Arm-to-thigh bracing for light-to-moderate lifting tasks reduces lumbar spine loads

One-handed lifts, frequently used for lifting of light objects or activities of daily living (ADL), are understudied in the biomechanics literature. Twenty healthy participants (30-70 years old) matched in age and sex to 18 participants with low back pain (LBP) were recruited to compare a one-handed braced-arm-to-thigh (BATT) lifting technique to common unsupported one-handed and two-handed lifting techniques. Three-dimensional (3D) trunk kinematics and L4/L5 spinal loading were estimated using a full-body OpenSim model, with detailed lumbar spine. The BATT lift significantly reduced trunk flexion, compared to stoop lifts. Extension moments, compression and antero-posterior shear forces at L4/L5 were significantly reduced with the BATT, compared to unsupported lifting techniques. Peak bracing force on the thigh varied substantially between participants.