Abstract
This paper examined the changes of the motion during tennis stroke due to the difference of rackets. To analyze it, the actual tennis stroke using the 12 motion capture devices was measured. In the experiments, the strokes of 12 male subjects using 4 rackets were measured and were digitized. Analyzing a position in the vertical direction of each marker, the changes and characteristics of the stroke motion using each rackets were considered. At the same time, subjects answered to the questionnaires created basis on evaluation grid method. Comparing the obtained psychological evaluation with the measurement result of the motion, an indication of motion and psychology was derived. As a result, firstly, in the motion of tennis stroke, there were two characteristics by subjects. The first one was the characteristic to raise the racket during take-back operation, and nine subjects did this behavior. Another was the characteristic to lower the racket during take-back operation, and two subjects did this behavior. Secondly, it was confirmed that there were dispersions in the motion of tennis stroke using each racket. The dispersions were quantitatively expressed using the sum of the standard deviations and compared with the psychological evaluation. As a result, it was found that the sum of the standard deviations was an indication for experienced persons relating to the racket's comfort. On the other hand, it was shown that it was possible to objectively suggest the most suitable racket to not only experienced persons but also novices presenting the sum of standard deviations. Therefore, the result showed the sum of the standard deviations of the motion during tennis stroke was one indication of evaluation of rackets.