AbstractLaterality between lower limbs can affects sports performance when Taekwondo athletes completing kicking movements, and Side Kick (SK) is the one of the most used kicking movements in Taekwondo competitions. Therefore, the aim of the present study was to explore whether there is biomechanical laterality of the dominant side (DS) and non-dominant side (NS) of the lower limbs in competitive Taekwondo athletes during SK movements when effectively scored. Fourteen Taekwondo elite athletes were selected as subjects. The kinematic and kinetic data of the SK performed by subjects were collected using motion capture system and a three-dimensional force platform. The collected data were imported into Visual3D software for inverse kinematic calculations. There are biomechanical indicators with laterality in the lower limbs of the DS and NS: For attacking leg, there are significant differences between DS and NS in peak hip flexion moment and extension power; peak knee flexion moment and extension angular velocity; and peak foot linear velocity, translational energy, and linear momentum. For Support leg, there are significant differences between DS and NS in peak hip joint abduction angle; peak knee joint flexion moment; and peak vertical ground reaction force of the foot. In summary, Taekwondo athletes have a certain degree of laterality when performing SK in their lower limbs, and their sports performances can be impaired when Taekwondo athletes using SK techniques in DS and NS. To achieve the same strike effect when using DS and NS to complete SK, unilateral resistance training and other training methods should be employed.
IntroductionTaekwondo is one of the most important competitive fighting sports at present, it is also an official competition of the modern Olympic Games. In Taekwondo competition of the 2008 Beijing Olympics, electronic protective equipment replaced manual referees as the new judgement method at the first time. In the context of new regulations and electronic protective equipment, Taekwondo athletes have undergone significant changes in their selection of kicking techniques and tactics. Side Kick (SK) has gradually become one of the main kicking techniques due to its fast movement and high accuracy1,2. In research of the technical and tactical skills of outstanding Taekwondo athletes both domestically and internationally, it was found that utilization rate and for SK of Taekwondo champions were significantly higher than other athletes3. This also highlights the importance of SK in competitive Taekwondo games.Competitive Taekwondo athletes who want to create effective scores when hitting electronic protective equipment not only need to hit the right position, the attacking leg also needs enough speed to hit the target4,5. Because there are sensors inside the electronic protective equipment, then the system only gives a valid score if the kick movement has enough impact. Research has shown that the main biomechanical factors affecting the striking speed of the attacking leg in SK, including the knee joint’s flexion and extension6, and the hip joint’s flexion, extension, and abduction7. The biomechanical indicators of the hip joint of the support leg can play a vital role in maintaining the balance of body8, and the biomechanical indicators of the ankle joint’s extorsion also have a significant impact on shortening the duration of the action9. It can be seen that the biomechanical characteristics of the joints of the Taekwondo athlete’s attacking leg and supporting leg are directly related to the scoring effect of the competitive Taekwondo game.Lateralization is manifested as asymmetry in the structure or function of the bilateral limbs, that is, one side of the athlete’s limbs is stronger than the other side in terms of muscle strength, flexibility, etc., and is very common among athletes of various sports. If there is asymmetry between the lower limbs of athletes, their sports performance may be affected10. Taekwondo movements belong to unilateral asymmetrical movements between limbs. The specific manifestation of limb laterality is the Dominant side (DS) and Non-Dominant side (NS). In Taekwondo competitions, athletes need to alternate the use of their DS and NS leg as attacking leg to complete SK based on the game condition11, which may be affected by factors such as the opponent’s attacking intentions and position in the field. Researches have shown that limb laterality has a significant impact on the dynamic balance ability of the human body12, jumping height13, sprint speed, and speed of changing direction14. For competitive Taekwondo athletes, lower limb laterality is reflected in the differences of biomechanical indicators during joint movement between DS and NS, which affects the striking speed and power of Taekwondo kicking techniques15. It will also affect the striking effect to the electronic protective gear, ultimately resulting in a reduction in scores and affecting the outcome of the game. There may be an association between limb laterality differences and the risk of sports injuries, especially the non-dominant side may have an increased risk of injury due to accumulated fatigue during long-term exercise16.In Taekwondo training, athletes often choose one leg as the DS based on their habits, and the functional structural differences between the left and right hemispheres of cerebrum are one of the main reasons that lead to this phenomenon in athletes17. Besides, Taekwondo athletes usually train their DS lower limbs more both in muscle strength and SK techniques, leading to further increased asymmetry between the DS and NS of the lower limbs18. Nowadays, there are some studieson the biomechnical laterality of the lower limbs in kicking techniques of Taekwondo athletes15,18,19, such as Roundhouse Kick and Double Roundhouse Kick, but the impact of laterality on Taekwondo SK is not yet clear. Therefore, to explore the differences in biomechanical characteristics between the DS and NS of Taekwondo athletes when completing SK movements, this study used a motion capture system, a three-dimensional force measurement platform, and sports biomechanical analysis software to analyze the biomechanical characteristics of SK techniques of Taekwondo athletes’ DS and NS under the effective score of DaeDo electronic protective equipment. This study is expected to help athletes and coaches better understand the mechanism of movements between DS and NS, thereby providing effective theoretical support for training and improving competition performance.Materials and methodsParticipantsG Power 3.1.9.2 was used to calculate the predicted sample size. Perform correlation analysis using a effect value of 0.65. Under the conditions of α = 0.05 and a statistical power of 80%, 13 participants were needed. This study recruited 14 elite athletes from the Taekwondo training team and sports training major of Wuhan Sports University for the experiment. All subjects were high-level athletes at national level 2 or above(gender; all males; age: 17.8 ± 2.2 years; height: 181.9 ± 8.3 cm; body mass: 69.4 ± 14.4 kg; and training period: 3.4 ± 1.7 years), which means all of them have at least achieved 2nd to 4th place in individual events at provincial games or championships (or championship series) organized by provincial sports administrative departments. Only male athletes were selected as our subjects. Among the 14 subjects, 4 of them had the DS on the left leg as attacking leg, right leg as supporting leg; and others had the DS on the right leg as attacking leg, left leg as supporting leg, which was categorized limbs based on perceived dominant leg, for example, the skill dominance20. All subjects did not injure seriously within six months, this was defined as any injury that affected the subject’s normal motor function or required medical intervention. Subjects with severe diseases that affect motor ability were excluded. Specific evaluation methods include physical examination and Taekwondo kicking ability test to ensure that each subject meets the inclusion requirements. All subjects provided written informed consent and all procedures were conducted in accordance with the Declaration of Helsinki and were approved by the local Ethics Committee (review unit - Medical Ethics Committee of Wuhan Sports University; number 2022048).MethodologyPreparationThe test was conducted in the Key Laboratory of the General Administration of Sport of China. Reflective markers with a diameter of 14 mm were pasted on the head, torso, and hip, knee, and ankle joints of subjects (see Supplementary Fig. S1 online). Before the test, the subjects jogged on the treadmill at a speed of 5 m/s with a slope of 0% for 5 min, followed by stretching for 5 min according to the pre-training stretching methods. Then, the experimental movements were practiced once in advance, allowing the subjects to adapt to the position and size of the force platform in the Laboratory.Measurements and proceduresThe test movement of the subject is Taekwondo SK. When the laboratory technician gives an order, the subjects can transition from a stationary state to a moving state and use SK to hit the dummy wearing Daedo electronic protective equipment according to their own competition habits. Data needs to be collected more than three times successfully.InstrumentsNine infrared high-speed cameras (T40, Vicon, UK, sampling frequency 200 Hz) and four Kistler 3D force measurement platforms (9260AA6, Kistler, Switzerland, sampling frequency 1 kHz) were used to collect the original kinematic and kinetic data of the subjects. DaeDo electronic protective equipment and its electronic scoring system were worn on a dummy and used as a kicking target. The protective gear includes an electronic head gear, trunk protector, and sensor sock, which are equipped with sensors inside.Event divisionTo better analyze the SK movements in Taekwondo, the movements were divided into three phases based on four events8 (Fig. 1). And the attacking leg was defined as the leg that complete the SK movement towards the target, support leg was defined as the leg that stand on the ground to support the whole body.Preparation moment (E1): The moment when the attacking foot leaves the force measuring platform and the ground reaction force reaches zero.Knee lifting moment (E2): The moment of Maximum flexion of the attacking leg of knee joint.Strike moment (E3): The moment of maximum extension of the knee joint of the attacking leg.Retract moment (E4): The moment when the attacking foot touches the force measuring platform and experiences a ground reaction force.Initiation phase (P1): from preparation moment to knee lifting moment, (E1-E2).Strike phase (P2): from the knee lifting moment to strike moment (E2-E3).Retract phase (P3): from the strike moment to the retract moment (E3-E4).This study mainly studied the biomechanical characteristics of the lower limbs of competitive Taekwondo athletes during the P1 and P2 of SK.Fig. 1Definition for E1-E4 and workflow.Full size imageIndicatorsTaekwondo SK movement is similar to Taekwondo Roundhouse Kick movement, their lower limbs’ joints mainly perform the knee flexion and extension, hip flexion and extension, and abduction and adduction during the movement phase. However, the main difference is that intorsion and extorsion are the main support leg ankle movement in SK, less in dorsiflexion and plantarflexion7. And the commonly used biomechanical indicators should include peak joint angle, peak joint angular velocity, peak joint moment, peak attacking leg foot linear velocity, and peak vertical reaction force17,18,21,22. The specific indicators selected are as follows:Kinematics: Peak angle of hip and knee joints (°), peak angular velocity of hip and knee joints(rad·s−1), and linear velocity of feet (m·s−1).Kinetics: Normalized peak vertical ground reaction force (N·kg−1); normalized peak moment of the hip, knee, and ankle joints (N·m·kg−1), as well as normalized peak power of the hip, knee, and ankle joints (W·kg−1).In addition, the peak Translational Energy Scalar (J) and linear momentum of the attacking leg and foot were also selected(Kg·m·s−1).It is stipulated that the X-axis in the human joint coordinate system is the coronal axis, the Y-axis is the sagittal axis, and the Z-axis is the vertical axis. Among them, flexion and extension are movements around the coronal axis. Abduction and adduction are movements around the sagittal axis. Intorsion and extorsion are movements around the vertical axis.Data processing and statistical analysisFirst, markers modeling was performed using marker coordinates captured by a Vicon 3D motion capture system. Then, the c3D files were first exported to Visual3D (C- Motion Inc, Maryland, USA) software for skeleton modeling, and then the motion file was imported into the static model for matching23. All the indicators were calculated based on Visual3D standard algorithms for kinematic and kinetic analysis. Besides, peak vertical ground reaction force, peak joint moment, and peak joint power were normalized to body weight. Select data according to the event division and process the signals separately. The kinematic data is filtered at 10 Hz, while the kinetic data is filtered at 25 Hz. Subsequently, SPSS 26.0 (IBM Corp, Armonk, NY, USA) was used to perform the Shapro-Wilk test on the DS and NS data to determine whether the data belonged to a normal distribution. Descriptive statistics were presented in the form of mean ± standard deviation (x ± SD), with outliers removed. Subsequently, paired sample t-tests were performed on the data of DS and NS. When P < 0.05, it indicates a significant difference in biomechanical indicators between the DS and NS.ResultsDifferences in biomechanical characteristics of hip joint in attacking leg.The peak flexion moment of hip was greater on the DS than on the NS in P1, and there was a significant difference (P = 0.050, Cohen’s d = 0.604), other indicators have difference but no statistical significance (P > 0.05). The peak extension power of hip is greater on the DS than on the NS in P2, and there is a significant difference (P = 0.033, Cohen’s d = 0.638), other indicators have difference but no statistical significance (P > 0.05); there is no statistically significant difference of abduction of the hip joint in the biomechanical characteristics between the DS and NS in P2 (P > 0.05)(See Fig. 2. (a), (b) and (c)).Fig. 2Biomechanical characteristics of hip joint in attacking leg. (a) Hip Flexion, (b) Hip Extension, (c) Hip Abduction. JA (Unit: °), Joint Angle; JAV (Unit: rad·s-1), Joint Angular Velocity; JM (Unit: N·m·kg-1), Joint Moment; JP (Unit: W·kg-1), Joint Power; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDifferences in biomechanical characteristics of hip joint in support leg.As Shown in Fig. 3 (a), there is no statistically significant difference of flexion of the hip joint in the biomechanical characteristics between the DS and NS in P1 (P > 0.05). In Fig. 3 (b), there is no statistically significant difference of extension of the hip joint in the biomechanical characteristics between the DS and NS in P2 (P > 0.05); in Fig. 3 (c), the process of hip joint abduction, the peak abduction angle on the DS is greater than that on the NS in P2, and there is statistical significance (P = 0.043, Cohen’s d = 0.240), other indicators have difference but no statistical significance (P > 0.05).Fig. 3Biomechanical characteristics of hip joint in supporting leg. (a) Hip Flexion, (b) Hip Extension, (c) Hip Abduction. JA (Unit: °), Joint Angle; JAV (Unit: rad·s-1), Joint Angular Velocity; JM (Unit: N·m·kg-1), Joint Moment; JP (Unit: W·kg-1), Joint Power; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDifferences in biomechanical characteristics of knee joint in attacking leg.As Shown in Fig. 4 (a), the peak flexion moment of the knee joint is greater on the DS than on the NS in P1, and there is statistical significance (P = 0.045, Cohen’s d = 0.593), other indicators have difference but no statistical significance (P > 0.05). In Fig. 4 (b), the peak extension angular velocity is greater on the DS than on the NS in P2, and there is statistical significance (P = 0.002, Cohen’s d = 0.961), other indicators have difference but no statistical significance (P > 0.05).Fig. 4Biomechanical characteristics of knee joint in attacking leg. (a) Knee Flexion (b) Knee Extension. JA (Unit: °), Joint Angle; JAV (Unit: rad·s-1), Joint Angular Velocity; JM (Unit: N·m·kg-1), Joint Moment; JP (Unit: W·kg-1), Joint Power; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDifferences in biomechanical characteristics of the knee joint of the support leg.In Fig. 5 (a), the peak flexion moment of the knee joint is greater on the DS than on the NS in P1, and there is statistical significance (P = 0.048, Cohen’s d = 0.609), other indicators have difference but no statistical significance (P > 0.05). In Fig. 5 (b), there is no statistically significant difference of the knee joint extension in P2 in the biomechanical characteristics between the DS and NS (P > 0.05).Fig. 5Biomechanical characteristics of knee joint in supporting leg. (a) Knee Flexion (b) Knee Extension. JA (Unit: °), Joint Angle; JAV (Unit: rad·s-1), Joint Angular Velocity; JM (Unit: N·m·kg-1), Joint Moment; JP (Unit: W·kg-1), Joint Power; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDifferences in biomechanical characteristics of ankle joint in support legs.As shown in Fig. 6, there is no statistically significant difference of ankle joint extorsion in the biomechanical characteristics between the DS and NS in P1 (P > 0.05).Fig. 6Biomechanical characteristics of ankle joint extorsion in supporting leg. JAV (Unit: rad·s-1), Joint Angular Velocity; JM (Unit: N·m·kg-1), Joint Moment; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDifferences in biomechanical characteristics of attacking leg and foot and ground reaction force of support leg.As Shown in Fig. 7, at E2, the peak ground reaction force of the support leg is greater on the DS than on the NS (P = 0.031, Cohen’s d = 0.678). At E3, the peak linear velocity (P = 0.027, Cohen’s d = 0.593), peak translational energy (P = 0.033, Cohen’s d = 0.698) and linear momentum (P = 0.041, Cohen’s d = 0.576) of the attacking leg is greater on the DS than on the NS (P < 0.05), the indicators above have statistical significance when comparing the differences.Fig. 7Biomechanical characteristics of foot in attacking leg and differences in ground reaction force of supporting leg. LV (Unit: m·s-1), Linear Velocity; TE (Unit: J), Translational Energy; LM (Unit: Kg·m·s-1), Linear Momentum; GRF (Unit: N·kg-1), Ground Reaction Force; DS, Dominant Side; NS, Non Dominant Side. *P<0.05.Full size imageDiscussionThe purpose of this study is to explore whether there are differences in the biomechanical indicators when Taekwondo athletes complete SK using the DS and NS respectively. The main finding is that there are differences in peak flexion moment of the hip joint in the attacking leg; peak abduction angle of the hip joint in the support leg. Besides, differences are found in peak flexion moment and peak extension angular velocity of knee joint in the attacking leg; peak flexion moment of the knee joint in the support leg. It also appears that there are differences in the peak velocity, translational energy, and linear momentum of the attacking leg and foot, as well as the peak ground reaction force of the support leg. However, the aforementioned differences may affect the hitting effect and effective score of SK.In the P1, the lower limb joint movements of competitive Taekwondo athletes mainly include the flexion and abduction of the hip joint, and the flexion of the knee joint of the attacking leg; Flexion and abduction of the hip joint, and flexion of the knee joint of the support leg. During this process, the thigh of attacking leg is bent towards the anterior of the body, while swinging towards the lateral side of the body. At the same time, the calf is bent towards the back of the thigh to complete the “knee lifting and hip rotation” action. The athlete’s trunk lean towards the support leg, and the thigh of support leg is relatively close to the lateral side of the body. At the same time, the calf is bent towards the back of the thigh to squat. In the P2, the lower limb joint movements of competitive Taekwondo athletes mainly include the extension of the hip joint and the extension of the knee joint of the attacking leg; also the extension the hip joint of the support leg, extension of the knee joint, and extorsion of the ankle joint. During this process, the attacking thigh moves away from the front of the body and bends towards the back of the body, while the calf bends towards the front of the thigh to complete the thrust and extension; the support leg also completes thrust and extension, making the athlete to move towards the target as a whole. However, when competitive Taekwondo athletes complete the above movements, there are certain differences in the biomechanical characteristics of the lower limb joints on NS compared to the DS.In P1, the hip joint of the Taekwondo athlete’s support leg mainly performs abduction and flexion movements to control the tilt angle of the human trunk and maintain balance. However, this study reveals that the peak abduction angle of the hip joint of the support leg is significantly greater on the DS than on the NS (P < 0.05). In order to sustain dynamic stability and better complete the thrust and extension movements when striking, competitive Taekwondo athletes will reduce the angle between the upper body and the horizontal plane, which relatively increasing the angle of hip joint abduction in the support leg. This is consistent with the research results of Heo et al.9, which indicate that when kicking in NS, the hip joint of support leg can only achieve a relatively limited degree of abduction when preparing for the attacking leg’s thrust and extension. When a competitive athlete’s attacking leg is extended, the attacking leg generates a tilting moment relative to the center of gravity of the human body, and the inclination of the athlete’s upper body can generate a torque in the opposite direction to maintain balance24. During knee lifting phase of SK, athletes need to control their muscles to exert force so that their trunks do not tilt towards the attacking leg. However, insufficient abduction angle of the support legs means that the inclination angle of the athlete’s trunk decreases, resulting in a decrease in the arm of force and ultimately a decreased moment. The athlete needs to control more core muscle groups to exert force to ensure body to be stable enough, thereby consuming more physical energy and affecting the athlete to complete subsequent Kicking techniques. The instability of the body can also make it more likely for the opponent to discover flaws when the attacking leg is retracted, allowing the opponent to seize opportunities for attacking and scoring.During the P2, Taekwondo athletes’ attacking leg complete the process of thrust and extension, and the knee joints of lower limbs change from the flexion state to the extended state when hitting the target using SK. Our results indicate that the maximum angular velocity of the knee joint extension of the attacking leg is significantly greater on the DS than on the NS (P < 0.05)(Fig. 4). According to the calculation formula of linear velocity and angular velocity, when the radius is constant, the larger the angular velocity, the greater the extremity linear velocity. When the length of the calf is constant, increasing the knee joint extension angular velocity can increase the linear velocity of the foot when hitting the target, thereby increasing the impact effect of the SK, which is consistent with previous research6. In athlete specialized training and competition, the dominant attacking leg is usually used to complete the SK, while the NS is used relatively less frequently, this may result in a decrease in the non-dominant lower limb’s familiarity with movement techniques and neuromuscular control21.During P1, the thigh of attacking leg is bent towards the anterior of the body, while swinging towards the lateral side of the body. At the same time, the calf is bent towards the back of the thigh to complete the “knee lifting and hip rotation” action. Our results reveal that the maximum flexion moment of the hip joint in the attacking leg is significantly greater on the DS than on the NS (P < 0.05)(Fig. 2). In rigid body dynamics, when the moment of inertia is constant, the angular acceleration of joint rotation increases with the increase of moment25. This indicates that although there is no significant difference in the amplitude and peak angular velocity of hip joint flexion between the DS and NS (P > 0.05) when completing the same hip joint flexion movement, a larger joint angular acceleration will make the attacking leg on the DS take a shorter time to reach the peak flexion angular velocity and enter the Strike phase faster. Additionally, the peak flexion moment of the DS of the knee joint of the attacking leg is significantly greater than that of the NS (P< 0.05), which is consistent with the results of Taekwondo emphasizing the training of the DS as attacking leg. The agonist muscles that complete the flexion action of the hip and knee joints both include the rectus femoris, and the stronger the contraction ability of the rectus femoris, the stronger the flexion moment generated. This may be the reason why the DS of the hip knee joint can produce a larger extension moment19,26. Similar to the hip joint, the DS as attacking leg completes knee flexion faster, shortens the time of the entire SK movement, thereby reducing the opponent’s reaction time and making it easier to achieve effective strikes.When competitive Taekwondo athletes complete the SK, while lifting the knee and turning the hip, the support leg generally steps forward to shorten the distance between the athletes and the opponent, that is, the supporting leg is bent to build momentum and then pushed toward the ground, moving the body in the direction of attack. However, our study indicates that the maximum flexion moment on the DS of the knee joint of the support leg is significantly greater than that on the NS (P< 0.05). During this process, in addition to the muscle strength generated by the agonist and antagonistic muscles that control knee joint flexion, the downward acceleration of the body during squatting will lead to an increase in joint stress, resulting in an increase in knee joint moment27. This is because DS has stronger lower limb muscle strength, which allows for faster completion of stepping and jumping further, thereby quickly approaching and striking their opponents.Joint power refers to the ability of human joints to generate or absorb power during movement. Joint power usually reflects the working state of muscles and joints. As shown in Fig. 2, the peak extension power of the hip joint in the attacking leg on the DS is significantly greater than that on the NS (P< 0.05), indicating that the DS of the hip joint has a stronger ability to quickly generate energy to complete hip extension process28. Researches have shown that joint power is related to striking speed and muscle strength29, which is consistent with the results above, that is, the lower limb muscle strength on the DS is stronger.The linear velocity of the attacking leg is one of the most important indicators for evaluating Taekwondo kicking techniques. Our results reveal that the peak linear velocity of the attacking leg of foot on the DS is significantly higher than that on the NS (P< 0.05), which is consistent with the results of comparing the knee joint extension angular velocity on the DS with that on the NS. That is, in the thrust and extension movement, a smaller knee joint extension angular velocity on the NS will lead to the foot obtaining a smaller linear velocity, which will leave more space and time for the opponent to react, making the attack easier to be avoided or counterattacked. And a larger foot linear velocity will also result in the foot having greater translational energy and linear momentum when hitting the target, thereby having stronger impact effects and reaching the score threshold for the force sensor of the electronic protective equipment30.This study also finds that there is a significant difference (p < 0.05) in the peak vertical reaction force of the support leg between the DS and NS. During the P2, the ground reaction force is influenced by changes in body movement amplitude and transfer of center of gravity. Taekwondo athletes tend to tilt their upper body towards the horizontal direction after completing a lateral rotation when using their DS to complete a SK. This allows the target of the attacking leg to shift from the trunk to the head. Even though the movement may be more difficult, under the new regulations, the penalty score for electronic protective equipment will also be higher.Taekwondo athletes with lower limb laterality can pose a threat on the sports performance of SK movements. The NS may fail to attack the target due to long completion time and slow striking speed, it may also fail to trigger the effective scoring of the electronic protective gear sensor due to insufficient striking speed, thereby losing the initiative of the attack and affecting the attacking pattern of the competition. To minimize the occurrence of such situations, Taekwondo athletes can adopt training methods on NS leg, such as explosive strength training, unilateral resistance training, integrative neuromuscular training, rapid retraction compound training, balance training and core training to reduce limb laterality21,31.This study has certain limitations. Firstly, the technical movements of athletes are completed through co-muscle activity. Therefore, comparing the electromyographic characteristics of the muscles in the lower limbs of athletes during SK by NS or DS may clearly explain the mechanisms for laterality. Secondly, when athletes hit electronic protective equipment, the force value of the pressure sensor will be converted into a score value. Comparing the difference in the score value of the athlete’s DS and NS completing SK can better reflect the impact of laterality on sports performance.ConclusionTaekwondo athletes have a certain degree of laterality when performing SK in their lower limbs. The biomechanical indicators with laterality between DS and NS include: peak hip and knee joint flexion moment of attacking legs, peak hip joint extension power, peak knee joint extension angular velocity and foot line velocity, translational energy and linear momentum. The peak hip joint abduction angle, peak knee joint flexion moment, and peak ground reaction force of the support leg, Taekwondo athletes can reduce the asymmetry between their limbs through unilateral training, balance training, and other methods, so that they can achieve the same strike effect when using both sides of their limbs to complete SK. Enable athletes to break through their opponent’s defense by attacking target on both sides during the competition, exposing defensive gaps and creating favorable conditions for effective scoring.
Data availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
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Download referencesFundingor grants:This study was supported by the East Lake Scholars Sponsorship Program of Wuhan Sports University in China; Hubei Provincial Department of Education of China under Grant (D20194101); Natural Science Basic Research Program of Shaanxi Province under Grant (2022JQ-051); Science and Technology Team Foundation of Wuhan Sports University under Grant (21KT02); the 14th Five Year-Plan Advantageous and Characteristic Disciplines (Groups) of Colleges and Universities in Hubei Province under Grant (2021-05).Financial benefits to the authors:The authors report no financial benefits.Details of any previous presentation of the research:The authors report that the manuscript has not been previously published.Author informationAuthors and AffiliationsEngineering Research Center of Sports Health Intelligent Equipment of Hubei Province, Wuhan Sports University, Wuhan, 430079, P.R. ChinaRuifeng Huang, Yong Ma, Weitao Zheng & Mengyao JiaSpecialised Research Centre for High-Quality Development of Competitive Sports, Wuhan Sports University, Wuhan, 430079, P.R. ChinaRuifeng Huang, Yong Ma, Weitao Zheng & Mengyao JiaKey Laboratory of Sports Engineering of General Administration of Sports of China, Wuhan Sports University, Wuhan, 430079, P.R. ChinaRuifeng Huang, Yong Ma, Weitao Zheng & Mengyao JiaDepartment of Physical Education, Northwest Polytechnical University, Xi’an, 710072, P.R. ChinaShijie LinSchool of Education (Normal School), Dongguan University of Technology, Dongguan, 523808, P.R. ChinaLin LiuAuthorsRuifeng HuangView author publicationsYou can also search for this author inPubMed Google ScholarYong MaView author publicationsYou can also search for this author inPubMed Google ScholarShijie LinView author publicationsYou can also search for this author inPubMed Google ScholarWeitao ZhengView author publicationsYou can also search for this author inPubMed Google ScholarLin LiuView author publicationsYou can also search for this author inPubMed Google ScholarMengyao JiaView author publicationsYou can also search for this author inPubMed Google ScholarContributions Ruifeng Huang: conceptualization, investigation, methodology, acquisition and analysis of data, writing - original draft. Yong Ma methodology, acquisition and analysis of data. Shijie Lin: conceptualization, methodology, funding acquisition, writing - review & editing. Weitao Zheng: funding acquisition, supervision, writing - review. Lin Liu: investigation, acquisition of data. Mengyao Jia: analysis of data, investigation.Corresponding authorsCorrespondence to
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Reprints and permissionsAbout this articleCite this articleHuang, R., Ma, Y., Lin, S. et al. Research on the biomechanical laterality of athletes’ lower limbs during side kick in the competitive Taekwondo.
Sci Rep 15, 10180 (2025). https://doi.org/10.1038/s41598-025-94516-xDownload citationReceived: 27 May 2024Accepted: 14 March 2025Published: 25 March 2025DOI: https://doi.org/10.1038/s41598-025-94516-xShare this articleAnyone you share the following link with will be able to read this content:Get shareable linkSorry, a shareable link is not currently available for this article.Copy to clipboard
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KeywordsHip jointKnee jointAnkle jointVertical ground reaction forceElectronic protective equipment