Comparison of Lower Limb Segments Kinematics in a Taekwondo Kick. An Approach to the Proximal to Distal Motion

Correlation analysis between biomechanical characteristics of taekwondo double roundhouse kick and effective scoring of electronic body protector

Objective: To explore the inherent relationship between lower limb biomechanical indicators and effective scoring values of double roundhouse kick (DRK) by taekwondo athletes, and to find key biomechanical factors that trigger effective scoring. Methods: Using the DAEDO Protector and Scoring System (PSS) in conjunction with the Vicon optical motion capture system and Kistler 3D force plate, kinematic and dynamic indicators of the front kicking motion were obtained from 12 professional taekwondo athletes (18.00 ± 2.20 years, 182.15 ± 8.62 cm and 70.00 ± 14.82 kg). The correlation between kinematics, dynamics, and scoring values was initially analyzed using bivariate linear correlation. Subsequently, based on the results of the linear correlation analysis, a stepwise regression analysis was performed to establish a stepwise regression equation. Results: The results reveal that during the First Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak hip flexion angular velocity of the dominant leg, knee abduction angle, and peak foot horizontal plane linear velocity of the non-dominant leg with effective score. On the other hand, peak ankle flexion angular velocity of the non-dominant leg, peak foot sagittal plane linear velocity, peak hip abduction angle, and peak hip flexion angle of the dominant leg exhibit a significant negative correlation (r < 0, p < 0.05) with effective score. These correlations hold statistical significance (DW> 1.023). During the Second Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak ankle internal rotation angular velocity of the dominant leg, foot coronal plane linear velocity, hip adduction angular velocity, and peak ankle internal rotation moment of the non-dominant leg with effective score. Conversely, peak hip flexion angle of the dominant leg shows a significant negative correlation (r < 0, p < 0.05) with effective score. All these variables have a statistically significant impact on effective score (DW > 1.023). Conclusion: Explosive power, body posture, adequate terminal velocity, and body rotation have an association with effective scoring of the electronic protector. The peak angular velocity of the ankle joint of the dominant leg and the peak linear velocity of the foot horizontal plane of the non-dominant leg significantly contribute to the effectiveness score of the electronic protector.

Differences in kick-leg kinematics in various side-kick heights

This study aims to explore the variation of lower extremity kinematic characteristics when elite taekwondo athletes perform the side-kick on protective gear placed at various heights. Twenty distinguished male national athletes were recruited and were asked to kick targets at three different heights adjusted according to their body height. A three-dimensional (3D) motion capture system was used to collect kinematic data. Kinematic parameters differences in the side-kick at three different heights were analyzed by using a one-way ANOVA (p < .05). The results revealed significant differences in the peak linear velocities of the pelvis, hip, knee, ankle, and centre of gravity of the foot during the leg-lifting phase (p < .05). Significant differences between heights were noted in the maximum angle of pelvis left tilting and hip abduction in both phases. In addition, the maximum angular velocities of pelvis left tilting and hip internal rotation were only different in the leg-lifting phase. This study found that, to kick at a higher target, athletes increase the linear velocities of their pelvis and all lower extremity joints of attacking leg in the leg-lifting phase; however, they only increase rotational variables on the proximal segment at the peak angle of the pelvis (left tilting) and hip (abduction and internal rotation) in the same phase. As an application in actual competitions, according to the opponent's body height, athletes can adjust both linear and rotational velocities of their proximal segements (pelvis and hip) and deliver into distal segements (knee, ankle, foot) linear velocity to perform accurate and rapid kicks.

Differences in Velocities of Crucial Body Segments while Executing Roundhouse Kicks for Both Sides

Lower limb kinematics of the roundhouse kick is a well-known topic studied by many researchers. However, there is a lack of data about the velocity of the core and upper limbs during the execution of this technique. The aim of this study was to evaluate the differences in velocities of all crucial body segments while executing roundhouse kicks for both sides of the body. Thirteen elite taekwon-do athletes participated in this study. They performed kicks to a table tennis ball three times using each leg. The spatial-temporal data of markers placed on toes, knees, hips, shoulders, elbows, hands, and sternum were captured with the use of the Human Motion Lab equipment composed of 10 infrared cameras NIR Vicon MX-T40. There were statistical differences in the maximal velocity of the sternum and opposite shoulder. There were different correlations between the time of acquiring maximal velocities of specific body segments and the maximal velocity of the toe marker for each kicking side. Higher correlations were observed for the left kick despite the participant’s declaration of their preference for the right leg. The obtained results facilitate the conclusion that small non-resistant targets require different motor control depending on the kicking side, despite not revealing significant differences between maximal velocity. While such an indicator could be perceived as a suitable benchmark of an athlete’s performance, more detailed analysis seems to be required for a better understanding of martial arts techniques.

Kinematic and kinetic demands on better roundhouse kick performances

The roundhouse kick is one of the most widely applied techniques in a taekwondo competition. Because the scoring system of taekwondo has been changed, the skill of roundhouse kick has been affected. Therefore, coaches and athletes are attempting to better understand how to control the movement of the kick to gain points more effectively. The aim of this study was to investigate the differences in the biomechanical characteristics between the roundhouse kicks with higher and lower impact magnitude using an electronic body protector. Eighteen elite college Taekwondo athletes participated in this study. A motion capture system measured the kinematics data of the kicking leg. The results indicated that elite athletes can obtain a high-impact index of the electrical body protector through increasing the peak linear velocity of shank, even with the same foot velocity level. In regard to kinetic skills, the roundhouse kicks a high impact. The velocity of proximal kicking limb could predominantly contribute to the powerful roundhouse kicks to achieve the high-impact force for electrical body protector. Moreover, when the kick cannot be effectively scored during the game, coaches and masters should consider adjusting to increase the velocity of proximal kicking.

Kinematic Effects of the Target on the Velocity of Taekwon-Do Roundhouse Kicks

The phenomena of target kinematic effects under different striking conditions and applying different techniques constitute one of the fields of research for sports biomechanics. However, the influence of some kinematic variables which change under different strike conditions for specific parts of the lower limb remains unknown. The aim of this study was to extend the knowledge on how targets of different shapes or the lack of a physical target would affect maximal velocity registered by a marker placed on the foot, knee and hip during the execution of a roundhouse kick. In total, 15 adult males were included in this study. All participants were taekwon-do elite athletes. The displacement of markers placed on the lateral side of the foot, knee and hip during movement execution was registered by a stereophotogrammetry apparatus. Participants performed taekwon-do roundhouse kicks for three target types (into the air, a table tennis ball and a training shield) applying either a sport or a traditional style. The highest maximal velocity was obtained for kicking into the training shield. When applying the sport style, the highest maximal velocity of foot markers for the executed kicks was registered. Kicking into air resulted in higher velocities for proximal body parts than kicking into a tennis ball, but the effect was reversed for the foot marker. In conclusion, a large resistance target is suitable for athletes' motor preparation as it allows the highest maximum velocity to be reached. Small non-resistant targets are recommended for technical training.