無線微機電感測器應用於羽球正拍切球之球拍振動分析

WIRELESS MEMS SENSORS IN BADMINTON FOREHAND DROP SHOT VIRATION ANALYSIS

目的：本研究探索運用無線微機電感測器，分析優秀和次優秀選手在羽球正拍切球的拍振動差異。對象：受測優秀選手目前世界排名第11名(參加2012年第三十屆夏季奧林匹克倫敦奧運會)；次優秀選手目前全國排名賽乙組第三名。方法：將無線微機電感測器放在球拍上，內含有三軸加速規，取樣頻率為3333Hz，當擊正拍切球時無線擷取運動學資料，並作統計分析。結果：一、兩位選手個人在無配戴與有配戴感測器在球速方面，經比對t檢定後，無顯著差異。二、球拍加速度頻譜振動頻率次數分佈，X軸優秀選手482Hz，次優秀選手振動頻率在365和378Hz；Y軸次優秀選手振動頻率在325Hz，優秀選手不明顯；Z軸優秀選手在482Hz，次優秀選手振動頻率在325和404Hz。三、球拍振動時間經檢定後發現優秀與次優秀選手在Y軸與Z軸有顯著差異(顯著差異α為0.05)。四、在球拍加速度的時域分析，優秀選手在X和Z軸最大和最小平均值與次優秀選手有顯著差異，得知優秀選手瞬間擊球點較高、較前面，明顯小於次優秀選手。結論：一、配戴感測器不會影響選手的表現。二、在球拍加速度頻譜振動頻率次數分佈中，優秀選手的X軸與Z軸頻率全高於次優秀選手。三、在振動時間中，優秀選手明顯時間短於次優秀選手，代表優秀選手在瞬間擊球後能放鬆握把，使手臂肌肉放鬆，以較容易準備下一拍擊球。四、球拍時域資料，經F和t檢定後，發現在三軸的最大和最小平均值有顯著差異，所以優秀選手瞬間施力較小，且能較容易精準的控球。

Purpose: This research explored the use of Wireless Micro Electro Mechanical Systems (MEMS) sensors to analysis the difference of badminton forehand cut vibration. Subjects: The elite athlete is ranked number 14 in the world and the sub-elite are ranked the third of group B in this Taiwan. Methods: Underneath the racket is placed a wireless MEMS sensors which includes a tri-axis accelerometer. The sample is taken on the frequency of 3333Hz. When athletes strike forehand cut racket， sensors capture measuring point of numerical data， and statistical analysis. Results: 1. Two of the contestants not worn and wore sensors in ball speed， paired t testing， no significant differences. 2. The number racket acceleration spectrum amplitude testing， the elite athlete had higher vibration frequency than sub-elite in X and Z asix. The sub-elite got 325Hz in Y asix; however， the elite athlete had no obviously performance. 3. From the test of racket vibration time， verification revealed that the elite athlete and the sub-elite had obviously difference. 4. The analysis of racket time zone， it indicated that athletes had obviously difference during the max and min average values on X and Z axis. The elite athlete stroke with the higher hitting and the ball felt in the front area than the sub-elite. Discussions: 1. Wearing sensors would not affect the athletes’ performance. 2. In the distribution rate of racket acceleration spectrum amplitude， the elite athlete had higher vibration in X and Z axis. 3. In the vibration time， it indicated that the elite athlete had shorter period than the sub-elite. The elite athlete was significantly better than sub-elite. 4. From the time zone of the racket， the max and min average in tri-axis got obviously difference paired F and t test. The elite athlete got less power in a flash hitting and got better control in striking.