The purpose of this study was to examine the effect of visual limitations on the motion involved in ball-catching tasks. Of the 19 female participants, 7 were intermediate-level softball players, while 12 were primary-level softball players. The 2 groups of players performed the ball-catching tasks under 3 different conditions. In the normal condition, no limitations were imposed on the participants. The visual limitation condition included limitations of about 20 degrees of down view, and the third condition included the limitation involved in the visual limitation condition and a fastball condition. The intermediate-level players adapted to their visual limitations by using a ball-catching position in which they moved forward by increasing the distance between their feet and hands, while primary-level players adapted by moving their head more downward. These differences in adaptation observed, show the differences between the 2 groups in relation to the motion involved in ball-catching tasks. However, these differences are difficult to explain in the context of basic motion. We therefore conclude that visual limitations can help intermediate-level players acquire the expert motion involved in ball-catching tasks.

    The purpose of this study was to clarify the mechanism of pick play, with a view to increasing the understanding of pick play in basketball. The procedure for study was used “notational analysis”. The mechanism of pick play clarified as a result of this study can be summarized as follows. It can be concluded that the pick play in basketball is characterized mutually regulation relation of “within 3 seconds,” “priority placing” of “ball handlerʼs location,” “screenerʼs angle,” “playerʼs combination” and “perimeter playerʼs arrangement,” and “flow”

    本研究は，バスケットボールの個人的攻撃局面における状況判断について，状況判断能力テストの結果を探索的因子分析によって包括的な要因を検討し，さらに，抽出された状況判断能力因子の構造から共分散構造分析を用いて状況判断能力の習得の順次性について仮説的構造モデルを作成して検証した．
    標本は，大学のバスケットボール部に所属する158名であり，全テスト67問をプレイの特徴から23項目にまとめそれらのテスト結果を観測変数としてAMOSによる共分散構造分析を行った．
    個人的な攻撃の局面における状況判断能力の8つの因子は，個人的な攻撃の局面におけるそれぞれの特徴から3つの2次因子にまとめ，仮説的概念モデルとして｢並列型3次因子モデル｣，｢順列型モデル｣などの4つを表した．それらに抽出された因子を当てはめて分析したところ，「並列型3次因子モデル」が最も当てはまりの度合いが高かった．
    「並列型3次因子モデル」は，2次因子にはそれぞれ独立した判断基準が存在する可能性が示唆されたものと考えられ，プレイや戦術の理解とともに状況判断力の向上のためには各状況における指導の必要性が認められた．

    The purpose of this research is to estimate the anthropometric characteristics and jump performance differences between professional and college volleyball players. Thirteen professional players group (TG) and twenty-eight college volleyball players group (NG) performed anthropometric (i.e., height, standing reach height, body mass) and performance tests (i.e., flexibility, squat jump [SJ], countermovement jump [CMJ], countermovement jump with arms [CMJA], repeated rebound jump [RJ], repeated rebound jump with arm [RJA], standing long jump, standing 3-steps jump and spike jump reach height with one step [SPJ1] and three steps [SPJ3]). RJ-index (RJ-index) was calculated by dividing the jumping height by the corresponding contact time (jumping height / contact time). Anthropometric and performance comparisons between college and professional players were accomplished by unpaired student’s t-tests. A criterion alpha level of p<0.05 was used to determine statistical significance.
    Height (187.2±6.8cm vs. 180.7±8.4cm: p<0.05), standing reach height (243.0±11.6cm vs. 232.3±12.8cm:p<0.05), and body mass (82.0±7.3kg vs. 73.9±5.3kg: p<0.001) were significantly higher in TG than NG. Flexibility (51.8±7.0cm vs. 53.4±11.4cm) was not significant difference between groups. While standing long jump (273.5±16.4cm vs. 261.8±18.4cm) was not significant difference between groups, standing 3-steps jump (793.4±60.2cm vs. 736.1± 45.7cm: p<0.01) was significantly higher in TG than NG. CMJ (50.2±4.9cm vs. 46.7±3.6cm: p<0.05), RJ-index (2.05 ±0.29 vs. 1.79±0.28: p<0.01) and RJA-index (2.40±0.35 vs. 2.07±0.45: p<0.05) were significantly higher in TG than NG. However, SJ (46.1±4.4cm vs. 43.9±3.8cm) and CMJA (60.3±6.9cm vs. 57.2±4.5cm) were not significant difference between groups. SPJ1 relative height (83.9±8.0cm vs. 72.3±7.1cm: p<0.001) and SPJ3 relative height (88.5 ±9.5cm vs. 80.4±8.7cm: p<0.05) in TG were significantly higher than NG.
    These results indicate that anthropometric and stretch-shortening cycle efficiency differences exist between groups.

    This cross-sectional study investigated the comprehensive physical fitness and motor ability for Japanese elite age-group tennis players. Sixty one male players were divided into three age groups : group A (12-14 yr), group B (15-17 yr), group C (18- yr). It was found that : 1) There was a significant correlation between total Principal Component Analysis score (all PCAS) which summed up laboratory and field test results and match performance based on the Japan Tennis Association ranking points per 1 tournament（ JTA RP/1tournament). 2) Several variables such as jump ability and medicine-ball throw did not show differences significantly from groups B to C, but only isokinetic strength in leg and trunk showed differences significantly across the three age groups. 3) A significant regression between the laboratory test and field test scores was found (y＝0.863x-0.108, r＝0.802, p<0.01). Based on this regression, some players were judged to poor motor ability for their physical fitness. These results suggest that well-balanced training between physical fitness and motor ability was essential to progress tennis performance.

    The purpose of this study were to study practical wisdom of coaching, and reconsider “coaching” from soccer coaches’ life-story. Semi-structured interviews were conducted with two coaches (former J-league soccer players) who are directing top-level youth soccer team in Japan. The result showed that coaches are learning from their own coaching experiences. Therefore, it seems important that coaches should work on practices that include “organic improvement” based on “reflective thinking”. In conclusion, “coaching” was reconsidered as “the workings of growth for coaches through their coaching practices” and this appears to be a different view from “conventional coaching”.

    This study aimed to investigate the method of evaluating the ability of power exertion at the lower limb for female collegiate athletes. A total of 103 female collegiate athletes belonging to the athletic club performed vertical and squat jumps (VJ and SJ, respectively) on the laboratory floor. The vertical ground reaction forces of both legs were determined by using a force platform (500 Hz) for calculating these jumping heights. The increase ratio of the jumping height (％) was calculated as ((height of VJ - height of SJ) / height of SJ) × 100. Significant positive relationships were observed between the heights of VJ and SJ (r＝0.836, p<0.001), and the increase ratio of jumping height (r＝0.249, p<0.05). Based on each average of the height of SJ and the increase ratio of jumping height, the athletic clubs (9 groups) were divided into the Excellent, Power, Technique, and Poor types. Athletic clubs that have superior athletic performance had a greater height of VJ, and are classified in the Excellent type. This study method could be useful to evaluate the ability of power exertion at the lower limb of athletic clubs.

    The purpose of this study was to investigate the read blocking techniques against quick attacks with combination attacks in volleyball. 28 occurrences of blocking motions in 4 games (Poland vs Iran, Poland vs Japan, Cuba vs Argentina, Cuba vs Serbia) from the 2011 Men’s World Cup Volleyball were analyzed by the Direct Linear Transformation Method.
    The findings were as follows:
(1) The number of occurrences of double blocking (Middle blocker with side blocker) was 11 (Right-side blocker 5 times, Left-side blocker 6 times). Most blocks were single blocks by the middle blocker.
    The average of the highest finger-tip heights for blocking motions were right-side 2.80m, middle block 2.97m, and leftside 2.84m.
(2) In 11 occurrences of when a middle blocker touched the ball, the average of the finger-tip height for the right fingertip was 2.91m (range: 2.76 to 3.04m), and the left finger-tip height was 2.85m (range: 2.70 to 2.99m). In 8 occurrences, the middle blocker took off －0.016 to －0.134 seconds before the quick spiker hit the ball.
(3) When the quick spiker took off, the distance from the net to the middle blocker’s position averaged 0.90m (range: 0.38 to 1.91m). On the other hand, when the quick spiker hit the ball, the distance from the net to the middle blocker’s position averaged 0.66m (range: 0.31 to 1.34m). There was a significant difference between the distance at the time the quick spiker took off and the distance at the time the quick spiker hit the ball (p<0.01). Middle blockers took off 0.150 seconds later when their stance was usually wider than 0.6m.

    This study investigated the effects of plyometric training on change-of-direction speed (CODS) among college athletes who specialized in ball sports. Forty male college athletes (age, 19.9±1.06years; height, 173.4±6.24cm; Weight, 66.8±6.65kg) were participated in this study. The participants were randomly divided into 2 groups: training group and control group. The subjects in the training group had a 12-week plyometric training session. The subjects in this control group had no training sessions. Before and after the 12-week period, all subjects had a testing session to evaluate their physical abilities.
    In the training group, significant improvements were observed in all comparisons including all jumping items, straight-line sprinting, and CODS (p<0.05) and effects size was great. Moreover an improvement in VJ and RJ-index could make advance on CODS significantly.