RecruitingBehavioural interventionActivity Tracking, Care Partner Co-participation, Text Reminders, Instructional Education, Video-Guided Physical Rehabilitation, and ExerciseThis is a multi-methods two-arm, crossover, analyst-blinded randomized controlled trial with embedded qualitative interviews, enrolling 50 dyads (older adult-care partner). Participants will receive the ACTIVE intervention, which includes a Fitbit smartwatch, motivational text messages to engage in walking exercise, instructional educational videos, and virtual physical therapy sessions. Intervention components will be delivered over 3 weeks, with continuous monitoring of physical activity via Fitbit data, read receipts of the motivational text messages, and log of engagement in the virtual physical therapy and educational videos.