Task-specific pain-related fear influences lifting biomechanics differently in individuals with and without occupations involving repetitive lifting tasks

Higher task-specific pain-related fear has been linked to restricted lumbar spine range of motion (ROM) during lightweight object lifting in chronic low back pain (LBP) patients and reduced lumbar spine flexion angles in healthy individuals, suggesting protective movement strategies. However, it remains unclear whether these findings apply to individuals who repetitively lift heavier objects at work. This study aimed to determine whether the effect of task-specific pain-related fear on lifting kinematics differs between individuals with (LIFTER) and without (NON-LIFTER) occupations involving repetitive lifting, and to quantify how this effect depends on object weight, task (lifting or lowering), and LBP history. 156 healthy individuals provided information on previous LBP episodes, completed pain-related fear questionnaires, and lifted 5-kg and 15-kg boxes. Kinematic outcomes included lumbar spine ROM and whole-body lifting strategy. Linear mixed models revealed that the effect of task-specific pain-related fear on lumbar spine ROM significantly differed between group (NON-LIFTER vs. LIFTER: -0.087), weight (5 kg vs. 15 kg: 0.026), and task (lifting vs. lowering: 0.059), but not LBP history (No LBP vs. LBP: -0.005). Higher task-specific pain-related fear was associated with reduced lumbar spine ROM in NON-LIFTER but not in LIFTER, suggesting that fear-driven protective movement strategies vary by occupation.