“…[17][18][19] Factors that may play an important role in explaining the exercise behavior of people with OA include self-confidence and self-efficacy, 14,17,19 -21 knowledge of the disease and the effects of exercise, 14,18,20 -22 the support and attitude of others, 14,18,20 -24 mental health, 21 and former experience of exercising. 14,18,20,22 Pain and stiffness are common symptoms of arthritis that also can have a significant impact on the attitude and capability of people to exercise, 22,25 as well as the common misunderstanding that OA is something that comes naturally with older age and that nothing can be done about it. 22,26 Moreover, encouragement by a physician to exercise or the lack of such encouragement has been shown to be of importance.…”