Stay@Work was designed as a cluster-RCT to investigate the effects of a PE programme to prevent LBP and NP among workers. Based on their workload, 37 departments from four Dutch companies (a railway transportation company, an airline company, a university including its university medical hospital, and a steel company) were classified into: mentally, mixed mentally and physically, light physically, or heavy physically demanding work [
19]. To avoid contamination from workers allocated in the intervention group to those in the control group randomisation was performed at a departmental level. Within each company, pairs of departments with comparable workloads were randomly allocated to either the PE intervention group or the control group (no PE). By using a computer-generated randomisation programme, 19 departments were allocated to the intervention group and 18 to the control group.
Each intervention department formed a working group, consisting of eight workers and one (department) manager. Workers invited for the working group had to have worked at least two years in their current job, and for more than 20 hours per week in the department. The (department) manager in the working group, had to have decision authority on organisational and financial aspects.
Under the guidance of an ergonomist, 16 working groups (for 19 intervention departments) followed the steps of the Stay@Work PE programme during a six-hour working group meeting. In this meeting, working group members added risk factors of LBP and NP, and judged all mentioned risk factors on their frequency and severity (step one). Based on the perceptions of the working group, the most frequent and severe risk factors were prioritised, resulting in a top three of risk factors (step two). Subsequently, the working group held a brainstorming session about different types of ergonomic measures to target the prioritised risk factors and evaluated the ergonomic measures according to a criteria list considering: relative advantage, costs, compatibility, complexity, triability, feasibility, and visibility [
20]. Further, the ergonomic measures had to be implementable within a timeframe of three months. On a consensus basis, the working group prioritised the three most appropriate ergonomic measures (step three). An implementation plan was formed containing information on the prioritised risk factors for the development of LBP and NP and the prioritised ergonomic measures to prevent LBP and NP (step four). The implementation plan also described which working group member(s) was/were responsible for the implementation of the prioritised ergonomic measure(s); these working group members were called 'implementers.' At the end of the meeting, the working group was requested to implement the ergonomic measures (step five) and was asked whether an appointment for a second, optional meeting was necessary to evaluate or adjust the implementation process (step six). Altogether the working group meetings resulted in 66 prioritised ergonomic measures. According to the classification by van Dieën and van der Beek (2009) the prioritised ergonomic measures were classified into three categories [
21]: individual ergonomic measures that were aimed at the individual worker (
i.e., improving awareness regarding ergonomics, worksite visit, physical activity programs); physical ergonomic measures that were aimed at redesigning the workplace (
i.e., ergonomic modification, new equipment, or manual handling aids), and organisational ergonomic measures that were aimed at changing the system level (
i.e., pause software installation, job rotation, or restructuring management style). Most of the prioritised ergonomic measures addressed either individual (n = 32) or physical (n = 27) ergonomic measures, whereas organisational ergonomic measures (n = 7) were less prevalent [
9]. To improve the implementation process, two or three implementers from each working group were asked to voluntary follow a training programme to become a Stay@Work ergocoach. A total of 40 implementers attended the ergocoach training [
9]. In this additional four-hour implementation training, they were educated in different implementation strategies to inform, motivate, and instruct their co-workers about ergonomic measures. Moreover, ergocoaches were equipped with a toolkit consisting of flyers, posters, and presentation formats. These types of implementation strategies have been recommended to induce behavioural change [
22,
23].