Examining the sustainability and effectiveness of co-created physical activity interventions in vocational education and training: a multimethod evaluation

BACKGROUND: Co-creation approaches are increasingly used in physical activity promotion to develop interventions tailored to the target group and setting. The resulting complexity of such interventions raises challenges in evaluation. Accordingly, little is known about the effectiveness of co-created interventions and the underlying processes that impact their sustainable implementation. In this study, we attempt to fill this gap by evaluating co-created multi-component physical activity interventions in vocational education and training in nursing care and automotive mechatronics regarding (1) their sustainable implementation at the institutional level and (2) the effectiveness of single intervention components at the individual level. METHODS: Following a multimethod design, we conducted a questionnaire survey (n = 7) and semi-structured interviews (n = 4) to evaluate the sustainability of the interventions. Quantitative data were analyzed descriptively, and qualitative data were analyzed using qualitative content analysis. To examine the interventions’ effectiveness, we conducted two non-randomized controlled trials (n = 111). Analysis of variance was used to examine differences between groups. RESULTS: At the institutional level, long-term implementation of single intervention components in nursing care was observed; in contrast, long-term implementation in automotive mechatronics was not observed. In this context, various factors at the outer contextual (e.g., COVID-19 pandemic), inner contextual (e.g., health-promoting leadership), intervention (e.g., acceptance), and personal levels (e.g., champion) influenced sustainability. At the individual level, no significant intervention effects were found for changes in physical activity behavior and physical activity-related health competence. CONCLUSION: The role of co-creation on the effectiveness and sustainability of physical activity promotion in vocational education and training cannot be answered conclusively. Only in the nursing care sector, a co-creation approach appeared promising for long-term intervention implementation. Sustainable implementation depends on various influencing factors that should be considered from the outset. Demonstrating effectiveness at the individual level was challenging. To conclusively clarify both the role and impact of co-creation, methodologically complex and elaborate evaluation designs will be required in future research projects. TRIAL REGISTRATION: This study was retrospectively registered at clinicaltrials.gov on 24/08/2021 (NCT05018559). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-022-13133-9.