A participatory physical and psychosocial intervention for balancing the demands and resources among industrial workers (PIPPI): study protocol of a cluster-randomized controlled trial

The public finance and social welfare of western societies is challenged by demographic changes and increasing global commercial competition. Unskilled and semi-skilled workers (blue-collar workers) have an elevated risk of premature and hence costly drop-out from the labor market compared to skilled and white collar workers [1], possibly due to high physical work demands negatively influencing their health [2].

High work demands require high efforts which may deplete the resources of the workers. Over a time period, if sufficient recovery opportunities are not present, continuous depletion of resources can lead to negative effect on individual’s health and well-being and ultimately, in absence of adequate recovery, lead to negative long-term effects such as exhaustion, losses of function, and physical and mental impairment [3,4].

Recent studies demonstrate that these long-term effects are preceded by short-term effects which are indicative of acute current fatigue such as need for recovery (a person’s desire to be temporarily relieved from demands in order to restore his or her resources) ([4], p. 330)). Need for recovery is a very early stage of long-term strain process, and is noticeable in the immediate off-work situation [4]. If sufficient recovery is not achieved, a person must exert additional effort to meet the demands of job next day, and this process may start a vicious cycle leading to prolonged fatigue [4]. Empirical studies have shown that an elevated need for recovery is a predictor of high employee turnover [5], impaired well-being [6], sickness absence [5], psychosomatic [7], sleep and emotional complaints among workers [8]. Therefore, a high need for recovery after work might be a useful indication for the need to initiate preventive interventions and aim to achieve a personal psycho-physiological homeostatic balance [9].

Another scientific concept reflecting the balance between demands and resources of workers is work ability [10,11] defined as “how good is the worker at present, in the near future, and how able is he/she to do his/her work with respect to work demands, health, and mental resources” ([12], p. 3). A decreasing work ability has been documented to be associated with high work demands [13-15], low work resources and stress and burnout [16,17], as well as being a predictor for future sickness absence [13,18] and early retirement [13,19].

A significant proportion of the work tasks in industrial production is performed by blue-collar workers. Blue-collar workers generally experience higher fatigue and need for recovery [8,20] and increased risk of reduced or impaired work ability [21-23]. These conditions make it challenging for blue-collar workers to remain in the workforce until the age of retirement. To the best of our knowledge, few workplace interventions studies have attempted to reduce the need for recovery among blue collar workers [24-26]. Two studies have observed positive results from interventions to reduce need for recovery and increase work ability among female healthcare workers [25,26]. However, it has not been investigated if these intervention effects can be generalized to other work sectors. Similarly, many interventions have focused on improving the work ability of workers, but most studies have observed minor or no improvements [27-30]. Although the ground principle of improving work ability and need for recovery is similar (restoring the balance between demands and resources), none of the previous studies have conducted an intervention focusing on both of these concepts among blue-collar workers [24-30].

The general recommendations for conducting workplace health intervention is that success is more likely if (a) it considers multifactorial components of workers’ health [31], (b) is non-expert driven [32], (c) utilizes a structured approach for generating new action plans and subsequent implementation [33-35], (d) utilizes a participatory approach, and (e) optimally utilizes available resources in the organization to facilitate the implementation of new interventions [31]. It is furthermore important to utilize a multi-dimensional approach, focusing on organizational, psychosocial and physical (ergonomic) work environment factors, in interventions aiming to reduce the need for recovery and improve work ability, as both work ability and need for recovery concepts build on a bio-psycho-social framework [36-38]. Previous studies have predominantly used predetermined expert-developed interventions targeting need for recovery [25] and work ability [27,39]. However, expert driven interventions often result in high noncompliance and problems matching the intervention to the expectations and needs of participants [28]. Thus, tailoring of the intervention through a participatory approach has been shown to promote sustainability of the intervention, empowerment of the workers, increased commitment to the intervention, and increased credibility and implementation of the intervention at multiple levels of the organization [35,40-42]. Another key element to consider when planning an effective intervention is the optimal utilization of available resources in the organization (e.g. health and safety initiatives, management, human resources, and specialists) [31] to facilitate the intervention. The adaptation to contextual resources ensures a better fit of the intervention with the organizational culture, reduces the need for the research group or external consultants to run the intervention and likewise empowers the employees and managers who instead run the intervention, contributes to smooth implementation of the intervention and hence minimizes the financial costs for the company [35]. Finally, interventions targeting need for recovery or work ability are mostly conducted at the individual level only [24,25,27,28,39] with no or short-lasting effects [24,28]. In contrast, organizational interventions [35,43] have the potential to reduce or remove the causes of strain for entire work groups [44] and not only for vulnerable workers. Thus, organizational level interventions are generally recommended for intervening on occupational health problems [45].

To summarize, effective interventions for reducing need for recovery and improving work ability theoretically require a bio-psycho-social, participatory, and structured organizational approach, involving all levels of the organization (i.e. individual, group, leader and organizational) and optimally using the onsite resources.

Therefore, the aim of our study is to evaluate the effectiveness of an intervention based on the aforementioned features on need for recovery and work ability among industrial workers. The objective of this paper is to present the background, design, protocol and evaluation of the “Participatory Physical and Psychosocial Intervention for Balancing the Demands and Resources among Industrial Workers” (PIPPI) intervention. The primary hypothesis of PIPPI is that the intervention will decrease the need for recovery and improve the work ability of the workers.