Combined Spinal Motion and Loading in Occupational Low Back Disorders

Abstract

Low back disorders (LBDs) are considered the most prevalent musculoskeletal disorders in occupational settings. There is significant epidemiological and biomechanical evidence that implicates combined motion and loading as important risk factors for LBDs. The purpose of this paper is to demonstrate a potential approach for quantifying 3-D combined motion, loading, and loading rates in ergonomic research. Data from a field study were used to quantify combined; three-dimensional (3-D) trunk velocities of low and high-risk groups, and data from lifting study were used to assess the 3-D combined spinal loading and loading rate. The results showed that evaluating the percent of time the magnitude of 3-D vectors was over defined limits (velocities, loads, or load rates) provides the important temporal aspect of risk factors, which is commonly ignored in LBD risk assessment. The results also showed that loading rate was a sensitive indicator of dynamic loading. In conclusion, the present approach allows the detailed assessment of combined loading and motion, and evaluates the sensitivity of these patterns to various workplace conditions.