Background
mental disorders
CHRONIC DISEASES
Globalisation and persistent advances in information as well as communication technologies have shaped the modern working world. Also, as a result of these advances, the number of office workers (OWs) has steadily increased in recent decades in western societies [Partially as a result of these typically inactive and mostly digital occupational activities, OWs are exposed to an increased risk of developing chronic diseases, such as mental disorders [To promote HRQOL, the World Health Organisation (WHO) addresses the health behaviour of individuals and specifically underlines the value of physical activity (PA) [Whereas these findings illustrate the potential of HEPA promotion in OWs, explaining PA behaviour is intricate [The Physical Activity-related Health Competence (PAHCO) model specifies competencies that are required in order to lead a physically active, healthy lifestyle and can be placed at the scientific intersection of physical literacy and health literacy [The Physical Activity-related Health Competence (PAHCO) model [In turn, these three sub-competencies arise from the specific coupling and integration of basic elements for PA behaviour [In addition to the basic elements and sub-competencies that foster a physically active, healthy lifestyle, the authors of this model postulate that PAHCO holds the characteristics of a personality trait [Several empirical studies endorse the theoretical assumptions of this model with respect to their relationship to indicators of HEPA and HRQOL by displaying positive connections with PAHCO in various adult samples [However, the findings regarding the effect of PAHCO on HEPA and HRQOL remain tentative, as most of the research on this model has been cross-sectional [The theoretical potential of PAHCO to target the need for promoting HEPA and HRQOL in OWs, in combination with the dearth of longitudinal research on this model, underscores the relevance to testing changeability and temporal stability of the sub-competencies as important conceptual assumptions of the PAHCO model. More specifically, the relevance with respect to temporal stability is particularly indicated for the period beyond 4 months, which was the maximum follow-up period investigated in previous studies. Owing to the importance of these theoretical assumptions for the development of interventions, the first research goal of this study concerns changeability and temporal stability of PAHCO and the sub-competencies of this model in OWs over the course of 18 months, following an in-person, three-week HEPA intervention. The second aim of the present study is to add empirical evidence regarding the postulated effect of the PAHCO subscales on HEPA and HRQOL over the period of 18 months. This second research goal will extends previous cross-sectional findings concerning the connections between PAHCO, HRQOL and indicators of HEPA over the course of the in-person intervention and the 18 month follow-up period.