The purpose of this study was to develop a new tactics on kick-off and 50m restart kick (KO) play with corresponding to the change in recent years in rugby football, and was to verify its effectiveness using the method of game analysis. In order to attain the purpose, game performance after introducing the new tactics on KO was compared with that before the introduction in T univ., which is at the 16 best level in Japanese university team. Samples of the game analysis were 14 matches in 2003 and 12 matches in 2004. As a result, it was shown that the new KO tactics had the following effect: 1) causing the receive team not to use lifting, 2) advancing the field position of the next restart after KO, 3) improving defensive performance after KO, 4) lengthening time of occupying the opposite territory continuously and raising the probability of scoring after KO. Though the new KO tactics developed in this study is considered to be promising, accumulating additional data using the various teams as the subject will be necessary in future.

 The purpose of this study was to attempt to have a quantitative evaluation for the ball carrier's contact action in rugby football, and was to get the practical suggestion. After 3m approach with the ball,10 subjects(6 trained,4 beginners)contacted against the hung tackle bag on the right shoulder side. Subjects had to stop immediately after the contact. The subject's momentum at the contact moment was compared with the tackle bag's momentum after the contact,then each subject's contact action was evaluated by the efficiency of the momentum transmission.

 The results were as follows

1)lt is important to keep the approachve locity as fast as possible.

2)In view of efficiency and safety,it is also important for the ball carrier to keep head up and to contact on the front part of the upper body.

3)The subjects whose upper bodies faced the tackle bag transmitted the momentum more efficiently than the others who turned their upper bodies to the left hand side. Thus it seems important for the ball carrier to keep the upper body posture for the approach run even at the contact moment.

    The purpose of this study was to clarify effective tactics of attack on the sport of rugby sevens using notational analysis of game performance on the menʼs rugby sevens at Olympic games 2016. The main results of this study were as follows; 1) The rate of attack to the open-side and reverse-direction are higher. 2) To breakthrough the defence-line is more difficult than the gain-line. 3) In the number of passes before contact, the rate of breakthrough the defence-line unused pass were the lowest and the rate of unused pass in the Top6 teams was lower than the bottom6 teams and therefore the attack option using pass is effective. 4) In the attack options, the rate of breakthrough the defence-line under the overlap situation is the highest and therefore the attack option to carry the ball at vacant space is effective. 5) In the starting points in attack, the rate of breakthrough the defence-line in attack from turn-over and therefore turn-over is one of the effective starting points.

    The purpose of this study was to clarify attack aspects from ruck in the breakdown and to compare the difference of the attack aspects from ruck of southern hemisphere and of northern hemisphere. This study was analyzed mainly by two points. The first were the options of attack from ruck. The second were situations of ruck. The main results of this study were as follows;
1) The most 39% of the attack from ruck is Side Attack. There is Line Attack of 27％ in the second, and Pick Attack of 14％ in the third.
2) In total, eighty percent of ball out from ruck was ruck of less than 5 seconds. Comparing the Southern Hemisphere and Northern Hemisphere, ruck of less than 5 seconds is high ratio in the southern hemisphere, and ruck of more than 5 seconds is high ratio in the northern hemisphere.
3) Line Attack decrease at attack from ruck of more than 5 seconds, and Pick Attack and Kick Attack increase.

    The purpose of this study was to investigate the physical activities of referees during rugby games. Referees in 6 games (including 2 company games, 2 university games and 2 high school games) were filmed with 2 video tape recorder to estimate the distance and velocity using a DLT method. Accelerate phase and tum movement of referees were videotaped using another video tape recorder.

    The results were summarized as follows:

(1) The mean time of out-of-play per a play was almost 30 second.

(2) The mean time of in-play per a play in high school games was almost 20 second.

(3) The longest total distance was 6567.4m in university games.

(4) Jogging (under 4m/sec.) shared the highest percentage of almost 90%.

(5) There were 286 times of accelerate phase in university games.

(6) There were 379 times of tum movement in high school games.

コリジョンスポーツ選手においては頸椎の退行変性をきたすことがあり，変性が進行すると頚髄損傷などの重大事故につながる危険性も示唆されている．頸椎退行変性とくにアライメント異常には頸部周囲筋力バランスが関与していることも報告されている．コリジョンスポーツ選手の頸椎退行変性予防さらには重症頸椎頚髄損傷予防を目的とし，頸部屈曲・伸展筋力バランスの異常が頸椎退行変性やアライメント異常に関与していると仮説のもと柔道選手及び

 Two game analytical studies were conducted to examine kick-off play in rugby football. In study 1, fourteen rugby matches at the top level in domestic university teams were analyzed to verify the importance of kick-off play in the game of rugby football. Main results were as follows: 1) The number of kick-off plays averaged about 13 per match. 2) The average percentage of gaining balls were very low at the kicking side in kick-off play. 3) Whether the ball could be gained in kick-off play related significantly to the length of time the kicking side occupied the opponent ground after kicking off, and it related significantly to the rate of the kicking side's getting score and score chance. From these results, kick-off play was concluded to be an important set play in the game of rugby football at the level concerned. In study 2, four matches were analyzed to diagnose the kick-off play of a team which was at the top level in the domestic university teams. The diagnosis found out some problems on the kickers, the catchers, and the supporters. Making better these faults of kick-off play will be an important task in coaching the team.