Physical activity and fitness are increasingly recognized as important outcomes in the follow-up and treatment of patients with juvenile idiopathic arthritis. In the past, major concerns were on the detrimental effects of physical exercise; now evidence is growing on the beneficial effects of exercise. The purpose of these exercise programs is to promote a more active lifestyle and/or enhance physical fitness. This article will review the findings of recent studies in juvenile idiopathic arthritis in the area of physical fitness, physical activity and training. It is advised that clinicians are discussing appropriate levels of physical activity (daily participation in >60 min of moderate-to-vigorous physical activity) with their patients in clinical consultations.