Taekwondo training and fitness in female adolescents

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.

Effects of combat sports on cognitive function in older people: a systematic review

INTRODUCTION

This systematic review aimed to analyze the available body of published peer-reviewed studies on the effects of combat sports compared with active/passive control on cognitive function and electrophysiological markers of brain activity in older people.

EVIDENCE ACQUISITION

The studies were searched in Scopus, Web of Science, PubMed, MEDLINE, and PsycINFO databases from deadline to June 2023. The PRISMA, TESTEX, RoB, and GRADE scales assessed the evidence's methodological quality and certainty of evidence. The protocol was registered in PROSPERO (code: CRD42022361695).

EVIDENCE SYNTHESIS

After reviewing 3768 studies, seven combat sports interventions (score ≥60% in methodological quality) were selected, composed of 381 older people (63% female), with a mean age of 66 years. In the selected studies, interventions based on judo, karate, and taekwondo were carried out, where it was not possible to verify the benefits of combat sports in cognitive function and electrophysiological markers of brain activity regarding active/passive control groups, although the individual results of the analyzed studies indicate that the practice of combat sports favor selective attention, divided attention, executive function, visual perception, and cognitive processing speed in older people.

CONCLUSIONS

The available evidence does not allow a definite recommendation regarding combat sports as an effective cognitive function intervention in older people.

Jumping Rope Improves the Physical Fitness of Preadolescents Aged 10-12 Years: A Meta-Analysis

To systematically review the effects of jumping rope on physical fitness among 10 to 12-year-old preadolescents, and to provide evidence-based support for its use in school physical education curriculum work. The PubMed, Web of Science, SPORTDiscus, ScienceDirect, and CNKI databases were searched for randomized controlled trials that assessed jumping rope and physical fitness among preadolescents aged 10-12 years. Meta-analyses were used to calculate the standardized mean difference (SMD) values and 95% confidence intervals (CI), and subgroup analyses were conducted on intervention duration, frequency and period. A total of 1048 subjects from 15 studies were included. Compared to regular physical education courses, jumping rope did not show a significant advantage in terms of body morphology. In terms of physical function, boys showed greater improvements in vital capacity, and girls showed greater improvements in resting HR. In terms of physical performance, boys showed greater improvements in speed, upper-body strength, lower-body strength, muscular endurance and agility, while girls showed greater improvements in coordination and balance. Boys experienced a minimal improvement in flexibility, while girls did not show a significant difference. Combining the results of the subgroup analyses, the optimal session time, frequency and intervention length of jumping rope for significantly improving the physical fitness of preadolescents were >40 min, 2 times/week and 8-12 weeks, respectively. In conclusion, jumping rope provides small to large benefits over regular physical education for both boys and girls aged 10-12 years in terms of physical function and physical performance indicators other than flexibility, while showing no significant advantage in terms of body morphology. Based on the available research, it is recommended that children aged 10-12 years participate in jump rope sessions for at least 40 minutes once or twice a week for 8-12 weeks to better develop physical fitness.

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.

A new taekwondo-specific field test for estimating aerobic power, anaerobic fitness, and agility performance

The present study aimed to propose a new multidimensional taekwondo-specific test to estimate aerobic power, anaerobic fitness, and agility. Out of sixty-five male volunteers, forty-six, forty-eight, and fifty athletes (18–35 years; black- and red-belt level) were included in the final analysis for aerobic, anaerobic, and agility assessments, respectively. Maximum oxygen uptake (VO_2max, using a graded exercise test on a treadmill), anaerobic power (using the 30-s Wingate anaerobic test, WAnT), and agility performance (using the agility T-Test) were measured via non-specific laboratory and field tests across a two-week period. The taekwondo-specific aerobic-anaerobic-agility (TAAA) test comprised six 20-s intervals of shuttle sprints over a 4-m distance, and the execution of roundhouse kicks alternating the legs at the end of each distance, with 10-s rest intervals between the sets. The multiple linear regression revealed that the difference between heart rate (HR) after and 1 minute after the TAAA test (p < 0.001), and body mass index (BMI; p = 0.006) were significant to estimate VO_2max. Likewise, there was a very large (R = 0.79) and large (R = 0.55) correlation between the average and maximum number of kicks performed in the TAAA test and the WAnT mean and peak power, respectively (p < 0.001). Moreover, a linear relationship was found between the T-Test and agility performance acquired in the TAAA test (R = 0.74; p < 0.001). The TAAA test can be considered a valid simple tool for monitoring VO_2max, anaerobic fitness, and agility in male taekwondo athletes.

Subjective Perceptions of South Korean Parents Regarding the Effectiveness of Taekwondo Education for Adolescents and Its Characteristics: The Q Methodology Application

This study aims to determine why Korean parents provide adolescent children with continuous physical education through Taekwondo. The Q methodology was applied. The final 25 Q-samples were selected by composing the Q-population. Twenty parents who provided their children with Taekwondo education for more than 10 years were designated as the P-sample. Q-sorting was performed on the P-sample. Centroid factor analysis and varimax rotation were performed using version 2.35 of PQ method program. The study observed four factors with a total explanatory variance of 69%. Types 1 to 4 (N = 5, 7, 5, and 3) pertained to a powerful means of enhancing mental health, the driving force behind stable school life and social development, improvement in psychological and social areas for a successful transition to adulthood, and increased awareness of the values of Taekwondo and importance of physical activity, with eigenvalues of 4.59, 6.42, 3.16, and 1.18 and explanatory variances of 0.16, 0.32, 0.12, and 0.09, respectively. Furthermore, consensus statements for each type were investigated as Q18 and Q17. These findings supported the academic foundation of proper Taekwondo education in adolescence and confirmed it as a powerful means of exerting a positive impact on adulthood.

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.

Regular Taekwondo Training Affects Mood State and Sociality but Not Cognitive Function among International Students in South Korea

We aimed to investigate the effect of Taekwondo training on physical fitness, mood, sociality, and cognitive function among international students in South Korea. We randomly assigned 24 international students to a control group (CG, n = 12) and experimental group (EG, n = 12). The EG performed Taekwondo training for 16 weeks, while the CG did not train. Each participant underwent a physical fitness test and sociability questionnaire before and after the intervention. We also examined changes in mood state and cognitive function, using the Korean version of the Profile of Mood State-Brief (K-POMS-B), and the Stroop Color and Word test, respectively. Regarding the physical fitness variables, sit-and-reach records in the EG significantly increased after intervention (p < 0.05). In the sub-variable of K-POMS-B, Vigor-Activity scores significantly increased (p < 0.05) after intervention, while the Fatigue-Inertia scores significantly decreased in the EG (p < 0.05). Furthermore, in the EG, peer relationship scores, a sub-variable of sociability, significantly decreased after intervention (p < 0.05). These findings suggest that Taekwondo training can not only improve flexibility among physical fitness factors, but can also be effective in improving the mood state and sociality of international students.

Effects of Adding Small Combat Games to Regular Taekwondo Training on Physiological and Performance Outcomes in Male Young Athletes

This study investigated the effect of area sizes (4 × 4, 6 × 6, and 8 × 8 m) and effort-pause ratios (free combat vs. 1:2) variation on the physiological and perceptive responses during taekwondo combats (Study 1). In a second study, the effects on physical performance of 8 weeks of small combat-based training added to regular taekwondo training were investigated (Study 2). In random order, 32 male taekwondo athletes performed six (i.e., two effort-to-pause ratios × three area sizes conditions) different 2-min taekwondo combats (Study 1). Thereafter (Study 2), they were randomly assigned to three experimental groups (4 × 4, 6 × 6, and 8 × 8 m) and an active control group (CG). Regarding Study 1, blood lactate concentration [La] before and after each combat, mean heart rate (HRmean) during each combat, and rating of perceived exertion (CR-10) immediately after each combat were assessed. Regarding Study 2, progressive specific taekwondo (PSTT) to estimate maximum oxygen consumption (VO2max), taekwondo-specific agility, and countermovement jump (CMJ) tests were administered before and after 8 weeks of training. Study 1 results showed that 4 × 4 m elicited lower HRmean values compared with 6 × 6 m (d = -0.42 [small], p = 0.030) and free combat induced higher values compared with the 1:2 ratio (d = 1.71 [large], p < 0.001). For [La]post, 4 × 4 m area size induced higher values than 6 × 6 m (d = 0.99 [moderate], p < 0.001) and 8 × 8 m (d = 0.89 [moderate], p < 0.001) and free combat induced higher values than 1:2 ratio (d = 0.69 [moderate], p < 0.001). Higher CR-10 scores were registered after free combat compared with 1:2 ratio (d = 0.44 [small], p = 0.007). For Study 2, VO2max increased after training [F (1, 56) =30.532, p < 0.001; post-hoc: d = 1.27 [large], p < 0.001] with higher values for 4 × 4 m compared with CG (d = 1.15 [moderate], p = 0.009). Agility performance improved after training [F (1, 56) = 4.419, p = 0.04; post-hoc: d = -0.46 [small], p = 0.04] and 4 × 4 m induced lower values in comparison with 6 × 6 m (d = -1.56 [large], p = 0.001) and CG (d = -0.77 [moderate], p = 0.049). No training type influenced CMJ performance. Smaller area size elicited contrasting results in terms of metabolic demand compared with larger sizes (i.e., lower HRmean but higher [La] and CR-10), whereas free combat induced variables' consistently higher values compared with imposed 1:2 ratio (Study 1). Taekwondo training is effective to improve VO2max and agility (Study 2), but small combat training modality should be investigated further.

The Effect of Sports Rules Amendments on Exercise Intensity during Taekwondo-Specific Workouts

We aimed to compare the change in exercise response to taekwondo-specific circuit workouts before and after competition rule amendments. A total of 240 workouts in 15 elite athletes were analyzed over two years. Physiological and kinematic data were gathered with the wireless Bioharness system along with capillary blood samples for lactate concentration. Progressive exercise tests until exhaustion were periodically performed to obtain reference data. The rule changes resulted in significant increases (mainly medium or large effects) in the physiological (2.9-14.4%) and kinematic (4.8-10.1%) response to taekwondo-specific workouts. The largest increases were for peak breathing rate (12.0%), energy expenditure (6.6%), blood lactate immediately after exercise (10.2%) and at the 30th min of recovery (14.4%), and peak kinematic activity (10.1%). Significant differences between taekwondo-specific workouts and tournament combats persisted after the shift from old to new rules, ranging from 2.4 to 38.5% for physiological and from 2.9 to 15.5% for kinematic variables. The largest workout-combat differences were revealed for post-exercise (15.9%) and recovery (38.5%) blood lactate, peak (-15.8%) and relative (-15.0%) breathing rate, and mechanical (13.5%) and physiological (14.2%) intensity. Our study suggests that the rule amendments significantly modify the exercise response to discipline-specific workouts and that taekwondo-specific training sessions do not fully recreate the tournament demands in terms of physiological and kinematic load.

Physical, physiological and psychological profiles of elite Turkish taekwondo athletes

Study aim: To identify the physical, physiological and psychological profiles of elite Turkish taekwondo athletes.

Material and methods: Twelve players of the Turkish national taekwondo team (age = 22.7 ± 2.8 years, BMI = 22.2 ± 1.4 kg/m2, body fat = 12.8 ± 3.4%) participated in the study. Anthropometric measurements including leg length and foot size were assessed. Maximal oxygen uptake, explosive power of leg extensors, isokinetic peak torque, muscular endurance, anaerobic power, agility, flexibility, maximal speed, reaction time, and postural balance were examined by incremental treadmill running, vertical jump, isokinetic strength, sit-ups and push-ups, Wingate, shuttle run, sit-and-reach, 30-meter sprint, multiple-choice reaction time, and General Postural Stability and Athlete Single Leg stability tests, respectively. Psychological characteristics including mental skills and mood states were evaluated using OMSAT-3 and POMS tests.

Results: VO2max, isokinetic peak torque and Wingate test mean power values were 54.1 ± 4.4 mL ∙ kg−1 ∙ min−1, 191.7 ± 19.2 N ∙ m, and 9 ± 0.7 W/kg, respectively. Postural stability index 0.18 ± 0.06, single leg stability index 0.82 ± 0.11, reaction time 0.344 ± 0.032 s, 10 × 5-m shuttle run 17.09 ± 0.68 s, 30-meter sprint 4.60 ± 0.23 s, and vertical jump 43.5 ± 6.1 cm were the other values reported. The highest scores for the 12 mental skills in OMSAT-3 were for goal setting (6.25 ± 0.45) and self-confidence (6.16 ± 0.45). The lowest score was for Imagery (5.64 ± 0.36). The results of six mood states of POMS showed higher scores on the Vigor-activity, Anger-Hostility and Tension-Anxiety scales and lower scores on Depression-Dejection, Fatigue-Inertia and Confusion-Bewilderment than norms.

Conclusions: The findings of this study revealed the physical, physiological, and psychological characteristics in taekwondo. The results of the tests could be useful for performance assessment of taekwondo players.

Effects of Regular Taekwondo Intervention on Oxidative Stress Biomarkers and Myokines in Overweight and Obese Adolescents

Purpose: Regular exercise can alleviate oxidative stress related to obesity and can induce secretion of myokines that are involved in the regulation of metabolic homeostasis. There are no studies examining changes in these variables as a result of Taekwondo training intervention. We aimed to investigate the effect of Taekwondo training on oxidative stress and myokine levels in overweight and obese adolescents. Methods: We randomly assigned 20 overweight and obese adolescents to control (control group; CG, n = 10) and experimental (experimental group; EG, n = 10) groups. The EG performed Taekwondo training five times a week for 16 weeks. Physical parameters (height, weight, body mass index (BMI)), physical fitness (maximal oxygen uptake (VO₂max) (cardiorespiratory endurance), grip and leg strength (muscular strength), sit-and-reach (flexibility), Sargent jump (power), and stork stand test (balance)) were measured before and after intervention. We measured levels of serum oxidative stress markers (plasma malondialdehyde (MDA) and superoxide dismutase (SOD)) and myokines (serum interleukin-15 (IL-15), brain-derived neurotrophic factor (BDNF), irisin, and myostatin). Results: The weight and BMI in the EG after intervention were significantly lower and leg strength (muscular strength), sit-and-reach (flexibility), and Sargent jump (power) were significantly improved compared to those of the CG (p < 0.05). There were no significant interaction effects in terms of height, VO₂ max, grip strength, or stork stand test (p > 0.05). The SOD and BDNF level after intervention were significantly higher in the EG after the intervention, whereas MDA and irisin levels were significantly lower than those of the CG (p < 0.05). There were no significant interaction effects in terms of serum IL-15 and myostatin levels (p > 0.05). Conclusions: Taekwondo training can reduce obesity and increase physical fitness with respect to muscular strength, flexibility, and power as well as alleviate oxidative stress and modulate myokine secretion in adolescents.

Taekwondo Enhances Cognitive Function as a Result of Increased Neurotrophic Growth Factors in Elderly Women

The purpose of this study was to investigate the effects of regular taekwondo (TKD) training on physical fitness, neurotrophic growth factors, cerebral blood flow (CBF) velocity, and cognitive function in elderly women. Thirty-seven women aged 65 or older were randomly assigned to either TKD (n = 19) or control (n = 18) group. TKD training was performed at 50⁻80% maximum heart rate (HRmax) for 60 min, five times per week for 16 weeks. All participants underwent the following examinations before and after the intervention: Senior Fitness Test; serum levels of neurotrophic growth factors, including brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1); systolic, diastolic, and mean blood flow velocity and pulsatility index of the middle cerebral artery using Doppler ultrasonography; Mini-Mental State Examination for dementia screening (MMSE-DS); and Stroop Color and Word Test (word, color, and color-word). In the TKD group, lower body strength and flexibility, aerobic endurance levels, BDNF, VEGF, and IGF-1 serum levels as well as the color-word test scores were significantly increased after as compared to before the intervention (p < 0.05). No statistically significant differences were found in cerebral blood flow velocities and the MMSE-DS score (p > 0.05). These findings suggest that regular TKD training may be effective in improving not only fitness but also cognitive function in elderly women. The latter effect may be due to increased neurotrophic growth factor levels.

Validity and Reliability of a New Test of Planned Agility in Elite Taekwondo Athletes

Chaabene, H, Negra, Y, Capranica, L, Bouguezzi, R, Hachana, Y, Rouahi, MA, and Mkaouer, B. Validity and reliability of a new test of planned agility in elite taekwondo athletes. J Strength Cond Res 32(9): 2542-2547, 2018-This study aimed to examine the validity, reliability, and sensitivity of a new test of planned agility in elite taekwondo athletes and to establish its relationship with sprint-time, jumping ability, and dynamic balance. Twenty-seven (20 males and 7 females) taekwondo athletes participated in this study. They performed taekwondo-specific agility test (TSAT) in 2 occasions (i.e., test-retest). In addition, they performed jumping ability (i.e., squat jump, countermovement jump, standing long jump, and 3-hop jump), sprint-time (5- and 20-m dash), and dynamic balance (i.e., Y-test) tests along with a planned agility test (i.e., T-test). To establish TSAT's construct validity, 2 subgroups were identified based on their international and national taekwondo results: top elite (9 males and 2 females) and elite (11 males and 2 females). Taekwondo-specific agility test showed high relative and absolute reliability as well as a good ability to detect small and meaningful performance change. Top-elite athletes showed greater (p < 0.001) TSAT performances (4.5 ± 0.4 seconds) compared with their elite (5.3 ± 0.4 seconds) counterparts. Receiving operating characteristic (ROC) analysis showed that TSAT was able to discriminate athletes of different competitive level as revealed by an area under the ROC curve of 0.94 (95% confidence interval: 0.76-0.99). Taekwondo-specific agility test demonstrated significant association with the T-test (r = 0.71; shared variance = 50%), which is considered as a gold-standard planned agility test. In addition, results showed moderate-to-large associations between TSAT and jumping ability, sprint-time, and dynamic balance tests. The TSAT might be considered as a valid and reliable test to evaluate specific agility of taekwondo athletes.

Taekwondo Training Improves Mood and Sociability in Children from Multicultural Families in South Korea: A Randomized Controlled Pilot Study

Purpose: Children from multicultural families face physical, social, mental, and intellectual hurdles; however, relative interventions are lacking in South Korea (hereafter Korea) in this regard. The purpose of this study was to investigate the effects of regular Taekwondo (TKD) training on physical fitness, mood, sociability, and cognitive functions in these children. Methods: This study included 30 children from multicultural families in Korea who were randomly assigned to a TKD group (n = 15) and control group (n = 15). The children in TKD group underwent 16 weeks of TKD training once a week for 60 min. Each participant underwent a basic fitness test and sociability questionnaire before and after the intervention. Furthermore, we examined the changes in the mood and cognitive function by determining the profile of mood states (POMS), and Stroop color and word test, respectively. Results: Results of the Stork test of balance were significantly higher in the TKD group after intervention (p < 0.05). In terms of sub-variables, POMS, tension, and depression scores were significantly lower (p < 0.05) after the intervention, while the vigor score was significantly higher in the intervention group than those in the control group (p < 0.05). Furthermore, sociability and ‘being left out’ score, a sub-variable of sociability, was significantly lower (p < 0.05) after the intervention, while sociability score was significantly higher (p < 0.05). Conclusions: Our findings suggest that participation in regular TKD training can be effective for balanced improvements in variables of basic fitness and that it exerts a positive effect on the mood and development of sociability.

Effect of Physical Activity Interventions for Girls on Objectively Measured Outcomes: A Systematic Review of Randomized Controlled Trials

INTRODUCTION

Most girls are not meeting physical activity (PA) guidelines, and 30% are overweight or obese. The purpose of this systematic review was to evaluate the evidence for PA intervention effects on accelerometer-measured PA, body mass index (BMI), and percent body fat (% BF) among girls.

METHODS

The Cumulative Index of Nursing and Allied Health Literature, PubMed, PsychInfo, and SportDISCUS databases were searched for randomized controlled trials published from 1985-2014. Studies with a PA intervention and outcomes of accelerometer-measured PA, BMI, or % BF were included.

RESULTS

Fifteen studies were reviewed. PA, BMI, and % BF were measured in 5, 15, and 10 studies, respectively. Effect sizes (ES) were highly variable. In one intervention, PA increased (ES = -0.17 to 0.08); in two interventions, BMI was reduced (ES = -0.11 to 0.62); and in five interventions, % BF was lowered (ES = 0.12 to 0.93).

DISCUSSION

Future research should involve preadolescent girls, improve methods for handling missing data, include objective measures of PA, and increase intervention attendance rates.

Age- and sex-related differences in the anthropometry and neuromuscular fitness of competitive taekwondo athletes

Anthropometry and neuromuscular fitness have been shown to relate with taekwondo (TKD) performance; however, little information is available on the variation of these fitness components by sex and age in athletes practicing this sport. The aim of the present study was to examine the anthropometry and neuromuscular fitness of TKD athletes by sex and age. A total of 393 athletes (7-48 years old), separated into six age groups (7-9, 10-11, 12-13, 14-17, 18-32, and 33+), were examined for anthropometry and performed a series of neuromuscular fitness tests (flexibility, agility, muscle power, and isometric strength). An age × sex interaction on body mass, body height, and body fat percentage (BF, p≤0.003, η²≥0.045), but not on body mass index (p=0.172, η²=0.020), was shown, where a larger increase in body mass and body height from 12-13 to 14-17 groups was observed in males than in females, and the sex difference in BF increased from 12-13 to 14-17 age group. An age × sex interaction on sit-and-reach (SAR) test, mean power output in the Bosco test, and Abalakov jump (p≤0.038, η²≥0.031) was observed with larger differences between 12-13 and 18-32 groups in males than in females. In SAR, it was remarkable that the male athletes achieved similar scores as female athletes in the 18-32 group. An age × sex group interaction on measures of isometric muscle strength (right and left handgrip, trunk, and legs) was also shown (p≤0.002, η²≥0.068), where larger differences in male than female athletes were observed between the 12-13 and 14-17 groups. From a practical perspective, coaches can use these findings as reference for the evaluation of their athletes. Because the anthropometric characteristics and neuromuscular fitness varied by sex (i.e., highest scores in males, except flexibility) and age (i.e., highest scores in the 18-32 age group) with unique sport-specific patterns in TKD athletes, these findings would be important for the development of specific training programs.

International variability in 20 m shuttle run performance in children and youth: who are the fittest from a 50-country comparison? A systematic literature review with pooling of aggregate results

OBJECTIVES

To describe and compare 20 m shuttle run test (20mSRT) performance among children and youth across 50 countries; to explore broad socioeconomic indicators that correlate with 20mSRT performance in children and youth across countries and to evaluate the utility of the 20mSRT as an international population health indicator for children and youth.

METHODS

A systematic review was undertaken to identify papers that explicitly reported descriptive 20mSRT (with 1-min stages) data on apparently healthy 9-17 year-olds. Descriptive data were standardised to running speed (km/h) at the last completed stage. Country-specific 20mSRT performance indices were calculated as population-weighted mean z-scores relative to all children of the same age and sex from all countries. Countries were categorised into developed and developing groups based on the Human Development Index, and a correlational analysis was performed to describe the association between country-specific performance indices and broad socioeconomic indicators using Spearman's rank correlation coefficient.

RESULTS

Performance indices were calculated for 50 countries using collated data on 1 142 026 children and youth aged 9-17 years. The best performing countries were from Africa and Central-Northern Europe. Countries from South America were consistently among the worst performing countries. Country-specific income inequality (Gini index) was a strong negative correlate of the performance index across all 50 countries.

CONCLUSIONS

The pattern of variability in the performance index broadly supports the theory of a physical activity transition and income inequality as the strongest structural determinant of health in children and youth. This simple and cost-effective assessment would be a powerful tool for international population health surveillance.

International normative 20 m shuttle run values from 1 142 026 children and youth representing 50 countries

OBJECTIVE

To develop sex-specific and age-specific international norms for the 20 m shuttle run test (20mSRT) in children and youth (aged 9-17 years), and to estimate the prevalence meeting the FITNESSGRAM criterion-referenced standards for healthy cardiorespiratory endurance (CRE).

METHODS

A systematic review was undertaken to identify papers explicitly reporting descriptive 20mSRT (with 1 min stages) data on children and youth since 1981. Data were included on apparently healthy (free from known disease/injury) 9-17 years old. Following standardisation to a common metric and for protocol differences, pseudo data were generated using Monte Carlo simulation, with population-weighted sex-specific and age-specific normative centiles generated using the Lambda Mu and Sigma (LMS) method. Sex-related and age-related differences were expressed as per cent and standardised differences in means. The prevalence with healthy CRE was estimated using the sex-specific and age-specific FITNESSGRAM criterion-referenced standards for [Formula: see text].

RESULTS

Norms were displayed as tabulated centiles and as smoothed centile curves for the 20mSRT using 4 common metrics (speed at the last completed stage, completed stages/minutes, laps and relative [Formula: see text]). The final data set included 1 142 026 children and youth from 50 countries, extracted from 177 studies. Boys consistently outperformed girls at each age group (mean difference±95% CI: 0.86±0.28 km/h or 0.79±0.20 standardised units), with the magnitude of age-related increase larger for boys than for girls. A higher proportion of boys (mean±95% CI: 67±14%) had healthy CRE than girls (mean±95% CI: 54±17%), with the prevalence of healthy CRE decreasing systematically with age.

CONCLUSIONS

This study provides the most comprehensive and up-to-date set of international sex-specific and age-specific 20mSRT norms for children and youth, which have utility for health and fitness screening, profiling, monitoring and surveillance.

Effect of a Six-Week Preparation Period on Acute Physiological Responses to a Simulated Combat in Young National-Level Taekwondo Athletes

The aim of this study was to examine changes in physical attributes, physiological characteristics and responses that occurred in a simulated combat during a six-week preparatory period in young taekwondo athletes. Seven athletes (age 12.17 ± 1.11 years) were examined before (pre-intervention) and after (post-intervention) a preparatory period for physical fitness and physiological responses to a 2×90 s simulated bout with a 30 s rest period. The heart rate (HR) was monitored during the simulated combat, and handgrip muscle strength (HMS) along with the countermovement jump (CMJ) were recorded before and after the combat. When compared with pre-intervention values, in post-intervention we observed a decrease in body mass, body fat percentage, and the HR at rest and during recovery after a 3 min step test, and an increase in maximal velocity of the cycle ergometer force-velocity test, the CMJ and mean power during the 30 s continuous jumping test (p<0.05). Furthermore, HR responses to a simulated combat were lower in the post-intervention session (p<0.05). CMJ values increased after the bout in both pre and post-intervention, with higher absolute values in the latter case (p<0.05), whereas there was no difference in HMS. Based on these findings, it can be concluded that the acute physiological responses to a simulated taekwondo combat vary during a season, which might be explained by changes in physical fitness.

Effect of 8 weeks of pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic muscle strength in male and female collegiate taekwondo athletes

The purpose of the study was to determine the effect of 8 weeks pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic strength in collegiate taekwondo athletes. Thirty-four collegiate athletes (male: 22, female: 12) participated. Body composition, bone mineral density, physical fitness, anaerobic capacity, and isokinetic muscle strength were tested. After statistical analysis was performed the results indicated that there were significant decreases in body weight, percent body fat, and fat tissue after 8 weeks of pre-season training. Bone mineral density increased significantly only in males. There were significant improvements in the 50 m shuttle run and 20 m multistage endurance run in both males and females. The sit & reach test and standing long jump were not significantly changed after 8 weeks. Relative peak power and anaerobic capacity were significantly improved in males. Significant increases in angular velocity were observed for knee extension at both % BW 60°/sec and 180°/sec in both males and females. A significant increase in angular velocity was seen for right knee flexion at % BW 60°/sec for males, but it decreased at % BW 180°/sec for both males and females. In conclusion, this study suggests that 8 weeks of pre-season training has a positive effect on body composition, physical fitness, anaerobic capacity, isokinetic muscular strength, and endurance. Nevertheless, an exercise approach with the goal of increasing lean tissue, and improving power in knee flexors and flexibility of athletes, should be included in the training program.

A follow-up study on the physique, body composition, physical fitness, and isokinetic strength of female collegiate Taekwondo athletes

The purpose of the study was to analyze changes in physique, body composition, physical fitness, and isokinetic strength in female collegiate taekwondo athletes. The study included 14 subjects, of whom 8 were followed up throughout the study. Anthropometric characteristics included body weight, height, sitting height, circumferences, and bone width. Physical fitness parameters included flexibility, agility, muscle strength, muscular endurance, power, speed, and cardiorespiratory endurance. Peak torque, mean power, and H/Q ratio were analyzed by using Cybex 770. All data were analyzed by using the SAS statistical program. Paired t test was performed, with 0.05 as the significance level. The results indicated significant changes in body weight, and upper arm and flexed upper arm circumferences during the experimental period. Test scores for plate tapping, and sit and reach significantly increased, but that for power decreased. In addition, the peak power of right flexion at 180°/sec was significantly increased, as well as the mean power of right and left flexion, and the H/Q ratio at 180°/sec.

Physical and physiological profiles of taekwondo athletes

Taekwondo has evolved into a modern-day Olympic combat sport. The physical and physiological demands of modern-day taekwondo competition require athletes to be competent in several aspects of fitness. This review critically explores the physical and physiological characteristics of taekwondo athletes and presents implications for training and research. International taekwondo athletes possess low levels of body fat and a somatotype that characterises a blend of moderate musculoskeletal tissue and relative body linearity. While there is some variation in the maximum oxygen uptake of taekwondo athletes, moderate to high levels of cardio-respiratory fitness are necessary to support the metabolic demands of fighting and to facilitate recovery between consecutive matches. Taekwondo athletes demonstrate high peak anaerobic power characteristics of the lower limbs and this attribute appears to be conducive to achieving success in international competition. The ability to generate and sustain power output using both concentric and 'stretch-shortening cycle' muscle actions of the lower limbs may be important to support the technical and tactical actions in combat. Taekwondo competitors also display moderate to high maximum dynamic strength characteristics of the lower and upper extremities, and moderate endurance properties of the trunk and hip flexor musculature. The dynamic nature of the technical and tactical actions in the sport demand high flexibility of the lower limbs. More extensive research is required into the physical and physiological characteristics of taekwondo athletes to extend existing knowledge and to permit specialised conditioning for different populations within the sport.

The Healthy for Life Taekwondo Pilot Study: A Preliminary Evaluation of Effects on Executive Function and BMI, Feasibility, and Acceptability

There is growing consensus that exercise improves cognitive functioning, but research is needed to identify exercise interventions that optimize effects on cognition. The objective of this pilot study was to evaluate Taekwondo implemented in public middle school physical education (PE). Two classes were randomly assigned to either: five sessions per week of PE or three sessions of PE and two sessions of Taekwondo. In PE sessions, evidence-based curriculum to address the Presidential Core Fitness Guidelines and California Physical Fitness Tests was implemented. Taekwondo sessions included traditional techniques and forms taught in an environment emphasizing respect and self-control. Sixty students were evaluated at baseline and during the last week of the intervention (nine months later). Differences in mean residualized change scores for parent-rated inhibitory behavioral control yielded a significant, large effect size (d =.95, p =.00), reflecting greater improvement among Taekwondo students. Results from an executive function computer-administered task revealed greater accuracy on the congruent trial (d = 2.00, p = .02) for Taekwondo students. Differences in mean residualized change scores for BMI z scores yielded a moderate, non-significant effect size (d = - .51, p = .16). The majority of Taekwondo students reported positive perceptions of Taekwondo and perceived self-improvement in self-control and physical fitness. Results suggest that Taekwondo is an exercise program that improves cognitive functioning and is both feasible and acceptable to implement in a public school setting.

Salivary cortisol and alpha-amylase reactivity to taekwondo competition in children

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(peak). Athletes spent 78% of the time working at HR > 90% HR(max), 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.