Patients are recruited from primary care health care settings in Västervik and Luleå in Sweden and in Trondheim and Mosjöen in Norway. Patients are informed about the project both verbally and also through written information. Based on this information, patients that would like to participate in the project, contact the local investigation center to be assessed for possible inclusion. We are planning to include a total of 200 patients with radiographic-verified knee osteoarthritis with knee pain and decreased function. The patients have to be within the 45 to 85 age group, come for three treatments a week, a total of 36 treatments for 12 weeks, and must not have had any treatments or organized form of exercise therapy for their knee pain the last three months. Patients are also excluded if they have been scheduled for knee surgery or have some other form of illnesses/disease that limits exercise tolerance (e.g. heart disease or systemic/metabolic diseases or chronic obstructive airways disease). Patients that fulfill the inclusion criteria will be randomized either to high dosage medical exercise therapy or low dosage exercise therapy.