Comparison of four peak spinal loading exposure measurement methods and their association with low-back pain

Objectives This paper examines the performance of 4 different methods of es timating peak spinal loading and their relationship with the reporting of l ow-back pain. Methods The data used for this comparison was a subset of subjects from a c ase-referent study of low-back-pain reporting in the automotive industry, i n which 130 random referents and 105 cases (or job-matched proxies) were st udied. The peak load on the lumbar spine was determined using a biomechanic al model with model inputs coming from a detailed self-report questionnaire , a task-based check list, a video digitization method, and a posture and l oad sampling technique. Results The methods were directly comparable through a common metric of new tons or newton meters of spinal loading in compression, shear, or moment mo des. All the methods showed significant and substantial associations with l ow-back pain in all modes (odds ratios 1.6-2.3). The intraclass correlation coefficients (TCC) showed strong similarities between the checklist and vi deo digitized techniques (ICC 0.84-0.91), moderate similarities between the se techniques and the work sampling method (ICC 0.49-0.52), and poor correl ations (ICC 0.16-0.40) between the self-report questionnaire and the observ er recorded measures. Conclusions While all the methods detected significant odds ratios, they ca nnot all be used interchangeably for risk assessment at the individual leve l. Peak spinal compression, moment, and sheer are important risk factors fo r low-back pain reporting, no matter which measurement method is used. Ques tionnaires can be used for large-scale studies. At the individual level a t ask-based checklist provides biomechanical model inputs at lower cost and e qual performance compared with the criterion video digitization system.