Relation between functional characteristics of the trunk and the occurrence of low back pain : Associated risk factors

STUDY DESIGN: A 2-year prospective study relating a set of subject characteristics (professional and extraprofessional constraints, personal and anthropometric characteristics, and static and dynamic performance of the trunk) and incidence of low back pain in a population of male Belgian steel workers. OBJECTIVES: To investigate the relation between occurrence of new cases of low back pain and prior personal, anthropometric, or functional characteristics. SUMMARY OF BACKGROUND DATA: Some functional characteristics--in particular, dynamic parameters of the trunk such as the velocity--have been shown to be significantly reduced for low back pain in workers in cross-sectional studies. The question remained as to whether modifications of these parameters preceded the development of low back pain. METHODS: The protocol included a questionnaire, a clinical examination, anthropometric measurements, and a set of functional tests on an isoinertial dynamometer. It was carried out twice, after a 1-year interval, on a sample of 215 workers without any history of low back pain. The reports of low back pain were again investigated 1 year later. RESULTS: The development of low back pain is related to frontal plane imbalance of the trunk, lower body weight, and perception of heavy lifting efforts at the workplace. Individuals performing dynamic tests at higher velocities appear also to be at a greater risk of low back pain. CONCLUSIONS: Although workers with a history of low back pain performed dynamic tests at significantly lower velocities, the probability for development of low back pain in the following year is greater for workers performing such tests at greater velocities.