Abstract des Autors

The maximal oxygen uptake (VO2mx) is commonly used for assessing the individual aerobic fitness. Many studies have shown in elderly subjects that an increase in cardiorespiratory function and VO2max can be achieved with endurance training, but the effects of strength conditioning on cardiovascular fitness and aerobic power have not been extensively examined in older subjects. The lack of data concerning the effects of isokinetic training on cardiopulmonary function in elderly subjects has prompted the present study. Eight sedentary men (average 68+/-4 years) underwent 13 weeks of isokinetic training, two sessions per week lasting one hour each. One week before and two-three days after the training period each subject performed: a) isokinetic strength test evaluating the knee extensor and flexor muscles, b) incremental exercise on a bicycle ergometer up to voluntary exhaustion. In addition, measurement of quadriceps cross-sectional area (CSA) was carried out by means of nuclear magnetic resonance imaging. At all investigated angular velocities there was, after training, a significant increase of both extensor and flexor muscles isokinetic strength. After training all investigated subjects showed during exercise b) lower values of heart rate (HR) both at rest and at the same absolute workload. The average value of maximal oxygen consumption (VO2peak) increased from 24.9 to 27.6 ml/min/kg. A linear relationship was found between VO2peak and CSA values obtained both before and after training. The results of the present study have shown that, at least in our limited group of sedentary elderly men, isokinetic strength training program besides improve muscle mass and strength may also increase maximal aerobic power. Furthermore this latter resulted close correlated with the quadriceps CSA value, supporting a causal role for peripheral factors in determining VO2peak. From these findings it appears beneficial for elderly population to add to traditional aerobic rehabilitation/training protocols, a series of isokinetic exercises. Verf.-Referat