HIGH-INTENSITY KNEE EXTENSOR TRAINING, IN PATIENTS WITH CHRONIC HEART-FAILURE - MAJOR SKELETAL-MUSCLE IMPROVEMENT

Skeletal muscle adaptations to high intensity knee extensor strength a nd/or endurance training in patients with chronic heart failure were i nvestigated. Eleven patients with chronic heart failure were randomize d into two groups and exercised the m. quadriceps femoris 3 days/week for 8 weeks. After training, the maximal exercise intensity tolerated on the ergometer cycle was raised from 99 (32) to 114 (40) watts (W, P <0 . 05) for all 11 patients. Peak dynamic knee extensor work rate sho wed the greatest increase after endurance training (40%, P<0 . 01). Ma ximal dynamic and isometric strength were elevated by 40-45% (P<0 . 05 ) after strength training. The cross-sectional area of m. quadriceps f emoris was increased in the strength-trained legs (9%, P<0 . 05), and the capillary per fibre ratio of m. vastus lateralis was raised by 47 and 58% in the endurance-trained legs (P<0 . 05). The oxidative enzyme activity in m. vastus lateralis was significantly raised above 50% af ter endurance training, whereas glycolytic enzyme activity was unalter ed. The peripheral skeletal musculature in patients with chronic heart failure adapts fairly quickly to high intensity knee extensor trainin g. This results in a marked rise in local, and a small rise in total w ork capacity, indicating maintained plasticity of skeletal muscle in c hronic heart failure patients.