Recently, ankle braces became available not only at hospitals but also at retail sports shops and are now used by many volleyball players. Nevertheless, the incidence of ankle sprain is not very low, even when the players wear braces. Therefore the effectiveness of ankle braces has sometimes been questioned by coaches. In this study the cause of ankle sprains were examined when the players were wearing braces. The subjects were 112 female top-level volleyball players in Japanese high school. Fifty-two subjects were wearing ankle braces. Of these 52 subjects, 17 (32.7% ; group A) have sprained their ankles while wearing the ankle braces. Of these 52 subjects, 35 (67.3% ) have not sprained their ankles while wearing the braces. One hundred and ten subjects were not wearing ankle braces. Of these 110 subjects, 86 (78.2% ) have sprained their ankles while not wearing ankle braces. Of these 110 subjects, 24 (21.8% ) have not sprained while not wearing braces. Sprain protective efficacy of ankle braces was analyzed using chi-square test. The deviation of the number was significant(χ2 ＝ 31.6 p＜0.05, df=1), which showed ankle braces protect ankles effectively under the level of significance 5% . Of 88 subjects with history of ankle sprain, 36 had repeated sprains. In group A, 15 out of 17 subjects had repeated sprains. It is statistically significantly higher number of repeated sprains than group B by chi-square analysis (p＜0.01). As for the cause that some players sprained even at the time of wearing them, ankle braces was not enough effective to prevent players from spraining but there were some factors in the players who were wearing them. In group A, the rate of medical consultation for the first injury was low, and even when they had medical consultation, some of them received lighter treatments. So, it is recommended that the players should take medical consultations and receive treatments that were recommended by the doctors when they sprained them and players should be educated on this topic. Above all, it is recommended to wear ankle braces in appropriate　way for prevention of ankle sprains only at the time of a match form preventively for all volleyball players.

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　The purpose of this study was to examine the relationship between spike speed and trunk flection power in volleyball. The subjects of this study were nine volleyball female players. In this study, Cybex TMC was used to examine the muscle characteristics of kinetic movement in trunk flection-extension exercise. 　The results were follows; 1) There were significant correlations between spike speed and peak torque at 240 and 300deg/sec by higher speed hitter. 2) It was found out that it was related with the improvement of the ball speed that the high power could be performed at a high-speed muscle contraction velocity. 3)The results suggests that dynamic resistance training with speed is important more than static muscle training to increase a spike speed.

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The purpose of this study was to acquire the knowledge of coaching concerning jump toss of the setter. This study analyzed the transformation of motion by repetition training for acquisition of better jump toss techniques. A college male volleyball player repeated the jump toss 5000 times in this training. Through observation of preparatory phase for motion, this study analyzed the relation between the number of repetitions and the resulting transformation of motion. Results obtained are as follows: 1) As for the good position for the jump toss (front, center, back）. a. The good setting was center position. This position increased through about 2500 times practice. b. When the setter was in this good setting position, the rate of successful tossing increased. c. The rate of successful tossing increased through about 5000 times practice. 2) As for the vertical good bodily positions (low, middle, high）. a. The good setting was high position. This position increased through about 2500 times practice. b. When it was good setting position, it was high position and the rate of successful tossing increased. c. When the setter tossed in the high position, the trajectory of toss was ideal. 3) As for the transformation of compensational motion a. The compensational motion with the arms and the legs decreases through about 5000 times practice. b. Even if the rate of successful tossing increased, the compensational motion appeared again. 4) Transformation of time for taking off. a. The time required for taking off decreased through about 2500 times practice. b. The time for taking off influences jumping height. Moreover, few transformations of motion were seen in the first term. They increased in the middle term, and the rate of successful tossing increased in the last term. Finally, the ability of space criterion for timing improved ahead of the ability of time criterion for timing.

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The purpose of this study was to investigate the playing system that the international-class women’s volleyball teams used. The game matches of Russian, Brazilian, Chinese female players who participated in 2006 Women’s World Championships held in Osaka were taken a picture with video. The playing system for service reception, combination attack, block & dig were analyzed with the scouting program developed by Hashihara and others (2005). The playing system for service reception and block & dig were similar through top three teams. But the combination attack was different from team to team. Most of Russian attack were the spiking from high set ball by two ace players. Brazil used often the four-hitter attack that was played in men’s volleyball game. China used such a combination that two quick hitters approached simultaneously for the different two kinds of quick sets, for example, one for quick set and the other for one-leg takeoff set.

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　Almost volleyball scouting systems are developed for top-level teams such as national teams and V-league teams. Therefore we are studying new scouting system named Touch Volley, which is easy operation for junior or senior high school student. 　By using laptop PC with touch sensor screen, the data input method on Touch Volley makes the user intuitive interface. By experimental result, we found this system is easy to put data. 　On the other hand, IT-related developments have grown remarkably. Especially various services are provided by Web-applications. When a user can analyze volleyball games by game-data and movies on the web, players and coaches are more possible rather than the current systems. 　Therefore we developed web-application for analyzing volleyball data by uploading game data to web-server. The user can analyze volleyball game anywhere, anytime by using browser. In the future, it will also be possible to link image data of volleyball games.

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This study clarified the relation of win and loss between the reception frequency of Libero and the result of receiving the ball which returned by Libero. This study also compared the success rate of attack assemblies and attacks of setting; - performed by Libero - performed by other players We have pursued possibility of Libero to have the function as the substitute of the setter, aimed to gain references for future volleyball guidance. Here are the results; 1） Reception frequency In the winning set, there was a significant difference in attack reception (ATR). When the blocking is efficiently functioning, Libero has more opportunity to receive attacks. This leads to counterattack and contribute to win a set. 2） The result of receiving the ball returned by Libero In the winning set, there were significant differences in serve reception (SR), attack reception (ATR), and block follow reception (BFR). Number of attack reception which enable attacking would be an important factor for win or loss of the game. 3） Success rate of attack assemblies and attacks of overhand setting In the winning set, the success rate of attack assemblies and attacks of overhand setting by Libero shows higher numerical value than other players except setter. Active performance on overhand setting by Libero enables other players to prepare attacking more earlier; numbers of plyaers which participating attacking increased. This may indicate that overhand setting by Libero is second best which follows setter and is most likely to have the substitutional role of the setter.

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The purpose of this study was to analyze side-out and break rate in volleyball games from a viewpoint of rotation. The samples consisted of 102 sets of Kanto University men’s volleyball league match in 2006. As a result, it was summarized as follows; 1) About Side-out evaluation, higher than rotation evaluation 4 affect victory, and lower than the evaluation 2 affect defeat. 2) It has an influence on improvement of results to get higher than side-out evaluation 3 with each set. 3) About Break evaluation, higher than rotation evaluation 4 affect victory, and lower than the evaluation 2 affect defeat. 4) It has an influence on improvement of r esults to get higher than break evaluation 4 with each set. 5) About side-out + break evaluation, higher than rotation evaluation 7 affect victory, and lower than evaluation 5 are connected for a defeat. 6) It has an influence on improvement of results to get higher than side-out + break evaluation 7 with each set, and less than 4 have an influence on the badness of results.

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