The purpose of this study was to clarify the relationship between knowledge and performance in invasion-type ball games. The relationship was addressed through a tactical knowledge test and a field performance test on tactical problems common to such games.
    A total of 154 college students took part in the study. Of those, 109 (mean age 20.3±1.3 years) were proficient in soccer, a typical invasion-type ball game. The other 45 participants were general college students (mean age 20.4±1.2 years) without any athletic club experience in high school or university. The following summarizes the results and observations:
(1) Regarding the tactical knowledge test, the average score of the soccer players was significantly higher than that of the general college students. This suggests that the players acquired tactical knowledge of invasion-type ball games through their sports experience.
(2) It also underlines an order of complexity regarding tactical problems in invasion-type ball games.
(3) The average score on the performance test among the soccer players was significantly higher than the average score of the general students. Thus, acquisition and structure of knowledge can be seen as factors in determining performance.
(4) Lastly, the results indicate a need for tactical training in the field.

    The purpose of this study was to examine the characteristics of the kick start lateral. Subjects were 13 male college swimmers and 14 male physical education students, and they were divided into the upper skilled group (n＝6), the lower skilled group (n＝7) and unskilled group (n＝14) by the 5m time.
    The higher the group’s skill was, the higher the 5m time and the 5m velocity (p<.05-01). The higher the group’s skill was, the shorter the block time were (p<.05-01), due to the shortening of the start of knee angle extention in the rear leg (p<.01). There was no significant difference between each groups in the entry velocity. The higher the group’s skill was, the higher the velocity maintenance rate (the entry velocity / the 5m velocity) was (p<.05-0.1), however. The angle of projection on take-off significantly correlated with the difference in height of the center of gravity between the time of start position and take-off (p<.01), and the latter significantly correlated with the difference in upper body angle between the time of start position and take-off and with the minimum knee angle in the front leg (p<.01).
    It was thought that the difference of the velocity maintenance rate was caused by the high entry technique of skilled groups, because the differences between the skilled groups and the unskilled group were most noticeable (p<.01) in the angle of projection on entry, the attitude angle on entry and the angle of attack on entry.

    The purpose of this study was to clarify the basic movement patterns and factors for changing these patterns at the catching of grounders among the infielders of college players. Three college baseball players who had had more than ten yearsʼ experience as infielders received 100 fungoes thrown from the shortstop position to first base. All these attempts were recorded using a video camera. The three persons who had had a baseball career of more than ten years watched these images of playing and categorized these plays into 5 categories (“direction of the batted ball”, “catching bound”, “handling”, “the stepping manner”, and “throwing”). And they also assigned 12 labels for the 5 categorized plays with the agreement of all three of them for all plays. After categorization, we counted the number of each label in each category. Moreover, we performed statistical analysis using the chi square test with the cross tabulation for examining the relationship of two categories. When the result of the chi square test was statistically significant, we processed the residual analysis. The infielders of college players were assumed to have the following movement as the basic movement pattern. Namely, “direction of the batted ball” was the “front”, “catching bound” was “long bound”, “handling” was “both hands”, “the stepping manner” was “one-step”, and “throwing” was “overhand throw”. However, as a result of residual analyses, “handling” used “single hand” when “direction of the batted ball” was the “right side”, and “the stepping manner” used “plural steps” when “catching bound” was “half bound”. The above results show that the infielders of college baseball players changed their movements quickly in response to such change of situation. Therefore, it is necessary for the coaches to instruct them in the basic movement patterns and also corresponding plays for sudden situation changes in defense coaching.

    The purposes of this study were to investigate load characteristics of the throw with the competition hammer (7.26kg) and the heavier hammer (8.0kg). Sixteen male hammer throwers threw the competition hammer and the heavier hammer with their maximum effort. Utilizing three high-speed video cameras (300fps), three-dimensional coordinates of the hammer head and left middle metacarpophalangeal joint were obtained using the direct linear transformation method. Main results were as follows: 1) The maximum centrifugal force of each phase in the heavier hammer was significantly higher than that of competition hammer during double support phase (DSP) of 3^rd and 4^th revolution. However, significant difference was not found in the average centrifugal force. 2) The centrifugal force in the heavier hammer was significantly higher than that of competition hammer during 14％－23％ and 47－51％ of DSP4. 3) Thirteen throwers showed positive values and three throwers showed negative values of force increment (absolute difference of maximum centrifugal force between the heavier hammer and the competition hammer). These results indicate that throwing the heavier hammer causes load increment, which is intrinsic purpose of resisted training.

    This study aims to investigate the intracycle velocity fluctuations（ IVF） and stroke parameters （Stroke Length and Stroke Rate） during the 200 m swimming of the breaststroke. Twenty-four competitive collegiate swimmers （females, n＝11; males, n＝13） performed with the maximum effort required to keep steady pace. Swimming performances were videotaped simultaneously using two cameras at different views（ i.e., frontal and lateral views）. Stroke cycles for each 50 m were analyzed over the 200 m swim course. IVF was employed during the breaststroke performance analysis to measure （1） the peak velocity during the kick （V K_peak）, （2） the peak velocity during the pull （V A_peak）, （3） minimum linear body velocity before the arm pull motion （V Glide）, and （4） minimum velocity with leg recovery （V Recovery） calculated as a percentage of the mean swimming velocity. Videotaped swimming performances were analyzed to obtain the stroke rate, stroke length, and mean swimming velocity.
    V K_peak significantly decreased in the last 50 m of the course. In addition, a significant increase was observed over the same interval for V Glide. Although V K_peak decreased, swimmers maintained the mean swimming velocity, and V Glide increased simultaneously. Thus, for a given subject, even if the mean swimming velocity remained constant, changes in IVF were observed during the 200 m swimming of the steady pace breaststroke.
    It is concluded that the evaluation associated with IVF and stroke parameters provided useful and detailed race strategy and evaluation.

    The purpose of this study was to investigate the effects of CM-CB distance (the distance between the center of mass and center of buoyancy) on gliding performance and passive drag in a streamlined position. Fourteen well-trained male college swimmers participated in this study. The CM and the CB were measured in a streamlined position. Also, the gliding performance after wall push-off, and the passive drag forces and drag coefficients in a streamlined position at various velocities (1.0, 1.3, 1.6, 1.9, 2.2 m/s) were measured.
    There was a significant negative relationship between CM-CB distance and the gliding distance (p < 0.01，R² ＝ 0.61). CM-CB distance was not significantly correlated to the time to 5 m from wall push-off, but significantly correlated to the transit time to 10 m from the wall push-off (p<0.05，R² ＝ 0.40). No significant correlation was found between CM-CB distance and the passive drag force. However, there was a significant correlation between CM-CB distance and the passive drag coefficient only at the velocity of 1.0m/s (p<0.05，R² ＝ 0.31). The results suggested that the effects of CM-CB distance on gliding performance and passive drag in a streamlined position were greater at slower than at faster swimming velocities.

    The purpose of this study is to obtain the coaching data for improving setting skill about set to the accurate position that is easy for attackers to spike, by three-dimensional motion analysis.
    The setter of this study was checked sufficient level of skill about handling motion and the timing of stepped into the level point. However, set to both sides were sometimes short because the posture of setting didnʼt balance. From these results, according to Grosser, it was assumed that the setter of this study was the middle-class which it was easy to carry out the technique under a simple situation, but it was hard to carry out the technique under a complicated situation such as a game.
    To improve setting skill, it was assumed that the practice drill should show a game scene so that the unique exercise program of the movement task was developed.

    The purpose of this study is to examine influence of teammates on motivational climate of high school baseball teams, to find relationship between motivational climate patterns and teammates factors, and to contribute to improve teamwork and motivation of team members. The study was done on 389 high school players (age of 16.31 ±0.76 years old) belonging to the four high school baseball teams in Japan. The research was carried out to ask each baseball team to fill out a questionnaire that I had made for the study. The contents in the questionnaire were based on their individual profile, such as ages, gender, and so on, and some questions to measure motivational climate of the team and to understand the interaction among the teammates, and to clarify how deeply the individuals were affected by his teammates. From the research, I found the following results: In case some players in the teams show some players who are physically gifted don’t feel the need to practice, this negative factors often influence strongly the players’ performance climate. There is a possibility that promote the improvement of competitive levels by intra-team competition progress. To enhance the teammates unity helps teams improve their mastery climate and competition results.

    This study aimed to clarify techniques for kicking along various trajectories toward variously positioned targets in direct free kicks in soccer. Four experienced soccer players (career：12±0.8 years) belonging to a university soccer club participated in this study. Participants were asked to kick a soccer ball to 4 targets at various combinations of vertical and lateral positions in the goal (3.5 m left of center and 3.5 m right of center; 1.2 m from the ground and 2.2 m from the ground) from behind a screen (height 1.8 m×width 2.5 m) positioned 9.15 m in front of kicking points. Participants kicked from 3 positions located 20m from the goal (center of goal, 3.5 m left of center, 3.5 m right of center). The behavior of the kicked ball was recorded by 4 normal-speed video cameras and analyzed using three-dimensional direct linear transformation. Two high-speed video cameras were used to capture parameters related to ball rotation; one was placed facing the kicker and another was placed beside the kicker to capture the moment the ball was kicked. Results indicated that the lateral component of the Z-coordinates tended to approach the center of the goal and varied more widely than the vertical component. Additionally, lateral kicking direction was the most important parameter to kicking along various trajectories for all participants and combinations of target positions. The kicking direction for greatest reduction of error appeared to differ by strategies for kicking along various trajectories. Lastly, vertical kicking direction was an important parameter to kicking along various trajectories for some participants, but for other participants, initial velocities as well as kicking direction were important parameters.

    Under current rules, coaches and gymnasts are permitted to object to the decisions of judges. However, if gymnasts/coaches feel distrust towards the decisions of judges, it is undesirable for gymnastic competitions. If the criteria for rating performances are vague, there cannot be a common understanding between gymnasts/coaches and judges, making it difficult to organize competitions. In light of this, in this study we conducted a structural analysis of the skills whose forming conditions are vague, to clarify the forming conditions of the skill and to provide some direction for developing an ideal image of skills.
    A structural analysis of the “backward uprise and salto forward piked to support” was performed.
    The analysis results clarified the following.
    It is not possible to show the forming conditions of the skill under the name “backward uprise and salto forward piked to support.”
    It is possible to specify an ideal image of the skill, by grasping it as a “rise” maneuver.

    This practical case study for coaches presents a scientific investigation of a single coaching practice using the qualitative method of episode description, which assesses the background of an episode and the episode itself and draws considerations from the assessment．The subjects belonged to a womenʼs volleyball team that belongs to the first division of the university volleyball federation in which the researcher is involved as a coach．The focus of the observation yielded an episode labeled “What are your aesthetics as a spiker ?”
    This finding revealed that the researcher, in his role as coach, tend to be blind when faces on the scene of coaching and yielded the consideration that “Repeat inquiry into oneʼs own coaching philosophy and sense of ethical practice is warranted.”