Spine-Pelvic Coordination Measured by Lumbar Action Meter (LAM)

Abstract

The spine-pelvic coordination was monitored to find the different pattern when subjects lift different weight. Six healthy subjects participated in the experiment. The free dynamic stooped lifting and lowering was monitored by using lumbar action meter (LAM) developed in Ergomechanics laboratory. LAM is a device with two pieces of portable and wireless parts using tilt and gyro sensors. The top piece was placed on the T12 and the bottom piece was placed on the S1 area. Each subject was requested to perform lowering and lifting three different weights in sagittal plane. Angle-angle plot was drawn to show the spine-pelvic pattern. The velocity and acceleration of the spine and pelvis were also examined to find the different coordination pattern as the weight increased. In results, the spine contribution decreased as the weight increased. However, this pattern varied depending on the temporal phase of lifting. The decrease of the spine contribution was also shown in velocity and acceleration as the weight increased. The spine/pelvis (S/P) ratio showed different coordination patterns in various lifting phases. The application of LAM could be expanded to examine the more complex trunk motion in workplace such as combination of symmetric and asymmetric lifting.