In sports that use tools, it is necessary to master tool manipulation with a high degree of accuracy because proficiency in tool manipulation leads to victory or defeat in a competition. The purpose of this study was to clarify the force transfer of the body, including the racket, from the perspective of vibration analysis to realize training to efficiently improve tennis skills. In this study, we measured the propagating vibration, surface electromyography of finger flexors and extensors, and racket movement under two conditions of strong- and weak-volleying in tennis and aimed to explain the meaning of the measured propagating vibration in terms of muscle control and racket kinematics. Based on the experimental results, it was confirmed that it is feasible to measure the change in stiffness from the racket to the wrist due to the muscle co-contraction owing to the propagating vibration signal intensity. These results indicate the possibility of evaluating tennis shot skill by analyzing the propagating vibrations measured using a wearable vibration measurement system.

1. [1] M. Rana and V. Mittal, “Wearable sensors for real-time kinematics analysis in sports: A review,” IEEE Sensors J., Vol.21, No.2, pp. 1187-1207, 2021. https://doi.org/10.1109/JSEN.2020.3019016
2. [2] M. Biggio, A. Bisio, L. Avanzino, P. Ruggeri, and M. Bove, “This racket is not mine: The influence of the tool-use on peripersonal space,” Neuropsychologia, Vol.103, pp. 54-58, 2017. https://doi.org/10.1016/j.neuropsychologia.2017.07.018
3. [3] R. Martínez-Gallego et al., “Movement characteristics of elite tennis players on hard courts with respect to the direction of ground strokes,” J. of Sports Science and Medicine, Vol.12, No.2, pp. 275-281, 2013.
4. [4] R. Srivastava et al., “Efficient characterization of tennis shots and game analysis using wearable sensors data,” Proc. of 2015 IEEE SENSORS, 2015. https://doi.org/10.1109/ICSENS.2015.7370311
5. [5] A. Anand, M. Sharma, R. Srivastava, L. Kaligounder, and D. Prakash, “Wearable motion sensor based analysis of swing sports,” 2017 16th IEEE Int. Conf. on Machine Learning and Applications (ICMLA), pp. 261-267, 2017. https://doi.org/10.1109/ICMLA.2017.0-149
6. [6] S. T. E. Ellabany and M. A.-H. I. Attaallah, “Kinematic analysis of the whole body center of gravity trajectory and time structure of the tennis serve performance,” J. of Applied Sports Science, Vol.5, No.4, pp. 76-81, 2015.
7. [7] X. Peng and L. Tang, “Biomechanics analysis of real-time tennis batting images using Internet of Things and deep learning,” The J. of Supercomputing, Vol.78, No.4, pp. 5883-5902, 2022. https://doi.org/10.1007/s11227-021-04111-w
8. [8] T. Allen, S. Choppin, and D. Knudson, “A review of tennis racket performance parameters,” Sports Engineering, Vol.19, No.1, pp. 1-11, 2016. https://doi.org/10.1007/s12283-014-0167-x
9. [9] Y. Kawazoe, “Experimental identification of a hand-held tennis racket and prediction of racket vibration during impact,” Trans. of the Japan Society of Mechanical Engineers, Series C, Vol.61, No.584, pp. 1300-1307, 1995 (in Japanese). https://doi.org/10.1299/kikaic.61.1300
10. [10] R. J. Collier and R. J. Donarski, “Non-invasive method of measuring resonant frequency of a human tibia in vivo part 1,” J. of Biomedical Engineering, Vol.9, No.4, pp. 321-328, 1987. https://doi.org/10.1016/0141-5425(87)90080-X
11. [11] R. J. Collier and R. J. Donarski, “Non-invasive method of measuring the resonant frequency of a human tibia in vivo part 2,” J. of Biomedical Engineering, Vol.9, No.4, pp. 329-331, 1987. https://doi.org/10.1016/0141-5425(87)90081-1
12. [12] N. Funato and K. Takemura, “Estimating three-axis contact force for fingertip by emitting vibration actively,” 2017 IEEE Int. Conf. on Robotics and Biomimetics (ROBIO), pp. 406-411, 2017. https://doi.org/10.1109/ROBIO.2017.8324451
13. [13] A. Ikeda, S. Kosugi, and Y. Tanaka, “Analysis of sound propagation in an ankle using active bone-conducted sound sensing system,” Japanese J. of Clinical Biomechanics, Vol.39, pp. 247-251, 2018 (in Japanese).
14. [14] A. Ikeda, S. Kosugi, and Y. Tanaka, “Analysis of bone-conducted sound propagation in a lower leg of healthy young subjects,” Japanese J. of Clinical Biomechanics, Vol.41, pp. 263-269, 2020 (in Japanese).
15. [15] J. W. Chow, D. V. Knudson, M. D. Tillman, and D. P. S. Andrew, “Pre- and post-impact muscle activation in the tennis volley: Effects of ball speed, ball size and side of the body,” British J. of Sports Medicine, Vol.41, No.11, pp. 754-759, 2007. https://doi.org/10.1136/bjsm.2007.037184
16. [16] G. H. Banwell, J. R. Roberts, B. J. Halkon, S. J. Rothberg, and S. Mohr, “Understanding the dynamic behaviour of a tennis racket under play conditions,” Experimental Mechanics, Vol.54, No.4, pp. 527-537, 2014. https://doi.org/10.1007/s11340-013-9803-9