Effectiveness of physical training for self-employed persons with musculoskeletal disorders: a randomized controlled trial

Background: Despite the fact that the population of self-employed persons is still growing and at risk for long term disability due to a number of risk factors, there is still a lack of information on the effectiveness of interventions for this specific group. Methods: To determine the effectiveness of physical training without a cognitive behavioral component and workplace specific exercises (PT) and physical training with a cognitive behavioral component and workplace specific exercises (PTCBWE), we conducted a pragmatic Randomized Controlled Trial, stratified into two groups. Self-employed persons with a new work disability claim because of musculoskeletal disorders were randomized to PT (n = 53) or PTCBWE (n = 76), or to a corresponding usual care group (n = 50 and n = 75 respectively). Both types of training consisted of cardiovascular training, strengthening, relaxation and posture exercises and took place two or three times a week, for 11.5 hours, during three months, also if someone had already returned to work full-time. The primary outcome measure was claim duration (in days) during 12 months follow-up. Pain severity and functional status were secondary outcome measures. All data were assessed at baseline and at 6 and 12 months follow-up. The data with regard to claim duration were analyzed by survival analysis and Cox regression analysis. Secondary outcome measures were analyzed by means of linear regression analysis. Results: After 12 months of follow-up there was no difference in claim duration between PT and usual care (Hazard Ratio 0.7; 95% CI, 0.4-1.1; p = 0.12) or PTCBWE and usual care (Hazard Ratio 0.9; 95% CI, 0.6-1.4; p = 0.72). Both types of physical training and usual care improved in pain and functional status over time, but there was only a statistically significant difference in favor of PT on pain improvement at 6 months. Conclusion: In this study, physical training with and without a cognitive behavioral component and workplace specific exercises for self-employed persons with musculoskeletal disorders was not shown to be effective on claim duration, pain severity and functional status at 12 months follow-up.