I would value your thoughts and comments in relation to a theory to support the adoption of an existing training program (within the health space) using co-design and co-production principles.
By reading the related articles to your field you can find the best theory to support your hypotheses. Just read valuable articles that are published in top journals in your field.
I see your research to be very important during the current COVID-19 pandemic. I searched for YOU articles that are relevant:
1) Noella Edelmann, Ines Mergel (2021). Co-Production of Digital Public Services in Austrian Public Administrations, Adm. Sci. 2021, 11(1), 22; https://doi.org/10.3390/admsci11010022, Open access: Article Co-Production of Digital Public Services in Austrian Public ...
2) Elke Loeffler (2020). The Future of Co-production: Policies, Strategies and Research Needs, Co-Production of Public Services and Outcomes, Chapter 7, Nature Public Health Emergency Collection, Open access: Chapter The Future of Co-production: Policies, Strategies and Research Needs
3) Audia, C., Berkhout, F., Owusu, G. et al. Loops and Building Blocks: a Knowledge co-Production Framework for Equitable Urban Health. J Urban Health (2021). https://doi.org/10.1007/s11524-021-00531-4 Open access: Article Loops and Building Blocks: a Knowledge co-Production Framewo...
4) A case-study: Norström, A.V., Cvitanovic, C., Löf, M.F. et al. Principles for knowledge co-production in sustainability research. Nat Sustain 3, 182–190 (2020). https://doi.org/10.1038/s41893-019-0448-2, Open access: https://www.nature.com/articles/s41893-019-0448-2?proof=t
5) Rebecca Hewett, Amanda Shantz (2021). A theory of HR co-creation, Human Resource Management Review, 4 March 2021, In Press, Corrected Proof, Open access: https://www.sciencedirect.com/science/article/pii/S1053482221000024
What do you have in mind? I just recently wrote a paper about using co-design or participatory design practices in the learning design space, so I spent some time on the theoretical backdrop of this approach.