Relation between Biomechanical Spinal Load Factors and Risk of Occupational Low-Back Disorders

Abstract

The objective of this study was to identify individual and combinations of biomechanical parameters which are associated with the probability of risk for occupationally related low-back disorders. Ten subjects performed lifting tasks simulating warehouse order selection. During the lifting exertions dynamic trunk motion, EMG, and workplace data were collected. Risk of low-back disorder was assessed from an epidemiologic model incorporating workplace factors and trunk motion data. Comparison with biomechanical results indicated that static estimates of spinal compression poorly predicts the probability of risk. Spinal compression computed from dynamic models improve the correlation, and regression models including multi-dimensional dynamic spinal loads and load rates best predict the probability of risk. The results agree with biomechanical research demonstrating vertebral failure modes are influenced by complex biomechanical interactions. This study highlights the limitations of ergonomic assessment via static compression, demonstrates the influence of biomechanical interactions upon risk of LBD, and advocate greater efforts toward understanding complex dynamic interactions in human factors research.