A prospective, cluster-randomized controlled trial of exercise program to prevent low back pain in office workers
The objective of this study was to evaluate the effects of an exercise program focusing on muscle stretching and endurance training on the 12-month incidence of low back pain (LBP) in office workers. A 12-month prospective cluster-randomized controlled trial was conducted in healthy office workers with lower-than-normal trunk extension flexibility or trunk muscle endurance. Healthy office workers (n = 563) were randomly assigned at the cluster level into either intervention (n = 282) or control (n = 281) groups. Participants in the intervention group received an exercise program that included daily stretching exercise and twice-a-week muscle endurance training. Those in the control group received no intervention. The 12-month incidence of LBP was the primary outcome. Secondary outcome were pain intensity, disability level, and quality of life and health status. Analyses were performed using the Cox proportional hazard models. Over the 12-month follow-up, 8.8 % of participants in the intervention group and 19.7 % in the control group developed incidence of LBP. Hazard rate ratios showed a protective effect of the exercise program for LBP (HR = 0.37, 95 % CI 0.22–0.64) after adjusting for biopsychosocial factors. There was no significant difference in pain intensity, disability, and quality of life and health status between those who reported incidence of LBP in the intervention and control groups. An exercise program consisting of muscle stretching and endurance training is an effective intervention to reduce incident LBP for office workers with lower-than-normal trunk extension flexibility or trunk muscle endurance.