially cause LBP. The association between some particular motion in sit-to-stand motion and LBP was investigated in a motion analysis using an inertial measurement unit. However, the role of other motion characteristics, such as muscle load, as risk factors of LBP remains unclear. Hence, the determination of causative factor of LBP in sit-to-stand motion based on assessments of both motion and muscle activation is required for managing LBP during pregnancy. Therefore, the purpose of this study was to investigate the relationship among motion, muscle load, and severity of LBP during pregnancy. For this, motion analysis was first conducted in pregnant women to obtain motion, force, and electromyogram data by using an inertial measurement unit, a Wii balance board, and surface electromyography, respectively. Subsequently, the relationship among motion evaluation indexes, erector spinae muscle activation was calculated from obtained data, and the intensity of LBP during sit-to-stand motion were investigated. A statistically significant positive correlation was observed between the pitch angular velocity of the trunk movement and the erector spinae muscle activation and between the muscle activation and the intensity of LBP during pregnancy.
