Objectives This study aimed to evaluate the effects of an exercise programme focusing on muscle stretching and endurance training on the 12-month incidence of neck pain in office workers.

Methods A 12-month prospective cluster-randomised controlled trial was conducted in healthy office workers with lower-than-normal neck flexion movement or neck flexor endurance. Participants were recruited from 12 large-scale enterprises. A total of 567 healthy office workers were randomly assigned at the cluster level into either intervention (n=285) or control (n=282) groups. Participants in the intervention group received an exercise programme that included daily stretching exercise and twice-a-week muscle endurance training. Those in the control group received no intervention. The primary outcome measure was the 12-month incidence of neck pain, and the secondary outcome measures were pain intensity, disability level, and quality of life and health status. Analyses were performed using the Cox proportional hazard models.

Results Over the 12-month follow-up, 12.1% of participants in the intervention group and 26.7% in the control group developed incident neck pain. Hazard rate ratios showed a protective effect of the exercise programme for neck pain (HR=0.45, 95% CI 0.28 to 0.71) after adjusting for biopsychosocial factors. There was no significant difference in pain intensity, disability and quality of life and health status between those who reported incident neck pain in the intervention and control groups.

Conclusions The exercise programme reduced incident neck pain and increased neck flexion movement for office workers with lower-than-normal neck flexion movement.