Use and appreciation of combined computer- and mobile-based physical activity interventions within adults aged 50 years and older: Randomized controlled trial

Objective To investigate whether six combined computer- and mobile-based physical activity interventions differ regarding use, attrition, usability and appreciation among adults aged 50 years and older. Methods The interventions were studied in a randomized controlled trial. Participants were allocated to the computer-based Active Plus or I Move program including a mobile-based activity tracker, or ecological momentary intervention (EMI), or chatbot, or to a waiting list control group. Use and attrition were investigated via log data gathered within the intervention software. Appreciation was assessed via online evaluation questionnaires. ANOVAs and Chi-squares were performed to test for intervention differences on use, attrition and appreciation (p <= .05). Results A total of 954 participants aged 50 years and older with varying health conditions were included. Attrition differed between interventions (chi(2) = 27.121, p < .001) and was the highest in I Move including chatbot (58.4%) and lowest in I Move including activity tracker (33.0%). Appreciation differed between interventions (p < .001) and was the highest for interventions including activity tracker, followed by interventions including EMI and lowest for interventions including chatbot. Technical issues were primarily faced by EMI- and chatbot-participants. EMI-participants reported mainly that they received no or few text messages. Chatbot-participants reported mainly that the step count application was not working properly. Conclusions The integration of mobile-based activity trackers with computer-based interventions has high potential for increasing use and lowering attrition among adults aged 50 years and older. The process evaluation findings can guide future intervention optimization procedures, other eHealth and mHealth developers and practitioners.