Swedish healthcare and national strategies advocate person-centred care (PCC), emphasising partnership and individualised communication. For lifestyle-related diseases such as knee osteoarthritis, physical activity is a cornerstone of treatment. Yet, how patients perceive physical activity remains underexplored, despite its potential impact on adherence and outcomes. This study applies a phenomenographic approach to examine perceptions of physical activity among 20 participants in a digital osteoarthritis programme. Interviews explored how patients define physical activity and assess their own activity levels. Data analysis is ongoing, and full results will be presented at the conference. Preliminary findings indicate diverse perceptions, with most participants associating physical activity primarily with exertion and strenuous exercise. This contrasts with scientific definitions, which often include all bodily movements resulting in energy consumption or any daily activity. The discrepancy may result in misunderstandings and affect how patients respond to advice and create barriers to effective self-management. Such discrepancies, underscoring the need for tailored communication that aligns with individual understanding. Understanding these different perceptions of physical activity is critical for implementing PCC in practice. Tailored communication strategies that reflect patients’ perceptions could enhance engagement and improve outcomes. These results will inform future research and policy initiatives aimed at integrating PCC principles into digital health interventions for lifestyle-related conditions.