In the dark about physical activity - exploring patient perceptions of physical activity after elective total knee joint replacement: a qualitative study.

Limited understanding of physical activity recommendations, prioritisation of participation in meaningful life situations, rehabilitation that was impairment focused and other health and social reasons appeared to contribute to low levels of moderate-intensity physical activity for adults after knee joint replacement. Addressing being in the dark about physical activity may be an important first step to increase the effectiveness of behavioural interventions designed to promote physical activity after total knee joint replacement.