The purpose of this study is to examine relationship between subjective effort levels and objective achievements in ground strokes of tennis.
1）Subjective effort levels and objective achievements in tennis strokes had a positive correlation. That is, as subjective effort level got higher, objective achievement (ball speed) also got higher.
2）As for the grading ability, results from multiple comparison were 70％<80％<90％,70％<80％<100％. These results seem to have been brought about by the subject’s habitual increscent training and by their past experiences.
3）Subjective effort levels and the accuracy of outputs had a negative correlation. This seems to show the difficulty in execution of the movement at lower subjective levels. It seems to have been difficult for the subjects of this study to execute the movement accurately because the attempts were not many enough.
4）Subjective effort levels and the targeting accuracy had a negative correlation. From this study, it is inferred that individual competitive levels, characteristics of the sport, individual technical features and so on, as well as athlete’s career, play some roles in order to establish both the ball speed and accuracy of the hitting –movement.
5）As for reproducibility of ground strokes, correlative relation with subjective effort levels was observed. The reproducibility also, like the targeting accuracy, seems to be affected by athlete’s characteristics, features of the sport, the content of the attempts and so on.
