The investigators' purpose is to study which exercise training modality: aerobic physical activity in conjunction with either resistance training or balance training, is most beneficial in patients with chronic kidney disease (CKD 4-5: GFR < 30 ml/min/1.73mUP[2]). Furthermore, our purpose is to evaluate the long-term effects of exercise training on functional status, cardiovascular morbidity, blood pressure control, heart rate variability, cardiac function, inflammation, body composition, nutritional status, progression of uraemia and health related quality of life. This interventional study is prospective, randomized and controlled comprising 150 prevalent and incident patients from our outpatient clinic. Patients are invited to participate in the study consecutively, irrespective of basic functional status. At start patients are randomised either to resistance or balance training and the programme is adapted and individualised to each patient's actual physical status and ability. The exercise prescription is to exercise for 30 minutes/day, 5 days/week, keeping the intensity constant at a level of "somewhat strenuous" to "strenuous" on the Borg scale rate of perceived exertion. The total observation period is 12 months with checks every four months. Although exercise training is a recommended therapy in CKD, there is a lack of medical and scientific evidence on optimal prescription. We hope that this study will provide evidence-based knowledge on exercise prescription and its effects on various risk factors in CKD patients. Finally, if patients achieve a higher degree of physical functional capacity they should be able to maintain an autonomous lifestyle, resulting in considerable reductions in societal costs for care and transportation.