This experiment involved two parts. 1. To approach the changes of ANF and the cardiac structure and function during the intensive training period of preparing the 8th National Games of China. Ten elite male weightlifters were observed systematically. The contents of plasma ANF were determined by radioimmunoassays and the cardicac structures and functions of the athletes were measured by Doppler ultrasonic echocardiograph. By monitoring physiological and biochemical indexes, observing the behaviour of the weightlifters and by the feedback of the coaches, the weightlifters` functional states evaluated synthetically. 2. To approach the mechanism of the effects of training on the synthesis and secretion of ANF, 51 male SD rats were divided into the sedentary group (n=15), the training for 4 week group (n=12), the 6 week group (n+12), the 8 week group (n=12) (swimming in 30+/-2dC of water) randomly. The mRNA of cardiac muscles of rat was quantified by the method of RT-PCR. The contents of plasma ANF was determined by radioimmunoassays. SDS electrophoretic analysis was made to measure the proportion of the cardiac muscle parenchyma and mesenchyma in cardiomegatia. The results showed that, as a main tendency, the ventricular fold was thickened during the intensive training period of preparing competitions. The interventricular septum and the posterior wall of the left ventricle was thickened, this leading to cardiomegalin of the athletes heart. The increase of the left ventricle end-diastolic volume, proved that the improvement of the cardiac reserve, the stroke output, the cardiac output, the ejection fraction was due to exercise training. However, the changes of plasma ANF level were just opposite to the cardiac structure and function. It tended to decrease with the protraction of the duration of the pre-competition training. As for the individual athlete, the one who was in good function state tended to have the above results. But the others who were in bad functional state or their training was interfered by unexpected conditions, their indexes were opposite. It was suggested that the level of ANF and function of the heart were the important factors influencing the functional state of athletes. During cardiomegalin, resulted from training, the contents of cardiac muscle mosenchyma tended to increase, and there was no significant changes in the proportion of cardiac muscle collagenous fibres I and III.
© Copyright 1999 5th IOC World Congress on Sport Sciences with the Annual Conference of Science and Medicine in Sport 1999. All rights reserved.