The Japan Journal of Coaching Studies
Online ISSN : 2434-0510
Print ISSN : 2185-1646
Volume 25, Issue 2
Displaying 1-13 of 13 articles from this issue
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Original articles
  • Yukako Fukase, Sekiya Koike, Tetsu Yamada, Satoshi Motoya
    2012 Volume 25 Issue 2 Pages 137-147
    Published: March 20, 2012
    Released on J-STAGE: September 02, 2019
    JOURNAL FREE ACCESS

        The purpose of this study was to reveal effective takeoff skills for dynamic pike mount in wheel gymnastics vault. Takeoff motions of the players who have different features in motion were comparatively analyzed in the biomechanical view points to clarify the effective takeoff skills. Four subjects (2 males and 2 females) were analyzed. Effective takeoff skills were revealed as indicated as follows : 1) Using hinged-movement to convert horizontal velocity with run-up into greater vertical velocity for jump-up by leaning the body backward at touchdown. It helps to jump up higher. Positional relation of the body and the wheel at takeoff must be considered preliminarily because the wheel rolls forward while the legs on the ground. 2) Getting larger angular impulse thorough takeoff to rotate the body forward by leaning the body backward at touchdown. It helps to raise the feet higher. 3) Minimizing extension torques at shoulder joints by taking hold the wheel with the elbows extension preliminarily and with the shoulders keep narrowing. That leads to flex the shoulders during mounting phase. It helps to raise the hip higher.

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  • Focus on the target parts of coaching in movement phase
    Tetsuya Kanahori, Takashi Kawamura, Tomoyuki Matsuo, Masao Asaoka, Yuk ...
    2012 Volume 25 Issue 2 Pages 149-156
    Published: March 20, 2012
    Released on J-STAGE: September 02, 2019
    JOURNAL FREE ACCESS

        The purpose of this study is to get the basic data for build up the systematic coaching method, to elucidate key coaching points related to movement in baseball hitting, to integrate and assemble these points, to elicit experiential knowledge from expert baseball coaches. Forty guidance books of baseball hitting were published in Japan which were transcribed onto text data, and divided into segments on the basis of meaning unit. We labeled “target parts (posture, axis, head and face, arm, viewpoint, trunk, hip, leg, object, equipment)” and “movement phase (stance, take back, top, step, approach, impact, follow-through and comprehensive)” to these text data. For this process, we conducted triangulation to improve reliability and validity. We extracted 3215 units and analyzed the number of each labels. The most frequent label was “equipment” and the next frequent label was “leg” and “arm” and “trunk”. These results suggest that key coaching points of baseball hitting shift from “leg” to “trunk” to “arm” in progress of movement phase. From the number of “target parts” in “movement phase” suggest that baseball hitting is coached for target both the comprehensive and partial, and it became clear what many baseball coaches were coaching who have common knowledge in the movement phase.

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  • In case of female basketball players
    Tetsu Nakaoji, Naomi Yamada, Koji Fukuda, Yuya Muraki, Akira Ito
    2012 Volume 25 Issue 2 Pages 157-165
    Published: March 20, 2012
    Released on J-STAGE: September 02, 2019
    JOURNAL FREE ACCESS

        The purpose of this study was to clarify which factors on skill and physical strength could influence the success rate of two-handed three-point shots (SR) by means of a motion analysis and measurements of long throwing ability.
        The results of this study were as follows. A significant correlation were recognized between SR and the number of shots for a month (r=0.682, p<0.01).
        Next, there had no significant correlation between the initial velocity or the angle of projection of balls, and SR. In the shots, the players with a high SR had less time from take-off to ball-release (r=0.659, p<0.01), and performed both jumping movements and the movements increasing the angular velocity of shoulder or elbow joints synchronously.
        Moreover, another result was that the superior players had the ability to throw farther (r=0.692, p<0.01).

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Practical research
  • Forward-stepping follow-up after functional reach
    Takako Hiwa, Atsushi Itaya, Satoshi Motoya, Kiyonao Hasegawa
    2012 Volume 25 Issue 2 Pages 167-176
    Published: March 20, 2012
    Released on J-STAGE: September 02, 2019
    JOURNAL FREE ACCESS

        This study aims at getting fundamental knowledge useful for instructing fitness exercise for elderly people’s saftyagainst-overturning. The investigation was carried out, by targeting elderly people, by measuring Functional Reach (FR) and Center of Pressure Excursion (COPE) combined with stepping-forward motion. Together with the usual FR, ‘Functional Reach and Forward-Stepping Follow-up’ (FR-FS), where the action of stepping forward following FR is analyzed, were used. Subjects are 18 women (average age 72.0 ± 4.0 years). Two tests were performed: one was a usual FR test, and the other was an FR-FS test. There, FR lengths and the most forward positions in COPE were measured, and the follow-up motion was video-recorded.
        The results are as follows.
    1. The values of FR and the most forward positions in COPE are significantly larger for FR-FS than for FR (respectively, p=0.005 and 0.025). As for FR values and the most forward positions in COPE, there is a strong correlation between FR and FR-FS (respectively, r=0.887 and 0.840). This fact suggests that the FR-FS can possibly be used for a method to measure dynamical balancing ability.
    2. The FR-FS can be classified into two categories from the characteristics of the movement, an ‘anteversion-stepping’ type and a ‘standing-posture-stepping’ type. In the former, stepping-forward motion is initiated in the unbalanced condition keeping anteversion. While in the latter, an action to restore the standing posture is observed as in FR.
        As a result of comparison and analysis between FR and FR-FS, the following has been suggested. Mere measurements of measurable muscle strength and balancing ability are not enough. Studies of measurement methods which have a relationship to the actual body movement to avoid overturning are thought to be necessary.

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Research data
  • Seshito Shimizu, Tomoyuki Nagami, Noriyoshi Moriyama, Mitsuru Satoh
    2012 Volume 25 Issue 2 Pages 177-187
    Published: March 20, 2012
    Released on J-STAGE: September 02, 2019
    JOURNAL FREE ACCESS

        This study focused on the takedown movements of female Japanese World Champion wrestlers in competition. Take down time which conducted from touching leg to getting point and these movements of two World champions were compared with those of other of other high level athletes.
        As a result, World Champion had much higher number of effective takedown and much shorter the takedown time than other wrestlers. The following four findings were obtained as characteristics of a successful takedown movement.
    1)Stayed in a forward leaning stance.
    2)Head direct movement toward trajectory with little up and down motion.
    3)The step back (jab step) of the trail leg was short.
    4)Takes a leg attack with the opponentʼs loss of balance.
        It is thought that a practical application of these findings could result in more effective coaching and training.

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