The purpose of the present study was to elucidate the characteristics of the throwing techniques and physical fitness of a top-level Japanese discus thrower (JDT) who had held the national record (60 m 74) using comparisons with a college top-level discus thrower (CDT). Two subjects performed the following fitness tests: 1 Repetition Maximum bench press, the bench press power test using Fitrodyne, and three types of medicine ball throws. In discus throw tests, subjects performed two types of throws: a standing throw and normal throw with a turn movement. The throwing motion of each subject was recorded by two high-speed video cameras. The motion of the discus throw was then divided into five phases: the double support phase (P1), single support phase by the left foot (P2), non-support phase (P3), single support phase by the right foot (P4), and delivery phase (P5). The velocity of the center of mass and rotational velocities of the hip and shoulder were calculated. Regarding physical fitness characteristics, bench press power was greater for JDT than for CDT, while the throwing distances of the three types of medicine ball throws were smaller for JDT than for CDT. Regarding the duration time of the throwing motion, the time of the P5 phase was longer for JDT than for CDT, and the peak angular velocities of the shoulder and hip during P5 were greater for JDT than for CDT. These technical differences between JDT and CDT were attributed to the position of the body at left foot-on.

    This study aimed to clarify the step variables and three-dimensional joint kinematics of the pelvis while increasing running speed on a treadmill. Sixteen male track and field athletes ran on an instrumented treadmill at three different running speeds: 4.0, 6.0, and 8.0 m/s. The step variables, such as step frequency, step length, contact time, and flight time, and the kinematic data of each running speed were recorded using a high-speed video camera (300 fps) and a Vicon T20 system (250 Hz). In addition, the pelvic angular displacement (Δ) was calculated by subtracting the minimum from the maximum values of the pelvic angle in the stance phase. The results were as follows: (1) Stride length and step frequency were significantly greater at higher running speeds. Although contact time was significantly shorter at the faster speeds, flight time was significantly shorter when transitioning from 6.0 to 8.0 m/s and from 4.0 to 8.0 m/s. (2) The pelvis of the swing leg side elevated from toe off to early half of swing phase with increasing running speeds. In addition, the pelvis of the stance leg side rotated to the swing leg side from mid stance phase to toe off with increasing running speeds. (3) Δelevation showed a significant negative correlation with step frequency but a significant positive correlation with stride length for each running speed. In addition, Δrotation showed a significant positive correlation with step frequency but a significant negative correlation with stride length at 8.0 m/s.
    Therefore, increased pelvic elevation improves the stride when transitioning from a low to high speed, and increased pelvic rotation leads to a higher step frequency during the stance phase when running at 8.0 m/s. In addition, it was suggested that it is necessary to run at minimum 8.0 m/s for the pelvis to behave differently compared with running at slower speeds to learn the high speed running movement.

    The score aspects of the sevens rugby game were analyzed according to total score per game and its breakdown, total score of both teams by time zone, and points difference between winner and loser, and first score and consecutive score by using 450 matches for men and 204 matches for women of 2018-19 World Rugby Sevens Series representing world top level sevens rugby as samples. The results were compared between men and women and men and women respectively. Main findings as follows. 1) The total score and the number of tries and conversions per match were more in men. And the scores by time periods were higher at the end of the first half of both men and women. 2) 73-74％ of the winning teams scored first for both men and women. The winning rate increased to 89％ for men and 94％ for women by scoring two consecutive points from the first score. 3) In the first half, 7 points led to a win rate of 81％ for men and 89％ for women, and led over 8 points for women showed a high win rate of 96％. 4) If be led in the first half, the beginning of the second half is important. No score in this period, the possibility of comebacks is small. And no reversal occurred when the difference was 22 points for Men and 16 points for Women. 5) In the close game, the influence of one point was large, and CG was considered to be an important play to distinguish the outcome.

    This study aimed to clarify practical tips for groundstroke instruction that might aid in the coaching of individual tactics in tennis. An interview survey was conducted on the content and method of coaching regarding shot combinations, and narratives were qualitatively analyzed. The following results were obtained.
1） An outstanding tennis coach assesses individual tactics regarding shot combinations by analyzing “tactical ability against the opponent” instead of “the playerʼs movement.”
2） In order to improve individual tactics regarding shot combinations, the priority of shots to be mastered is clarified, rather than working on various shots concurrently.
3） With regard to coaching to improve tactical thinking ability, the outstanding tennis coach would provide a specific fact about selective attention to the surrounding game situation and give hints that help players to recognize or anticipate game situations, leaving the players to decide how to play the game for themselves.
4） As for coaching to acquire technical skills, the outstanding tennis coach incorporates game-style practice with more powerful boy players into drill-style training, in which the players hone their technical skills without setting certain conditions.

    This study aimed to identify collective efficacy and group cohesion seen in rugby players belonging to top-ranking universities and high schools, and to verify, for each age group, the differences between these two concepts in relation to the opportunity to participate in a game. As the participants of our study, university student group comprised 100 regular, 24 semi-regular, and 216 non-regular of belonging to five teams, while the high school student group comprised 141 regular, 20 semi-regular, and 173 non-regular of belonging to five teams. The scales used were the Collective Efficacy Questionnaire for Sports (CEQS) for collective efficacy, and the Group Environment Questionnaire (GEQ) for group cohesion. We performed a non-paired, single-factor analysis of variance. An ex post facto test was conducted if a significant difference was seen. The results showed no significant differences in CEQS values among university students for any of the items. In the high school participants, meanwhile, regular team members showed higher values than no-nregular team members for all the items. Regular university team members showed higher GEQ values than non-regular team members for only two of the subscales. Regular high school team members showed higher values than non-regular team members for total score and two other subscales. Our findings therefore suggest that, even in groups that specialize in the same athletic sports and play at a set competitive level, different age groups are differently affected by the presence or absence of opportunities to participate in a game.

    The aim of this study is to quantify the movement characteristics of High-intensity running. To achieve a goal, data from Global Positioning System were synchronized with game footage by Sportscode (Version 10.3.21), which were categorized to Source of possession and Ruck and Mauls (R/Ms).
    The results of this study indicate that
1) High-intensity running of BK is more than FW. Furthermore, attack situation is more than defense situation (FW：5.0 vs BK：12.0).
2) In the Source of possession, BK recorded significantly more High-intensity running than FW on Turnover and Kick in attack situation, and also Turnover in defense situation.But FW recorded more High-intensity running Restart on defense situation.
3) In R/Ms, FW recorded more High-intensity running on Restart in defense situation, BK recorded more High-intensity running on Kick and Turnover, which is transition phase of ball possession.
These findings show movement characteristics of High-intensity running during rugby competition. And these findings can be used to help planning an effective training.

    Majority of athletes spend their competitive careers as sports team members and share time with other teammates. It is an essential practice for sport coaches to build team relationships. Team unity is one index for assessing these conditions. Therefore, it was hypothesized that team unity would facilitate the athletesʼ performance. This study examined whether team unity predicts athleteʼs competitive motivation as a major contributory factor of performance, and whether collective efficacy and sports commitment mediate the relationship between team unity and competitive motivation in Japanese athletes. Data were collected via questionnaires; 957 athletes from 43 sports participated in this study. The questionnaire included four scales assessing psychological variables: the Unity Scale for Sports Teams, the Volition for Competition Scale, the Psychological Performance Collective Efficacy Scale, and the Sport Commitment Scale. The results showed significant positive correlation between team unity, competitive motivation, collective efficacy, and sport commitment. Covariance structure analysis showed that team unity indirectly predicted competitive motivation, and both collective efficacy and sport commitment were mediators for the relationship between team unity and competitive motivation regardless of athleteʼs gender, sport types, or roles within the team. Results indicated that team unity was positively related to competitive motivation. Furthermore, although enhancing team unity did not directly improve athletesʼ competitive motivation, it would indirectly improve competitive motivation. Collective efficacy and sports commitment were particularly helpful in facilitating the competitive motivation of athletes. These findings suggested that coaches and athletes should attend to team psychological factors including unity for developing sports performance.