Wireless MEMS Sensors Applied in the Movement and Racket of Tennis Single-backhanded Under Spin Return

• Main Authors: Ti-Jen pan, 潘帝仁
• Other Authors: 賴慶安
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/06178571232892039889

碩士 === 樹德科技大學 === 資訊工程系碩士班 === 100 === Objective This study applies the wireless MEMS sensors to analyze the single backhand under spin in tennis. The subjects are senior high school tennis athletes in Physical Education class. The subjects are divided into two groups, elite and sub-elite, based on their performance. There are mainly seven limb segments and the acceleration and angle speed of the racquet vibration in difference analysis when using under spin. The study tries to find out the difference between elite and sub-elite athletes. Methodology: The Wireless MEMS sensors composed of tri-axis accelerometer and tri-axis gyroscope is used .Then five elite athletes and five sub-elite athletes are selected to test the single backhand under spin. After the movement starts, wireless transmission is used to collect data from seven limb segments and the acceleration and angular velocity of the racquet vibration. MS Excel and MatLab are used to do statistical analysis. Results：1. There are no significant differences with or without sensors between elite and sub-elite athletes. 2. The comparison of transmission chain shows the stability of elite athletes are better than that of sub-elite athletes. 3. The analysis of acceleration and angular velocity of racquet indicates that elite athletes are better than sub-elite athletes in movement stretch stability. 4. The wrist stability of the racquet hand is less different in elite athletes while larger differences are found in sub-elite athletes. 5. The sequence of developing power in single backhand under spin is different in elite and sub-elite athletes. 6. Significant differences of elite and sub-elite athletes in racquet acceleration vibration spectrum are found in three axes from low to high frequency. The differences in YX axis are more obvious, and the largest difference is in middle frequency. 7. In racquet angular velocity spectrum, the elite and sub-elite are highly different in whole frequency and high frequency, but less different in low frequency. 8. The domain analysis of acceleration vibration shows X axis is the main power appliance point for both elite and sub-elite athletes in backhand under spin. 9. Timing diagram analysis of acceleration vibration indicates the maximum of both elite and sub-elite athletes is in Z axis. 10. The output power of three axis shows the application of force by sub-elite athletes is better than that of elite athletes. 11. Elite athletes are better than sub-elite athletes in angular velocity. 12. The performance of right palms concentrates on X axis, which means backhand under spin is a motion from top to down to accelerate the ball’s rotation. Conclusion：From the data analysis, the elite and sub-elite athletes are close in the performance of X axis of acceleration, which means the sequence of developing power is very close. But the sub-elite athletes with larger figure in Y axis need improvement in motion. From the data of angular velocity, the performances between elite and sub-elite athletes are different in Z axis of motion. Suggestion：The sequence of developing power is different in under spin between elite and sub-elite athletes. The coaches’ training focus is in x axis of acceleration and z axis of angular velocity. From this the difference between elite and sub-elite athletes can also be studied. The results of the study can be the training target for skill strengthening in the future.