Search

Conventional IoT wearable sensor Taekwondo motion image recognition model mainly uses Anchor fixed proportion whole body target anchor frame to extract recognition features, which is vulnerable to dynamic noise, resulting in low displacement recognition rate of motion image. Therefore, a new IoT wearable sensor Taekwondo motion image recognition model needs to be designed based on hybrid neural network algorithm. That is, the wearable sensor Taekwondo motion image features are extracted, and the hybrid neural network algorithm is used to generate the optimization model of the wearable sensor Taekwondo motion image recognition of the Internet of Things, so as to achieve effective recognition of Taekwondo motion images. The experimental results show that the designed wearable sensor of the Internet of Things based on the hybrid neural network algorithm has a high recognition rate of the motion image displacement of the Taekwondo motion image recognition model, which proves that the designed Taekwondo motion image recognition model has good recognition effect, reliability, and certain application value, and has made certain contributions to optimizing the Taekwondo movement. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the effects of acute caffeine supplementation on physical performance and perceived exertion during taekwondo-specific tasks in male and female athletes with varying expertise. In a double-blinded, randomized, placebo-controlled crossover study design, 52 young athletes from elite (n = 32; 16 males and 16 females) and sub-elite competitive level (n = 20; 10 males and 10 females) participated. Athletes performed taekwondo-specific tasks including the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10 s) and multi-bout FSKT (FSKT-multi) under the following conditions: (1) Caffeine (CAF; 3 mg kg−1), placebo (PLA), and no supplement control (CON). Session rating of perceived exertion (s-RPE) was determined after the tests. Findings show that regardless of condition, males performed better than females (p < 0.05) and elite athletes had superior performance compared to their sub-elite counterparts (p < 0.05). For the TSAT (p < 0.001), FSKT-10s (p < 0.001), and FSKT-multi (p < 0.001), CAF enhanced performance in elite female athletes compared to sub-elite females. Likewise, CAF ingestion resulted in superior performance in elite males compared to sub-elite males for FSKT-10s (p = 0.003) and FSKT-multi (p < 0.01). The ergogenic potential of CAF during taekwondo-specific tasks appears to be related to a competitive level, with greater benefits in elite than sub-elite athletes. [ABSTRACT FROM AUTHOR]

Transcranial Direct Current Stimulation (tDCS) is a growing empirical approach to improve athletic performance. Some recent studies have investigated the effects of transcutaneous spinal direct current stimulation (tsDCS) on the motor performance such as reaction time. TDCS and tsDCS can lead to alteration of the spontaneous neural activity, and the membrane potentials of motor neurons in cerebral cortex and spinal interneurons, respectively. Given the paucity of experimental studies on the non-invasive brain stimulation in the field of sports neuroscience, especially martial sports, the present study aimed at investigating the effects of neurostimulation in potentiating the motor and cognitive functions in experienced taekwondo practitioners. The study sample included 15 experienced male taekwondo players who received real or sham direct current stimulation on the primary motor cortex (M1) and the lumbar spinal segment (T12-L2) over two sessions, 72 h apart. Next, the performance of the participants was evaluated through a simulation of taekwondo exercise directly after the sham and real sessions. Moreover, a cognitive platform (CBS: Cambridge Brain Science) was used to investigate the participants' cognitive profile in each instance. Unlike sham stimulation, real tDCS was associated with improved selective attention and reaction time in both in the simulated task performance and cognitive examination. The concurrent cortical and trans-spinal tDCS was found to improve selective attention (31% performance improvement) (P < 0.0001) [EFFECT SIZE; 1.84]. and reduce reaction time (4.7% performance improvement) (P < 0.0001) [EFFECT SIZE; 0.02]. Meanwhile, the intervention failed to leave a significant change in cognitive functions evaluated through CBS (P > 0.05). As informed by our results, the present dual-mode neurostimulation could improve motor functions potentially through the effect of tsDCS over the spinal interneurons and tDCS over the primary motor cortex. Likewise, our findings suggested an improved performance in simulated taekwondo task after real- but not sham-stimulation. This study paves the way for designing neurostimulation protocols to improve the performance of professional athletes, namely martial art practitioners, including their accuracy and velocity of reactions. Such positive effects of neuostimulation in athletic performance as demonstrated in this research and similar reports are expected to enhance the athletes' success in professional competitions. [ABSTRACT FROM AUTHOR]

The anterior cruciate ligament (ACL) is part of the knee joint injured during taekwondo kicking. However, few studies have investigated the ACL injury mechanism and its inherent risk factors. In this study, we compared the knee joint kinematics in the pivoting leg during eight typical taekwondo kicks (back, roundhouse, turning-back, hook, side, push, axe, and front kicks) to investigate the possible risk of ACL injury. Standard inverse dynamics analyses were used to calculate axial tibial rotation and knee joint varus-valgus moment using a musculoskeletal model of the lower extremity and a motion analysis system with six high-speed digital cameras and a force plate. The maximum values of internal tibial rotation and valgus moment in the pivot leg were investigated. In addition, the time interval when the internal rotation and/or valgus moment exceeded the upper limit of the safe region during the kicking was analyzed. The results revealed that most kicks had time intervals of excessive amounts of internal tibial rotation and/or knee valgus moment, which are related to the risk of ACL injury. Moreover, one particular kicking motion, the hook kick, has a relatively high ACL injury risk in the pivot leg compared to other kicking motions. We suggest that athletes and coaches be aware of these risky kicks. [ABSTRACT FROM AUTHOR]

Competitive taekwondo composes a high stress situation leading to an increase in the stress hormone cortisol. Little is known about cortisol’s relation to outcome (winning vs. losing) and performance in taekwondo. Therefore, the aim of the study was to investigate cortisol relation to outcome, performance and whether cortisol can predict performance during a competition. Twenty taekwondo combatants (13 males; Mage = 15) provided four salivary samples (C1: 30 min prior, C2: during, C3: after, and C4: 30 min after competition) during an international competition. Total points made in the two rounds during their first fight were used as a performance indicator. Results show no difference in cortisol between winners and losers, before or after competition. However, a negative correlation between performance and C1 as well as C4 was detected. Unexpected, a positive correlation between cortisol during the competition (C2) and performance was identified. A stepwise multiple regression analyses showed that C2 predicted 25.5% of the performance variance. Even if the sample size is relatively small due to the field experimental setting, some conclusions can be drawn to motivate future research. Potentially, in taekwondo it seems advantageous for performance to have higher levels of stress as indicated by cortisol during a competition, whereas particularly before the competition, sport psychological interventions should be provided to combatants to reduce their psychophysiological stress level. [ABSTRACT FROM AUTHOR]

Background: Progressive specific taekwondo test (PSTT) was designed to evaluate aerobic indicators and maximum frequency kick (FKMAX) in taekwondo athletes. Both can be used as specific aerobic power variables to estimate maximum oxygen uptake (VO2MAX).Aim: To determine a linear regression equation to estimate the VO2MAX during PSTT in taekwondo athletes.Methods: Twenty-two taekwondo athletes performed a PSTT. Oxygen consumption was measured and the equations to estimate VO2MAX were established by multiple linear regression. Regression coefficient (R), coefficient of determination (R2), and standard error of estimate (SEE) were stablished and p < 0.05 was considered.Results: Two significant regression equations were obtained: VO2MAX absolute (L.min−1) = 7.230-0.029 (heart rate deflection point) + 0.048 (FKMAX), with R 0.616, R2 0.379, and SEE = 0.428; and VO2MAX relative (mL.kg−1.min−1) = 28.946 + 0.761 (FKMAX)—0.030 (height), with R = 0.622, R2 = 0.387, and SEE = 4.665Conclusions: Significant but moderate multiple regression coefficients to predict absolute and relative VO2MAX were found. The SEE observed suggests that more control of the actions during the test (i.e., control of the kick speed or its impact and standardization of step intensity) must be established. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to analyze the effects of Taekwondo match on blood and salivary lactate concentration, and their correlations, pre- and post-Taekwondo matches.Methods: For that eleven Taekwondo fighters (18 ± 3.6 years old, 59.18 ± 14.2 kg, 1.61 ± 0.1 cm, and 70.81 ± 97.4 months of practice) were enrolled. An experimental study with pre- and post-match measures was conduct were blood and salivary lactate measured, as well as vertical height and rating of perceived exertion. For data analysis Student’s t test, Pearson’s coefficient and linear regressions were applied using SPSS software version 22.0 and statistical significance was set in 5%.Results: Blood and salivary lactate measures changed significantly from PRE to POST (p = 0.001 and p = 0.04, respectively) with large and moderate effects, respectively. Correlations between lactate measures did not show significance (r = 0.35; p = 0.39). Otherwise, POST values showed moderate significant correlations (r = 0.61; p = 0.04). Additionally, linear regressions indicated that POST blood lactate concentrations can explain only 37.8% of POST salivary lactate concentrations (p = 0.04).Conclusion: To conclude, blood and salivary lactate responses do not present similar responses for TKD athletes after combat simulation. [ABSTRACT FROM AUTHOR]

Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran. Behnam Keshtkarhesamabadi was incorrectly affiliated with 'Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran'. [Extracted from the article]

Purpose: The purpose of this study was to compare the gender differences in isokinetic hamstring to quadriceps ( H/ Q) and hip abductor to adductor (AB/AD) strength ratios at different angular velocities in collegiate taekwondo athletes. Methods: Thirty collegiate taekwondo athletes (15 females and 15 males) participated in this study. Maximal isokinetic hamstring and quadriceps strengths were measured at different angular velocity (60° s, 120° s, and 240° s) with isokinetic dynamometer (Cybex 770, USA). They also performed five isokinetic hip abductor and adductor contractions at 30° s, and 60° s on a following day. Results: Female athletes showed significantly lower in H/ Q peak torque ratios than male athletes at 60° s (right and left, p < 0.05) and 120° s (right and left, p < 0.05). This difference was disappeared at high angular velocity (240° s) when female athletes significantly increased the H/ Q peak torque ratio as angular velocity increased (right and left, p < 0.05). However, there were no significant differences in hip AB/AD peak torque ratios between male and female. Conclusions: This preliminary study revealed that female taekwondo athletes show lower H/ Q peak torque ratio than male athletes at slow angular velocity. The previous studies suggest that lower H/ Q peak torque ratio could increase the potential risk of lower limb injuries especially female TKD athletes. Therefore, applications of additional training specially designed for strengthening hamstring muscles are recommended in clinical setting. [ABSTRACT FROM AUTHOR]

Purpose: To determine if there is a home advantage effect in combat sports (boxing, fencing, judo, taekwondo and wrestling) in the Olympic Games during the period between 1996 and 2012. Methods: This study analyzed the performance of United States of America, Australia, Greece, China and Great-Britain in this period, considering only boxing, fencing, judo, taekwondo and wrestling. Relative frequency was calculated considering number of medals won by each country as a percentage of the total number of medals disputed in these sports. A multilevel mixed-effects Poisson regression was used to estimate the incidence rate ratio (IRR) and 95 % confidence intervals (95 % CI) for the association of factor of interest as hosting country and country. In multilevel analyses, total number of medals disputed in each sport was included as the exposure in the models. As athletes in each sport changed over time, they were included as random parameters. All significance tests were 2-tailed, and p values less than 0.05 were considered statistically significant. Results: There was a home advantage effect for total number of medals [IRR = 1.97 (1.38-2.80); p < 0.001], gold [IRR = 2.62 (1.45-4.73), p = 0.001] and silver medals [IRR = 2.13 (1.09-4.17); p = 0.027] adjusted for the total number of medals disputed in each situation, country and sport. However, there was no effect for bronze medals [IRR = 1.40 (0.78-2.51); p = 0.267]. Conclusion: This study provided evidence for the home advantage effect in combat sports during the Olympic Games disputed between 1996 and 2012 for total number of medals, gold and silver medals, doubling the quantity won when competing at home. [ABSTRACT FROM AUTHOR]

This paper finally aims to make the public confident, fair and objective Taekwondo evaluation environment through development of publically certified remote Taekwondo Dan(Poom) promotion evaluation platform and, further vitalize Taekwondo and arrange the base for popularization and distribution of remote Taekwondo Poomsae promotion evaluation system. For this, this paper proposed the remote Poomsae evaluation system which may judge and evaluate the accuracy of motion comparing Taekwondo Poomsae motion of the evaluator to that of black belt player using the motion recognition technology which may recognize Taekwondo Poomsae motion through the trace of certain joint regions. In addition, the researcher investigated the accuracy of each algorithm for the date of relatively simple motions trained using the various motion recognition technologies. Also, the final establishment platform was proposed based on the system configuration, module architecture and the entire process according to the remote Taekwondo Poomsae evaluation platform to be implemented in future. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate energy system contributions and energy costs in combat situations. The sample consisted of 10 male taekwondo athletes (age: 21 ± 6 years old; height: 176.2 ± 5.3 cm; body mass: 67.2 ± 8.9 kg) who compete at the national or international level. To estimate the energy contributions, and total energy cost of the fights, athletes performed a simulated competition consisting of three 2 min rounds with a 1 min recovery between each round. The combats were filmed to quantify the actual time spent fighting in each round. The contribution of the aerobic ( W), anaerobic alactic ( W), and anaerobic lactic $$ (W_{ [{\rm La}^-]}) $$ energy systems was estimated through the measurement of oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the change in blood lactate concentration in each round, respectively. The mean ratio of high intensity actions to moments of low intensity (steps and pauses) was ~1:7. The W, W and $$ (W_{ [{\rm La}^-]}) $$ system contributions were estimated as 120 ± 22 kJ (66 ± 6%), 54 ± 21 kJ (30 ± 6%), 8.5 kJ (4 ± 2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity actions). [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of an official taekwondo competition (three 1-min rounds with a 1-min recovery in-between) on heart rate (HR), salivary alpha-amylase (sAA), and salivary-free cortisol (sC) in children. Parental consent was obtained for 12 young (10.4 ± 0.2 years) male taekwondo athletes. Saliva sample were collected 15 min before and 1 min after an official taekwondo competition, and at 30, 60, and 90 min of the recovery period. To evaluate the exercise intensity during the competition, HR was measured and expressed as a percentage of individuals HR. Athletes spent 78% of the time working at HR > 90% HR, with significant increases from round 1 to round 2 and 3. Peak sAA observed at the end of the match (169.6 ± 47.0 U/mL) was different ( P = 0.0001) from the other samplings (pre-competition 55.0 ± 14.0 U/mL, 30-min recovery 80.4 ± 17.7 U/mL, 60-min recovery 50.5 ± 7.6 U/ml; 90-min recovery 53.2 ± 9.6 U/mL). Peak sC values observed at 30-min recovery (17.9 ± 3.5 nmol/L) were different ( P < 0.0001) from pre-competition (5.6 ± 0.9 nmol/L), post-competition (9.0 ± 2.0 nmol/L), 60-min recovery (10.3 ± 2.6 nmol/L) and 90-min recovery (4.2 ± 0.8 nmol/L) values. These findings confirm that taekwondo competitions pose a high stress on young athletes. The different sAA and sC reactions in response to the physical stressor mirror the faster reactivity of the sympathetic-adrenomedullary system relatively to the hypothalamic-pituitary-adrenocortical system, respectively. This experimental paradigm might represent a useful model for further research on the effects of various stressors (i.e., training and competition) in taekwondo athletes. [ABSTRACT FROM AUTHOR]

This study analyzes the performance of knee extension and flexion of Taekwondo and Kickboxing athletes. The power values were extracted through electromyography obtained by an isokinetic dynamometer at 60° per second. These values are resulted from the square of the electromyography signal. The analysis of kick power was made using a modified wavelet algorithm considering values with 95% significance. Both groups presented equivalent power and torque capacity with different training times and experience, on the other hand, the wavelet analysis showed better results in muscular recruitment performance in athletes with more experience, in other words, power is not only performance but also power plus recruitment produces better results. This study uniquely showed that muscular enhancement capacity is not only related to the power capacity of contraction but also to motor coordination. [ABSTRACT FROM AUTHOR]

This article outlines the results of a grounded-theory, phenomenological study about the impact of the martial arts on the process of family development. Thirty-two couples and families with at least four months of martial arts study experience were interviewed to identify data and data themes about how the martial arts enhanced family development. Themes identified were self-defense, self-confidence, physical vitality, concentration, respect, friendship, moral development, spirit, training for life, grades, respect for life, and the importance of the martial arts instructor. [ABSTRACT FROM AUTHOR]

The original version of this article unfortunately contained a mistake in text under “Subject” section. The text portions masked for peer review were erroneously overlooked during the later stage “[country deleted to maintain the integrity of the review process]” and “[organization deleted to maintain the integrity of the review process]” should be replaced with “German” and “Bundesinstitut für Sportwissenschaft” respectively. [ABSTRACT FROM AUTHOR]