Objectives: to determine whether exercise is more effective than usual care to reduce work disability in patients with non-acute non-specific low back pain, and if so, to explore which type of exercise is most effective. Methods: Systematic review and meta-analysis of randomized controlled trials investigating the effectiveness of exercise in non-acute non-specific low back pain, and reporting on work disability. Data sources: MEDLINE, EMBASE, PEDro, Cochrane Library databases, NIOSHTIC-2, and

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... sycINFO until August 2008. Work disability data were converted to odds ratios. Random effects meta-analyses were conducted. Results : A total of 23 trials met the inclusion criteria, 20 of which were suitable for inclusion in meta-analysis allowing 17 comparisons of exercise interventions with usual care and 11 comparisons of 2 different exercise interventions. A statistically significant effect in favour of exercise on work disability was found in the long term (odds ratio (OR) = 0.66, 95% confidence interval (CI) 0.48-0.92) but not in the short (OR = 0.80, 95% CI 0.51-1.25) and intermediate term (OR = 0.78, 95% CI 0.45-1.34). Meta-regression indicated no significant effect of specific exercise characteristics. Conclusion: Exercise interventions have a significant effect on work disability in patients with non-acute non-specific low back pain in the long term. No conclusions can be made regarding exercise types.