Can low back loading during lifting be reduced by placing one leg beside the object to be lifted?

Abstract

Background and Purpose. Lifting technique could, through its effect on low back loading, affect the risk of developing low back pain. In this study, 2 lifting techniques (a straddle technique and a 1-leg kneeling technique), which aimed to reduce low back loading by placing one leg beside a load, were compared with stoop lifting and squat lifting with respect to their effect on low back loading. Subjects, Twelve men with no history of low back pain participated in the study. Methods. The subjects lifted wide and narrow 20-kg boxes from 2 initial hand heights. With measured kinematics, ground reaction forces, and electromyography, 3-dimensional spinal forces were calculated. Results. When the subjects lifted a narrow box from a 290-mm height, peak L5-S1 compression forces were 5,060 (SD=827), 3,980 (SD=701), 4,208 (SD=762), and 4,719 (SD=1,015) N for the stoop, squat, straddle, and kneeling techniques, respectively. When the subjects lifted a wide box from 50 mm, spinal compression forces were much higher and distributed differently over lifting techniques: 5,926 (SD=610), 6,868 (SD=924), 6,472 (SD=1,042), and 6,064 (SD=968) N, respectively. Discussion and Conclusion. The authors conclude that no single lifting technique can be advised for all lifting conditions.