In recent years, increased attention has been devoted to intergenerational physical activity (PA) programs because they may have several benefits for both children and older adults (e.g., the reduction of ageism). An intergenerational PA program focusing on grandchildren and grandparents in a 'standard' family setting that combines PA and cognitive function is innovative and may hold potential for promoting PA and improving cognitive functioning in both grandchildren and grandparents. The aim of this study is to describe the protocol of the GRANDPACT (GRANDparents and GRANDchildren improve their Physical Activity and Cognitive functions using co-creaTion) Project, focusing on the development of an intergenerational, cognitively enriched, movement program for grandchildren and grandparents using the theoretical framework of the "Behaviour Change Wheel" in combination with a co-creation approach. Two co-creation trajectories will be organized to develop the program, followed by a pilot study to refine the program and an RCT with a pre-test (at baseline), a post-test (after 24 weeks), and a follow-up (after 36 weeks) to measure the outcomes of co-PA, cognitive functions, psychosocial well-being, and the quality of the family relationship ingrandchildren and grandparents. The outcomes will be measured using accelerometry for PA, the Cambridge Neuropsychological Test Automated Battery (CANTAB) for cognitive functions, and questionnaires for the psychological well-being and quality of the family relationship. Co-development with end-users and stakeholders during both co-creation trajectories is expected to result in an effective, attractive, and feasible program. Co-PA is expected to improve PA, cognitive functioning, psychosocial well-being, and the quality of the family relationships between grandchildren and grandparents.
Keywords: cognitive functioning; grandchildren; grandparents; intergenerational; intervention; physical activity; study protocol.