Physical training in patients with stable chronic heart failure: effects on cardiorespiratory fitness and ultrastructural abnormalities of leg muscles. - Hambrecht,R.; Niebauer,J.; Fiehn,E.; Kalberer,B.; Offner,B.; Hauer,K.; Riede,U.; Schlierf,G.; Kubler,W.; Schuler,G. (J Am Coll Cardiol, 1995)