Objective This study evaluated the effectiveness of the promotion of postural shift intervention using a dynamic seat cushion on the 6-month incidence of neck and low-back pain among high-risk office workers.

Methods In a cluster-randomized controlled trial (RCT), 133 office workers were randomly assigned, at cluster level, to intervention (N=67) and control (N=66) groups. The intervention group received a dynamic seat cushion to encourage postural shifts during sitting, while the control group received a placebo seat pad. Primary outcomes were 6-month incidence of neck and low-back pain. Secondary outcomes included sitting discomfort, pain intensity, disability, and trunk muscle performance. Analyses utilized Cox proportional hazard models.

Results During the 6-month period, 15% of participants in the intervention group developed neck pain and 10% developed low-back pain. For the control group, this was 65% and 59%, respectively. Hazard rate (HR) ratios, after adjusting for biopsychosocial factors, indicated a protective effect of the intervention for neck pain [HR_adj 0.19, 95% confidence interval (CI) 0.09–0.39, P<0.001] and low-back pain (HR_adj 0.16, 95% CI 0.07–0.35, P<0.001). The intervention group demonstrated a significant reduction in sitting discomfort and improvement in trunk muscle performance compared to the control group (P<0.05). However, the intervention did not reduce pain and disability in individuals experiencing pain compared to the control group.

Conclusions The dynamic seat cushion effectively reduced the incidence of neck and low-back pain by promoting postural shifts. These findings suggest that the key factor in reducing the risk of developing neck and low-back pain is the facilitation of postural shifts during sitting, which can potentially be achieved with other dynamic interventions designed to reduce prolonged and static sitting among office workers.

Key terms cluster-randomized controlled trial; discomfort; dynamic sitting; low-back pain; muscle activity; neck pain; office worker; postural shift; seat cushion

• Supplementary material