The authors developed a computerized scorebook for tennis. The scorebook records time duration of shots, points and inter-points. It gives an immediate feedback to coaches and players and evaluates the performance of players. In this research, the time duration of service strokes was verified. A statistical analysis was done between the data recorded from the scorebook and the data recorded from high-speed video camera (HSV). The correlation coefficient was significant between the data from the scorebook and HSV (p< 0.01). The difference between the data from the scorebook and HSV was not significant. These results showed that the scorebook was able to record time duration accurately. It needs to consider where the scorer looks at and how the scorer manipulates the scorebook. It is suggested that the scorebook can provide useful information for tennis players and coaches.
