Kinematic Analysis of the Spine during Pelvic Tilting in the Sitting Position

Abstract

The purpose of this study was to clarify the relationship between spinal curvature and hip joint angle during pelvic tilt movement in the sitting position. [Subjects] The subjects were 18 healthy adult males (mean age: 24.7±3.7). [Methods] We measured the pelvic tilt angle, hip joint angle, and spinal curvature (upper thoracic spine, lower thoracic spine and lumbar spine) during pelvic tilt movement with a three-dimensional motion analysis system. [Results] The hip flexion, the lower thoracic extension and the lumbar extension increased with increasing pelvic anterior tilt in the sitting position. The hip extension, lower thoracic flexion and lumbar flexion increased with pelvic posterior tilt. The movable range of pelvic tilt exhibited positive correlation with the movable range of the lower thoracic spine (anterior tilt: r=0.47, posterior tilt: r=0.54). [Conclusion] The pelvis movement and the hip and spine motion influenced each other. The results suggest that the movable range of pelvic tilt is required to maintain spinal mobility, because there was a positive correlation between the movable range of the pelvic tilt and that of the lower thoracic spine.