A kinematic study of lateral movement in the sitting position

Abstract

Lateral movement in the sitting position is a task which is used in evaluation and treatment in clinical practice. Also lateral movement in the sitting position can be seen in many activities of daily living. However, patients with dysfunction of the hip muscles have more difficulty performing lateral movement in the sitting position than healthy person, because, they cannot raise the opposite side buttock from the weight-bearing surface. To do lateral movement in the sitting position is reported to require lateral tilt of the pelvis. The trunk is displaced to the moving side by this lateral tilt of the pelvis. Furthermore, lateral movement in the sitting position requires muscle activity of the hip muscles that hold the lateral tilt position of the pelvis. Lateral tilt of the pelvis in lateral movement in the sitting position is a movement of the hip joint. TO promote smooth lateral movement in the sitting position, it is necessary to know the kinematics of the hip joint. However, the kinematics of the hip joint are different between sitting and standing postures. For this reason, interpretation of the kinematics of the hip joint is difficult in lateral movement in the sitting position. In this paper, we measured COP, and surface EMG of the hip girdle muscles during lateral movement in the sitting position following the procedures of a previous study, and carried out a video analysis of the displacement of the pelvis. We also examined the factors involved in successful lateral tilt of the pelvis in lateral movement in the sitting position.