Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011 was larger than ML and vertical directions, and its trajectory was large and smooth in expert KINEMATIC ANALYSIS OF THE SUPPORTING LEG BETWEEN DIFFERENT group. The COM trajectory of beginner group is less smooth with smaller displacement (Fig. WEIGHT DIVISIONS IN THE ROUNDHOUSE OF 2), thus, potential balance loss is anticipated. The present study predicts that if the anterior- posterior COM velocity-position trajectory is located inside the feasible region after enticing Ying-Xun Wang, Shih-Yu Kuo, Ling-Hua Wang and Kuangyou B. Cheng circle, the neutralizing response can still be carried out. The increased AP COM in the expert group suggests that they can have better control and direct their COM. Inclusion of the COM Institute of Physical Education, Health and Leisure Studies, National Cheng as a dependent variable is necessary to discern differences between TCC expert and beginner (Baird & Van Emmerik, 2009). Push hands movements are performed by two Kung University, Tainan, Taiwan persons who have different practice experiences and whose TCC levels may not be equal. The purpose of this study was to compare kinematic differences in the supporting leg Therefore, the definition and selection of control group is not easy. between two weight divisions in the Taekwondo . Collegiate Taekwondo athletes participated in the study and differences in maximum joint angles and ranges of CONCLUSION: The skill differences described here indicate that TCC beginners may have motion on the supporting leg during executing the Roundhouse Kick were examined. The certain difficulties with movement transfers, because of not only inability to generate the results showed significantly larger (p<.05) ankle displacement and less inversion/eversion forces required but also disruptions in the temporal sequencing of the forces. Our in the heavy division group during performing the Roundhouse Kick. It is inferred that the investigation reveals that the experience-related differences with regards to COM transfers strategy adopted by the heavy division group has the tendency of using ankle are reflected in the push hands movement cycle. Further investigation is required in order to displacement for achieving a stable ankle angular motion in the supporting foot. determine whether it is possible to improve the circle of COM transfer in TCC beginners by practicing and training. KEY WORDS: revolution, range of motion, .

REFERENCES: INTRODUCTION: Taekwondo, which is known for its kicking techniques, has become an official event in the Olympic Games from the year 2000. Competitors can score points by Baird, J.L. & Van Emmerik, R.E.A. (2009). Young and older adults use different strategies to perform a standing turning task. Clinical Biomechanics, 24, 826-832. their feet and fists in the game, but most of the Taekwondo athletes usually get points by the feet kicking on the torso and head. One of the most used kicking techniques is the Dempster, W.T. (1955). Space requirements of the seated operator WADC-TR-55-159. Wright-Patters Roundhouse Kick which is also called Bandal Chagui (Lee, 1983). The characteristics of the on Air Force Base, Ohio. Roundhouse Kick are rapid execution speed (Falco, 2009) and ease for counter-attack. Hong, Y., & Li, J.X. (2007). Biomechanics of Tai Chi: A review. Sports Biomechanics, 6(3), 453-464. In the performance of the Roundhouse Kick, a successful motion is not only dependent on Kuo, A. D. (1995).An optimal control model for analyzing human postural balance. IEEE Transactions the kicking leg but on the supporting leg. The supporting leg plays an important role in the on Biomedical Engineering, 42(1), 87-101. Roundhouse Kick because of being the rotation axis of the body and adjusting the trunk Lai, J.S., Lan, C., Wong, M.K., & Teng, S.H. (1995). Two-year trends in cardiorespiratory function orientation during kicking. In addition, Taekwondo athletes between different weight divisions among older Tai Chi chuan practitioners and sedentary subjects. Journal of the American Geriatrics Society, 44, 1222-1227. have considerable diversity on the kicking patterns (Tang, 2001).There is virtually no study focusing on the kinematics of the supporting leg. Thus the purpose of this study was to run a McConville, J.T., Churchill, T.D., & Kaleps, I. (1980). Anthropometric Relationships of Body Segments kinematics analysis of the supporting leg between different weight classes during performing of Inertia. United States Air Force Aerospace Medical Research Laboratory, AFAMRL-TR-80–119. the Roundhouse Kick performance. Olson, S.A. (1998). Tai Chi Sensing-Hands. Multi-Media Books, unique Publications, Inc., Burbank, California P.3 METHODS: Subject: Four collegiate athletes who have practiced Taekwondo for over 7 Pai, Y.C. (2003). Movement termination and stability in standing. Exercise and Sport Sciences years voluntarily participated in this study. No subjects reported any acute injuries or Reviews, 31(1), 19-25. disorders when the experiments were carried out. Experimental procedures were explained Pai, Y.C. & Patton, J. (1997). Center of mass velocity-position predictions for balance control. Journal in detail before collecting kinematic data. Basic subject information is shown in Table 1. of Biomechanics, 30(4), 347-354. Procedure: Roundhouse Kick movements were collected by a 3-D capture system with eight Wang, L.H., Lo, K.C., Lin, C.J. & Su, F.C. (2010). Multijoint coordination of lower extremity in Tai Chi cameras at 200 Hz sampling rate. The marker set included nine reflective markers placed at exercise. Journal of Mechanics in Medicine and Biology, 10(3), 479-493. the scrum and Anterosuperior iliac spine (ASIS), middle points of the thigh and shank, greater trochanter, lateral knee joint, lateral malleolus, fifth metatarsal-phalangeal joint, and Acknowledgement calcaneus of the supporting leg. The dominant leg was identified by placing a ball on the This study was supported by the National Science Council grant NSC 97-2410-H-006-087, TAIWAN. ground and the dominant leg was the one that kicked the ball. After warming up, each subject was asked to practice the Roundhouse Kick so that they could be used to perform these movements further in the laboratory environment. Each subject then performed five Roundhouse by the dominant leg as fast as possible. Between each trial, the participant took a break of 30 seconds to avoid muscle fatigue. In addition, distance between the supporting foot and kicking foot was 60% of the leg length measured from the trochanter to lateral malleolus. The choice of this separated distance was based on the average of the preferred distance of all the subjects. In this study, subjects were asked to place the kicking leg at the posterior position and the supporting leg at the anterior position. The kicking target was held at the height of the subject’s umbilicus and the distance of Roundhouse Kick was defined as 1.5-fold leg length from the anterior of supporting leg.

ISBS 2011 423 Porto, Portugal Table 1 Basic information of the subjects

Vilas-Boas, Machado, Kim, Veloso (eds.) Light weight (n=2) Heavy weight (Portuguesen=2) Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011 Body weight 64.2±2.89 71.8±1.77 Table 1 Table 3 Body Height Basic information 169.2±1.04 of the subjects 173.8±1.13 The range angle of the supporting Leg in phase 2 Light(S.D) Heavy(S.D) Note: Light weight : 58 - 68kg Light; Heavy weightweight: (68n=2-80kg.) Heavy weight (n=2) o * o * Table 1 Ankle For/backward Rotation 3.82±1.57 7.40±1.00 Body weight Basic information 64.2±2.89 of the subjects 71.8±1.77 Ankle E/Inversion 4.22±1.18o * 2.02±1.11o * o o BodyData analysis:Height Kinematic data Light of169.2±1.04 theweight supporting(n=2 ) leg was Heavy 173.8±1.13 processedweight with (n=2 Visual) 3D. Knee Fle/Extension 8.52±5.63 6.12±4.04 Hip Fle/Extension 10.73±3.88o 14.18±4.55o BodyNote:Movement Lightweight ofweight the Roundhouse : 58 - 68kg Kick ; Heavy was 64.2±2.89 definedweight to: 68 have - 80kg. three phases. 71.8±1.77 Phase 1 was defined Hip Ex/Internal Rotation 20.03±5.52o * 12.55±1.69o * Bodyfrom propelling Height the kicking foot (with 169.2±1.04 ankle plantar flexion) to maximum 173.8±1.13 kicking knee flexion. Data analysis:Phase 2 was Kinematic defined from datamaximum of kicking the supporting knee flexion to leg kicking was the processedtarget including with trunk Visual 3D. Note: * denote significant difference (p<.05) between two group. For/Backward: MovementNote: of the Light Roundhouseweight: 58-68kg Kick; Heavy was definedweight: 68to -have80kg. three phases. Phase 1 was defined Forward and Backward. Fle/Extension=Flexion and Extension. from propellingand pelvis the rotation. kicking Joint foot angles (with on anklethe supporting plantar leg flexion) were calculated to maximum for flexion, kicking extension, knee flexion. DataPhase analysis:2 wasforward defined rotation, Kinematic from backward maximum data rotation, of kicking inversion,the supporting knee eversion, flexion dorsiflexion, leg to waskicking processedplantar the flexiontarget with during including Visual trunk 3D. DISCUSSION: Both the supporting leg and the kicking are important factors influencing andMovement pelvis rotation.of the Roundhouse Joint angles Kick on thewas supporting defined to leghave were three calculated phases. forPhase flexion, 1 was extension, defined athletes’ ability to perform the Roundhouse Kick. Athletes need rapid rotation movement by forwardfrom propelling rotation,the Roundhouse the backward kicking Kick. foot rotation, (with ankle inversion, plantar eversion, flexion) dorsiflexion, to maximum plantar kicking flexion knee flexion. during using the supporting leg to raise the power or velocity of the kicking leg (Chang, 2008). A thePhase Roundhouse 2 was defined Kick. from maximum kicking knee flexion to kicking the target including trunk good rotational movement of the supporting leg may help athletes to kick more effectively. and pelvis rotation. Joint angles on the supporting leg were calculated for flexion, extension, The contribution of the rotation on the supporting leg is the increase in the attack distance forward rotation, backward rotation, inversion, eversion, dorsiflexion, plantar flexion during and reduction of the area directly facing the opponent (by using the other lateral side of the the Roundhouse Kick. torso to face the opponent). The less exposure of the frontal plane of the upper body, the less area can be kicked. The main finding of the study was that the heavy division group have more range of ankle for/backward rotation which could prevent injury on the supporting leg. A previous study has demonstrated that the low extremity sustained the body weight and rotation torque (Kellis, 2004), but this probably had negative effect on the supporting leg. In the range of ankle eversion and inversion, the heavy division group has significantly higher values indicating that movement in the heavy group is more stable in phase 2 during kicking. This is because extra ankle eversion/inversion will increase the shaking variance at the foot. Our study indicated larger range of the knee flexion/extension in the light division group, possibly producing more momentum from the supporting to kicking leg, which is similar to the Figure 1: Definition of the three phases of the Roundhouse Kick results of Wu (2008). A larger push-off movement of the supporting leg lead to greater impact force. But the theory needs further examination on the relationship between the range of Statics analysis: The t-test was used to compare the difference between two weight knee joint movement and impact force. divisions.Figure All 1: FiguretheDefinition joints 1: Definition ofangular the of threethe data three phases phaseswere ofcalculated thethe Roundhouse Roundhouse by SPSS Kick Kick 17.0 software package. The significant level was set at p<.05. CONCLUSION: The purpose of the study was to examine the kinematics variables of four Statics analysis: The t-test was used to compare the difference between two weight Taekwondo athletes. The present study indicated that there were higher range of ankle RESULTS:divisions. StaticsAll Table the analysis:joints 2 and angular The 3 present t-test data was kinematic were used tocalculated compare data of the bythe differenceSPSS Roundhouse 17.0 between software Kick two weight performance package. The in forward/backward rotation and less range of ankle eversion/ inversion, which may increase phasesignificant 1 anddivisions. level phase was All theset2, respectivelyjoints at p<.05. angular data. In werephase calculated 1, maximum by SPSS joint17.0 softwareangles package. of the supportingThe leg the stability of the supporting leg. In future studies, the kinetics and ground reaction forces were calculated. Maximum ankle inversion angle in the light division group was significantly should be included in the analysis in order to demonstrate whether the impact force can be RESULTS:lower thansignificant that Table of levelthe 2 and washeavy 3set present at division p<.05. kinematic group. In datathe maximum of the Roundhouse angle of knee Kick flexion, performance the light in influenced by the variable such as knee range of motion. divisionphase 1 groupand phase was significantly 2, respectively larger. In thanphasethat 1, ofmaximumthe heavy joint division angles group. of the In supporting phase 2, theleg rangewere calculated of ankle. M forwardaximum Table 2 and/backward ankle 3 present inversion kinematicrotation angle data and ofin thetheeversion/ Roundhouse light divisioninversion Kick group performance showed was in significantly significant REFERENCES: differencelower thanRESULTS: betweenthat of the two heavy group divisions. In the group. light division In the group,maximum the anglerange of ankleknee flexion,forward therotation light Chang W.G. (2008). Gender diffence on knee 3D dynamic and EMG activity of the support leg for wasdivision lower groupphasethan was1 andthe significantly phaseheavy 2, respectively group. larger C.ontrarily Inthan phasethat , 1, the m ofaximum rangethe heavy joint of angles ankle division of eversion/the group.supportinginversion In legphase of 2, lightthe Tae-kwon-do Double Jump Roundhouse Kick during landing. Unpublished master thesis. National college of physical education and sports, Taoyuan, Taiwan.. grouprange was of were hi ankleg calculatedher thanforward. Mheavyaximum/backward group. ankle inversionFinally,rotation angle there and in thewas eversion/light significantly divisioninversion group difference was significantlyshowed in the significant range of hipdifference internal/external between tworotation group betweens. In the the light two divisiongroup sgroup,. the range of ankle forward rotation Falco C, Alvarez O, Castillo I, Estevan I, Martos J, Mugarra F, & Iradi (2009). Influence of the distance lower than that of the heavy division group. In the maximum angle of knee flexion, the light in a roundhouse kick’s execution time and impact force in Taekwondo. Journal of biomechanics was lower than the heavy group. Contrarily, the range of ankle eversion/inversion of light 42(3):243-8. group wasdivision higher group than was heavy significantly group. largerFinally, thanTablethat there of 2the was heavy significantly division group. difference In phase 2, in the the range of The maximum angle of the supporting Leg in phase 1 Kellis E, Katis A & Gissis I. (2004). Knee biomechanics of the support leg in soccer kicks from three hip internal/externalrange of ankle rotation forward between/backward therotation two group and eversion/s. inversion showed significant angles of approach. Medicine and Science in sports and exercise 36(6):1017-28. Light(S.D) Heavy(S.D) Lee, S.K.(1983). Frequency analysis of the Taekwondo techniques used in a tournament. Journal of difference between two groups. In the light Tabledivision 2 group, theo range of ankle forward rotationo Ankle Dorsiflexion 88.12±9.13 89.78±10.85 Taekwon 24,122-130. The maximum angle of the supportingo Leg* in phase 1 o * wasAnkle lower Inversionthan the heavy group. C ontrarily 36.29, the range.±17 . of60 ankle eversion/ 44.86inversion±8.03 of light Tang, H.W.(2001). A comparative analysis of the kinetics and kinematics of five different Roundhouse Knee Flexion 5Light(S.D)5.68±1.73 o * Heavy(S.D)41.55±1.64o * group was higher than heavy group. Finally, there was significantlyo difference in the rangeo of kick in Taekwondo. Unpublished master thesis. National college of physical education and sports, AnkleNote: * Dorsiflexiondenote significant difference (p<.05)88.12±9.13between group 89.78±10.85s. Taoyuan, Taiwan. hip internal/external rotation between the two groups. o * o * Ankle Inversion 36.29.±17.60 44.86±8.03 Wu, C.H.(2008). The sports biomechanical analysis of Whip-Kick in WuShu ShanShou. Unpublished o * o * Knee Flexion 55.68±1.73 41.55±1.64 master’s thesis. Chinese culture university, Taipei, Taiwan. Note: * denote significant differenceTable(p<.05) 2 between groups. The maximum angle of the supporting Leg in phase 1 ISBS 2011 Light(S.D)424 Heavy(S.D) Porto, Portugal Ankle Dorsiflexion 88.12±9.13o 89.78±10.85 o Ankle Inversion 36.29.±17.60o * 44.86±8.03o * Knee Flexion 55.68±1.73o * 41.55±1.64o * Note: * denote significant difference (p<.05) between groups. Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011

Table 1 Table 3 Basic information of the subjects The range angle of the supporting Leg in phase 2 Light(S.D) Heavy(S.D) Light weight (n=2) Heavy weight (n=2) Table 1 Ankle For/backward Rotation 3.82±1.57o * 7.40±1.00o * Body weight Basic information 64.2±2.89 of the subjects 71.8±1.77 Ankle E/Inversion 4.22±1.18o * 2.02±1.11o * o o Body Height Light 169.2±1.04 weight (n=2 ) Heavy 173.8±1.13weight (n=2) Knee Fle/Extension 8.52±5.63 6.12±4.04 Hip Fle/Extension 10.73±3.88o 14.18±4.55o BodyNote: Lightweightweight : 58 - 68kg ; Heavy 64.2±2.89weight: 68 - 80kg. 71.8±1.77 Hip Ex/Internal Rotation 20.03±5.52o * 12.55±1.69o * Body Height 169.2±1.04 173.8±1.13 Data analysis: Kinematic data of the supporting leg was processed with Visual 3D. Note: * denote significant difference (p<.05) between two group. For/Backward: MovementNote: of the Light Roundhouseweight: 58-68kg Kick; Heavy was definedweight: 68to -have80kg. three phases. Phase 1 was defined Forward and Backward. Fle/Extension=Flexion and Extension. from propelling the kicking foot (with ankle plantar flexion) to maximum kicking knee flexion. DataPhase analysis:2 was defined Kinematic from maximum data of kicking the supporting knee flexion leg to waskicking processed the target with including Visual trunk 3D. DISCUSSION: Both the supporting leg and the kicking are important factors influencing andMovement pelvis rotation.of the Roundhouse Joint angles Kick on thewas supporting defined to leghave were three calculated phases. forPhase flexion, 1 was extension, defined athletes’ ability to perform the Roundhouse Kick. Athletes need rapid rotation movement by forwardfrom propelling rotation, the backward kicking foot rotation, (with ankle inversion, plantar eversion, flexion) dorsiflexion, to maximum plantar kicking flexion knee flexion. during using the supporting leg to raise the power or velocity of the kicking leg (Chang, 2008). A thePhase Roundhouse 2 was defined Kick. from maximum kicking knee flexion to kicking the target including trunk good rotational movement of the supporting leg may help athletes to kick more effectively. and pelvis rotation. Joint angles on the supporting leg were calculated for flexion, extension, The contribution of the rotation on the supporting leg is the increase in the attack distance forward rotation, backward rotation, inversion, eversion, dorsiflexion, plantar flexion during and reduction of the area directly facing the opponent (by using the other lateral side of the the Roundhouse Kick. torso to face the opponent). The less exposure of the frontal plane of the upper body, the less area can be kicked. The main finding of the study was that the heavy division group have more range of ankle for/backward rotation which could prevent injury on the supporting leg. A previous study has demonstrated that the low extremity sustained the body weight and rotation torque (Kellis, 2004), but this probably had negative effect on the supporting leg. In the range of ankle eversion and inversion, the heavy division group has significantly higher values indicating that movement in the heavy group is more stable in phase 2 during kicking. This is because extra ankle eversion/inversion will increase the shaking variance at the foot. Our study indicated larger range of the knee flexion/extension in the light division group, possibly producing more momentum from the supporting to kicking leg, which is similar to the Figure 1: Definition of the three phases of the Roundhouse Kick results of Wu (2008). A larger push-off movement of the supporting leg lead to greater impact force. But the theory needs further examination on the relationship between the range of Statics analysis: The t-test was used to compare the difference between two weight knee joint movement and impact force. divisions.Figure All 1: theDefinition joints ofangular the three data phases were ofcalculated the Roundhouse by SPSS Kick 17.0 software package. The significant level was set at p<.05. CONCLUSION: The purpose of the study was to examine the kinematics variables of four Statics analysis: The t-test was used to compare the difference between two weight Taekwondo athletes. The present study indicated that there were higher range of ankle RESULTS:divisions. All Table the joints 2 and angular 3 present data kinematic were calculated data of bythe SPSS Roundhouse 17.0 software Kick performance package. The in forward/backward rotation and less range of ankle eversion/ inversion, which may increase phasesignificant 1 and level phase was set2, respectively at p<.05. . In phase 1, maximum joint angles of the supporting leg the stability of the supporting leg. In future studies, the kinetics and ground reaction forces were calculated. Maximum ankle inversion angle in the light division group was significantly should be included in the analysis in order to demonstrate whether the impact force can be RESULTS:lower than that Table of the 2 and heavy 3 present division kinematic group. In datathe maximum of the Roundhouse angle of knee Kick flexion, performance the light in influenced by the variable such as knee range of motion. divisionphase 1 groupand phase was significantly 2, respectively larger. In thanphasethat 1, ofmaximumthe heavy joint division angles group. of the In supporting phase 2, theleg rangewere calculated of ankle. Mforwardaximum/backward ankle inversionrotation angle and in theeversion/ light divisioninversion group showed was significantly significant REFERENCES: differencelower than betweenthat of the two heavy group divisions. In the group. light division In the group,maximum the anglerange of ankleknee flexion,forward therotation light Chang W.G. (2008). Gender diffence on knee 3D dynamic and EMG activity of the support leg for wasdivision lower groupthan was the significantly heavy group. larger Contrarily than that, the of rangethe heavy of ankle division eversion/ group.inversion In phase of 2, lightthe Tae-kwon-do Double Jump Roundhouse Kick during landing. Unpublished master thesis. National college of physical education and sports, Taoyuan, Taiwan.. grouprange was of hi anklegher thanforward heavy/backward group. Finally,rotation there and was eversion/ significantlyinversion difference showed in the significant range of hipdifference internal/external between tworotation group betweens. In the the light two divisiongroup sgroup,. the range of ankle forward rotation Falco C, Alvarez O, Castillo I, Estevan I, Martos J, Mugarra F, & Iradi (2009). Influence of the distance in a roundhouse kick’s execution time and impact force in Taekwondo. Journal of biomechanics was lower than the heavy group. Contrarily, the range of ankle eversion/inversion of light 42(3):243-8. group was higher than heavy group. Finally,Table there 2 was significantly difference in the range of The maximum angle of the supporting Leg in phase 1 Kellis E, Katis A & Gissis I. (2004). Knee biomechanics of the support leg in soccer kicks from three hip internal/external rotation between the two groups. angles of approach. Medicine and Science in sports and exercise 36(6):1017-28. Light(S.D) Heavy(S.D) Lee, S.K.(1983). Frequency analysis of the Taekwondo techniques used in a tournament. Journal of Table 2 o o Ankle Dorsiflexion 88.12±9.13 89.78±10.85 Taekwon 24,122-130. The maximum angle of the supportingo Leg* in phase 1 o * Ankle Inversion 36.29.±17.60 44.86±8.03 Tang, H.W.(2001). A comparative analysis of the kinetics and kinematics of five different Roundhouse Knee Flexion 5Light(S.D)5.68±1.73 o * Heavy(S.D)41.55±1.64o * o o kick in Taekwondo. Unpublished master thesis. National college of physical education and sports, AnkleNote: * Dorsiflexiondenote significant difference (p<.05)88.12±9.13between group 89.78±10.85s. Taoyuan, Taiwan. o * o * Ankle Inversion 36.29.±17.60 44.86±8.03 Wu, C.H.(2008). The sports biomechanical analysis of Whip-Kick in WuShu ShanShou. Unpublished o * o * Knee Flexion 55.68±1.73 41.55±1.64 master’s thesis. Chinese culture university, Taipei, Taiwan. Note: * denote significant difference (p<.05) between groups.

ISBS 2011 425 Porto, Portugal