The purpose of this study was to investigate college students on

Sport Science Review, vol Sport XXI, Science no. 5-6, Review, 2012, vol. 129 XXI, - 144No. 5-6, December 2012 DOI: 10.2478/v10237-012-0022-6 A Lab Study on Speed of Self-defense Skills of American College Men and Women Jing YU 1 Liu LIU 1 Gong CHEN 2 The purpose of this study was to investigate college students on their speed of performing different types of self-defense skills commonly taught in American university self-defense courses. The results indicated that close defense skills and distance punches are faster than distance kicks in most single skills or combination skills. Women can do most skills as fast as men. The results also indicated that all kicks with back-foot are slower than kicks with front-foot in distance defense. Women need 2.42-6.12 seconds to escape from all 20 holds, while men need 1.14-5.54 seconds for people who successfully escaped. Escaping from different holds is not as difficult as what most people think. After proper learning and practice, a majority of college women and men can escape from many holds in 1-6 seconds. Keywords: self-defence skills, speed, college students 1 Beijing Sport University, Beijing, China 2 Department of Kinesiology, San Jose State University, San Jose, California, USA ISSN: (print) 2066-8732/(online) 2069-7244 2012 National Institute for Sport Research Bucharest, Romania 129

Speed of self-defence skills Introduction Speed is a key factor in most sports in the world. There are intensive studies on the speed of performance and on improving the speed of athletes in track, swimming, biking, tennis, and much more sports. Often these studies may lead to a new world record in track or an Olympic champion won by a split of second. However, these studies, world records, Olympic champions do not seem to benefit common people at all, except making a few athletes famous and rich. The fast movement in martial arts has been recognized as an important factor in Aikido (Bennett, 98), in Chinese martial arts (Chen, 89), in Thaiboxing (Dong, 94), in police training (Du, 93), in wrestling (Mysnyk, 94), in Jujitsu (Kirby, 93), in other martial arts (Soet, 91), and in selfdefense (93). As an old saying in Chinese martial arts put it quick hands defeat slow hands (Liu, 91). A split of second often determines the win or loss in martial arts competitions and in self-defense situations. The speed of applying defensive skills at crime scene concerns the life or death of millions of people every day in the world. A split of second in self-defense situation can determine if the defender can successfully escape from physical attacks. Studies on improving the speed of self-defense skills may help save the lives of common people, and can benefit millions of people in the long term (Chen, January 2011) because violent crimes has become a main factor that threatens the lives of common people in the world. For example, 16 thousand people become victims of murder, thousand women become rape victims, 900 thousand become victims of aggravated assaults, and 400 thousand people become robbery victims annually in the United States (Federal Bureau of Investigation, 98-2010). The purpose of this study was to investigate college students on their speed of performing different types of self-defense skills. These skills are commonly taught in American university self-defense courses (Chen, 98), but there is little research on how fast students can perform each skill, and how fast can people escape from holds. There is a lack of research on how to improve the speed of performing self-defense skills. Self-defense as an unique activity in physical education and sports has attracted few researchers and professionals. The few studies found include the pilot study by Chen and Liu (February, 2011) on number of kicks and punches in 30 seconds, and the chance of stabs in five seconds among college students (Chen, Liu, & Liu, February 2011). The expected results of this study and suggested applications of these results in teaching and learning self-defense include the following. 1) Investigate 130

Sport Science Review, vol. XXI, No. 5-6, December 2012 the average speed of college men and women on performing main self-defense skills, use the new knowledge to stimulate student learning, and use the results as norms to evaluate learning outcomes. 2) Identify fast and slow self-defense skills, and use the know knowledge to help students and instructors choose fast and effective self-defense skills. 3) Study how fast male and female subjects can escape from different types of holds and grabs when attacked by men, and use the new knowledge to improve their skills in the first several seconds of attacks. Research method Content analysis technique was used in the study. The contents were records of designed experiments of students in self-defense classes in an university. Three types of experiments were conducted to examine the speed of self-defense skills on each female or male student so that they could assess their speed of escaping from different types of holds, and their speed on performing different kicks and punches in single movement or a combination of movements. Subjects ranged from 15 to in different experiments. All attacks and defense skill are introduced in the book A comprehensive guide to self-defense. Subjects learned and practiced for approximately 20 hours in class on the following types of self-defense skills: distance self-defense, close self-defense, grab and throw defense, floor self-defense, release defense, and a combination practice and applications of all physical skills from SmarTough Self-defense System (Chen, 2004; Zhang & Chen, 2004). The speed of single or combination was measured based on individual performance for ten seconds. Then the speed of one second came from the total number of kicks or punches dividing by 10 seconds. Then the speed of each single skill was measured by the one second movement dividing by the number of kicks or punches in one second. The part compared speed of men and women, different skills or combinations, and front hand/foot and back hand/foot. The t-test was used to analyze data. The speed of releases was measured by the time used to escape from each attack by a male partner performing as an attacker. The male students were used to perform as male attacker due to the fact that more than 90% real attackers were males (Conklin, 99; Federal Bureau, 2010) in real life situations. The attacker held the defender based on the required attacking situation. The defender started escaping using skills learned in classes while keeping the time that they used to successfully escape as the speed of escape. Ten seconds was the maximum time each defender could use. The data was based on those students who successfully escaped in ten seconds. The data was not used if the defender used more than 131

Speed of self-defence skills ten seconds to escape or he/she could not escape. For safety reason, no real punches or kicks were allowed but subjects could use fake motions to distract the attacker. The z-test was used to analyze data. These experiments had several limitations and cannot completely reflect students actual escaping speed in real life situations. The first limitation was that even though the male students imitated the roles of male attackers, they could not imitate their attacks as violently as what the criminals use in real life situations. The second limitation is that the experiment was conducted when the imitated defenders were ready for each attack, while in real situation attackers usually attack without any warning. Therefore, the results of this lab study can only help college students estimate their speed of escape in real life based on classroom experiments. However, even though this lab experiment does not reflect their actual speed to deal with similar attacks in real situations, college students demonstrated their physical self-defense ability to deal with males attackers and obtained a basic estimate on their self-defense abilities when dealing with different physical attacks. This study represented the maximum effort that the self-defense class can do to teach college students self-defense skills and to evaluate their self-defense ability in imitated situation that was close to the real situation without causing injuries in the process. Results and discussion 1. Speed of single skills in distance, close, and floor open-handed self-defense. Table 1 listed the repetitions of the same skills that subjects could perform with their maximum speed and power in good forms in 10 seconds. Among selected common self-defense skills, men showed faster speed on jab punch and floor knee strike than women. There was no significant difference between men and women on other 17 single or combination self-defense skills. The results indicated that women can do as fast as men on performing most open-handed self-defense skills. Among all skills, the roundhouse kick, side kick, and heel kick were slowest skills although these are powerful kicks for both men and women in distance self-defense. Jab and cross punch as well as snap kick were faster in distance defense than these power kicks. In close defense, short punches and elbow strikes were faster than knee strikes. In floor defense, floor short punches and jabs were faster than kicks. In combination skills, the punch combination and elbow/knee strike combination was faster than any other combinations with leg motion. Any combinations with kick were the slower. 132

Sport Science Review, vol. XXI, No. 5-6, December 2012 The results can be used as a normal to evaluate performance of students in self-defense classes to provide feedback for more effective learning and teaching. The results can also help self-defense teachers and students choose the proper skills for situations that require fast kicks or punches. Table 1 Movement speed in 10 seconds for women and men Skills and Combination A. Single skills Women (n=34) Men (n=21) Mean sd. Mean sd. t-test 1. Jab punch 13.7 3.1 17.7 4.6 <.01** 2. Cross punch 12.5 1.9 13.9 2.5 <.05 3. F-snap kick 11.5 1.8 12.9 2.5 <.05 4. B-roundhouse 8.1 1.9 8.2 1.9 >.05 5. F-side kick 8.2 1.0 8.3 1.5 >.05 6. B-heel kick 8.2 1.2 8.7 1.6 >.05 7. Floor side kick 17.6 2.2 17.5 4.4 >.05 8. Floor jab 18.3 3.7.4 4.3 >.05 9. Floor knee strike 14.4 2.3 16.2 3.4 <.05* 10. Floor short punch 20.9 4.0 21.4 5.1 >.05 11. Knee strike (both legs) 17.2 2.1 16.6 2.0 >.05 12. Elbow strike (both arms) 20.2 1.7 20.8 2.7 >.05 13. Short punch (high-low) 22.0 1.3 22.0 1.4 >.05 B. Combination skills 1. Snap-round 11.2 1.2 11.0 1.6 >.05 2. Side kick-jab-cross 15.6 1.4 16.8 1.4 >.05 3. Jab-cross-hook-hook 23.6 1.9 25.2 1.8 >.05 4. Knee-knee-elbow-elbow 20.4 1.7 21.2 1.6 >.05 5. Jab-cross-round 18.6 1.2 17.7 1.7 >.05 6. Floor side-heel-jab-roll 24.8 2.9 25.6 1.3 >.05 133

Speed of self-defence skills The results in Table 2 listed the speed of each skill by second(s) based on the range from fast to slow skills in three categories. Both men and women showed very similar patterns. In distance and close defense, the fastest skill was short punch and the slowest skill was roundhouse kick. Among these skills, the close defense skills (short punch, elbow strike, and knee strike) were faster than distance skills (including cross punch and all kicks) except men s jab punch was faster than knee strike. Short punch was also the fastest skills in floor defense for both men and women, while floor knee strike or side kick was slower than punches. In combination skills, the floor combination, punch combination, and elbow and knee strike close defense were faster than other combinations with kicks in. The results in Table 2 also show the absolute speed of each open-handed self-defense skills. These results can be used as a guide for students to choose more effective skill when defenders identify an opening on the attacker that they have to use the fasted skills to disable the attacker. Table 2 List of single movement speed for women and men (from 10 seconds experiment) Standing Women (n=34) Skill(s) Second/ per trial Men (n=21) Skill(s) Second/ per trial 1. Short punch (high and 0.45 1. Short punch (high and low) low) 0.44 2. Elbow strike 0.50 2. Elbow strike 0.48 3. Knee strike 0.58 3. Jab punch 0.56 4. Jab punch 0.73 4. Knee strike 0.60 5. Cross punch 0.80 5. Cross punch 0.72 6. Front leg snap kick 0.87 6. Front leg snap kick 0.78 7. Front leg side kick 1.22 7. Back leg heel kick 1.14 8. Back leg heel kick 1.22 8. Front leg side kick 1.20 9. Back leg roundhouse kick 1.23 9. Back leg roundhouse kick 1.22 134

Sport Science Review, vol. XXI, No. 5-6, December 2012 Table 2 (continued) Floor 1. Floor short punch 0.48 1. Floor short punch 0.47 2. Floor jab 0.55 2. Floor jab 0.52 3. Floor side kick 0.58 3. Floor one knee strike 0.62 4. Floor knee strike 0.69 4. Floor side kick 0.75 Combination skills 1. Floor side-heel-jab-roll 0.40 1. Jab-cross-hook-hook 0.39 2. Jab-cross-hook-hook 0.42 Floor side-heel-jab-roll 0. 3. Knee-knee-elbow-elbow 0.49 3. Knee-knee-elbow-elbow 0.47 4. Jab-cross-back leg roundhouse 0.54 4. Jab-cross-back leg roundhouse 0.56 5. Front leg side kick-jabcross 0.64 5. Front leg side kick-jabcross 0.60 6/ Front leg snap kick-back leg roundhouse 0.89 6. Front leg snap kick-back leg roundhouse 0.91 2. Comparison on speed of front hand/foot and back hand/foot punch/kick. The purpose of this section was to compare the movement speed between the front hand-punch/front foot-kick and back hand-punch/back foot kick. Table 3 listed the results of six comparisons for women. The results indicated that the front hand jab punch was significantly faster than the backhand cross punch. It may be due to the bigger body rotation motion in the cross punch. The front hand and backhand hook punch were at the same speed. All four front foot kicks were significantly faster than back foot kicks. It may be due to the rotation of the body and balance concerns. It seems that the front hand punches or front foot kicks should be more effective when female defenders need to use faster skills to catch the short time opening of attackers 135

Speed of self-defence skills Table 3 Difference between front and back hand/foot punches/kicks and for women (10 seconds) n mean std difference t p 1. F-hand jab 2. B-hand cross 14.98 13.80 4.20 2.09 1.17 2.10.040* 3. F-hand hook 4. B-hand hook 13.30 13.04 2.05 2.04 0.26 1.05.301 5. F-foot snap 6. B-foot snap 11.97 10.02 2.09 1.41 1.96 7.13.000* 7. F-foot heel 8. B-foot heel 11.93 9.58 1.63 1.58 2.35 9.43.000** 9. F-foot round 10. B-foot round 11.22 9.13 1.60 1.61 2.09 10.26.000** 11. F-foot side 12. B-foot side 11.76 7.80 1.70 1.17 3.96 15.67.000** Table 4 listed the results of six comparisons for men. The results indicated that the front hand and backhand jab and cross punch showed similar speed and both hook punches were at the same speed as well. At the other side, all four front foot kicks were significantly faster than back foot kicks. It seems that the front foot kicks should be more effective when male defenders need to use faster skills to catch the short time opening of attackers. 136

Sport Science Review, vol. XXI, No. 5-6, December 2012 Table 4 Difference between front and back hand/foot in kicks and punches for men (10 seconds) n mean std difference p 1. F-hand jab 2. B-hand cross 14.36 14.00 4.58 3.16 0.36 0.52 3. F-hand hook 4. B-hand hook 13.05 13.05 2.87 3.50 0 1.00 5. F-foot snap 6. B-foot snap 12.94 10.10 3.55 2.49 2.84.000** 7. F-foot heel 8. B-foot heel 11.68 10.15 2.64 2.38 1.53.001** 9. F-foot round 10. B-foot round 11.73 9.36 2.92 2.62 2.36.001** 11. F-foot side 12. B-foot side 11.47 7.42 2.56 1.53 4.05.000** 3. Speed of release from different holds. This section investigated the speed of releases from 20 different holds in five types. Among the groups subjects who successfully released from high arm--hold, low arm-hold, back arm-hold, and back wrist-lock, women used 3-4.53 seconds and men used 1.81-2.75 seconds to escape from these holds. Women released faster on high-hold but slower on back-hold and wrist-lock, while men released faster on low-hold but slower on wrist-lock. men used significantly less time than women to escape from lowhold, back-hold, and wrist-lock. 137

Speed of self-defence skills Table 5 Release from arm-holds attacked by men in 10 seconds Situation Women Men t-test n mean sd. n mean sd. High arm-hold 17 3.76 2.05 16 3.13 1.45 >.05 Low arm-hold 3.00 2.31 16 1.81 1.05 <.05* Back arm-hold 4.53 2.56 16 2.56 1.26 <.01** Back wrist-lock 4.37 2.31 16 2.75 1.53 <.05* Among the groups of successfully released from four bear-hugs, women used 4.67-6.12 seconds and men used 3.94-5.54 seconds to escape from these hugs (Table 6). Women released faster on front-hugs but slower on back-hugs, while men used about similar time to escape from these four hugs. There was no significant difference between men and women on the speed of escaping from all four bear-hugs. Table 6 Release from bear-hugs attacked by men in 10 seconds Situation Women Men t-test n mean sd. n mean sd. Front bear-hug arms-free 16 4.88 2.33 16 3.94 3. >.05 Front bear-hug arms-locked 18 4.67 3.12 15 4.13 2.85 >.05 Back bear-hug arms-free 15 6.00 2.83 13 5.54 2.76 >.05 Back bear-hug arms-locked 17 6.12 2.83 13 4.62 3.23 >.05 Among the groups of successfully released from three chokes, women used 2.42-4.7 seconds and men used 1.7-3.9 seconds to escape from these hugs (Table 7). Women released faster on front-choke but slower on back-choke, while men escaped faster on front-choke but slower on back-choke and headlock. There was no significant difference between men and women on the speed 138

Sport Science Review, vol. XXI, No. 5-6, December 2012 of escaping from front-choke and head-lock, but men released faster on backchoke. It may be due to the fact that release from the back-choke requires more muscle strength and men usually have stronger than women. Table 7 Release from chokes attacked by men in ten seconds Situation Women Men t-test n mean sd. n mean sd. Front choke 2.42 1.54 16 3.50 1.51 >.05 Back choke 20 4.70 1.87 16 3.50 1.51 <.05* Head lock 18 3.72 1.53 16 3.50 2. >.05 Among the groups of successfully released from three hair-pulls, women used 2.44-3.53 seconds and men used 1.14-1.86 seconds to escape from these pulls (Table 8). Women released faster on front-pull but slower on back-pull, while men showed the same pattern. There was significant difference between men and women on the speed of escaping from all hair-pulls. Men escaped from all hair-pulls in much faster speed than women. It may be due to the fact that most men have short hair and women have long hair. Table 8 Release from hair-pulls attacked by men in 10 seconds Situation Women Men t-test n mean sd. n mean sd. Front hair-pull 18 2.44 1.04 7 1.14 0.38 <.00** Back hair-pull 3.26 2.38 7 1.57 0.79 <.01** Back hair-pull-down 3.53 2.61 7 1.86 0.90 <.05* 139

Speed of self-defence skills Among the groups of successfully released from floor holds, women used 3.87-5.94 seconds and men used 2.63-4.81 seconds to escape from these holds (Table 9). Women released faster on all floor chokes but slower on pin-arms and hits, while men showed the same pattern. There was no significant difference between men and women on the speed of escaping from five out of six hold, but men released faster on floor top-choke. Table 9 Release from floor-holds attacked by men in 10 seconds Situation Women Men t-test n mean sd. n mean sd. Floor side-choke 21 3.87 1.76 15 3.29 1.96 >.05 Floor top-choke 4.53 2.20 16 2.63 0.96 <.00** Floor back-choke 21 3.90 2.14 15 3.80 1.90 >.05 Floor pin-arms 17 5.94 2.66 15 4.73 2.63 >.05 Floor punching 5.42 2.80 15 4.73 2. >.05 Floor knife-stab 18 5.28 2.72 16 4.81 2. >.05 Table 10 listed the time used to escape from all 14 standing releasing skills from less to more time for both men and women. It seemed that all bear-hugs required longer time to release. Besides, attack from behind (except hair-pulls) for women required longer releasing time while the chokes for men needed longer time to release. Table 10 Release time from 14 standing holds attacked by men in 10 seconds 140 Situation Women (seconds) Situation Men (seconds) Front choke 2.42 Front hair-pull 1.14 Front hair-pull 2.44 Back hair-pull 1.57 Low arm-hold 3.00 Front choke 1.69

Sport Science Review, vol. XXI, No. 5-6, December 2012 Table 10 (continued) Back hair-pull 3.26 Low arm-hold 1.81 Back hair-pull-down 3.53 Back hair-pull-down 1.86 Head lock 3.72 Back arm-hold 2.56 High arm-hold 3.76 Back wrist-lock 2.75 Back wrist-lock 4.37 High arm-hold 3.13 Back arm-hold 4.53 Back choke 3.50 Front bear-hug arms locked 4.7 Head lock 3.50 Back choke 4.70 Front bear-hug arms-free 3.94 Front bear-hug armsfree 4.88 Front bear-hug armslocked 4.13 Back bear-hug arms free 6.00 Back bear-hug arms locked 4.62 Back bear-hug arms locked 6.12 Back bear-hug arms-free 5.54 Table 11 listed the time used to escape from all six floor releasing skills from less to more time for both men and women. It seemed that all floor chokes used less time to release for both men and women. Pinning-arm, punching, and stabbing needed longer time to escape. Table 11 Release time from floor-holds attacked by men in 10 seconds Situation Women (seconds) Situation Men (seconds) Floor side-choke 3.87 Floor top-choke 2.63 Floor back-choke 3.90 Floor side-choke 3.29 Floor top-choke 4.53 Floor back-choke 3.80 Floor knife-stab 5.28 Floor pin-arms 4.73 Floor punch 5.42 Floor punch 4.73 Floor pin-arms 5.94 Floor knife-stab 4.81 141

Speed of self-defence skills The results in this section showed that the group of defenders who escaped successfully from these holds used 1-6 seconds as the average speed of release. Therefore, it is critical that defender develop their skills that allow them to escape during the first six seconds of attacks. Intensive practice on the same skills can improve the efficiency and speed of escapes, while combined skills practice can improve the spontaneous responses to different attacks based on years of teaching and research experience. Escaping from different holds is not as difficult as what most people think. After proper learning and practice, both women and men can escape from many holds in a short time. Conclusions Close defense skills (short punches, elbow and knee strikes) and distance punches (jab, cross, and hook) are faster than distance kicks (side, heel, round) on single skills. The combination skills involving close defense skills and distance punch are also faster than combinations with kicks. Out of skills and combinations, men did faster than women on jab and floor knee strike only. Women can do other 17 defense skills as fast as men. All kicks with back-foot are slower than kick with front-foot. Women s front-hand jab is faster than backhand cross punch. The speed of men s all punches and women s hook punches is the same for front-hand and back-hand. Women need 2.42-6.12 seconds to escape from all 20 holds, while men need 1.14-5.54 seconds for people who successfully escaped. All bear-hugs required longer time to release for both men and women. Furthermore, attack from behind (except hair-pulls) for women required longer time releasing time while the chokes for men need longer time to release. Men are faster on escaping from arm-holds and hair-pulls. Escaping from different holds is not as difficult as what most people think. After proper learning and practice, a majority of college women and men can escape from many holds in 1-6 seconds. Applications The results can be used as a norm to evaluate performance of students. They also can be used as a goal for students to achieve in self-defense classes. 142

Sport Science Review, vol. XXI, No. 5-6, December 2012 The results can be used for instructors and students to choose fast skills for the self-defense curriculum. They also can help students make decisions on which skill(s) or foot/hand they should use for fast defense. All results were obtained in lab situation and it will be different from the real situation. Therefore, the results should be used as reference, instead of as the data for real situation. References Bennett, G. (89). Aikido Techniques and Tactics. Champaign: Human Kinetics. Chen, G. (Fall 98). A study on subjects taught in American nationwide university self-defense courses, Journal of International Council of Health, Physical Education, Recreation-Sport and Dance, XXXV(1), 28-33. Chen, G. (June 2004), A comprehensive guide to self-defense. Dubuque, IA: Kendall/ Hunt Publishing Company. Chen, G. (January 2011). Monitor their growth to stay away from violent crimes - dialogue with Chinese parents on self-defense of their children. A book in Chinese language for parents in China. Beijing Sport University Publisher, China. Chen, G., Liu, L. (February 2011). A study on exercise intensity in physical self-defense skills practice in university self-defense classes. Journal of Academic Perspective, 6, 54-67. Chen, Z. K. (89). Practical kicks in Wu Shu. China: Tour and Education Publisher. Conklin, J. E. (99). Criminology (4th ed.). New York: Macmillan Publishing Company. Dong, Z. H. (94). Thai Boxing. China: Beijing Physical Education University Publisher. Du, Z. G. (93). Controlling skills for police training. China: Beijing Physical Educa tion University Publisher. Federal Bureau of Investigation (98-2010), Uniform Crime Report, Retrieved from www.fbi.gv/ucr. Kirby, G. (93). Jujitsu--Basic techniques of the gentle art. Burbank: Ohara Publication. 143

Speed of self-defence skills Liu, H. C. (91). Wudang Traditional Tai Chi. China: Shanxi Science and Technology Publisher. Mysnyk, M., Davis, B., & Simpson, B. (94) Winning Wrestling Moves. Champaign: Human Kinetics. Soet, J. S. (91). Martial Arts around the world. Burbank: Unique Publications. Sun, B. Y. (94). 91 skills for self-defense. China: Beijing PE University. Zhang, R., & Chen, G. (June 2004). Safety education for college students. China: Beijing Sport University Publisher. 144 Gong CHEN, Ph.D. is a full professor at the Department of Kinesiology at San Jose State University in U.S.A. He has earned his bachelor degree from Shenyang Sport University, the master degree from Beijing Sport University in China and doctoral degree of Kinesiology from University of Arkansas, Fayetteville in USA. He has been teaching self-defense at university level since 87 and has presented numerous papers at local through international level. He has published five self-defense books and numerous papers on self-defense in English and Chinese (his last book Self-defense. A bilingual book of Chinese and English, Xi-an: Northwest Polytechnic University, China - was released in September 2009). He has lectured many self-defense instructor workshops in China and United States. Corresponding address: Gong Chen Department of Kinesiology San Jose State University One Washington Square San Jose, CA 952-0054 U.S.A Phone: (408) 924-3033 Email: gong.chen@sjsu.ed Liu LIU is a doctoral candidate at Beijing Sport University specialized in teaching physical education, and she currently is a visiting professor at San Jose State University conducting research. Jing YU, is a doctoral candidate at Beijing Sport University, currently a visiting professor at San Jose State University, while remains as an instructor at Shenyang Sport University