This study will test the within and between day variability of spinal kinematics and trunk muscle activity in healthy subjects and chronic low back pain patients during various daily-life activities. Participants will come twice to the motion laboratory. During the first session, participants will first perform different functional activities (V1), such as sit-to-stand, gait, lifting tasks, stepping up. Their spinal kinematics will be measured with a camera-based system (VICON) using a multi-segment spinal model and trunk muscles activity will be recorded with surface electromyography. After a break, participants will have to perform all the functional activities a second time (V2). These two measures (V1 and V2) will be used to determine the within day variability of spinal kinematics. Finally, all participants will come one week later (V3) to repeat all the measurements to determine the between day variability.
This study will test the within and between day variability of spinal kinematics and trunk muscle activity in healthy subjects and chronic low back pain patients during various daily-life activities.