Physical and physiological profiles of taekwondo athletes

Effects of Ischemic Preconditioning on Sport-Specific Performance in Highly Trained Taekwondo Athletes

Ischemic preconditioning (IPC), which involves episodes of blood flow restriction followed by reperfusion, has uncertain effects on athletes. Additionally, employing sports-specific tests that are highly familiar to athletes can enhance methodological rigor in determining IPC's effects on taekwondo performance. This study aimed to investigate IPC's influence on taekwondo athletes' performance through two studies. To induce occlusion in both studies, the cuff was inflated to an individualized occlusion pressure established for each athlete's lower limb, with four cycles of occlusion lasting five minutes each, alternated with five-minute reperfusion intervals. Both traditional frequentist statistics and Bayesian analysis were employed. In the first study, eleven high-level athletes were subjected to either IPC or a placebo (SHAM) procedure on both legs, followed by performing countermovement jumps (CMJs) and a specific taekwondo endurance test. However, no significant differences were observed in taekwondo endurance performance or CMJ between the IPC and SHAM conditions. The second study involved fourteen elite athletes who underwent the same IPC or SHAM conditions, performing CMJ and three bouts of the Multiple Frequency Speed of Kick test (FSKTmult) in three blocks, each separated by approximately thirty minutes. Again, the results indicated no significant differences in FSKTmult measures or CMJ performance between the two conditions. In conclusion, IPC did not significantly affect neuromuscular (in both studies), endurance (in the first study), or anaerobic (in the second study) performance in these taekwondo athletes.

Correlation analysis between biomechanical characteristics of lower extremities during front roundhouse kick in Taekwondo and effective scores of electronic protectors

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.

Warm-up music and low-dose caffeine enhance the activity profile and psychophysiological responses during simulated combat in female taekwondo athletes

To assess the effects of warm-up music and low dose (3 mg·kg-1) of caffeine (CAF) on female taekwondo athlete's activity profile and psychophysiological responses during simulated combat. In a double-blinded, randomized, crossover study, 16 female athletes participated in simulated combats under one control and 5 experimental conditions [i.e., CAF alone (CAF), placebo alone (PL), CAF with music (CAF + M), PL with music (PL + M), and no supplement with music (M)]. After warming-up, athletes rated their felt arousal (FAS). Mean (HRmean) and peak (HRpeak) heart rate values were determined for each combat. After fighting, athletes rated their perceived exertion (RPE), feeling scale (FS), FAS, and physical enjoyment (PACES). Time-motion and technical-tactical variables were analyzed. CAF + M induced shorter skip and pause time, while attack time increased compared to other conditions (p < 0.05). Moreover, CAF + M increased single attacks, combined attacks, counter-attacks (p < 0.001), and defensive actions (p < 0.05) than other conditions. HRmean and HRpeak were lower under CAF + M than other conditions (p < 0.05). Additionally, higher FAS post-combat, FS, and PACES were observed under CAF + M, while RPE was lower (except CAF condition) compared to the other conditions (p < 0.05.Using CAF with warm-up music may increase combat cadence and improve the psychological state in female athletes more effectively than either strategy alone.

A 5-Year Analysis of Age, Stature and Armspan in Mixed Martial Arts

Purpose: Athlete stature and armspan is anecdotally assumed to provide an advantage in mixed martial arts (MMA), despite an absence of supporting data. In contrast, winners of MMA bouts have been shown to be younger than bouts losers. Whilst absolute measurements of stature, armspan and armspan:stature scale (A:S) have been shown to not distinguish between winners and losers of MMA bouts, relative differences between competitors have not been analysed. This study aimed to analyse 5 years of athlete age and morphological data to replicate and expand previous studies to determine whether absolute and/or relative age and morphological variables effect winning and losing in MMA. Methods and Results: Bayes factor (BF>3) inferential analyses conducted on the cohort overall (n = 2,229 professional bouts), each year sampled and each individual body mass division found that only absolute (winners = 29.8 ± 4 years; losers = 30.7 ± 4.2 years) and relative age (winners = 0.82 ± 5.3 years younger than losers) differentiates between winners and losers across the whole cohort, in 4 of the 5 years, and in 4 of the 13 divisions sampled. Armspan appears to provide an advantage in heavyweight only (winners = 198.4 ± 6.6cm; losers = 196.1 ± 7.7cm), with greater A:S being a disadvantage (winners = 1.003 ± 0.022cm∙cm-1; losers = 1.010 ± 0.023 cm∙cm-1) in women's strawweight only. No variables had any effect on how bouts were won. Conclusions: These results confirm previous reports that the effect of athlete morphology is greatly overstated in MMA, appearing to be irrelevant in most divisions. Bout winners tend to be younger than losers, particularly in divisions displaying more diverse skill requirements.

The enhancement of explosive power contributes to the development of anaerobic capacity: A comparison of autoregulatory progressive resistance exercise and velocity-based resistance training

Objectives

Due to the character of the taekwondo, the adenosine triphosphate-phosphocreatine system provides the energy for each kick, the glycolytic system supports the repeated execution of kicks, and the aerobic system promotes recovery between these movements and the bout. Therefore, taekwondo athletes require high explosive power and anaerobic capacity in order to carry out sustained and powerful attacks. So, the purpose of this study is to compare the effects of APRE and VBRT on lower-limb explosive power and anaerobic capacity in college taekwondo players.

Methods

A total of 30 taekwondo players completed an 8-week training intervention with autoregulatory progressive resistance exercise (APRE; n = 15) and velocity-based resistance training (VBRT; n = 15). Testing included the one-repetition maximum squat, countermovement jump (CMJ), taekwondo anaerobic intermittent kick test (TAIKT), and 30-s Wingate anaerobic test (WAnT).

Results

(1) Intragroup comparisons revealed significant effects for one-repetition maximum squat, peak power of CMJ (CMJPP), relative peak power of CMJ (CMJRPP), and total number of TAIKT (TAIKTTN) in both the APRE and VBRT groups. The VBRT group exhibited small effect sizes for time at peak power of WAnT (WAnTPPT) and moderate effect sizes for peak power of WAnT (WAnTPP), relative peak power of WAnT (WAnTRPP), and fatigue index of TAIKT (TAIKTFI), whereas the APRE group exhibited small effect sizes for TAIKTFI. (2) Intergroup comparisons revealed no significant effects in any of the results. However, VBRT demonstrated a moderate advantage in WAnTPP and WAnTRPP, whereas APRE had a small advantage in CMJPP and CMJRPP.

Conclusions

These findings suggest that APRE improved explosive power (CMJPP and CMJRPP) more, whereas VBRT improved anaerobic power output (WAnTPP and WAnTRPP) more. Both methods were found to have similar effects in improving the anaerobic endurance (WAnTPPT and TAIKTTN) and fatigue index (power drop of WAnT and TAIKTFI).

A Comparison of Different Strength Measurement in Taekwondo: Herman Trainer, Manual Tester, and Standing Long Jump

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.

The effect of 8-week combined balance and plyometric on the dynamic balance and agility of female adolescent taekwondo athletes

OBJECTIVES

To investigate the effect of combined balance and plyometric training (PT) on the agility and dynamic balance of adolescent taekwondo athletes.

METHODS

Thirty female adolescent taekwondo players volunteered to participate and were randomly assigned to the combined balance training and PT (CT; n = 15) and PT (n = 15) groups. The CT group performed balance training combined with PT 3 times a week for 6 weeks (40 minutes of plyometrics and 20 minutes of balance training) while the PT group performed only PT for the same period (3 sets × 8-12 reps for each exercise). Both groups received the same routine technical taekwondo training.

RESULTS

Post-intervention assessments revealed that both groups significantly improved their dynamic posture stability index scores (DPSI; forward jump [F-DPSI] and lateral jump [L-DPSI]). However, participants in the CT group achieved notably superior outcomes in the F-DPSI and L-DPSI scores compared with those achieved by their PT counterparts. The center of pressure metrics exhibited improvements post-intervention, with scores of specific measures in the PT group surpassing those in the CT group. Additionally, the 5-0-5 test scores exhibited improvements post-intervention, with scores of specific measures in the PT group surpassing those in the CT group, and the TAST (Taekwondo Specific Agility Test) of the CT group and the PT changed significantly after the intervention.

CONCLUSION

An 8-week regimen that integrates balance and plyometric training effectively augments knee function and proprioception in adolescent Taekwondo athletes. This study underscores the potential benefits of a combined training approach, providing coaches and athletes with valuable insights into Taekwondo training.

Short intermittent taekwondo test to assess athlete's physiological and metabolic profile

BACKGROUND

The aim of this study was to assess the effectiveness of a new Short Intermittent Taekwondo Test (SITT) in 17 black belt athletes.

METHODS

Maximal oxygen uptake (V̇O2max), carbon dioxide production (V̇CO2), respiratory exchange ratio (RER), heart rate (HR), and blood lactate concentration [La]+ during treadmill cardiopulmonary exercise test (CPET) and SITT were compared. SITT started with 10 sec of all-out kicks, alternating legs, and progressively increasing 5 s on each stage until the 4th stage. After the 4th stage the participants performed 25 s of turning kicks (Dolleo chagi), on each stage until the last (10th stage). The passive recovery phase after the 4th and the 7th stage lasted 30 s.

RESULTS

V̇O2max and maximal HRmax were not significantly different (P=0.85 vs. P=0.76) between tests, while RER and [La]+ were significantly higher in SITT than in CPET (P=0.002 vs. P=0.001). No difference in RPE (P=0.84) was found. A significant positive correlation between two tests for V̇O2max and HRmax was found.

CONCLUSIONS

Our findings showed that SITT induces physiological responses like CPET suggesting that it can be used to assess aerobic power in national taekwondo athletes, thus helping coaches to select correctly training intensities and monitor athletes' aerobic performance along the training phases.

Cadet and Junior Performance Is Associated With Senior's World Championship and Olympics Achievement in Judo

Purpose: We determined whether cadet and junior Judo World Championship participation and medal achievement would predict senior performance at World Championship (WC) and Olympic Games (OG). Methods: We analyzed retrospectively a total of 7780 athletes who competed at the OG and WC in the cadet, junior, and senior between 2009 and 2021. Results: There was an increase in the probability of winning a medal in the senior category (WC and OG, and only WC) ranged from 4.3 to 4.5 for medal-winning cadets compared to non-medalists and this probability remained around 3.3-3.8 for medalists in the male and 5.3-5.4 for the female medalists in cadet WC. Moreover, the chance of winning a medal in the senior category (WC and OG) was 8.1-8.5 times greater for medalists when compared to non-medalists in the junior WC. In turn, the probability of winning a medal in the senior (WC) was 1.5-1.7 times greater for athletes who did not compete in the junior WC. In the OG, the probability of winning a medal was 3.5 greater times for medalists when compared to non-medalists at cadet and junior WC. Conclusion: Thus, being a cadet or junior WC medalist increases the probability of winning a senior WC or an Olympic medal.

Combat sport in the body composition of the elderly: A systematic review and meta-analysis study

OBJECTIVE

To analyze possible changes in body composition in elderly individuals with combat sports as an intervention.

METHODS

This study is characterized as a systematic review and meta-analysis. The PRISMA criteria were followed, and the study was registered in PROSPERO under the number CRD42023392613. The databases used were MEDLINE (via PubMed), Scopus, SPORTDiscus, Web of Science, and Science Direct. The risk of bias and methodological quality were assessed using Robins-I, Cochrane, and Testex tools.

RESULTS

Of the 126 publications found, 9 studies were included (5 controlled and randomized studies and 4 intervention studies). Of these studies, 6 provided data for the meta-analysis. A total of 126 publications were found and, the studies included in this systematic review had an average of 51 weeks, 3 times a week, and 50 min per session. In the results presented by the meta-analysis the variable body fat showed a reduction (SMD: -0.11; 95% CI: -0.99 to 0.09; p = 0.02; I2 = 0%).

CONCLUSION

Combat sports showed an improvement in the body composition of the elderly, with a reduction in the percentage of body fat.

Acute effects of plyometric-based conditioning activity and warm-up music stimuli on physical performance and affective state in male taekwondo athletes

Introduction

This study assesses the acute effects of combining a plyometric-based conditioning activity (CA) with different musical stimuli during warm-up on taekwondo (TKD) performance and related psychological aspects.

Methods

In a randomized cross-over study design, 16 male TKD athletes (age: 19.94 ± 1.12 years) performed the TKD-specific agility test (TSAT), frequency speed of kick test (FSKT-10s) and its multiple version (FSKT-mult) under 7 experimental and one control condition. For the experimental conditions, participants experienced varying combinations of music selection process [self-selected (SSM) vs. pre-selected (PSM)], and music tempo [fast (F) vs. slow (S)], within preferred (PG) and non-preferred (NPG) music genre; all in the presence of a plyometric based-CA. Athletes were instructed to rate their perceived exertion (RPE) after each test and their felt arousal (FAS), feeling scale (FS), and motivation after testing completion.

Results

Findings showed that combining a plyometric-based CA with SSMPG at both fast and slow tempo improved TSAT, FSK-10s, FSKT-mult, FAS, motivation, and RPE post-TSAT greater than the other conditions (all p < 0.05). Additionally, FSSMPG combined with CA improved FS, and RPE after both FSKT-10s and FSKT-mult better than the other conditions (all p < 0.05).

Conclusion

In conclusion, listening to fast self-selected music from a preferred genre in combination with a plyometric-based CA during warm-up setups an individualized warm-up strategy and serves to improve the subsequent specific performances and the related psychological aspects in TKD athletes.

Effects of high-intensity functional training on physical fitness and sport-specific performance among the athletes: A systematic review with meta-analysis

OBJECTIVE

This study aims to meta-analyze the impact of high-intensity functional training on athletes' physical fitness and sport-specific performance.

METHODS

A systematic search was conducted in five well-known academic databases (PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library) up to July 1, 2023. The literature screening criteria included: (1) studies involving healthy athletes, (2) a HIFT program, (3) an assessment of outcomes related to athletes' physical fitness or sport-specific performance, and (4) the inclusion of randomized controlled trials. The Physical Therapy Evidence Database (PEDro) scale was used to evaluate the quality of studies included in the meta-analysis.

RESULTS

13 medium- and high-quality studies met the inclusion criteria for the systematic review, involving 478 athletes aged between 10 and 24.5 years. The training showed a small to large effect size (ES = 0.414-3.351; all p < 0.05) in improving upper and lower body muscle strength, power, flexibility, and sport-specific performance.

CONCLUSION

High-intensity functional training effectively improves athletes' muscle strength, power, flexibility, and sport-specific performance but has no significant impact on endurance and agility. Future research is needed to explore the impact of high-intensity functional training on athletes' speed, balance, and technical and tactical performance parameters.

Examination of the effect of fascial therapy on some physical fitness parameters in taekwondo athletes

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.

Validity and reliability of a new hip flexor muscles flexibility assessment tool: The reactive hip flexor (RHF) test

BACKGROUND

The modified Thomas test is the most used and most reliable test to assess the hip flexors' flexibility. However it does not evaluate the interaction of both legs. The objective of this study is to propose a new assessment tool for hip flexor flexibility, the Reactive Hip Flexion (RHF) Test.

METHODS

An observational, intra-test, and test-retest study with repeated measures was carried out with the aim of assessing the validity and reliability of the RHF Test. The participants were males and females aged between 18 and 35 years old who had a training schedule of at least 2 days a week, without a musculoskeletal lower limb or lumbopelvic pathology. The reliability of the test was examined using the intraclass correlation coefficients (ICCs) by a two-way random model to establish inter-rater reliability and a two-way mixed model to assess intra-rater reliability. The precision was measured by the standard error of measurement (SEM). In addition, the minimum detectable change (MDC95%) was calculated.

RESULTS

Twenty-six participants (52 hips) (47% female) completed the study. No correlations were observed between anthropometric variables and RHF peak force or active knee extension (AKE) measurements. There was an excellent intra-rater and inter-rater ICC in the hip flexors' reactive peak force and the AKE measurements, with a low SEM.

CONCLUSIONS

This study demonstrated that the proposed RHF test technique is valid and reliable when used in healthy youth population.

Effects of caffeine consumption combined with listening to music during warm-up on taekwondo physical performance, perceived exertion and psychological aspects

The effects of caffeine (CAF) and music have been well documented when used separately, but their combined effects are not yet studied. Thus, the present study assessed the acute effects of combining a low dose of CAF with listening to music during warm-up on taekwondo physical performance, perceived exertion (RPE), and psychological responses during taekwondo-specific tasks in male elite athletes. In a double-blinded, randomized, placebo-controlled crossover study design, male taekwondo athletes (n = 16; age: 18.25 ± 0.75 years) performed the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10s) and the multiple version of FSKT (FSKT-mult) under the following conditions: 1) CAF without music (CAF+NoM), 2) placebo (PL) without music (PL+NoM), 3) CAF with music (CAF+M), 4) PL with music (PL+M), 5) no supplement with music (NoS+M) and no supplement without music (control). RPE, feeling scale (FS), felt arousal scale (FAS) and physical enjoyment (PACES) were determined after each test. Findings showed the CAF+M condition induced better performances than other conditions for TSAT, FSKT-10s, FSKT-mult, RPE, FAS and FS and PACES post FSKT-10s (all p<0.05). Moreover, CAF+M resulted in better responses than other conditions for PACES post TSAT (p<0.05) with the exception of CAF+NoM. Likewise, CAF+M condition induced better physical enjoyment than PL+NoM, NoS+M and PL+M conditions post FSKT-mult (p<0.05). Combining low dose of CAF with music during warm-up was an effective strategy that induced greater effects than their isolated use during taekwondo specific tasks.

Comparing the effects of traditional resistance training and functional training on the bio-motor capacities of female elite taekwondo athletes

BACKGROUND

The capabilities of the biomotors are essential to the success of the taekwondo athlete. This study aimed to compare eight weeks of functional training and traditional resistance on the bio-motor capacities of elite female taekwondo athletes.

METHODOLOGY

Seventeen elite taekwondo athletes (mean age = 21.7 years, mean height = 167.2 cm and mean weight = 60.8 kg) volunteered to participate in the study. They were randomly divided into two groups: functional training (FT) and traditional resistance training (TRT). Participants trained for 8 weeks, 3 sessions per week, for 75-90 min. Aerobic power, anaerobic power, speed, reaction time, agility, muscle power, dynamic balance, flexibility, upper and lower body muscle strength, core and upper body muscle endurance, and blood lactate level were measured before and after training programs.

RESULTS

Non-significant differences were observed in all indicators between the FT and TRT groups (P > 0.05). Both groups showed significant improvement in time-related outcomes except for fatigue and flexibility (P > 0.05). There was significant progress in both groups in aerobic power, muscle power, speed, agility, reaction time, lower body strength, upper body strength, dynamic balance of the right leg, and dynamic balance of the left leg indices from pre to post-tests. The FT group displayed significant improvement in peak power (P = 0.006) and mean power (P = 0.015) from pre- to post-test.

CONCLUSION

Both interventions improved most biomotor abilities in elite female taekwondo athletes. It should be noted that since muscle power is vital for taekwondo, therefore, it is recommended to include FT in the taekwondo workout program.

Time-motion analysis of taekwondo matches in the Tokyo 2020 Olympic Games

BACKGROUND

The aim of the present study was to determine the time-motion structure of high-level taekwondo matches during the Tokyo 2020 Olympic Games in relation to sex, match outcome, weight category and match round.

METHODS

Overall, 7007 actions were recorded during the analysis of 134 performances (67 rounds of 24 matches: four rounds of 16, eight quarterfinals, eight semifinals and four finals) in male and female flyweight (≤58 kg and ≤49 kg, respectively), and heavyweight categories (≥80 kg and ≥67 kg, respectively). The attack time (AT), number of AT (AN), skipping time (ST) and pause time (PT) were registered.

RESULTS

The AT/ST ratio was ~1:1.5. Male athletes performed significantly longer (P<0.001) sum PT than female athletes. Flyweight athletes differed significantly from their heavyweight counterparts by having longer (P<0.001) average and sum AT, greater (P<0.001) AN, higher (P<0.001) AT/ST ratio, shorter (P<0.001) average and sum ST, and lower (P<0.01) (AT+ST)/PT ratio. Rounds 2 and 3 had average PT significantly longer (P<0.01) than round 1. Round 3 had sum PT longer (P<0.001) and (AT+ST)/PT ratio lower than in round 1.

CONCLUSIONS

The rule changes and the implementation of the electronic score recording system had a major impact on the time-motion structure of combat by generating a considerably higher AT/ST ratio than in the past. The comparisons indicated that the structure of the combat is modulated by weight category and phase of the combat. In practice, coaches could develop sport-specific high-intensity interval training using the time-motion indexes of the present study as guidelines.

Effects of conditioning activity mode, rest interval and effort to pause ratio on post-activation performance enhancement in taekwondo: a randomized study

Introduction: The present study assessed the effects of conditioning activities, using different effort-to-pause ratios and rest intervals, on taekwondo physical performance. Methods: Twenty-one athletes (13 males and 8 females) (Mean ± SD; age = 20.4 ± 1.4 years) performed a control (CC) and twelve experimental conditions. Each condition contained a standard warm-up (i.e., CC: running at 9 km/h for 10 min) and conditioning activities comprising plyometrics P) or repeated high-intensity techniques (RT) using 1:6, 1:9 and self-selected rest (SSR) ratios, and two rest intervals (3 and 7 min). Athletes then performed a battery of fitness tests: countermovement jump (CMJ), taekwondo specific agility (TSAT), 10s and multiple frequency speed kick test (FSKT-10s and FSKT-mult, respectively). Results: All of the preloads provided higher performance outputs compared to the control trial (all p < 0.05). For CMJ, 1:6 ratio with 3 min induced lower values with RT compared to P (p = 0.037) and 1:9 ratio using 3 min induced higher values with RT compared to P (p = 0.027). Additionally, 1:6 ratio using 7 min induced higher values with RT compared to P (p = 0.016). For FSKT-10, 3 min using 1:6 induced higher values with P compared to RT, while RT induced higher values with 7 min using 1:6 ratio compared to P (both p < 0.001). Moreover, 3 min using 1:9 ratio induced higher values with P compared to RT (p = 0.034), while RT induced higher values with 1:9 ratio using 7 min compared to P (p < 0.001). Finally, 3 min using SSR ratio induced higher values with RT compared to P (p = 0.034). Conclusion: Plyometrics and RT activities improved performance with plyometrics requiring shorter rest interval to induce potentiation effects compared to RT, which required longer interval.

Repeated High-Intensity Technique Training and Repeated Sprint Training Elicit Similar Adjustment in Physiological Responses But Divergent Perceptual Responses and Combat-Related Performances in Adolescent Taekwondo Matches

PURPOSE

This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie, blood lactate), mean and peak heart rate, rating of perceived exertion, technical-tactical performance, and time-motion variables during simulated taekwondo combats.

METHODS

Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1] y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training.

RESULTS

Delta lactate and peak heart rate were attenuated following training (P < .001 and P = .03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P = .002). Time fighting and preparatory activities increased following training (P < .001), with higher values observed following RTT than RST (P < .001). Nonpreparatory time decreased after training (P < .001), with more pronounced reductions observed following RTT when compared to RST (P < .001). The number of single attacks decreased only following RST (P < .001), whereas combined attacks increased only after RTT training (P < .001).

CONCLUSIONS

Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat.

Caffeine and sport

Caffeine is a trimethylxanthine found in coffee and several other foods and beverages. Its stimulatory effects make it an interesting strategy to boost performance for athletic populations. Scientific evidence supports its efficacy to improve high-intensity endurance exercise, explosive and high-intensity efforts, resistance exercise, team sports and combat sports, though individual variation in the ergogenic response to caffeine exists. Supplementation can be taken in many forms including dissolved in water, via capsules, coffee, energy drinks and caffeinated gum; ingestion via capsules, dissolved in water or in caffeinated gum appear to be most effective. Variability in the exercise response following caffeine supplementation may be explained by genetic factors or habitual caffeine consumption. Caffeine is an excellent supplement for athletes looking to improve their exercise performance, though some consideration of side-effects and impact on sleep are warranted.

Energy System Contributions during Olympic Combat Sports: A Narrative Review

This narrative review focuses on the studies that estimate the energy systems' contributions during match simulations of striking (boxing, karate, and taekwondo), grappling (judo), and weapon-based (fencing) Olympic combat sports. The purpose is to provide insights into the metabolism of these athletes. In striking Olympic combat sports, the oxidative contribution varied from 62% (in karate and taekwondo) to 86% (in boxing), the ATP-PCr system contribution varied from 10% (in boxing) to 31% (in taekwondo), and the glycolytic contribution was between 3% (in the third round of taekwondo) and 21% (in karate). In grappling combat sports, only judo was studied, and for a 4 min match, the oxidative contribution was 79%, followed by 14% ATP-PCr system contribution and 7% contribution from the glycolytic system. In fencing, the only weapon-based Olympic combat sport, the oxidative contribution varied from 81% (in the first bout) to 90% (in the second bout), followed by 9% (bout 2) to 12% (bout 1) contribution from the ATP-PCr system, and 0.6% to 7% contribution from the glycolytic system during 3 × 3 min bouts of épée match simulation. Hence, Olympic combat sports are primarily powered by the oxidative system, but the key scoring actions are likely fueled by anaerobic pathways.

Effects of Strength Training on Physical Fitness of Olympic Combat Sports Athletes: A Systematic Review

This review aimed to identify the effects of strength training programs on the physical fitness of Olympic combat sports (OCS) athletes. The systematic review included peer-reviewed articles that incorporated interventions that included pre- and post-intervention physical fitness assessment. The search was performed in the SCOPUS, PubMed, and Web of Science databases between April and September 2022. PRISMA and the TESTEX checklist were used to select and assess the methodological quality of the studies. Twenty studies with 504 participants (428 males and 76 females) were included. Significant improvements were found in athletes' maximal dynamic and isometric strength, muscle power, flexibility, and balance. In addition, improvements in favor of the training groups in specific actions of judo, karate, fencing, and boxing were observed. In conclusion, interventions aimed at the development of muscle strength in OCS, specifically in judo, boxing, karate, wrestling, and fencing, proved to be beneficial at a physical fitness level, resulting in significant increases in favor of the training groups with OCS, which could be used by trainers and coaches to improve the physical performance of athletes.

Effects of Taekwondo Training on Growth Factors in Normal Korean Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The growth of children and adolescents is both an important health indicator and a major public health issue. Many recent studies have investigated the effects of taekwondo on growth factors, but no consensus has yet been reached. This meta-analysis aimed to determine the effects of taekwondo on the growth factors in children and adolescents (aged 8 to 16 years). Randomized controlled trials from PubMed, Web of Science, Cochrane Library, the Research Information Sharing Service, the Korea Citation Index, and the Korean-studies Information Service System were analyzed. The effect sizes (standardized mean differences, SMD) were calculated, the risk of bias and publication bias were assessed, and the effect size and subgroup analyses were pooled. We found that the taekwondo group had significantly higher levels of growth hormones (SMD 1.78, 95% confidence interval [CI] 0.98-2.58, and p < 0.001) and insulin-like growth factors (SMD 1.76, 95% CI 0.60-2.92, and p < 0.001) than the control group. For height, a medium effect size was observed (SMD 0.62, 95% CI -0.56-1.80, and p = 0.300), but the between-group difference was not significant. Thus, taekwondo had significant positive effects on the secretion of growth hormones and insulin-like growth factors in Korean children and adolescents. A longitudinal follow-up is necessary to determine the effect on height. This suggests that taekwondo can be recommended as an appropriate physical exercise for maintaining normal growth in children and adolescents.

A Systematic Review with Meta-Analysis on the Effects of Plyometric-Jump Training on the Physical Fitness of Combat Sport Athletes

We aimed to assess the athletic performance changes in combat sport athletes (CoSAs) after plyometric-jump training (PJT), compared to control conditions, through a systematic review with meta-analysis. Following PRISMA guidelines, three electronic databases were searched for includable articles, according to a PICOS approach. Using a random-effects model, Hedges' g effects sizes (ES) were calculated. Heterogeneity was assessed using the I² statistic, with values of <25%, 25-75%, and >75% representing low, moderate, and high levels of heterogeneity, respectively. Statistical significance was set at p ≤ 0.05. The certainty of evidence was assessed using the GRADE approach. Twelve eligible articles were identified for systematic review, seven of high quality and five of moderate quality, according to the PEDro scale. The studies recruited taekwondo, silat, wrestling, judo, fencing, and karate athletes (292 total participants), including specific-active and active controls. Most participants had a mean age of <18 years and were males (n = 225). Compared to the control, PJT programmes, involving 4-12 weeks and 2-3 sessions per week, induced small to moderate improvements (ES = 0.47 to 1.04) in athletes' maximal strength (e.g., 1RM squat), vertical jump height, change-of-direction speed, and specific performance (e.g., fencing movement velocity), although without meaningful effects on body mass, fat mass, and muscle mass (ES = 0.02 to -0.06). Most (7 of 8) outcomes attained low heterogeneity. The outcome-level GRADE analysis indicated a certainty of evidence from low to moderate. In conclusion, PJT, when compared to control conditions, may improve CoSA athletic performance.

A dual-mode neurostimulation approach to enhance athletic performance outcome in experienced taekwondo practitioners

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.

The investigation of isokinetic knee strength and injury risks of taekwondo and wrestling athletes

Taekwondo and wrestling are two different Olympic combat sports that need lower extremity strength in different ways. During the training process that lasts for many years, the harmony in the leg muscles may be dissimilar. This study aims to determine (1) the extension and flexion strength values of elite taekwondo and wrestling athletes with similar physical and demographic characteristics and (2) the muscle balances formed after long-term taekwondo and wrestling training. This study was conducted with the voluntary participation of 20 elite taekwondo and wrestling athletes (Avg. age 20.4±1.27 years; experience: 10.6±1.98 years; height 176.65±5.86 cm; weight 72.96±6, 96 kg; BMI 23.35±1.47 kg/m2). Following the determination of the demographic and physical characteristics of the athletes, their isokinetic knee strengths were examined at an angular velocity of 600/s and compared between branches. Accordingly, the differences between the relative and average peak torque strengths of the athletes were significant in favour of the taekwondo players in the extension strength; On the other hand, the hamstring/quadriceps strength ratios of the taekwondo athletes were lower (p0.05). The study results showed that taekwondo players have higher extensor strength; Thus, extended taekwondo training allows more balanced hamstring/quadriceps muscle harmony than wrestling. Eventually, long-term wrestling training can cause muscle imbalances and injuries in athletes.

Using Inertial and Physiological Sensors to Investigate the Effects of a High-Intensity Interval Training and Plyometric Program on the Performance of Young Judokas

The use of inertial and physiological sensors in a sport such as judo is scarce to date. The information provided by these sensors would allow practitioners to have a better understanding of sports performance, which is necessary for an accurate training prescription. The purpose of this study was to use inertial and physiological sensors in order to investigate the effect of a plyometric and high-intensity interval training (HIIT) training program on Special Judo Fitness Test (SJFT) performance and speed of execution of throws in young judokas. A total of 32 participants were divided into two groups: experimental and control. The intervention consisted of six sessions with a duration of 60 min for 3 weeks. Physiological sensors collected heart rate data to assess the Special Judo Fitness Test, and inertial sensors collected angular velocity. The results show a significant decrease in the SJFT index (Score pre: 22.27 ± 2.73; Score post: 19.65 ± 1.70; p ≤ 0.05; d = 0.61) and a significant increase in the angular velocity of the X-axis (Pre: 320.87 ± 51.15°/s; Post: 356.50 ± 40.47°/s; p ≤ 0.05; d = 0.45) and Y-axis (Pre: 259.40 ± 41.99°/s; Post: 288.02 ± 65.12°/s; p ≤ 0.05; d = 0.31) in the experimental group. In conclusion, this study demonstrates that using inertial and physiological sensors allowed us to analyze the effect that a high-intensity interval training program and plyometrics had on the performance of young judokas. Strength and conditioning coaches should consider these results because including plyometric training and HIIT in judokas' workout programming can be especially positive for eliciting increases in performance. However, future training interventions should investigate the training adaptations to longer interventions.

Does the Type of Anaerobic Test Matter? A Comparison between the Anaerobic Intermittent Kick Test and Wingate Anaerobic Test in Taekwondo Athletes

The specificity of training as well as the specificity of monitoring the training process are believed to be fundamental principles to efficiently plan and carry out the preparation and performance development of athletes. The Anaerobic Intermittent Kick Test (TAIKT) is a sport-specific field test used to specifically evaluate the anaerobic profile of Taekwondo athletes. The aim of this study was to verify whether TAIKT and the 'gold standard' Wingate Anaerobic test (WAnT) were both efficient means to optimally determine the anaerobic power and anaerobic capacity of Greek Taekwondo athletes at a middle-high technical level. Fifteen athletes, 10 females and 5 males (mean age 23.4 ± 4.14 years), underwent the two anaerobic tests (TAIKT and WAnT). The peak of power, the anaerobic capacity, and the peak of blood lactate (BL) were recorded. The two tests showed a moderate correlation with the r value ranging between 0.353 and 0.428, if applied to a sample of middle-high technical level athletes. Regarding the peak of BL, data indicated 40% concordance between the two tests with a coefficient of variation of 12%. Consequently, the two tests were correlated even if not interchangeable due to the different type of exercise required in these assessments. In conclusion, to assess the anaerobic performances and physiological characteristics of Taekwondo athletes, independently of their technical level, the WAnT resulted suitable, while to better assess the functional performance and specific demands of Taekwondo, the TAIKT is more indicated.

Effects of Caffeine on Performances of Simulated Match, Wingate Anaerobic Test, and Cognitive Function Test of Elite Taekwondo Athletes in Hong Kong

This study aimed to investigate the effects of caffeine on performances of simulated match, Wingate Anaerobic Test (WAnT), and cognitive function test of elite taekwondo athletes. Ten elite taekwondo athletes in Hong Kong volunteered to participate in two main trials in a randomized double-blinded crossover design. In each main trial, 1 h after consuming a drink with caffeine (CAF) or a placebo drink without caffeine (PLA), the participants completed two simulated taekwondo match sessions followed by the WAnT. The participants were instructed to complete three cognitive function tests, namely the Eriksen Flanker Test (EFT), Stroop Test, and Rapid Visual Information Processing Test, at baseline, before exercise, and immediately after the simulated matches. They were also required to wear functional near-infrared spectroscopy equipment during these tests. Before exercise, the reaction time in the EFT was shorter in the CAF trial than in the PLA trial (PLA: 494.9 ± 49.2 ms vs. CAF: 467.9 ± 38.0 ms, p = 0.035). In the WAnT, caffeine intake increased the peak power and mean power per unit of body weight (by approximately 13% and 6%, respectively, p = 0.018 & 0.042). The performance in the simulated matches was not affected by caffeine intake (p = 0.168). In conclusion, caffeine intake enhances anaerobic power and may improve certain cognitive functions of elite taekwondo athletes in Hong Kong. However, this may not be enough to improve the simulated match performance.

Acute Effects of Caffeine Supplementation on Physical Performance, Physiological Responses, Perceived Exertion, and Technical-Tactical Skills in Combat Sports: A Systematic Review and Meta-Analysis

Although the effects of caffeine supplementation on combat sports performance have been extensively investigated, there is currently no consensus regarding its ergogenic benefits.This systematic review with meta-analysis aimed to summarize the studies investigating the effects of caffeine supplementation on different aspects of performance in combat sports and to quantitatively analyze the results of these studies to better understand the ergogenic effect of caffeine on combat sports outcomes. A systematic search for randomized placebo-controlled studies investigating the effects of caffeine supplementation on combat sports’ performance was performed through Scopus, Pubmed, Web of Science and Cochrane Library databases up to 18 April 2022. Random-effects meta-analyses of standardized mean differences (Hedge’s g) were performed to analyze the data. Twenty-six studies of good and excellent methodological quality (based on the Pedro scale) fulfilled the inclusion criteria. The meta-analysis results revealed caffeine has a small but evident effect size (ES) on handgrip strength (ES = 0.28; 95% CI: 0.04 to 0.52; p = 0.02), and total number of throws during the special judo fitness test (SJFT) (ES = 0.42; 95% CI: 0.06 to 0.78; p = 0.02). Regarding the physiological responses, caffeine increased blood lactate concentration ([La]) in anaerobic exercise (ES = 1.23; 95% CI: 0.29 to 2.18; p = 0.01) and simulated combat (ES = 0.91; 95% CI: 0.34 to 1.47; p = 0.002). For Heart Rate (HR), caffeine increased HR final (ES = 0.31; 95% CI: 0.11 to 0.52; p = 0.003), and HR 1min (ES = 0.20; 95% CI 0.004 to 0.40; p = 0.045). However, caffeine had no impact on the countermovement jump height, the SJFT index, the judogi strength-endurance test, the number and duration of offensive actions, HR at the end of the fight, and the rating of perceived exertion. Caffeine supplementation may be ergogenic for a range of combat sports aspects involving isometric strength, anaerobic power, reaction time, and anaerobic metabolism. However, supplementation effects might be ineffective under certain circumstances, indicating supplementation needs to take into account the performance metric in question prior to creating a dosing protocol.

Ten years of collecting hematological athlete biological passport samples—perspectives from a National Anti-doping Organization

The hematological module of the Athlete Biological Passport (ABP) aims to reveal blood doping indirectly by looking at selected biomarkers of doping over time. For Anti-Doping Organizations (ADOs), the ABP is a vital tool in the fight against doping in sports through improved target testing and analysis, investigations, deterrence, and as indirect evidence for use of prohibited methods or substances. The physiological characteristics of sport disciplines is an important risk factor in the overall risk assessment and when implementing the hematological module. Sharing of experiences with implementing the hematological ABP between ADOs is key to further strengthen and extend its use. In this study, we present 10 years of experience with the hematological ABP program from the perspectives of a National ADO with special attention to sport disciplines' physiological characteristics as a potential risk factor for blood doping. Not surprisingly, most samples were collected in sport disciplines where the aerobic capacity is vital for performance. The study highlights strengths in Anti-Doping Norway's testing program but also areas that could be improved. For example, it was shown that samples were collected both in and out of season in a subset of the data material that included three popular sports in Norway (Cross-Country Skiing, Nordic Combined, and Biathlon), however, from the total data material it was clear that athletes were more likely to be tested out of competition and on certain days of the week and times of the day. The use of doping control officers with a flexible time schedule and testing outside an athlete's 60 min time-slot could help with a more even distribution during the week and day, and thus reduce the predictability of testing. In addition to promoting a discussion on testing strategies, the study can be used as a starting point for other ADOs on how to examine their own testing program.

The relationship between physical fitness and competitive performance of Taekwondo athletes

The competition and physical fitness test results of the 2020 National Taekwondo Championship Series were analyzed using curve fitting, linear regression, and other statistical methods. As far as we know, it is the first Taekwondo competition that uses physical fitness test (PFT) scores as the 8-in-4 selection criteria. The results show that the probability of the final total score of the series of championships entering the top 8 or top 3 is exponentially related to PFT results. It finds that athletes with better PFT scores are more likely to enter the quarterfinals. Among athletes entering the semifinals, the athlete with the best physical fitness has the greatest probability of winning the championship. The difference in physical fitness between athletes is mainly reflected in the 30-meter sprint. Overall, the competitive performance of professional Taekwondo athletes is significantly positively correlated with their physical fitness, especially for female Taekwondo athletes. Through the results obtained, it is concluded that Taekwondo athletes need to strengthen physical training, specifically enhancing the explosive power.

Reliability and Validity of a New Taekwondo-Specific Change-of-Direction Speed Test With Striking Techniques in Elite Taekwondo Athletes: A Pilot Study

The purpose of this study was to examine the test-retest reliability, and convergent and discriminative validity of a new taekwondo-specific change-of-direction (COD) speed test with striking techniques (TST) in elite taekwondo athletes. Twenty (10 males and 10 females) elite (athletes who compete at national level) and top-elite (athletes who compete at national and international level) taekwondo athletes with an average training background of 8.9 ± 1.3 years of systematic taekwondo training participated in this study. During the two-week test-retest period, various generic performance tests measuring COD speed, balance, speed, and jump performance were carried out during the first week and as a retest during the second week. Three TST trials were conducted with each athlete and the best trial was used for further analyses. The relevant performance measure derived from the TST was the time with striking penalty (TST-TSP). TST-TSP performances amounted to 10.57 ± 1.08 s for males and 11.74 ± 1.34 s for females. The reliability analysis of the TST performance was conducted after logarithmic transformation, in order to address the problem of heteroscedasticity. In both groups, the TST demonstrated a high relative test-retest reliability (intraclass correlation coefficients and 90% compatibility limits were 0.80 and 0.47 to 0.93, respectively). For absolute reliability, the TST’s typical error of measurement (TEM), 90% compatibility limits, and magnitudes were 4.6%, 3.4 to 7.7, for males, and 5.4%, 3.9 to 9.0, for females. The homogeneous sample of taekwondo athletes meant that the TST’s TEM exceeded the usual smallest important change (SIC) with 0.2 effect size in the two groups. The new test showed mostly very large correlations with linear sprint speed (r = 0.71 to 0.85) and dynamic balance (r = −0.71 and −0.74), large correlations with COD speed (r = 0.57 to 0.60) and vertical jump performance (r = −0.50 to −0.65), and moderate correlations with horizontal jump performance (r = −0.34 to −0.45) and static balance (r = −0.39 to −0.44). Top-elite athletes showed better TST performances than elite counterparts. Receiver operating characteristic analysis indicated that the TST effectively discriminated between top-elite and elite taekwondo athletes. In conclusion, the TST is a valid, and sensitive test to evaluate the COD speed with taekwondo specific skills, and reliable when considering ICC and TEM. Although the usefulness of the TST is questioned to detect small performance changes in the present population, the TST can detect moderate changes in taekwondo-specific COD speed.

Comparison of bilateral isokinetic and isometric strength differences in elite young male and female taekwondo athletes

Definition of strength imbalance between legs and muscles does not only play a decisive role for higher performance but also prevents sport injury. The purpose of this study was to determine bilateral differences on isokinetic and isometric strength of knee extensor and flexor muscles in male and female elite young taekwondo athletes. Ten male (age: 19.40±0.84 years) and female (age: 18.24±1.42 years) taekwondo athletes of the Turkish national team between 17–20-year of age participated in the study. Concentric peak torque of hamstring (H) and quadriceps (Q) of the dominant (D) and nondominant leg (ND) was evaluated using isokinetic machine (Cybex Humac Norm) at 60° and 180°/sec. Isometric peak torque of both legs was determined at 60°. Significant differences were found between genders (P<0.05). Concentric and isometric knee strength was significantly greater in male than that of female (P< 0.05). Although no significant bilateral strength difference was found in both sexes in concentric and isometric strength (P>0.05), and isometric H strength was in favor of the dominant leg 15% for men athletes and 11% for women. H/Q ratio was similar between gender and legs. The study revealed no bilateral knee strength asymmetry in both male and female taekwondo athletes. However, male had 20%–30% higher isometric and concentric knee extensor and flexor strength than female in both legs.

Effect of CrossFit Training on Physical Fitness of Kickboxers

Background: Kickboxing is a combat sport that is complex in technique, tactics, and movement structure, and requires an adequate level of motor skills as a foundation for activities during competitions. General physical fitness, defined as the effect of the externalization of motor skills, is the basis for athletic training regardless of the sport. The aim of this study was to determine the effect of modified training based on the principles of CrossFit on the development of general physical fitness in a group of kickboxers compared to a control group. Methods: The study was experimental in nature and was conducted in a group of 60 kickboxers, divided into experimental and control groups. Participants were selected by purposive sampling, and the criteria were training experience, sports skill level (minimum class 1 athletes), and consent to participate in the experiment. The intervention in the study group involved the introduction of CrossFit-based training into a conventional kickboxing training program. General and special physical fitness of the athletes were diagnosed. Results: Statistically significant differences were found in general fitness in terms of abdominal strength (p < 0.001), pull-ups (p < 0.001), dynamometric measurement of handgrip force (p < 0.001) (kg), clap push-ups (p < 0.001), standing long jump (p < 0.001), shuttle run (p < 0.001), sit-and-reach (p < 0.001), and tapping (p < 0.001). Furthermore, changes in special fitness were also demonstrated for the special kickboxing fitness test (SKFT) (p < 0.02), the total number of punches (p < 0.001), punching speed (p < 0.001), and hip turning speed (p < 0.001). There was also a correlation between characteristics of general fitness and special fitness (p < 0.001). Conclusions: The experimental training program based on the principles of CrossFit training had a positive effect on the general and special kickboxing physical fitness.

Maximal isokinetic elbow and knee flexor-extensor strength measures in combat sports athletes: the role of movement velocity and limb side

Background

Maximal isokinetic strength ratios of joint flexors and extensors are important parameters to indicate the level of muscular balance at the joint. Further, in combat sports athletes, upper and lower limb muscle strength is affected by the type of sport. Thus, this study aimed to examine the differences in maximal isokinetic strength of the flexors and extensors and the corresponding flexor–extensor strength ratios of the elbows and knees in combat sports athletes.

Method

Forty male participants (age = 22.3 ± 2.5 years) from four different combat sports (amateur boxing, taekwondo, karate, and judo; n = 10 per sport) were tested for eccentric peak torque of the elbow/knee flexors (EF/KF) and concentric peak torque of the elbow/knee extensors (EE/KE) at three different angular velocities (60, 120, and 180°/s) on the dominant and non-dominant side using an isokinetic device.

Results

Analyses revealed significant, large-sized group × velocity × limb interactions for EF, EE, and EF–EE ratio, KF, KE, and KF–KE ratio (p ≤ 0.03; 0.91 ≤ d ≤ 1.75). Post-hoc analyses indicated that amateur boxers displayed the largest EE strength values on the non-dominant side at ≤ 120°/s and the dominant side at ≥ 120°/s (p < 0.03; 1.21 ≤ d ≤ 1.59). The largest EF–EE strength ratios were observed on amateur boxers’ and judokas’ non-dominant side at ≥ 120°/s (p < 0.04; 1.36 ≤ d ≤ 2.44). Further, we found lower KF–KE strength measures in karate (p < 0.04; 1.12 ≤ d ≤ 6.22) and judo athletes (p ≤ 0.03; 1.60 ≤ d ≤ 5.31) particularly on the non-dominant side.

Conclusions

The present findings indicated combat sport-specific differences in maximal isokinetic strength measures of EF, EE, KF, and KE particularly in favor of amateur boxers on the non-dominant side.

Trial registration: This study does not report results related to health care interventions using human participants and therefore it was not prospectively registered.

Comparison between the KPNP and Daedo Protection Scoring Systems through a Technical-Tactical Analysis of Elite Taekwondo Athletes

Background: In the last two decades, the use of technology has been incorporated into taekwondo, changing the rules of the sport to employ a more objective scoring system. The current electronic Protection Scoring Systems (PSS) include sensors that register the number and power of the hits scored, but these may interfere with athlete’s techniques and tactics. This study aimed to analyze the technical-tactical differences in elite taekwondoists using two different PSS. Methods: We systematically observed 112 combats involving 224 athletes, and their actions were registered and analyzed using contingency tables. Results: Eight hundred twenty-seven effective actions were tagged, and differences were found in the types of kicks performed using different PSS. For the total sample, there were differences between PSS in technical actions (X2 = 36.08(10); p < 0.01; V = 0.21), tactical actions (X2 = 10.73(3); p < 0.05; V = 0.11), and hitting side (X2 = 30.97(1); p < 0.01; V = 0.19). In men, the differences in techniques and tactics between different PSS were found in technical actions (X2 = 27.15(10); p < 0.01; V = 0.25), guard position (X2 = 14.94(1); p < 0.01; V = 0.18), and hitting side (X2 = 11.07(1); p < 0.01; V = 0.16), while in women, significant differences were found in technical actions (X2 = 37.03(8); p < 0.01; V = 0.32), tactical actions (X2 = 24.45(3); p < 0.01; V = 0.26), guard position (X2 = 3.95(1); p < 0.05; V = 0.10), hitting side (X2 = 19.27(1); p < 0.01; V = 0.23), and laterality (X2 = 16.32(3); p < 0.01; V = 0.21). Conclusions: The present study evidenced a difference in the technical-tactical behavior of elite taekwondoists as a result of the PSS used in combat, with more marked differences in female athletes. These findings also suggest the need to adapt and review the PSS to effectively score in the same way.

Effects of 3 mg/kg Body Mass of Caffeine on the Performance of Jiu-Jitsu Elite Athletes

The effects of caffeine were investigated in judo, boxing, taekwondo and Brazilian jiu-jitsu. However, this substance was never investigated regarding traditional jiu-jitsu. Therefore, the aim of this research was to analyze the effects of caffeine in the Special Judo Fitness Test (SJFT) and technical variables during combat in traditional jiu-jitsu elite athletes. Methods: Twenty-two young professionals of traditional jiu-jitsu, 11 men and 11 women (age = 22 ± 4 (18−33) years, body mass = 66.6 ± 10.8 (46.2−86.1) kg, height = 1.70 ± 0.9 (1.55−1.85) m) with 15 ± 7 years of experience in traditional jiu-jitsu, participated in a double-blind, counterbalanced, crossover study. In two different conditions, the traditional jiu-jitsu athletes ingested 3 mg/kg body mass of caffeine or a placebo. After 60 min, they performed the SJFT test to measure throwing performance, and subsequently, combat to analyze offensive and defensive hitting techniques. Results: Caffeine had a main effect on the number of throws during the SJFT test (P < 0.01). In addition, it was effective in sets 2 (13 ± 2 vs. 14 ± 2; p = 0.01) and 3 (12 ± 2 vs. 13 ± 1; p = 0.03). There was also a main effect during the test on heart rate when caffeine was ingested (F = 12.48, p < 0.01). The effects of caffeine were similar compared to the placebo condition regarding performance during combat both in offensive and defensive fighting variables Conclusions: the pre-exercise ingestion of 3 mg/kg body mass of caffeine increased performance in the SJFT test, decreased fatigue perception, and increased power and endurance perception in professionally traditional jiu-jitsu athletes. However, it did not seem to improve offensive and defensive technical actions during combat.

Acute Effects of Different Activity Types and Work-To-Rest Ratio on Post-Activation Performance Enhancement in Young Male and Female Taekwondo Athletes

The study assessed conditioning activities’ (CAs’) effects involving different work-to-rest ratios (WRR) on taekwondo athletes’ physical performance. Adolescent taekwondo athletes (age: 16 ± 1 years) randomly participated in the control six experimental conditions. Each condition was composed of standard warm-up and CA composed of plyometrics (P) or repeated high-intensity techniques (RHIT) performed using three different WRR: 1:6, 1:7, self-selected rest time (SSRT). After rest, athletes performed countermovement jump (CMJ), taekwondo specific agility test (TSAT), 10 s frequency speed kick test (FSKT-10s), multiple frequency speed kick test (FSKT-mult). P1:7, SSRT induced techniques higher number in FSKT-10s (p < 0.001 for all comparisons) and lower TSAT time (p < 0.01 for all comparisons) compared with control. Kicks-number recorded during FSKT-mult was lower in the control compared with RHIT1:6 (p = 0.001), RHIT1:7 (p < 0.001), RHITSSRT (p < 0.05), P1:7 (p < 0.001), and SSRT (p < 0.001). Kicking decrement index (DI) during FSKT-mult was lower after RHIT1:6 compared with control (p = 0.008), RHIT1:7 (p = 0.031), P 1:6 (p = 0.014), PSSRT (p = 0.041). (1) P1:7 and PSSRT can be used to improve taekwondo-specific agility and kicks-number, (2) RHIT1:6 is beneficial to maintain low DI, and (3) plyometric and different WRR-repeated-techniques can enhance kicks-number.

Acute Effects of Low Dose of Caffeine Ingestion Combined with Conditioning Activity on Psychological and Physical Performances of Male and Female Taekwondo Athletes

This study investigated low-dose caffeine ingestion, conditioning activity (CA) effects on psycho-physical performances in young taekwondo athletes. In a randomized, double-blind, counterbalanced, crossover design, 20 athletes (10 males; 17.5 ± 0.7 yrs) performed taekwondo-specific agility test (TSAT), 10 s/multiple frequency speed of kick test (FSKT-10s/FSKT-mult) after ingesting 3 mg·kg−1 caffeine (CAF) or placebo (PL) 60 min before performing standard warm-up without (NoCA) or with CA (3 × 10 vertical jumps above 40 cm), resulting in four experimental (PL + NoCA, CAF + NoCA, PL + CA, and CAF + CA) and one control (warm-up session without CAF or CA) conditions. Mood/physical symptoms (MPSS), subjective vitality (SVS), and feeling (FS) scales were analyzed post-to-pre for all conditions. Ratings of perceived-exertion and perceived-recovery status were determined after tests. For TSAT, CAF + CA induced better performance compared with all conditions (p < 0.001). For FSKT-10s and FSKT-mult, CAF + CA induced better performance compared with all conditions (p < 0.001). For MPSS, FS, CAF + NoCA induced higher scores than PL + NoCA and PL + CA (p = 0.002, 0.009 for MPSS; p = 0.014, 0.03 for FS). For SVS, PL + CA elicited lower scores than PL + NoCA and CAF + NoCA (p = 0.01, 0.004). Sex comparisons resulted in better performances for males for TSAT (p = 0.008), FSKT-10s (p < 0.001), FSKT-mult (p < 0.01), MPSS (p = 0.02), SVS (p = 0.028), and FS (p = 0.020) scores. Caffeine and conditioning activity are two efficient performance-enhancing strategies, which could synergistically result in greater psycho-physical performances.

Relative and Chronological Age in Successful Athletes at the World Taekwondo Championships (1997-2019): A Focus on the Behaviour of Multiple Medallists

The aims of this study were to investigate the relative and chronological age among taekwondo world medal winners (by gender, Olympic 4-year period, Olympic weight category; N = 740), and to study the behaviour of multiple medallists (N = 156) to monitor changes in weight categories and wins over time. The observed birth quartile distribution for the heavyweight category was significantly skewed (p = 0.01). Female athletes (22.2 ± 3.5 years) achieve success at a significantly younger age (p = 0.01) than their male counterparts (23.6 ± 3.3 years). In the weight categories, female flyweights were significantly younger than those welterweights (p = 0.03) and heavyweight (p = 0.01); female featherweights were significantly younger than those heavyweights (p = 0.03). Male flyweights and featherweights were significantly younger than those welterweights and heavyweights (p = 0.01). When a taekwondo athlete won a medal several times, he/she did so within the same Olympic weight category group and won two medals in his/her career (p = 0.01). Multiple medallists of the lighter and heavier groups did not differ in the number of medals won but in the time span in which they won medals (p = 0.02). The resources deployed by stakeholders to achieve success in these competitions highlight an extremely competitive environment. In this sense, the information provided by this study can be relevant and translated into key elements.

Big Data Analysis of the Key Attributes Related to Stress and Mental Health in Korean Taekwondo Student Athletes

In the present study, we used big data analysis to examine the key attributes related to stress and mental health among Korean Taekwondo student-athletes. Keywords included “Taekwondo + Student athlete + Stress + Mental health”. Naver and Google databases were searched to identify research published between 1 January 2010 and 31 December 2019. Text-mining analysis was performed on unstructured texts using TEXTOM 4.5, with social network analysis performed using UCINET 6. In total, 3149 large databases (1.346 MB) were analyzed. Two types of text-mining analyses were performed, namely, frequency analysis and term frequency-inverse document frequency analysis. For the social network analysis, the degree centrality and convergence of iterated correlation analysis were used to deduce the node-linking degree in the network and to identify clusters. The top 10 most frequently used terms were “stress”, “Taekwondo”, “health”, “player”, “student”, “mental”, “exercise”, “mental health”, “relieve”, and “child.” The top 10 most frequently occurring results of the TF-IDF analysis were “Taekwondo”, “health”, “player”, “exercise”, “student”, “mental”, “stress”, “mental health”, “child” and “relieve”. The degree centrality analysis yielded similar results regarding the top 10 terms. The convergence of iterated correlation analysis identified six clusters: student, start of dream, diet, physical and mental, sports activity, and adult Taekwondo center. Our results emphasize the importance of designing interventions that attenuate stress and improve mental health among Korean Taekwondo student-athletes.

Exploring the age of taekwondo athletes in the Olympic Games: an analysis from Sydney 2000 to Rio 2016

BACKGROUND

The aim of this study was to quantify the age at which taekwondo athletes competed in the Olympic Games and to provide initial insights into weight category changes over time.

METHODS

For the first analysis, the study included all 611 taekwondo athletes who competed in the Olympics between 2000 and 2016; for each sex, a three-way ANOVA (edition of Olympic Games, competitive achievement, weight category) was performed to detect differences in the age of athletes. For the second analysis, we considered all 109 taekwondo athletes who took part in more than one edition of the Olympics between 2000 and 2016; chi-squared goodness of fit tests were performed to study the number of participations and changes in weight category of these athletes.

RESULTS

Female athletes, with a mean age of 23.8 ± 4.1 years, are significantly younger (p=0.001) than their male counterparts, with a mean age of 25.1 ± 3.9 years. In weight category, lighter athletes being younger than heavier ones in both females (22.7 ± 3.7 vs 24.5 ± 4.2 yrs., p=0.04) and males (23.6 ± 3.8 vs 26.7 ± 3.8 yrs., p=0.001; 24.2 ± 3.5 vs 26.7 ± 3.8 yrs., p=0.001). When an athlete reaches Olympic competition several times, he/she generally competes in the same weight category (p=0.001) and takes part in two consecutive editions (p=0.001). Heavier athletes have greater longevity at Olympic level than lighter athletes (p=0.002).

CONCLUSIONS

The current data provides important information for national federations engaged in the selection of athletes for Olympic competitions.

High-Intensity Conditioning for Combat Athletes: Practical Recommendations

Combat sports have been practiced for millennia and today are predominant sports at the Olympic games, with international organizations that host world, continental and national championships at amateur standard. There are also an increasing number of professional combat sports with global audiences. The growing popularity of professional combat sports and their importance at the Olympic games have led to an increase in scientific studies that characterize the physical, physiological, nutritional, biomechanical and training strategies of combat sports athletes. These studies characterize combat sports as high-intensity sports which require training strategies to develop the high-intensity capabilities of athletes. Therefore, the aim of this article is to (i) summarize the physiological demands of combat sports; (ii) present the primary considerations required to program high-intensity conditioning for athletes; (iii) define and present key high-intensity conditioning methods; and (iv) provide guidance for scientists and coaches to help prepare athletes under common but differing circumstances.

Olympic Sports Science-Bibliometric Analysis of All Summer and Winter Olympic Sports Research

Introduction: The body of scientific literature on sports and exercise continues to expand. The summer and winter Olympic games will be held over a 7-month period in 2021-2022. Objectives: We took this rare opportunity to quantify and analyze the main bibliometric parameters (i.e., the number of articles and citations) across all Olympic sports to weigh and compare their importance and to assess the structure of the "sport sciences" field. The present review aims to perform a bibliometric analysis of Olympic sports research. We quantified the following topics: (1) the most investigated sports; (2) the main journals in which the studies are published; (3) the main factors explaining sport-specific scientific attractiveness; (4) the influence of being in the Olympic programme, economic weight, and local influences on research output; and (5) which research topic is the most investigated across sports. Methods: We searched 116 sport/exercise journals on PubMed for the 40 summer and 10 winter Olympic sports. A total of 34,038 articles were filtered for a final selection of 25,003 articles (23,334 articles on summer sports and 1,669 on winter sports) and a total of 599,820 citations. Results and Discussion: Nine sports [football (soccer), cycling, athletics, swimming, distance & marathon running, basketball, baseball, tennis, and rowing] were involved in 69% of the articles and 75% of the citations. Football was the most cited sport, with 19.7 and 26.3% of the total number of articles and citations, respectively. All sports yielded some scientific output, but 11 sports (biathlon, mountain biking, archery, diving, trampoline, skateboarding, skeleton, modern pentathlon, luge, bobsleigh, and curling) accumulated a total of fewer than 50 publications. While ice hockey is the most prominently represented winter sport in the scientific literature, winter sports overall have produced minor scientific output. Further analyses show a large scientific literature on team sports, particularly American professional sports (i.e., baseball, basketball, and ice hockey) and the importance of inclusion in the Olympic programme to increasing scientific interest in "recent" sports (i.e., triathlon and rugby sevens). We also found local/cultural influence on the occurrence of a sport in a particular "sport sciences" journal. Finally, the relative distribution of six main research topics (i.e., physiology, performance, training and testing, injuries and medicine, biomechanics, and psychology) was large across sports and reflected the specific performance factors of each sport.

Effects of Different Tissue Flossing Applications on Range of Motion, Maximum Voluntary Contraction, and H-Reflex in Young Martial Arts Fighters

The purpose of this study was to investigate the effects of tissue flossing applied to the ankle joint or to the calf muscles, on ankle joint flexibility, plantarflexor strength and soleus H reflex. Eleven young (16.6 ± 1.2 years) martial arts fighters were exposed to three different intervention protocols in distinct sessions. The interventions consisted of wrapping the ankle (ANKLE) or calf (CALF) with an elastic band for 3 sets of 2 min (2 min rest) to create vascular occlusion. A third intervention without wrapping the elastic band served as a control condition (CON). Active range of motion for ankle (AROM), plantarflexor maximum voluntary contraction (MVC), and soleus H reflex were assessed before (PRE), after (POST), and 10 min after (POST10) the intervention. The H reflex, level of pain (NRS) and wrapping pressure were also assessed during the intervention. Both CALF and ANKLE protocols induced a significant drop in H reflex during the intervention. However, the CALF protocol resulted in a significantly larger H reflex reduction during and after the flossing intervention (medium to large effect size). H reflexes returned to baseline levels 10 min after the intervention in all conditions. AROM and MVC were unaffected by any intervention. The results of this study suggest that tissue flossing can decrease the muscle soleus H reflex particularly when elastic band is wrapped around the calf muscles. However, the observed changes at the spinal level did not translate into higher ankle joint flexibility or plantarflexor strength.

Effects of Beetroot Juice Supplementation on Cognitive Function, Aerobic and Anaerobic Performances of Trained Male Taekwondo Athletes: A Pilot Study

Studies have shown that nitrate (NO₃⁻)-rich beetroot juice (BJ) supplementation improves endurance and high-intensity intermittent exercise. The dose–response effects on taekwondo following BJ supplementation are yet to be determined. This study aimed to investigate two acute doses of 400 mg of NO₃⁻ (BJ-400) and 800 mg of NO₃⁻ (BJ-800) on taekwondo-specific performance and cognitive function tests compared with a placebo (PL) and control (CON) conditions. Eight trained male taekwondo athletes (age: 20 ± 4 years, height: 180 ± 2 cm, body mass: 64.8 ± 4.0 kg) completed four experimental trials using a randomized, double-blind placebo-controlled design: BJ-400, BJ-800, PL, and CON. Participants consumed two doses of BJ-400 and BJ-800 or nitrate-depleted PL at 2.5 h prior to performing the Multiple Frequency Speed of Kick Test (FSKT). Countermovement jump (CMJ) was performed before the (FSKT) and PSTT, whereas cognitive function was assessed (via the Stroop test) before and after supplementation and 10 min following PSTT. Blood lactate was collected before the CMJ tests immediately and 3 min after the FSKT and PSST; rating of perceived exertion (RPE) was recorded during and after both specific taekwondo tests. No significant differences (p > 0.05), with moderate and large effect sizes, between conditions were observed for PSTT and FSKT performances. In addition, blood lactate, RPE, heart rate, and CMJ height were not significantly different among conditions (p > 0.05). However, after the PSTT test, cognitive function was higher in BJ-400 compared to other treatments (p < 0.05). It was concluded that acute intake of 400 and 800 mg of NO₃⁻ rich BJ reported a moderate to large effect size in anaerobic and aerobic; however, no statistical differences were found in taekwondo-specific performance.

Physical Characteristics and Physical Fitness Profiles of Korean Taekwondo Athletes: A Systematic Review

This study aimed to present a standard and normal distribution of Taekwondo athletes’ physical characteristics and physical fitness profiles using a systematic review. A systematic search was conducted using four Korean databases (Research Information Sharing Service, National Digital Science Library, DBpia, and Korean Studies Information Service System). From 2010 to 2020, we reviewed 838 papers on Taekwondo athletes’ physical characteristics and physical fitness factors (e.g., body composition, muscle strength, muscular endurance, flexibility, cardiorespiratory fitness, power, agility, balance, speed, and reaction time). Of them, 24 papers were selected and analyzed. The criteria for selecting the physical characteristics and physical fitness factors for data extraction were set to have a total sample size of more than 30 individuals and included two or more studies. The sample size and average and standard deviation of physical characteristics and physical fitness factors were extracted from each selected study. In this study, the estimation error of all variables, except for the eyes-closed single-leg stance (15.71%), was less than 8%. Therefore, it was confirmed that there was no problem with the validity of the estimated values. These results could be used as an essential objective basis for evaluating the physical characteristics and physical fitness profiles of Taekwondo athletes in most countries worldwide and setting training goals.