高校男子長距離走選手を対象に，酸化ストレス指標を大会までの一定期間測定し，心理的状態，主観的コンディションとの変化からコンディショニングのための客観的指標として利活用するための知見を得ることを目的とした．期間は5週間実施し，週1回の項目として，酸化ストレス度（d-ROMs），抗酸化力（BAP），POMS，毎日の項目として主観的コンディション，睡眠及び練習状況のアンケートを実施した．d-ROMsの平均値は各測定日とも300U.CARR以上を示したが，大会を控えた第5，6週の測定日にかけては有意な低下（p＜0.05〜0.01）を示した．潜在的抗酸化能（BAP/d-ROMs）の経時的な推移を各選手の最大値を100%とした相対値として検討すると，A選手の推移は測定期間中右肩上がりの推移を示し，大会結果との関連を得た．酸化ストレスの評価はトレーニング状況や怪我などの影響を反映していることが示され，心理的状態とともに評価することで，より詳細にコンディションを把握することが可能であることが示された．また，酸化還元バランスを評価するBAP/d-ROMsが最もコンディショニングや競技パフォーマンスを予測する指標として有用であり，その評価については競技レベルを考慮することの必要性が示唆された．

Changes in the oxidative stress, mental state, and subjective condition of male high school long-distance runners
The present study aimed to find objective indices for conditioning male high school long-distance runners by measuring changes in runners’ mental state and subjective condition that are associated with oxidative stress for a period of time before a competition. The participants in the study were 10 male high school long-distance runners. The following were measured once a week: oxidative stress (measured by diacron-reactive oxygen metabolites; d-ROMs) and antioxidative activity (measured by a biological antioxidant potential test; BAP test). In addition, the participants completed the Profile of Mood States (POMS) questionnaire weekly, and, every day, completed a questionnaire about subjective condition, sleeping, and training status. The average value of d-ROMs in Carratelli units exceeded 300U.CARR at all measurement times, but it declined significantly (p<0.05~0.01) in the fifth and sixth weeks, which were immediately before a competition. The relative value of potential antioxidative activity (BAP/d-ROMs) for runner A over time showed a continuous increase during the period that corresponded to his results in competition. Because oxidative stress depends on training conditions and the influence of injuries, it may be possible to understand players’ condition in more detail if a measure of their mental state were added. BAP/d-ROMs is useful for evaluating the oxidation reduction balance, and can be the most useful index for anticipating conditioning and competitive performance if competition level is taken into account.

テニスは急停止と急加速，つまり，切り返し動作を行う競技である（Ferrauti et al., 2001）．通常，切り返しを行う際，ステップを数回行うことで減速し，打球して切り返しを行う．しかし，コート上を滑ることで減速し，打球して切り返しを行う，スライドフットワーク（以下SF）という技術がある（長尾ほか，2013）．このSFとは主にクレーコートで用いられる技術であるが，近年，世界のトップ選手がこのSFをハードコートでも用いるようになってきている．そこで本研究の目的は,テニスにおけるハードコートでのSFが切り返し時間に及ぼす影響を明らかにすることとした．その結果，切り返し時間を減速局面と切り返し局面に分類し比較したところ，フォアハンド及びバックハンドどちらにおいても減速局面の時間が短縮した（p<0.01）．しかしフォアハンドにおいて切り返し局面の時間が延長した．これらの結果から，フォアハンドにおいては，減速局面における時間が短縮するため，通常のフットワークでは追いつけないボールに追いつくことが可能になるが，その後の戻りが遅くなる可能性があるということが示唆された．

Effects of sliding footwork on switching time in hard court tennis
In tennis, players repeatedly stop abruptly and then accelerate, i.e., they perform a switching action (Ferrauti et al., 2001). Normally, a switching action is done after a few steps in order to slow down and hit the ball. However, in the technique called sliding footwork (SF), the player slows down by sliding on the court, hits the ball, and then switches (Nagao et al., 2013; in Japanese). This technique has mainly been used on clay courts, but recently, world top-ranked players have often used sliding footwork on hard courts. The present study examined effects of using sliding footwork on hard courts on the time taken for switching action. The results showed that the slowing down time was significantly shorter (p<0.01) for both forehand and backhand hits. In contrast, the switching time was prolonged in forehand hitting. These results suggest that sliding footwork can shorten the time for the slow-down in the forehand, making it possible to catch up with balls that cannot be caught up with using ordinary footwork, but that hitting the ball using that technique may result in a delay in the subsequent return.

本研究は学生全国大会（大学生対象全国大会）でトップレベルの競技成績を残した元学生テニス選手を対象に，経験を通じて獲得したライフスキルと，そのライフスキル獲得に結びつく経験の内容を明らかにすることとした．本研究ではライフスキルの中でも，特にテニス競技で競技成績と関係性が明らかにされている，個人的スキル（上野・中込，1998）の獲得に着目した．対象者9名に半構造化面接によるインタビュー調査を実施し，インタビュー内容をテキスト化した上で，テキストデータは質的データ分析を用いて分析した．その結果，選手は「内省」「逆境抵抗」「目標設定」「課題解決」「自律的指導受容」の5つの個人的スキルを獲得していることが示され，5つの個人的スキルの獲得に結びつく経験内容が明らかになった．

Life skills acquired by former top-level university tennis players: intrapersonal skills.
The present study examined life skills of nine adults who, while students at university, were ranked at the top-level in all-Japan university student tennis tournaments, and experiences that may have been related to their acquisition of those skills (Nozawa & Otani, 2017; in Japanese). The study focused on those intrapersonal skills (Ueno & Nakagome, 1998; in Japanese) that are considered to be especially related to the outcome of tennis competitions. The participants in the present research were interviewed using a semi-structured interview. The contents of the interviews were transcribed and then analyzed qualitatively. The results of this analysis suggested that the former athletes had acquired five intrapersonal skills: introspection, resistance to adversity, goal setting, problem solving, and autonomous acceptance of instruction; some of their relevant experiences were identified.

本研究では，男子体操競技における鉄棒の「懸垂前振り伸身背面とび越し懸垂(伸身トカチェフ)」について練習・指導の事例を示し，この技の習得に役立つ知見を得ることを目的とした．対象者は大学生体操選手1名であり，「伸身トカチェフ」を実施した経験はなかった．「伸身トカチェフ」の3つの練習段階に沿って，鉄棒での「伸身トカチェフ」の練習と各技術習得のための練習方法を実施した．その結果，対象者は「伸身トカチェフ」を習得することができた．そして，このことから本研究で行った練習方法が「伸身トカチェフ」の習得において，有効であることが示唆された．

Coaching the stretched Tkatchev (swing forward and vault backwards stretched to hang) on horizontal bar.
The present study describes exercises and coaching techniques for the stretched Tkatchev performed on the horizontal bar which were developed in order to prepare gymnasts for men’s gymnastics competitions, and explains how information was collected in order to be able to develop the exercises. The participant was a university student gymnast who had not previously done a stretched Tkatchev. When practicing three techniques necessary for performing the stretched Tkatchev, the gymnast did exercises suitable for the stretched Tkatchev on the horizontal bar and also exercises aimed at the acquisition of each of the three techniques. After doing those exercises, the participant was able to perform the stretched Tkatchev. This suggests that practicing the three techniques and doing the exercises might enable gymnasts to do the stretched Tkatchev.

本研究の目的は，競技レベルの異なる2名の泳者を対象に，背泳ぎの抵抗力と泳動作について調査することであった．対象者は背泳ぎを専門種目とし，日本代表経験を有する選手と，全国大会出場経験を有する選手の1名ずつであった．泳速度は1.20 m/s とし，実験は全て実験用回流水槽にて実施した．抵抗力はMRT法を用いて評価し，抵抗力を身体表面積で除して抵抗係数を算出した．泳動作は3次元モーションキャプチャシステムを用いて分析した．体幹の傾きを評価する指標として，第一胸椎棘突起と大転子の位置関係を評価し，手部の動作スピードは3次元方向と推進方向のそれぞれを分析した．結果として，抵抗力と抵抗係数の両方で競技レベルの高い泳者が大きな値を示したが，身体表面積で除した抵抗係数では両者の差が小さくなっており，体格の違いが背泳ぎでの抵抗力に影響したことが示唆された．泳動作について，ストローク頻度と手部の動作スピードでは競技力の低い泳者が高い値を示し，一方で体幹の傾きではわずかに競技力の高い泳者が高い値を示した．これらのことから，背泳ぎにおける抵抗力は，競技レベルが高い泳者の抵抗力が必ずしも低くなるわけではないことが示唆された．

Characteristics of resistive force and swimming motion in the backstroke of an international-level swimmer and a national-level swimmer: hand movements and inclination of the trunk
The present study compared the resistive force and swimming motion of two swimmers who were at different competitive performance levels. Both swimmers specialized in the backstroke; one of them had been selected as a member of Japan’s national team, the other had participated in a national tournament. The study was conducted in a swimming flume at a swimming speed of 1.20 m/s. Resistive force was measured using the method of measuring residual thrust (MRT method); the resistance coefficient was calculated by dividing the resistive force by the surface area of the swimmer’s body. Swimming movements were analyzed with a three-dimensional motion capture system. In order to determine the index of inclination of the trunk, the relationship between the position of the acantha of the first thoracic vertebra and the greater trochanter was analyzed. The speed of movement of the hands was measured in three dimensions and in the direction of propulsion. The results showed that the international-level swimmer had higher values both in resistive force and resistance coefficient, although the difference between the two participants in the resistance coefficient was rather small. This suggests that the difference in the physical size of their bodies may have been reflected in the resistance force. The national-level swimmer had a higher stroke frequency and faster hand movements, whereas the international-level swimmer had a slightly higher inclination of the trunk of his body. These results suggest that the resistive force when swimming backstroke may not necessarily be less in swimmers who are at a higher competitive level.

本研究の目的は，野球において超速球を見るトレーニングが打撃パフォーマンスに与える即時効果を明らかにすることであった．大学硬式野球部に所属する打者5名に，ピッチングマシンから約165km/hで投射される超速球を打席で見るトレーニングを15球×2セット行わせ，その前後に約150km/hで投球されるボールを10球打撃するパフォーマンス測定を行わせた．トレーニング前後の主観的な打撃感覚の変化を調べるためアンケート調査を行い，客観的なパフォーマンスの変化を調べるために高速度ビデオカメラで打撃動作を撮影した．その結果，全ての分析対象者が「トレーニング後は投球が遅く感じた」と回答した．また，個人差はみられたものの，その感覚は一定時間継続することが示唆された．さらに，トレーニング後では全ての分析対象者がより投手側でボールをインパクトしていた．一方で，トレーニング前後で空振りの割合に変化はなく，打撃の正確性は向上しなかった．そのため，打撃の正確性を向上させるためには普段から継続的に超速球を見る，あるいは打撃するトレーニングを行うことが重要であることが示唆された．

Effects of visual training with very fast balls on batting performance in baseball
The present study examined effects of visual training with balls pitched very fast on batting performance. The participants, 5 university baseball players, received training in which they stood in the batter’s box and looked at balls shot from a pitching machine at 165 km/h. The training was repeated with 15 balls in each of 2 sets. Before and after the training, the players tried to hit 10 balls that were pitched at 150 km/h. So that any changes in subjective hitting sense after the training could be identified, the players completed a questionnaire on that topic. In addition, their pre- and post-training batting performance and their batting motions were recorded with a high-speed video camera. All participants reported that the ball speed appeared to be slower after the training. Although there were some individual differences, that feeling seemed to be maintained for some time. Furthermore, when batting after the training, all participants made contact with the ball farther forward over the plate than before the training because of their improved perception of the ball. On the other hand, the number of strikes did not change, that is, there was no improvement in batting accuracy. The discussion suggests that, in order to improve batting accuracy, training with viewing very fast balls and hitting fast balls should be conducted regularly.

GPSを用いたラグビーのゲーム分析は，試合中の移動距離や走スピード，スプリント回数といった試合中のパフォーマンスの定量化を行った研究（古川, 2013）が行われている．サッカーにおいては，選手の動的な位置データを用いて，移動パターンおよび選手間の位置関係を測定することによって戦術的行動を評価する研究（Memmert et al., 2017）が行われている．しかし，GPSを活用したラグビーの研究は個人の移動様相を分析したものが多く，選手相互の位置関係を定量化した研究は行われていない．そこで，本研究の目的は，GPSから取得した位置データを用いて，7人制ラグビーのタックルにおける選手間距離を定量化することとした．その結果，ディフェンスラインの中にいる選手がタックラーである場合は，防御の成否に関わらずタックルにおける選手間距離を一定に保ちながら防御を行っており，ディフェンスラインの端にいる選手がタックラーである場合は，防御成功時にタックルにおける選手間距離が有意に短いことが明らかとなった．このことから，状況に応じてタックルにおける選手間距離を適切に保つことが防御において重要であると考えられる．今後は，攻撃状況や，防御状況等をより詳細に分類し分析を行うことで，現場で活用できる適切な選手間距離を定量できると考えられる．

Quantification with GPS of the distance between players when tackling in rugby sevens
GPS has been used in the analysis of rugby in order to quantify performance during games, such as distance traveled, running speed, and number of sprints. In soccer, evaluation of tactics has been done using the dynamic positional relations between players to measure movement patterns and distance between players. In rugby, however, most of the published studies using GPS analyzed the pattern of individuals’ motions; few studies have quantified relations between various players’ positions. The present study used GPS in rugby sevens to quantify the distance between players when tackling. It was found that when a player within the defense line become a tackler, the distance between the players was stable for defense, regardless of the success or failure of the tackle. Whereas, when a player at the end of the defense line became a tackler, the distance between the players was significantly shorter when the defense was successful. These results suggest that it is important when tackling to keep an appropriate distance between the players, depending on the situation. Further analysis of offense and defense situations may reveal the optimum distance between players.

本研究は内野手の一塁送球の正確性を高めるための練習方法を提案することを目的とした．筆者の考案した一塁送球時のターゲットの設定方法によって送球練習を一定期間実施することをトレーニング方法とし，一塁送球を行う際にターゲットを特別に設定していない，内野手を専門とする大学野球選手1名（A選手：年齢20歳，身長171.2cm，体重69.0kg，競技歴12年，内野手歴12年）を対象に，計8回トレーニングを実施した．各トレーニング日において，A選手には三塁手の定位置付近で捕球したゴロを一塁手の中心よりも左側をめがけて送球させ，これを30回繰り返させた．トレーニング実施前後に行った一塁送球テストの結果に向上傾向がみられたこと，A選手の内省において本トレーニング方法に対する肯定的な記述が見られたことから，一定の効果が期待できる．さらに，A選手の内省から，ターゲットを意識する中で導き出される動作に対する気づきがあることも示唆された．しかし，本研究では，動作比較を行っておらず，今後トレーニング効果を一層明確にするためには，動作分析をはじめとした詳細な検討が必要となるだろう.

Method for training a baseball infielder in order to improve his throwing accuracy
The present study investigated a method for training a baseball infielder that was aimed at increasing the accuracy of his throws to first base. In the study, a university baseball player (player A, age 20 years, height 171.2 cm, weight 69.0 kg, baseball experience 12 years, infield experience 12 years) who had no specific target when throwing to first base was given 8 sessions of training with the present authors’ method for setting up a target. In every training session, the player stood at third base, caught a ground ball, and threw it to the left side of the first baseman, repeating this 30 times. After that, the accuracy of his throws to first base improved. His introspective reports were positive, for example, he reported that he had become aware of the importance of the motion he made toward the target. However, because this study did not include any comparison of motions, more detailed analysis of infielders’ motions should be conducted in order to clarify further the effects of this training.

本研究では，男子やり投競技者の記録と体力との関係を検討することで，各競技レベルに必要とされる各種体力の基準値を提示することを目的とした．日本人男子やり投競技者138名（記録範囲：37.64-86.83m）を対象に，一般にフィールドテストやトレーニングで実施されている各種体力について質問紙法による調査を行い，やり投記録との関係を検討し，やり投記録に応じた標準値を作成した．各種体力とやり投記録との間には，30m走を除く全ての項目において有意な相関関係が認められた．また，相関関係の認められた項目について，やり投記録との単回帰式をもとに，40mから95mに至るまでの記録水準に応じた標準値を示した．本研究の結果から，やり投競技者には，身体の速度が高い状態において，全身で大きな力を発揮する能力が重要であることが示唆された．本研究で示した標準値は，競技者および指導者が，競技者の体力を適切に評価し，目標を設定する上で有用な資料であると考えられる.

Identifying standard values for the strength of male javelin throwers
The goal of the present study was to identify the standard strength required for male javelin throwers at various levels of competition. Male Japanese javelin throwers (N=138; range of record, 37.64 - 86.83 m) completed questionnaires asking about the strength that they used in field tests and training. The data from their responses were correlated with their javelin throw records, in order to obtain standard values. The correlation between strength and the other measures, except for 30-meter run times and javelin throw records, was significant. Among the significantly correlated items, standard values were calculated using a regression equation that included javelin throw records from 40 m through 95 m. The results suggest that javelin throwers must be able to perform with strong force when the speed of their body is high. The standard values obtained in the present study may enable athletes and coaches to get a more accurate evaluation of athletes’ fitness and set up more suitable goals.

本研究は，柔道初心者の前回り受身習得に向けた効果的な指導法と題し，使用するバランスボールの有効性について検証することを目的とした．被験者は，M大学教育学部の保健体育を専門とする大学生8名（男女比4：4）であり，柔道授業（90分×15回）においてバランスボールを使用した前回り受身の練習を毎授業行わせた．バランスボールの有効性を評価する項目として，授業前後での�@動画撮影による「受身動作」の変化，�Aアンケート調査による「恐怖感」の変化，�B授業終了後の被験者自身による「バランスボールの主観的効果」について検証した．その結果，前回り受身の持つ「回転軸が正中線から斜めにずれる」という難点と，「高さ」「勢い」のある投技に対して「恐怖感なく安全な受身をとる」という課題を解決する有効な手立てとなることが示唆された.

Effects of using a balance ball to teach forward-rolling ukemi to judo beginners
The present study examined a new method of teaching forward-rolling ukemi (break falls) to judo beginners by using a balance ball. The participants were 8 university students (4 males and 4 females) of the Faculty of Education of M university who were majoring in health and physical education. In 15 meetings of their judo class, they used a balance ball for 90 minutes in order to learn forward-rolling ukemi. The effects of practicing with a balance ball were evaluated by (a) videos of the participants’ ukemi motion before and after the classes, (b) questionnaires completed by the participants in which they reported by any change in their fear of forward-rolling ukemi, and (c) participants’ subjective evaluations of the lessons with the balance ball. The results suggested that the balance-ball method appeared to be effective for remedying the participants’ displacement of their axis of rotation from the midline when they did forward-rolling ukemi, and for acquisition of a safe ukemi that the participants could do without fear of high and strong throws.