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.