Background
Clinical guidelines recommend physical activity for the treatment of chronic low back pain. But engaging patients in physical activity has proven difficult. Known obstacles to physical activity include low self-efficacy and fear avoidance.

Objectives
This study tested the effectiveness of an enhanced transtheoretical model intervention (ETMI) aimed at increasing recreational physical activity in patients with chronic low back pain, in comparison to usual physical therapy.

Methods
Patients (n = 220) referred to physical therapy for chronic low back pain were allocated to ETMI or to a control group. The ETMI was delivered by physical therapists and based on behavior-change principles, combined with increased reassurance, therapeutic alliance, and exposure to reduce fear avoidance. The primary outcome was back pain-related disability (Roland-Morris Disability Questionnaire). Secondary outcomes included pain intensity, mental and physical health, and levels of physical activity.

Results
Intention-to-treat analysis in 189 patients at 12 months indicated that patients in the ETMI group had significantly lower disability compared to usual physical therapy. The difference in mean change from baseline between the interventions was 2.7 points (95% confidence interval: 0.9, 4.5) on the Roland-Morris Disability Questionnaire. At 12 months, worst pain, physical activity, and physical health were all significantly better in patients receiving ETMI. The average number of sessions was 3.5 for the ETMI group and 5.1 for controls.

Conclusion
Targeting obstacles to physical activity with an intervention that includes components to address self-efficacy and fear avoidance appears to be more effective than usual physical therapy care in reducing long-term disability. Further research is needed to explore the mechanisms that impact outcomes in this intervention package.