Healthy ageing is an important concern for many societies facing the challenge of an ageing population. Physical activity (PA) is a major contributor to healthy ageing [
1,
2] that has been shown to reduce risks for many chronic diseases and injuries. Enhanced PA improves cardiometabolic markers, lowers resting blood pressure and decreases the risk for diabetes mellitus type II [
3‐
5]. Positive mental health and cognitive effects of exercise have also been described [
6]. The World Health Organization (WHO) recommends that older adults aged 65 years and above should engage in at least 150 min of moderate-intensity aerobic physical activity weekly in order to gain and/or maintain health benefits [
7]. Flexibility and strength training is also recommended at least two times per week to increase mobility skills and reduce the risk of falling [
8]. Thus, PA is a key health resource for an ageing community. In spite of these well-known beneficial effects, only one third of older adults in Germany are physically active; 25.4% of male and 15.5% of female persons over the age of 70 reach the WHO-recommended levels [
9]. In addition, there are notable differences in participation rates in behaviour-oriented health promotion programs across socioeconomic status (SES) and sex [
10]. While a wide range of primary prevention activities on PA are available in Germany [
11], a major knowledge gap in identifying which interventions are successful for specific target populations remains. Evidence suggests that tailoring interventions to the needs of the target group increases the intervention’s reach and efficacy [
12]. Furthermore, it has been demonstrated that tailoring PA interventions to stages of individual behaviour change may enhance intervention reach and effectiveness [
13]. This may also be the case at a community level. A systematic review by Stith et al. [
14] concluded that a community should fulfil four conditions before a preventive intervention can be successfully implemented: (i) sufficient community capacity exists, i.e., a functioning community coalition is installed; (ii) the community recognizes that there is a problem, and that existing programs cannot solve the problem sufficiently (iii) a key person/ organization is identified; and (iv) an appropriate climate for implementation exists, i.e., stakeholders benefit from participation or at least have no drawbacks from or high cost for participation. The use of community capacity building approaches to reach and engage at-risk groups and local stakeholders in their natural living environment is a promising way of avoiding social selectiveness in service participation and achieving sustainable program implementation [
15‐
17]. The concept of community readiness outlines an approach to increase a community’s readiness to participate in a health behaviour change intervention. It applies a stage-based behaviour change model to the community level [
18,
19]. According to this concept, a certain degree of problem awareness and pre-planning in the community is crucial for a health promotion intervention to be successfully implemented [
18‐
20]. It is therefore recommended to assess and, if necessary, increase community readiness before starting an intervention. Depending on the stage of community readiness (9 stages ranging from no problem awareness to professionalization of interventions), the model suggests different strategies to enhance program implementation. The model has already been successfully applied in diverse fields of community based health promotion such as HIV/AIDS prevention, suicide prevention and prevention of cardiovascular disease [
21‐
23]. These studies report on the usefulness of the model for community capacity building. However its utility for reaching vulnerable populations for PA interventions and overall cost-effectiveness have not yet been systematically investigated.
The
Ready To Change (RTC) study is part of the
Physical Activity And Health Equity: Primary Prevention For Healthy Ageing (AEQUIPA) project, a regional prevention research network in Northwest Germany funded by the German Federal Ministry of Education and Research (BMBF). The AEQUIPA research network includes several interlinked projects which employ theory-based empirical research methods to develop, implement and evaluate PA and mobility interventions for older adults aged 65–75 years. The network’s overall aim is to strengthen the evidence base for PA in the context of healthy ageing. The RTC study investigates the utility of strategies to increase community readiness for older adults’ participation in a PA intervention. As reaching vulnerable groups is among the aims of community based strategies for health promotion, we specifically investigate whether increasing community readiness leads to higher participation rates in traditionally hard-to-reach population groups (e.g., low SES, migrants, physically inactive or obese persons). Models and empirical investigations of access to health service indicate that service uptake is influenced by system factors, such as community readiness, but also by individual factors (e.g., attitude, knowledge, need) [
24‐
26]. Hence, individual factors have to be considered when analysing non-participation in PA interventions. A qualitative investigation may add to a deeper understanding of non-participation by providing a biographical account of motives that led to non-participation. Thus, an exploration of reasons for (non-)participation was added to the aims of this study.