Up to now, as the game-analysis method for badminton, a game-analysis method for singles games has been developed and utilized as a fairly effective one. Namely, strategic interpretation has become possible by reading opponents' stroke movements through a chain of their relations given as spatial information. For doubles games, on the other hand, owing to the complexity of combinations which four players bring about, an analysis method good for practical use cannot necessarily be said to exist at present. For this reason, we have developed a new analysis method which can be applied effectively to the analysis of doubles games as well as singles games.
In order for the new analysis method to have further generality, the developed analysis-method has the following four view points newly added to the analysis method by Abe et al. which has been utilized so far. The view points are, 1) whether the approach-traveling phase is passive one or active one, 2) the purpose of the stroke movement, 3) how the state of opponents' stroke was made to shift, and 4) what was the effectiveness of the stroke. Next, the effectiveness of the new game-analysis method was examined by analyzing and assessing the effectiveness of strokes exerted at the rear court by the Malaysian pair who won the championship at YONEX Open Japan 2002 in men's doubles.
As a result of the analysis using the new method, it has become partially apparent how precisely the Malaysian pair were attacking in relation to the opponents. A possibility was found how the new analysis method described in this research would become a useful method by adding further improvements in the future.

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Generally, tennis players tend to regard the volley as a shot which is technically difficult to learn and are consciously clueless about it. The lower the level is of a player in tennis, the more reluctant the player is to volley. In this research, therefore, we aimed at obtaining fundamental materials for coaching the volleying skill by investigating the consciousness and learning environment of student players toward the volley. The results are as follows.
1) About half of the students lack confidence in their volleying skill and are consciously clueless about it.
2) They tend to have an excessive regard for the racket work.
3) Most of them think a sense ( in the meaning of inborn talent) is necessary to volley.
4) They do not have enough experience in practicing the volley prior to the age of junior high school.
5) College students, now, do not have enough chances to get appropriate advices to get rid of the reluctance to volley.
It was suggested that the chances of getting advices from coaches decrease for student tennis players. But there seems to be a possibility for them to acquire volleying skill, getting rid of the reluctance to volley, by giving them appropriate advices based on the consideration described above. Since tennis players are not necessarily active in acquiring the volleying skill prior to the age of junior high school, it was suggested that making an effort to acquire the volleying skill in the middle of the golden age may be a factor for them to get rid of their reluctance to volley having confidence in their skill.

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For coaches to acquire common understanding and knowledge in coaching of the skills in forehand strokes, practicing the following three points seems necessary. First, the skills in forehand strokes should be decomposed into several stages according to their roles; secondly, the tasks playing the central role in coaching should be clearly defined in each stage, and lastly, the most important task should be clarified in coaching skills in forehand strokes on the basis of the defined tasks in each stage. In this research, effectiveness is examined for the coaching of the skills in forehand strokes based on such view points. Test subjects were chosen comprising six female students of the middle class, and they were coached for the skill of forehand strokes for about one month. Three measurements were made as for the accuracy in strokes, and the degree of accomplishment of the tasks was evaluated twice. The employed tasks were concerned with racket swinging and foot works.
The results are as follows. The skill of accuracy in forehand strokes improved each time: it improved at the second measurement compared to the first, it improved at the third measurement compared to the second. On the first day of coaching, the average of the scores for the test subjects was 6.0. It went up to 10.8 at the second measurement. It further went up to 17.0 in a big stride at the third measurement. As for racket swinging, the following tasks were employed: the completion of a back-swing should be in time with the determination of the pivot foot; the motion of the racket-head in the first half of forward swinging should be synchronized with the bound of the ball; during the time between the last half of forward swinging and the impact, the motion should be in correlation with the motion of the body trunk; in the first half of follow through, the wrist should be stiffened and the swing should be forward and upward; the player should relax in the last half of follow through. Improvement was observed in all of these tasks after coaching the subjects, compared to accomplishment of the tasks before coaching them. As for the footwork, the following tasks were employed: movement of the first step toward the place of ball-hitting should be fast; the pivot foot should be determined about 50 cm before the ball bounds; more body weight should be retained on the pivot foot when the step-in foot is determined; movement of the first step in returning should be fast. All tasks were better accomplished after coaching than before coaching.

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