This research aimed to propose a new methodological approach for analyzing relative age effect (RAE) in different sports or samples named \"Relative age effect overall scale\" (RAEOS). The sample consisted of 1455 male and female young athletes who competed in four different sports (basketball, n = 159; handball, n = 215; swimming, n = 981; taekwondo, n = 100) at the Youth Olympic Games (YOG) in Buenos Aires in 2018. To construct the new model, the sample was classified into four unified quartiles of a specific range depending on the sport (swimming: 48-month range, taekwondo: 24-month range, and basketball and handball: 36-month range). Expected and observed frequencies for each sport, the winners/all athletes, and differences between team and individual sports were analyzed using a non-parametric Chi-square test. The obtained results confirm the existence of the RAE in all four analyzed sports (p > 0.01) in a sample of all participants and the sample of gold medalists. Differences between team and individual sports in the analyzed sample have also been found. The proposed methodological approach (RAEOS) is a simple and applicable tool that provides opportunities for comparison and analysis of different sports and competition formats, as well as improvement of the sports talent system in the context of RAE issues. It is suggested to the sports decision-makers to improve the YOG qualification and competition system to enable fairer competition and reduce the influence of RAE on the performance and development of young athletes.

TaeKwonDo (TKD) is a worldwide sport in both competitive among athletes and physical exercise among the public scenarios. Measuring TKD kicks have been studied a lot in a laboratory setting but rarely in a free-living situation. Machine learning algorithm combined with accelerometer data was used to study some martial art styles, e.g., Chinese KungFu but little in TKD. The purpose of this study was to discover a method to recognize different kicking techniques in TKD. A total of 20 participants (35 % male) were recruited to perform front kick, roundhouse kick, side kick and back kick 6 times on each side with three accelerometers wore on waist, right ankle and left ankle. SVM and decision tree were used to analyze data and classify kicking movements. The usage of different combination of accelerometers were also compared. The result showed that using accelerometers on waist and both ankles, on waist and only right ankle, on only waist and combined with SVM model could have at least 0.96 accuracy of classification, while decision tree had the accuracies around 0.8. It was concluded that using SVM model on only waist data is the optimal choice because of the high accuracy and less accelerometers used.

Objective: The purpose of this study is to analyze the inherent relationship between the score values and the biomechanical characteristics of the forward kicking motion, we aim to identify the fundamental variables influencing the score values of the forward kicking motion and establish the key biomechanical factors that effectively trigger scoring in the forward kicking motion. Methods: The DaeDo electronic scoring system was used with the Vicon optical motion capture system and the Kistler 3D force platform to obtain kinematic and kinetic variables of the front roundhouse kick motion. Linear bivariate correlation analysis and principal component analysis were used to analyze the associations between kinematic, kinetic variables, and scoring values, and summarize key biomechanical factors for effectively scoring. Results: The peak ankle plantar flexion angle and knee extension torque of the kicking leg showed a significant negative correlation with scoring values (r < 0, p < 0.05), while other variables showed no statistical significance. The peak knee flexion angle and hip extension angular velocity of the supporting leg showed a significant positive correlation with scoring values (r > 0, p < 0.01), while the peak ankle plantar flexion torque showed a significant negative correlation with scoring values (r < 0, p < 0.05), and other variables showed no statistically significant correlation. The absolute values of eigenvectors of the first and second principal components, which included hip angular velocity, ankle angle, knee torque, and hip torque, were relatively large, indicating their strong influence on effective scoring triggering. Conclusion: Maintaining ankle dorsiflexion and a larger knee flexion angle in the kicking leg is favorable for triggering scoring. Higher knee flexion angle and hip extension angular velocity in the supporting leg are also advantageous for triggering scoring. \"Body posture\" and \"Strength\" are key factors that effectively trigger scoring.

BACKGROUND: Researchers have investigated the physical and psychosocial advantages of Taekwondo for older adults. However, prior studies of Taekwondo\'s impact on physical function and psychological well-being in this demographic have produced inconsistent findings. Thus, this systematic review aimed to assess how Taekwondo practice affects the physical function and psychological well-being of older adults.
METHODS: We systematically searched PubMed, EMBASE, CINAHL, SPORTDiscus, Scopus, Korea Education and Research Information Service, Korean Studies Information Service System, Korean National Assembly Library, Research Information Sharing Service, National Digital Science Library, and China National Knowledge Infrastructure from their inception to December 2023. Two reviewers independently selected and extracted data from each study. We calculated effect sizes using a random-effects model with a 95 % confidence interval (CI) and evaluated study quality using the Physiotherapy Evidence Database scale.
RESULTS: This review included ten studies with 227 participants aged 66.1-73.6 years. The meta-analysis revealed significant enhancements in cognitive function [Korean Version of Mini-Mental State Examination, standard mean difference (SMD) = 0.700, 95 % CI (0.364-1.037), I2 = 0 %, p < .001], blood indicators [β-amyloid, SMD = 0.613, 95 % CI (0.103-1.123), I2 = 34.920 %, p < .05; brain-derived neurotrophic factor, SMD = 0.566, 95 % CI (0.166-0.966), I2 = 0 %, p < .01; high-density lipoprotein cholesterol, SMD = 0.677, 95 % CI (0.357-0.966), I2 = 0 %, p < .001; low-density lipoprotein cholesterol, SMD = 0.809, 95 % CI (0.376-1.242), I2 = 42.621 %, p < .001; and total cholesterol, SMD = 0.979, 95 % CI (0.603-1.356), I2 = 22.221 %, p < .001], and physical function [lean body mass, SMD = 0.465, 95 % CI (0.109-0.821), I2 = 0 %, p < .05, and handgrip strength, SMD = 0.929, 95 % CI (0.194-1.663), I2 = 48.217 %, p < .05].
CONCLUSIONS: This meta-analysis indicates that Taekwondo training is a beneficial therapy with protective effects on cognitive function, physical function, and body composition in older adults. These findings highlight its potential significance in cognitive rehabilitation and physiological health promotion among this demographic population.

BACKGROUND: Physical exercise can take on a multivariate form, including combat sports, specifically Taekwondo, a Korean sport characterized by strikes involving the hands and feet. This sport has been gaining popularity worldwide in recent years and is being practiced by diverse populations, including the older women.
OBJECTIVE: This study aimed to investigate the effects of Taekwondo training on self-esteem and body image in older women with low bone mineral density (BMD).
METHODS: This is an experimental research with a two-group design, where assessments were conducted pre- and post during a 12-week intervention period. The sample consisted of 27 inexperienced older women in taekwondo practice, aged between 60 and 70 years, randomly distributed into the experimental group (n=14) and Control Group (n=13). BMD, self-esteem, and body image were assessed. For the evaluation of self-esteem, the Rosenberg Self-Esteem Scale (RSES) was utilized. For the evaluation of body images, the body image questionnaire was administered.
RESULTS: The results showed that the practice of taekwondo improved (p<0.001) body image in the variables, including physical condition, body skills, and health, while the variable appearance showed no difference (p=0.581).
CONCLUSIONS: The results of this experimental study indicate an improvement in the self-esteem and body image of older individuals practicing Taekwondo.

BACKGROUND: Purpose In this study, the purpose of this study is to identify the determinants of winning and losing in taekwondo by applying decision tree analysis, one of the data mining techniques, based on the 2022 World taekwondo championships women\'s competition.
METHODS: 272 women\'s games in the taekwondo championships in Guadalajara held by the WT in 2022 were used. For data processing, an independent sample t-test was performed for differences in game content variables according to the win/lose group, and a decision tree analysis was performed to confirm game content variables affecting the win/lose group. To check the predictive power of the model, classification accuracy, standard error, and misclassification estimates were calculated. All statistical significance levels were set at 0.05.
RESULTS: First, it was found that there was no statistically significant difference only in body attack (attempt) and number of kicking variables according to the winning and losing groups(p > .05), and there were differences in all other game content variables(p < .05). Second, as a result of conducting a decision tree analysis to confirm the determinants of winning and losing in taekwondo sparring, winning situation, tie situation, and number of kicks were identified as important variables.
CONCLUSIONS: The World taekwondo championships are analyzed in the currently changed taekwondo competition rules to identify important factors, and at the same time, based on this, data-based coaching is expected to improve performance.

Taekwondo has evolved from a traditional martial art into an official Olympic sport. This study introduces a novel action recognition model tailored for Taekwondo unit actions, utilizing joint-motion data acquired via wearable inertial measurement unit (IMU) sensors. The utilization of IMU sensor-measured motion data facilitates the capture of the intricate and rapid movements characteristic of Taekwondo techniques. The model, underpinned by a conventional convolutional neural network (CNN)-based image classification framework, synthesizes action images to represent individual Taekwondo unit actions. These action images are generated by mapping joint-motion profiles onto the RGB color space, thus encapsulating the motion dynamics of a single unit action within a solitary image. To further refine the representation of rapid movements within these images, a time-warping technique was applied, adjusting motion profiles in relation to the velocity of the action. The effectiveness of the proposed model was assessed using a dataset compiled from 40 Taekwondo experts, yielding remarkable outcomes: an accuracy of 0.998, a precision of 0.983, a recall of 0.982, and an F1 score of 0.982. These results underscore this time-warping technique\'s contribution to enhancing feature representation, as well as the proposed method\'s scalability and effectiveness in recognizing Taekwondo unit actions.

Background and Objective: The accurate prediction of strength development relies on identifying the most appropriate measurement methods. This study compared diverse strength measurement techniques to assess their effectiveness in predicting strength development. Participants were taekwondo athletes competing at the red-black belt level or above. Methods: Technical striking forces (palding, dollyeo chagi, dwit chagi, and yeop chagi) were measured using a Herman Digital Trainer fixed to a striking stand. Quadriceps and hamstring strength were assessed with a Lafayette force measuring device. Explosive leg strength was evaluated through a standing long jump test, normalized for leg length. The Pearson correlation coefficient was used to examine relationships between measurement methods. Results: The standing long jump test showed no significant correlation with other strength assessments. A moderate positive correlation was found between Herman digital trainer measurements and Lafayette digital hand-held dynamometer results. A high positive correlation (r = 0.736, p < 0.001) emerged between hamstring strength and palding chagi technical strike force results. Technical strike kicks showed a significant positive correlation with each other and, also, a right foot-left foot correlation was observed. Conclusions: It was concluded that the standing long jump test, which was shown as one of the explosive leg strength measurement methods in field studies as an alternative to laboratory tests, did not correlate with other strength tests; therefore, this test is weak and insufficient to predict strength skills in taekwondo. In addition, this study showed that the hamstring muscle was more predictive in the measurement of technical strength. In future studies, it might be more useful to measure hamstring muscle strength or technical kick strength instead of a standing long jump field test.

To compare the muscular characteristics of \"hit\" and \"miss\" actions in roundhouse kicks among taekwondo athletes, and explore the similarities, differences, and implications for training, motion tests were conducted on ten taekwondo athletes using Noraxon32 and VICON. The results showed no significant differences (p > 0.05) in integrated electromyography (EMG) during the initiation and kicking phases between \"miss\" and \"hit\" actions. However, during the retraction phase, significant differences (p < 0.05) were observed in the left rectus femoris, left peroneus longus, right biceps femoris, right semitendinosus, and right tibialis anterior muscles. The tibialis anterior muscle of the swinging leg was activated first in the \"hit\" action, while the biceps femoris was activated first in the \"miss\" action. The supporting-side rectus femoris was activated first in the \"hit\" action, whereas it was the biceps femoris in the \"miss\" action. In both techniques, the gluteus maximus was the last muscle to be activated. The \"miss\" action had a longer cycle, and the duration of muscle work was longer than in the \"hit\" action. During the retraction phase of the front leg roundhouse kick, the muscles worked more than during the kicking phase, with the erector spinae and tibialis anterior being the core force-producing muscles in both techniques, characterized by high EMG values and long activation times. In the \"miss\" action, the thigh muscles drove the calf muscles, while the \"hit\" action exhibited the opposite pattern. \"Hit\" actions had a faster cycle compared to \"miss,\" with greater force generation in \"miss.\" The hip flexors and knee extensors of the kicking leg were the core force-producing muscles during the kicking process, determining the effectiveness and completion of the action.

One of the objectives of this study is to determine the effect of the eight-week fascial therapy program on flexibility, vertical jump, standing long jump, speed and anaerobic strength parameters in taekwondo athletes. Another aim of the research is to create a therapy protocol that can be used in athletes related to performance development through the relaxation of the fascial system, which is considered an indicator of physical fitness and has numerous functions in the body. This study included 32 taekwondo players who were licensed, actively attending taekwondo training. In the study, two groups were formed as fascial therapy group (FTG) (n ​= ​16) and control group (CG) (n ​= ​16). After the groups were randomized, fascial relaxation techniques were applied to the fascial therapy group for eight weeks, up to twice a week, and for 30 ​min. According to the findings obtained as a result of the research, FTG ([-0.36 ​± ​0.17] seconds [s]) for the 20 ​m (m) Sprint (T2-T1) had a lower mean time than CG (0.00 ​± ​0.07) s, FTG (0.06 ​± ​1.95) for the Flamingo Balance Test (T2-T1) had a lower mean fall than CG (1.25 ​± ​1.13), FTG ([3.56 ​± ​2.37] centimeters [cm]) for the Sit & Reach Test (T2-T1) had a lower mean fall than CG ([-0.19 ​± ​1.28] cm), FTG ([5.75 ​± ​2.54] cm) had a higher jump distance than CG ([1.88 ​± ​8.11] cm) according to the results of Vertical Jump Test (T2-T1) and finally FTG ([9.13 ​± ​5.56] cm) had a longer distance than CG ([-0.31 ​± ​1.85] cm) according to the results of Standing Long Jump Test (T2-T1). The result of our study has shown that fascial techniques can be used safely by experienced physiotherapists and can be included in the training program. It is recommended that coaches of sports disciplines work with experienced physiotherapists on this subject and include fascial methods in their training programs.