The Effects of Lifting Techniques on the L5-S1 Joint: Lifting Different Loads from Ground Level

Manual material lifting is a common activity in daily life and industrial work environments, placing significant stress on the L5/S1 joint in the lower back. This study aims to compare the biomechanical impacts of squat and stoop lifting techniques on the L5/S1 joint to assess load distribution and potential injury risks in manual handling tasks. In contrast to previous studies using boxes with handles, our experiments involve lifting cargo boxes from the bottom without handles, providing a more realistic simulation for cargo handling workers. Five healthy male participants performed squat and stoop lifts with weights of 4, 8, 12, and 16 kg. Markerless motion capture was conducted using the Kinect v2 sensor, and kinematic and kinetic data were analyzed with the OpenSim biomechanical modeling software. Results indicated that squat lifting reduced compression forces by approximately 9% and shear forces by 25% at the L5/S1 joint compared to stoop lifting for heavier loads. These findings align with previous literature, demonstrating that squat lifting may better distribute loads across the lumbar spine, suggesting it as a potentially safer method for handling heavier loads.