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.

    Subjective effort is an adjustment in output performance, dependent on an athlete’s perception and it is an important factor in sprint training. To gain information about utilizing subjective effort in sprint training, this study investigates changes in sprint running movement due to the different subjective effort of athletes at various performance levels. The participants were 15 male collegiate sprinters, who were divided into high-level (n＝7) and low-level (n＝8) groups based on their personal best times in the 100 m dash. The participants performed 50 m sprints at five levels of effort ranging from 60％ to 100％, with increases at 10％ intervals. The final 10 m of each sprint was recorded by two high-speed video cameras to analyze each participant’s movement. The results are summarized as follows.
    The decline in sprint speed at lower subjective effort was higher for the low-level group than high-level one. This was the reason why low-level group decreased swing back velocity of the leg with the change of knee joint angle increased below a subjective effort of 70％. And the achievement of sprint speed from a subjective effort of 90％ to maximum effort was not practical because of knee extension during support phase. Moreover, below a subjective effort of 70％, the low-level participants’ movement during support phase differed from that of maximum effort sprint running. In contrast, the high-level participants’ movement was the same even a subjective effort of 60％.

    This study investigated 8 canoe athletes to determine boat movements during 500m canoe sprint using Differential Global Positioning System (DGPS), and aimed to evaluate the relationship between each parameter and racing results. The findings are as follows:
1) During the first half of the race, improving Stroke Rate (SR) and Distance Per Stroke (DPS) influenced increase in Boat Speed (BS). For the second half of the race, the decrease of BS was suggested to be influenced by the decrease in SR, which was resulted by the increase in drive phase and recovery phase.
2) The athletesʼ paddling types could be classified using the T-Scores of each parameter obtained from DGPS. Therefore this classification enabled comprehensive evaluation of performance factors unique to canoe racing, e.g., relationship between their DPS and SR, and course changes. Thus, it could be a useful tool to customize the training programs for each individual athlete.

    The purpose of this research was to compare and make clear the difference between the side-foot kick motion of a stationary ball and a rolling ball. Twelve male university soccer players served as subjects. These subjects aimed for a target placed right in the middle of the goal, 7 meters ahead. The rolling ball was given by a 1.5 meter high 2-railed ball dispenser. The kick motion was taken picture by using an optical motion capture system. The kick motion of a rolling ball was distinctive by these ways. 1) The initial velocity of the ball was at the same level, but swing speed was slower than the side-foot kick motion of a stationary ball. 2) The kicking leg hip angle was not as extended as in a stationary ball kick.3) Considering that minimum flexion and extension angular velocity of that were large and small respectively, the kick was done by not practically using the knee jointʼs flexion/extension, and making the back swing small. From the above results, the kick motion of a rolling ball was overall compact compared to that of a stationary ball.

    The aim of this study was to investigate the trade-off relation between the speed and accuracy of a pitched baseball. To do this, the initial velocity of the ball at release and the distance between the arrival position of pitched ball and the target were measured at the four different subjective effort levels. Three baseball pitchers each performed 12 sets of 16 pitches at subjective effort levels of 100％, 90％, 70％, and 50％; in each of the sets, the target was set at a different height above home plate. Each pitcher threw 192 pitches in total. The pitching motion and trajectory of the ball were videotaped with a high-speed video camera and normal video camera, respectively, and analyzed by three-dimensional direct linear transformation. The following results were obtained. Although there were individual differences between participants, the initial velocity of each pitched ball at subjective effort levels of 100％, 90％, and 70％ was over 90％ of the participantʼs maximum velocity, and in general, the accuracy of the pitch and initial velocity of the ball at release had a trade-off relation: accuracy increased with decreasing initial velocity. However, at the 50％ subjective effort level, the opposite relation was observed: accuracy decreased with decreasing initial velocity. As the subjective effort level was reduced, all the participants changed their pitching motion at a certain subjective effort level. This change in pitching motion possibly caused the pitchers to change their technique for releasing the ball, and consequently the trade-off relation no longer held.

    The purpose of this study was to examine the practical use of Global Positioning System (GPS) in rugby coaching. Thirty-six male university rugby players were involved in six games in one official season. GPS technology was used to assess data about the players’ positioning, movement patterns, covered distance, number and speed of sprints, number and intensity of impacts associated with collisions. Comparison was performed on the changes of players’ performance during one game and between games, as well as between players and playing positions. Beside performance evaluation, the findings helped to appoint players for certain tactical needs, and to improve position specific training. In addition, body load could be measured which is difficult to obtain by video analysis. The results confirmed findings of previous studies that had compared playing positions focused on the total distance covered, and proved that GPS can be an efficient tool in rugby coaching.

    This study investigates the catcherʼs throwing time to second base (time from the ball being caught to the completion time of the thrown ball reaching second base). The throwing motion of college baseball catchers (n=12) and the catching motion of a second baseman were videotaped at 210 Hz using different high-speed cameras. The throwing time was divided into the motion time (time from the ball being caught to being released) and the airborne time (time from the ball being released to the ball reaching second base). The motion time was further divided into the hold time (time from the ball being caught to the ball being held in the right hand), the stride time (time from the ball being first held in the right hand to the lead foot contact), and the release time (time from the lead foot contact to the ball release). To evaluate the throwing ability of the catchers, the throw distance was measured. There were no significant correlations between the throwing time and the motion time, but there were significant positive correlations between the throwing time and the airborne time. These results indicate the importance of increasing the initial velocity of the ball after release. There were no significant correlations between the throwing time and the hold time, or between the throwing time and the stride time. However, there were significant negative correlations between the throwing time and the release time, and the airborne time showed a significant negative correlation with the release time. These results suggest that catchers exhibiting the shorter the throwing times attempted to increase the initial velocity of the ball after release, although the release time became longer. Throw distance showed a significant negative correlation with the airborne time. These results clearly demonstrate the necessity of increasing throw distance to obtain a higher initial velocity of the ball at release.

    Main purpose of this study was to clarify the coaching nodes which were defined as the invariant coaching points in pitching mechanics among the experienced coaches. We also investigated the differences of opinion to the coaching points between the experienced coaches and the novices or non-experienced coaches, and among the experienced junior high school coaches, the experienced high school coaches, and the experienced ex-professional pitchers. We got 1,833 replies of questionnaires consisting of 30 items, from the ex-professional baseball players, high school baseball coaches, and junior high school baseball coaches. Several items were regarded as the coaching nodes or semi-coaching-node for all levels in this study, and another item was regarded as the coaching node for only the junior high school players.