本研究は，大学女子テニス選手1 名を対象に，サービスのパフォーマンス向上を目的とした取り組みとその効果を事例的に検討したものである．対象とした女子選手は，比較的身長が高く，サービスを自身の武器として認識しており，そのパフォーマンスをさらに向上しようとする意欲を持っていた．指導者は対象とした選手のサービスの能力について高く評価しており，そのパフォーマンスをより良くすることを目指した．サービスのパフォーマンスを向上するための主な取り組みとして，技術面の具体的目標は1st サービスのスピードを上げることと，2nd サービスの回転数を増やすことを目指すものであった．およそ5 ヶ月間の取り組みの中では，スイングスピードを向上することや，回転数を増やすためにスイングの方向やラケットとボールの当て方を修正することなどを試みた．取り組みの前後で，対象選手の1st サービスのスピードは速く，2nd サービスのスピードは遅くなっていた．2nd サービスの回転数は大きくなる傾向にあった．また打点の高さが有意に低くなっており，1st サービスのスピードの向上に貢献していると考えられた．2nd サービスの回転数の増加には技術的課題の克服が貢献していると考えられた．

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After seven singles players had retired or withdrawn with injuries at Wimbledon 2013, the All England Club issued an extraordinary statement defending the state of its grass. According to the International Tennis Federation, the seven retirements and walkovers in singles were believed to be the most on the same day at a Grand Slam event in the Open era. All of the slipping and injuries led to questions of why. The suggested culprits included the length of the season, the short time to adjust to grass from clay, and the condition of the courts. There have been several significant falls, the most graphic being when Azarenka twisted her right knee during her first-round that left her lying on the court in tears for several minutes. With so many players being asked about court conditions in news conferences and so many news media requests to speak to the groundskeeper, the All England Club issued a statement about the grass."The court preparation has been to exactly the same meticulous standard as in previous years, and we expect them to continue to play to their usual high quality." It is said that different types of tennis injury have been associated with play on different court surfaces and current knowledge of tennis player and court interactions is limited. Some research with tennis injury incidence, player movements and the biomechanics of slips were begun and a new direction for assessing tennis player-surface interactions has discussed for practical use in the future regulation of tennis courts. On the other hand, in sports, moving body parts around a fixed joint is very popular, but it seems to limit one's power, whereas more power can be generated and the strain on the body is lessen by using the entire body without twisting motion and not resorting to just the fixed joint. This paper proposed the approach for realization of robust physical movements in tennis based on distributed control of physical body in humanoid biped robots, which uses only small active power making full use of equilibrium instability as a source of driving force with simple state transition. Making postures simultaneously by using the entire body produces natural movements.

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There has been no question that some strings do provide a better grip than others, but that did not guarantee that the ball will produce more spin. Furthermore, experiments with hand-held rackets has been needed to solve the difficult question of how players can tell the difference between different strings when laboratory tests indicate that they should play the same. The previous paper performed an experiment measuring the spin rates of used, notched strings in both their natural condition an.d after applying a lubricant to the string intersections to facilitate tangential string movement. It found that the lubricated notched strings produced 30% more spin than the unlubricated notched strings. The lubricant materials are effective to the notched strings, because the lateral movement and snap-back of the main strings increase spin. It also showed that the more spin results in the reduction of shock vibrations of the wrist joint during impact. Furthermore, it was shown that the used natural gut with notches decrease 70 % of spin rate compared to the new natural gut without notches in the another experiment, which has remained to be seen whether the same results will be obtained. Recently, International Tennis Federation researchers reported that the same movement that was observed with lubricated strings occurs with copoly as well. Copoly strings slippery and stiff generate more spin not because of more friction, but because of less. The old argument was that the better the grip between the strings and the ball, the more spin we would get, but that was not true. Many experiments has started to investigate whether the lateral movement and snap-back of the main strings increase spin, which strings generate the most spin, and so on. This paper discussed the improvement of performance and injury prevention with proper string and proper body movement of a player.

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