優秀男女網球選手正、反拍搶打截擊之運動力學分析
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2009
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目的:比較臺灣優秀甲組男女子網球選手在網球正反拍搶打截擊動作時之運動學參數、牽張反射對搶打截擊表現的影響。針對競技運動特殊性來探討網球選手在正反拍搶打截擊的過程中是否因為適當的啟動時機而增加搶打截擊的成功率。方法:甲組全國排名前32強之男子(平均年齡21.00 ± 2.33歲,平均身高182.06 ± 2.73公分,平均體重74.62 ± 6.23公斤)及女子(平均年齡20.90 ± 2.10歲,平均身高169.12 ± 3.52公分,平均體重60.38 ± 5.73公斤)各8名慣用手皆為右手的網球選手參與本實驗,在室內體育館內黏貼製作網球場地,利用送球員及控球員來控制實驗過程中的球速及方向,並在實驗場區外以兩台FASTEC Inline的高速攝影機同步收集控球員及受試者2D的運動學資料,九台VICON三維動作捕捉系統同步收集受試者的全身3D運動學資料以及用DASYLab收集下肢肌電訊號,並收集正反拍各三次成功的數據取其平均值來進行分析,並將所有數據以相依樣本t-test考驗來進行正反拍參數之差異。
經資料處理分析後,本研究運動學參數經討論獲得結論如下:
一、本研究男女子選手在正拍搶打截擊的成功率明顯高於反拍,但開跳步的啟動時機是沒有差異。
二、在搶打過程動量的來源以下肢為主,男子正拍在開跳步離心期的身體重心高度明顯高於反拍;女子反拍在動作腳跟著地的身體重心高度明顯高於正拍。在女子反拍在啟動腳跟著地及擊球的重心速度皆明顯快於正拍。搶打截擊必須縮短球拍與球接觸的時間,增加揮拍力量,雖然男女子在正反拍揮拍擊拍速度方面皆無顯著差異,但在反拍搶打回擊球的速度上是明顯高於正拍搶打。另外,在男子正拍搶打的動作反應時間明顯快於反拍。
經資料處理分析後,本研究肌電訊號經討論獲得結論如下:
一、在牽張反射動作上,在下蹲(離心)期時為了使肌肉能夠有較佳的儲存能量的效能,而花了比上跳(向心)期較多的時間,顯示開跳步動作可能具有利於瞬間能量轉換機制存在。
二、肌肉作用力的大小與預先準備啟動的方向有一致性的結果。
Purpose: Kinematics data and EMG data was collected from elite tennis players to determine the effects of the split step on the poaching action used in doubles tennis. Specifically the timing of the split step was examined to see if it affected the success rate of the poaching action. Methods: The subjects who participated in this study are: Eight male players (age 21 ± 2.33 years; height 182.06 ±2.73cm; weight 74.62 ± 6.23kg) and eight female players (age 20.9 ± 2.10 years; height 169.12 ± 3.52cm; weight 60.38 ± 5.73kg) who have no injury within six months and are ranked in the top 32 players of the country. The ball velocity and direction was controled by other players during the experiment. Two high-speed FASTEC Inline cameras were synchronized to collect 2D kinematics data. Nine Vicon Motion Capture System cameras and an EMG system were synchronized to collect 3D kinematics data. A dependent t-test was used to test the kinematic difference between forehand and backhand poaching. Conclusion: The following are the results of kinematics data : 1. The results of this research clearly show that the success rate of the forehand poaching for both male and female is much greater than the backhand poaching. Interestingly the speed of the split step is the same for both. 2. The change in the height of male’s center of gravity (CG) was greater on their backhand. This occurred at the time of the split step. For females, the greatest change in the height of the center of gravity (CG) occurred when their lead foot was planted on their forehand. The speed of the lateral movement of the center of gravity (CG) for female from the time the leading foot leaves the court to the moment the trailing foot is planted and the ball is struck, is faster on their backhand side. For male, the speed of the entire stroke for both forehand and backhand is the same. This is true for both male and female. Reaction time for male is fast for their forehand. The following are the results of electromyography (EMG) data : 1. The crouch of the split step takes longer than the jump. It is during the crouch that the muscle stores the energy needed for the jump. So the split step is an important step that prepares the leg muscles for the springing action needed in the footwork of the poaching action. 2. At the time of the crouch in the split step, the EMG activity of muscles is directly related to whether the player will hit a forehand or backhand stroke.
Purpose: Kinematics data and EMG data was collected from elite tennis players to determine the effects of the split step on the poaching action used in doubles tennis. Specifically the timing of the split step was examined to see if it affected the success rate of the poaching action. Methods: The subjects who participated in this study are: Eight male players (age 21 ± 2.33 years; height 182.06 ±2.73cm; weight 74.62 ± 6.23kg) and eight female players (age 20.9 ± 2.10 years; height 169.12 ± 3.52cm; weight 60.38 ± 5.73kg) who have no injury within six months and are ranked in the top 32 players of the country. The ball velocity and direction was controled by other players during the experiment. Two high-speed FASTEC Inline cameras were synchronized to collect 2D kinematics data. Nine Vicon Motion Capture System cameras and an EMG system were synchronized to collect 3D kinematics data. A dependent t-test was used to test the kinematic difference between forehand and backhand poaching. Conclusion: The following are the results of kinematics data : 1. The results of this research clearly show that the success rate of the forehand poaching for both male and female is much greater than the backhand poaching. Interestingly the speed of the split step is the same for both. 2. The change in the height of male’s center of gravity (CG) was greater on their backhand. This occurred at the time of the split step. For females, the greatest change in the height of the center of gravity (CG) occurred when their lead foot was planted on their forehand. The speed of the lateral movement of the center of gravity (CG) for female from the time the leading foot leaves the court to the moment the trailing foot is planted and the ball is struck, is faster on their backhand side. For male, the speed of the entire stroke for both forehand and backhand is the same. This is true for both male and female. Reaction time for male is fast for their forehand. The following are the results of electromyography (EMG) data : 1. The crouch of the split step takes longer than the jump. It is during the crouch that the muscle stores the energy needed for the jump. So the split step is an important step that prepares the leg muscles for the springing action needed in the footwork of the poaching action. 2. At the time of the crouch in the split step, the EMG activity of muscles is directly related to whether the player will hit a forehand or backhand stroke.
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Keywords
網球雙打, 搶打截擊, 開跳步, 肌電圖, 牽張縮短循環, tennis doubles, poaching, split-step, electromyography, stretch-shortening-cycle