Background/objectives:
Knowledge of individual preferences is central to designing interventions adaptable in terms of the different requirements of older adults regarding interventions for the promotion of physical activity (PA). This study aimed to evaluate acceptance and use of a blended PA intervention, including tailored home-based exercises and supervised on-site group sessions, and to identify requirements.

Methods:
As part of a nine-month randomized trial with a cross-over design, web- and print-based intervention materials to promote PA were tested in adults aged 60 and above (n=242). Use and acceptance of program components were assessed via self-administered questionnaires three and nine months after baseline. Additionally, participant feedback was assessed in fourteen guided group interviews and via protocols of onsite group sessions. Results were analyzed descriptively and using qualitative content analysis. Data were coded based on six social-ecological requirement levels (intrapersonal, interpersonal/sociocultural, intervention content, spatial, digital, organizational).

Results:
At the intrapersonal level, participants reported an increased awareness of health benefits resulting from participation. At the interpersonal level, they stated that group sessions provided companionship, encouragement from others, and opportunities for exchange with peers. At the content level, exercises and instructions for increasing strength, balance, and flexibility were appreciated. At the spatial level, participants raised small room sizes and lack of suitability of the spaces that group sessions were held in as issues. At the digital level, activity trackers were reported working well for keeping track of personal achievements and the website design was rated positively. However, some participants had difficulties handling the menus on the web interface or app. At the organizational level, regular appointments were rated positively, while the length of the program was criticized.

Conclusion:
Our analysis provided information regarding acceptance and use of PA intervention components in older adults and identified requirements for future interventions at various levels.