A posture and load sampling approach to determining low-back pain risk in occupational settings

A posture and load sampling approach to measure physical exposures was implemented within a case-control study of low-back pain reporting. The purpose of this paper was to determine how well this method was able to identify known low-back pain risk factors. Subjects, including both cyclic production and non-cyclic support workers, were studied while working in an automotive assembly facility. The study included 104 (with 20 proxies) cases, workers who reported low-back pain at work, and 129 randomly selected controls. Results indicate significant associations between low-back pain reporting and peak spinal loads (OR=2.0 for compression), shift-average spinal loading (OR=1.7 for compression), percent of time with loads in the hand (OR=1.5), maximum flexion angle (OR=2.2), and percent of time spent forward flexed beyond 45°(OR=1.3). Posture and hand load variables, considered to be intermediate exposure variables, were handled separately in multivariable regression analyses from variables of peak and average spine force which directly estimate tissue loading. The work and posture sampling approach is particularly useful for heterogeneous work situations where traditional task analysis is difficult and can provide information on work and tissue load parameters which have been directly associated with risk of reporting low-back pain.Relevance to industryThis paper demonstrates the effectiveness of an observational method in quantifying workplace exposures to physical risk factors for low-back pain. The method works for both cyclic and non-cyclic work. Quantified risk assessment provides key information for decision makers trying to control injury rates in industrial systems.