Higher intensity exercise reduces disability more than lower intensity exercise in adults with chronic low back pain: A systematic review and meta-analysis.

BACKGROUND Intensity is an important determinant of physiological adaptations and health benefits of exercise, but the role of exercise intensity on improving outcomes in people with chronic low back pain (CLBP) is unclear. This systematic review aimed to determine the effect of higher versus lower intensity exercise intensity on pain, disability, quality of life and adverse events in people with CLBP. METHODS Six databases and four clinical trial registries were searched from inception to 21 December 2022, for randomised controlled trials that compared two or more exercise intensities in adults with CLBP. Data were analysed using random-effects meta-analysis for disability and synthesised narratively for pain, quality of life and adverse events due to limited studies. Risk of bias was assessed using the Cochrane tool and certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluations framework. RESULTS Four trials (n = 214 participants, 84% male) reported across five studies were included. Higher intensity exercise reduced disability more than lower intensity exercise at end-treatment (SMD [95% CI] = -0.39 [-0.56 to -0.22]; very low certainty) but not at 6-month follow-up (SMD [95% CI] = -0.20 [-0.53 to 0.13]; very low certainty). Higher intensity exercise did not reliably improve pain and quality of life more than lower intensity exercise. Adverse events did not differ between exercise intensities. All studies were at high risk of bias. CONCLUSION Based on very low certainty evidence from a limited number of studies, exercise intensity does not appear to meaningfully influence clinical outcomes in people with CLBP.