Mediators and moderators of a walking intervention to prevent neck pain among high-risk office workers: a secondary analysis of a randomized controlled trial.

Objectives: To test hypothesized mediators and moderators of the benefits of an app-provided walking intervention for preventing neck pain in high-risk office workers.

Methods: Ninety-one office workers at risk for developing neck pain participated in the primary clinical trial. Two hypothesized mediators (the total number of steps taken and the number of days that participants exceed the number of recommended steps) were tested using a smartphone application every month during a 6-month period. Four hypothesized moderators (number of working hours, level of work psychological demands, chair height adjustability, and body mass index) were assessed at baseline. Parallel mediation and moderation analyses were conducted using the Hayes PROCESS macro, model 4 and 1, respectively, with post-hoc Johnson-Neyman techniques.

Results: The number of days that participants exceeded the recommended steps ‒ the specific number was tailored to each participant, but averaged 7735 steps/day ‒ mediated the benefits of the walking intervention for reducing the risk for neck pain at each of six assessment points (B's range -0.63 to -0.89, all p's < 0.05) over 6-month period. None of the hypothesized moderators evidenced statistically significant moderator effects of the walking intervention.

Conclusion: Workers should walk at rates greater than recommended levels on as many days as possible, rather than attempt to maximize walking within a limited number of days. Given that the walking program studied appeared to be similarly effective across multiple groups of workers, the findings suggest that regular walking can reduce the risk for developing neck pain among high-risk office workers.