INTRODUCTION & AIMSRunning is common and one of the most accessible forms of exercise training, yet the suitability for adults with chronic low back pain is unknown. This study assessed the efficacy and feasibility of running in adults with chronic low back pain (LBP) and explored the relationship between training parameters and pain intensity.METHODSThis two-arm parallel (1:1) individually randomised controlled trial allocated 40 participants (mean [SD] age: 33 [6] years, female: 50%) with non-specific chronic LBP to a 12-week intervention or waitlist control. The intervention was a progressive run-walk interval program comprising three 30-minute sessions per week, that were digitally delivered and remotely supported by an exercise physiologist. Efficacy outcomes were self-reported average and current pain intensity (100-point visual analogue scale) and disability (100-point Oswestry Disability Index). Training parameters examined were fortnightly adherence, pace and distance.RESULTSAt 12-week follow-up, the intervention decreased average pain intensity (mean net difference [95%CI]: -15.30 [-25.33, -5.27] points, P=0.003), current pain intensity (-19.35 [32.01, -6.69] points, P=0.003) and disability (-5.20 [-10.12, -0.24] points, P=0.038), compared to control. There was no attrition and mean (SD) training adherence was 70% (20%; i.e. 2.1 of 3 sessions per week). Nine non-serious adverse events deemed potentially study-related were reported (lower limb injury/pain: n=7, cardiac syncope associated with an underlying condition: n=1, LBP: n=1). Greater fortnightly adherence (-0.04 [-0.33, 0.25] points), pace (0.23 [-0.48, 0.02] points) and distance (-0.03 [-0.13, 0.06] points) tended to be associated with greater reductions in pain intensity, yet did not reach statistical significance.CONCLUSIONRunning was feasible and improved pain intensity and disability in individuals aged 18-45 years with non-specific chronic LBP when compared to control. An individualised and conservative run-walk program should be considered a suitable form of physical activity for adults with chronic LBP.