不同防守距離三分球投籃之運動學分析

Abstract

本研究目的在探討以三種不同距離 ( 1公尺、 1.5公尺、 2公尺) 防守時，選手在實施三分球跳投動作運動學參數上的差異。研究方法是使用一部 Redlake 高速攝影機（125Hz），收集六位高中男子甲級籃球隊選手，當對手在不同距離防守時，選手所做的三分球投籃的動作資料。以無母數 Friedman 檢定分析三種防守距離運動學參數上差異的顯著性，並以 Spearman 無母數相關進行計算及檢定。結果發現：出手速度、出手角度、出手高度隨防守距離縮短而增加。重心最低點在無防守、距離2公尺至距離 1.5公尺時，防守趨近下肢關節角度愈小，角速度愈大。防守距離 1公尺時，下肢關節角度變大，角速度變小。出手瞬間上肢關節角度沒有差異，上肢關節角速度與重心最低點下肢關節角度呈負相關。上肢關節角速度在無防守至距離 1.5公尺時，防守趨近上肢關節角速度愈小。防守距離 1公尺時，角速度變大，肩關節差異最大。出手重心角度對隨防守距離趨近而減小。投籃命中率在各防守距離間沒有顯著差異，但與防守距離還是有相關。由此可知，在不同防守距離的三分球投籃動作特徵及影響命中率皆不盡相同。防守距離在 1.5公尺以上時，重心較低、運用較多下肢力量，防守愈近力量愈大。防守距離在 1公尺時，重心提高、下肢力量變小，投籃者增加上肢動作速度以彌補下肢力量不足，但從實驗及命中率觀察發現，下肢力量變小容易影響投籃穩定性。因此未來教練指導學生投籃時，應瞭解不同防守距離投籃的動作特徵，並在教學上有所調整，較能達到事半功倍的效果。The purpose of this study was to examine the different kinematic parameters of 3-point jump shots with three disparate defense distances (1 meter, 1.5 meters, and 2 meters). The researcher collected the kinematic parametric data of 3-point jump shots with three kinds of defense distances by six male basketball players from senior high school Division A with a Redlake high speed camera (125Hz). A nonparametric Friedman test was adopted to analyze the significance of difference and Spearman rank correlation coefficient for the statistical calculation. The results indicated that the release velocity, release angle, and release height increased with shortened defense distances; the lowest center of gravity was demonstrated from no defense to a 1.5-meter defense distance. The angle of lower limb joints decreased and angular velocity increased with a shortened defense distance. The angle of lower limb joints increased and angular velocity decreased with a 1-meter defense distance; the angle of upper limb joints didn’t exhibit discrepancy at the moment of release, with the negative correlation between the angular velocity of upper and lower limb joints at the lowest center of gravity. The angular velocity of upper limb joints decreased from no defense to a 1.5-meter defense distance, and displayed greater angular velocity and the greatest difference of shoulder joints with a 1-meter defense distance; the release angle of center of gravity decreased when the defense distance shortened, and the percentage of 3-point shots didn’t exhibit significant difference with respective defense distances, but the two factors were still correlated. Therefore, the features of 3-point shooting actions and percentage were different in the disparate defense distances. The center of gravity was lower when the defense distance was more than 1.5 meters, while more lower limb power was exerted when the distance was shorter. The center of gravity was higher with less lower limb power when the defense distance was within 1 meter. The shooter increased the upper limb action velocity to compensate for the lack of lower limb power. However, from the experiment and the analysis of shooting percentage, the decrease of lower limb lower could influence the stability of shooting. As a result, coaches should understand the distinct action characteristics with respective defense distances when training students to shoot in the future. Better efficiency and efficacy could be expected with appropriate adjustment in the teaching methods.