sed individually minimum 40 minutes of endurance training, either an 
additional session with interval training or a session with long-distance training. The Danoprevir exercise program was individually adapted to the participant’s fitness level and a physical therapist was responsible for an adequate progression of the intensity level during the exercise period. The maximal HR of each participant was determined during the baseline test and the HR was controlled with a HR monitor to individually tailor the intensity. Attendance at the supervised exercise sessions was recorded by the physical therapist. The weekly self-imposed exercise session was first recorded in the pulse watch and thereafter weekly reported to the physical therapist. To fulfill the exercise protocol the participants had to attend at least 80% of the planned exercise sessions. Participants in the CG were asked to not start exercising during the intervention period. The CG was introduced to the exercise program post-intervention to reduce drop out. Procedures of assessments Assessments for efficacy and safety were performed at baseline and after 12 weeks and included questionnaires, clinical examinations and laboratory measurements. Personal characteristics, comorbidities and medication were self-reported in a questionnaire. All physical and performance based measures were recorded by an experienced physical therapist. The assessments of blood pressure, HR and arterial stiffness were performed by an experienced rheumatologist. Participants Patients fulfilling the following criteria were considered eligible: axSpA according to the Assessment of SpA International Society classification criteria, age 1870 years, no change in TNF-inhibitor use during the last 3 months, moderate to high disease activity and not performed regular endurance or strength exercise during the PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19717846 last year. Exclusion criteria were established CVD, other co-morbidity PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19717794 involving reduced exercise capacity, inability to participate in weekly exercise sessions in Oslo and pregnancy. The study was carried out at Diakonhjemmet Hospital in Oslo between October 2011 and June 2012, with recruitment of patients during the first six months. No formal sample size consideration was performed for this intervention due to the exploratory design of the study. Primary outcome measure The primary outcome was disease activity assessed by the AS Disease Activity Score . ASDAS is reported to be a valid measure of disease activity as it has shown acceptable concurrent validity with both patients and physicians global assessments. ASDAS is a composite continuous score consisting of three patient reported items in addition to C-reactive protein. Secondary outcomes measures Disease specific measures. Disease activity was also measured by the patient reported index BASDAI. The BASDAI consists of six items related to major symptoms in AS. BASDAI is reported to be valid as it reflects the entire spectrum of the disease and is sensitive to changes over time. Physical function was measured with Bath AS Functional Index which is a disease specific index that consists of eight questions regarding physical functioning and two questions reflecting the patient’s ability to cope with everyday life. For both BASDAI and BASFI each question was answered Intervention The exercise program followed the American college of sports medicine recommendations for maintenance and improvement of cardiorespiratory- and muscular fitness. Patients in the EG were enc