The purpose of this study was to investigate the validity of Ratings of Perceived Exertion (RPE) as indices of exercise intensity during swimming lessons of elmentary school children. The subjects were all 24 students selected at random from three levels of swimming lessons which were beginners' class, middle class and high class. These classes were divided beforehand according to their swimming performance. All swimming lessons were recorded by VTR in order to calculate the swimming distance, time and speed. At the same time, HR also were recorded. RPE was asked immediately after every series of swimming practices.
Swimming speeds during swimming lessons were 24.9 m?min^<-1> (beginners' class), 36.6 m?min^<-1> (middle class) and 31.5 m?min^<-1> (high class), respectively. Mean HR during swimming lessons were 110.9 beats?min^<-1> (beginners' class), 121.3 beats?min^<-1> (middle class) and 120.5 beats?min^<-1> (high class), respectively. Mean RPE during swimming lessons were 8.0 (beginners' class), 10.4 (middle class), and 12.4 (high class), respectively. Correlations between HR and RPE were r=0.159 (beginners' class), r=0.393 (middle class) and r=0.647 (high class), respectively. Therefore, when the exercise intensity during swimming lessons was set and evaluated, it seemed that RPE was not appropriate to use in beginners' class and middle class.