Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2013 The effect of table tennis racket design on wrist motion Sicong Chen Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Industrial Engineering Commons, and the Occupational Health and Industrial Hygiene Commons Recommended Citation Chen, Sicong, "The effect of table tennis racket design on wrist motion" (2013). Graduate Theses and Dissertations. 13358. https://lib.dr.iastate.edu/etd/13358 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. The effect of table tennis racket design on wrist motion by Sicong Chen A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Industrial Engineering Program of Study Committee: Richard T. Stone, Major Professor Gary Mirka Max Morris Iowa State University Ames, Iowa 2013 Copyright c Sicong Chen, 2013. All rights reserved. ii TABLE OF CONTENTS LIST OF TABLES iv LIST OF FIGURESv ACKNOWLEDGEMENTS vi ABSTRACT vii 1. Introduction1 1.1 Racket Sports . .1 1.2 Table Tennis Rackets . .3 1.3 Research Hypothesis . .6 2. Methodology7 2.1 Participants . .7 2.2 Apparatus . .7 2.2.1 Rackets . .7 2.2.2 Robot Pong . .9 2.3 Experimental Design . .9 2.3.1 Independent Variables . .9 2.3.2 Dependent Variables . 10 2.3.3 Measurements . 10 2.4 Experimental Process . 13 2.5 Data Analysis . 14 iii 3. Results 15 3.1 Overall Performance . 15 3.2 Overall Preferences . 17 3.3 Wrist Motion . 20 3.3.1 Wrist Range of Motion in Radial-Ulnar Plane . 20 3.3.2 Wrist Range of Motion in Flexion-Extension Plane . 22 3.4 Muscle Activities . 24 4. Discussion 26 4.1 Overall Performance . 26 4.2 Overall Preferences . 27 4.3 Wrist Motion . 28 4.4 Muscle Activities . 29 5. Conclusion 30 5.1 Limitations . 31 5.2 Future Work . 31 BIBLIOGRAPHY 32 A. Preliminary Test 34 B. Subjective Rating Form 36 iv LIST OF TABLES Table 1.1 Wrist motion analysis for different rackets . .5 Table 2.1 Training setup of novice group (Unit: hit) . 14 Table 2.2 Training setup of experienced group (Unit: hit) . 14 Table 2.3 Experiment setup (Unit: hit) . 14 Table 3.1 ANOVA results of hitting rate . 15 Table 3.2 Post Hoc Test results of hitting rate of forehand drive . 16 Table 3.3 ANOVA results of subjective ranking . 17 Table 3.4 Post Hoc Test results of subjective ranking (experienced group) . 19 Table 3.5 Post Hoc Test results of subjective ranking (novice group) . 19 Table 3.6 ANOVA results of wrist range of motion in radial-ulnar plane . 20 Table 3.7 Post Hoc Test results of wrist ROM in radial-ulnar Plane of forehand drive 21 Table 3.8 Post Hoc Test results of wrist ROM in radial-ulnar plane of service . 21 Table 3.9 ANOVA results of wrist range of motion in flexion-extension plane . 22 Table 3.10 Post Hoc Test results of wrist ROM in flexion-extension plane of forehand drive.......................................... 22 Table 3.11 Post Hoc Test results of wrist ROM in flexion-extension plane of service 23 Table 3.12 ANOVA results of Flexor Activities . 24 Table 3.13 ANOVA results of Extensor Activities . 24 v LIST OF FIGURES Figure 1.1 Tenaly racket . .3 Figure 1.2 Grip posture of Tenaly racket . .3 Figure 1.3 Brodmann racket . .4 Figure 1.4 Hotizontal racket . .4 Figure 1.5 Grip posture of hotizontal racket . .4 Figure 2.1 Four rackets used in this study . .8 Figure 2.2 Robot pong and control box . .9 Figure 2.3 Experiment settings . 12 Figure 2.4 The routs of balls and standing position . 13 Figure 3.1 Means of hitting rate . 16 Figure 3.2 Means of subjective ranking . 18 Figure 3.3 Means of wrist ROM in radial-ulnar plane . 21 Figure 3.4 Means of wrist ROM in flexion-extension plane . 23 Figure 3.5 Means of muscle activities . 25 Figure 4.1 Correct racket angle for forehand drive . 27 Figure 4.2 Wrong racket angle for forehand drive . 27 Figure 4.3 Wrist postures . 28 vi ACKNOWLEDGEMENTS It is a pleasure to express my deepest appreciation to all those who provided me the possi- bility to complete this thesis. First and foremost, my dear friends deserve special thanks for their continuing support, helps and endless words of encouragement and inspiration. I owe my deepest gratitude to Yanan Zhang who provided me support and help throughout the entire process. Without you, none of this would have been possible. I am also grateful for Peihan Zhong for providing invaluable suggestions for my experiment design and data analysis. Thank you, also, to Feibi Hou and all other friends who helped with my experiment. I am incredibly grateful for my major professor, Dr. Richard Stone, who always provides endless support to his students. I offer my sincerest gratitude for his guidance throughout my master education and support for this research. I would like to thank Dr. Gary Mirka and Dr. Max Morris for serving on my committee, spending valuable time and effort in reviewing my work and providing me with advices and feedbacks in this research. I am also thankful to Mr. Kevin Brownfield, mechanist of our department, for making the incredible rackets for me and Dr. Michael Dorneich for lending me the lab. Last but not the least, my sincere thanks go to my parents for their unwavering love and support throughout my life. vii ABSTRACT Unnatural postures have been identified as risk factors for hand/wrist injury problems. These postures are usually adopted among table tennis players. In attempt to alleviate wrist discomfort, alternative table tennis rackets have been designed to reduce awkward postures. Tenaly racket and Brodmann racket are the most representative rackets and are both currently available in the market. Additionally, a new horizontal racket was designed for this study, aiming to reduce wrist motion in the radial-ulnar plane. In this research, Tenaly racket, Brod- mann racket, horizontal racket, together with traditional racket were evaluated in terms of performance, wrist range of motion, muscle activities and subjective rating. Thirty Iowa State University students participated in this study. They were divided into two groups (experienced and novice) based on preliminary test. In the experiment, participants were required to per- form three stroke types: forehand drive, backhand drive and service with these four rackets. Hitting rate, wrist range of motion and muscle activities were obtained during the experiment. Participants were asked to fill out a subjective rating form after the experiment. Results from the experiment showed that subjects had best performance with Brodmann racket and worst performance with horizontal racket. Horizontal racket was the least favored racket in both groups. However, preferences of traditional, Tenaly and Brodmann racket differed between the two groups. The experienced group strongly favored traditional and Tenaly racket because they are powerful to speed balls. In the novice group, the subjective ranking scores of these three rackets were not significant. Also, Tenaly racket was proved as the only one that could improve the posture. No significant was found in terms of muscle activities. 1 CHAPTER 1. Introduction 1.1 Racket Sports Racket sports have a wide appeal to a large population due to its unique attributes. This type of sports requires players to have strong personal playing skills. Besides, ease of the arrangement, relatively low cost and no age limit make the population have large access to this type of sports. The major racket sports include badminton, squash, table tennis and tennis. In the game of racket sports, players use rackets to hit a missile (ball or shuttle) so that their opponents are unable to return it back. The different types of racket sports are characterized by different sizes and shapes of area, hurdle, missile and racket [1]. In the sport of table tennis, players hit a lightweight, hollow ball back and forth using table tennis rackets. The game takes place on a hard table divided by a net. The development and increasing popularity of racket sports in recent years has led to more scientific disciplines involved to understand all aspects of racket sports. Sports engineering is a field of engineering that involves the design, development and testing of sports equipment. There are four items of equipment that are important to all racket sports: the racket, the missile (ball or shuttle), the surface and the footwear [1]. Racket characteristics have changed markedly in recent years, largely as a result of the development of new materials [2]. The modern racket can be made lighter, stronger, stiffer and yield greater power than the one manufactured 20 years ago [3]. For table tennis, large amount of attention has been paid on the materials of blades and rubbers. Different types of blades and rubbers could produce various levels of speed, control and spin [4]. However, these improvements only focus on the performance while the prevention of musculoskeletal disoders (MSDs) are ignored. Ergonomics risk factors are usually found when hand tools are being used. The use of 2 racket is therefore associated with the development of work-related musculoskeletal disorders among racket sports athletes. Upper extremity cumulative trauma disorders (CTDs) have been largely reported in racket sports players. It has been estimated that 50% of racket sports athletes will sustain wrist injuries, and 25% to 50% of these are from overuse [5].