軟式網球低切割法發球之三度空間運動學分析

A Kinematical Analysis on the Low: Cut Service of Soft Tennis

劉俊概(Juen-Kai Lui) ； 李建勳(Chien-Hsun Lee) ； 邱永興(Yung-Shin Chiu) ； 涂瑞洪(Rei-Hung Tu)

《大專體育學術專刊》 93年度 (2004/05) Pp. 285-293

https://doi.org/10.6695/AUES.200405_93.0031

摘要

本研究之目的為利用三度空間攝影方法，探討軟式網球低切割法發球之運動學分析，主要分為三個動作階段進行探討：一、拋球動作階段，二、拉拍動作階段，三、揮擊階段。本實驗參與者為國立屏東師範學院軟式網球校隊一名（年齡為22歲，身高為180公分，體重為72公斤）。使用JVC9800U高速數位攝影機二台，以拍攝頻率120Hz拍攝發球動作，利用APAS動作分析系統分析影片，將所蒐集之資料數位化以獲取運動學參數，做為各項動作技術分析與探討之依據。本研究結果如下：一、拋球動作階段：（一）拋球高度、擊球點高度，相差約22公分，得知因拋球高度的不同，出現不同的擊球點高度，並分出斜切法與下切法之發球不同性質。（二）拋球高度至擊球點球落下距離的高度都在於31公分左右，顯示不管是斜切法或下切法，球所落下的距離至擊球點時的行走距離，兩者均相接近。（三）斜切法與下切法的拋球高度、擊球點高度，兩者雖有明顯之不同。但是，以兩者的擊球點球下落速度來敘述之，因受地心引力之影響，使之球下落速度，其兩者沒有太大之差別。二、拉拍動作階段：斜切法與下切法肘關節角度平均值136度與140.9度，因有更小的關閉角度。斜切法與下切法膝關節角度平均值146.7度與150.6度，也應增加屈膝的角度。降低重心，以利於在低切發球時，減少球上飄的現象，並讓球著地後降低球的反射角度。三、揮擊動作階段：以拍面與地面角度敘述之，斜切低切割法與下切低切割法平均數各為38.54±6.83度與57.83±4.79度，兩者相差19.9度。可得知，在起始的拋球階段動作階段與拉拍階段動作中，因兩種發球方式，所拋出球的高度與擊球點高度有所不同，導致在擊球前拉拍動作的肘與膝關節，為了達到發出理想角度之球路，而隨之改變。因而出現揮拍的角度有斜切低切割法與下切低切割法兩種形式呈現。

關鍵字

軟式網球 ； 低切割法發球 ； 三維運動學分析 ； 生物力學

並列摘要

The present study aims to analyze the low-cut service of soft tennis using three-dimensional video-shooting method. This research is divided into three phases. First, ball-toss phase, second, take-back phase and third, swing phase. The subject of this study (age 22, height 180 cm and weight 72 kg) is one of the members of the school team in National Pingtung Teachers College. Two high speed call1eras (JVC 9800U) are used to videotape the service action with the speed of 120 photos per second. In addition, APAS is used as the analytical instrument to analyze the video. The data obtained will be digitalized in order to receive kinematical parameters, which are later applied as the references to conduct 1l10tional analysis and investigation. The results of this study are addressed as following. 1 Ball-toss phase: 1.1 The spatial difference between the peak height of ball-toss and the height of swing is 22 cm. It implies that the different heights of ball-toss cause different heights of swinging. The low-cut service can be subcategorized into two different types: inclined low-cut and under-cut services. 1.2. The height from which the ball is being tossed to swung is 22 cm, revealing that, regardless of the angle of services, the distance between the height of ball tossing and swinging remains almost the same. 1.3 Even though there will be different consequence in which the heights of ball-toss cause different heights of swinging by using inclined low-cut and under-cut services, when considering the velocity caused by different angle of services, it indicates no significant differences because of the gravity. 2. Take-back phase: the average angles of elbow by using inclined low-cut and under-cut services are 136 and 140.9 degrees, respectively, because of the smaller close angle. Also, because the average angle of knee joint by using inclined low-cut and under-cut services are 146.7 and 150.6, the angle of knee-bending should be increased. By lowering the body central gravity, players can not only prevent the ball from floating, but decrease the reflexive angle after landing. 3. Swing phase: in terms of the angle between the racket and the ground, there are on average, 19.9 degrees of difference in inclined low-cut and under-cut services. It indicates that among the three phases mentioned earlier, the heights of ball-toss and swing will be varied by different ways of services, and consequently, the angle of elbow and knee before taking back will be different in order for players to serve with ideal angle. In short, two subcategories of serving are presented.

並列關鍵字

soft tennis ； low-cut service ； three-dimensional kinematical analysis ； biomechanics