• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.183-189
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• 2010

The balanced performance of dominant and non-dominant leg is very important to Taekwondo sparring. The purpose of this study was to investigate whether elite Taekwondo athletes would have balanced biomechanical performance and intra-limb coordination in executing different types of Taekwondo kicks. Twelve athletes(more than 10 year practice experience) participated in this study and performed six basic kicks(i.e., the front, roundhouse, side, back, thrashing, and turning-back kick). Results indicated no statistical difference on response time, peak kicking velocity, single limb vertical jump height, and angle-angle plot between dominant leg and non-dominant leg(p>.05). In conclusion, elite Taekwondo athletes had equivalent ability between dominant leg and non-dominant leg in performing Taekwondo kicks. This might be an advantage to elite athletes for Taekwondo sparring because they could use both leg without any restriction.

• Genomics & Informatics
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• v.17 no.1
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• pp.11.1-11.7
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• 2019

Athletic performance is a complex multifactorial trait involving genetic and environmental factors. The heritability of an athlete status was reported to be about 70% in a twin study, and at least 155 genetic markers are known to be related with athlete status. Mitochondrial DNA (mtDNA) encodes essential proteins for oxidative phosphorylation, which is related to aerobic capacity. Thus, mtDNA is a candidate marker for determining physical performance. Recent studies have suggested that polymorphisms of mtDNA are associated with athlete status and/or physical performance in various populations. Therefore, we analyzed mtDNA haplogroups to assess their association with the physical performance of Korean population. The 20 mtDNA haplogroups were determined using the SNaPshot assay. Our result showed a significant association of the haplogroup F with athlete status (odds ratio, 3.04; 95% confidence interval, 1.094 to 8.464; p = 0.012). Athletes with haplogroup F ($60.64{\pm}3.04$) also demonstrated a higher Sargent jump than athletes with other haplogroups ($54.28{\pm}1.23$) (p = 0.041). Thus, our data imply that haplogroup F may play a crucial role in the physical performance of Korean athletes. Functional studies with larger sample sizes are necessary to further substantiate these findings.

• Journal of Sport and Applied Science
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• v.5 no.2
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• pp.9-15
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• 2021

Purpose: Prior literature posits that leadership of coach influences athletes' performance via delegate interactions. The purpose of this study is to investigate the effect of the type of instructor on the exercise stress of university athletes and to provide instructors with informative coaching methods especially for their leadership. Research design, data, and methodology: In order to achieve the purpose of the research, Seoul and Gyeonggi Province Materials University athletes were selected as a sample, 360 college athletes participated in the survey and data were screened and finally 314 were analyzed. The collected data were analyzed via descriptive analysis and multiple regressions. To examine the validity and reliability of the survey items, factor analysis and Cronbach's α were computed. Results: Coaches' leadership types are found to influence university athletes' exercise stress significantly. In specific, transformational leadership negatively influences teaching Complaints. Transformational leadership also negatively influences time constraints. However, transformational and transactional leadership do not have any effect on career concerns. transformational and transactional leadership also do not influence functional instability of college athletes. Conclusions: Overall, leadership types of coach partially influence exercise stress of athletes. These findings posit that transformational leadership contribute in developing reliable relationship between athletes and instructors. Further implications were discussed.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.275-281
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• 2015

Objective : In order for Taekwondo athletes to perform destructive kicking performance, they are expected to have Taekwondo-specific muscle properties such as high muscle strength and power. The purpose of this study was to investigate the joint angle-dependent force-producing property of Taekwondo athletes' knee extensor muscles, which is one of the primary muscle groups involved in kicking performance. Method : Ten Taekwondo male athletes (age: $19.9{\pm}0.7yrs$, height: $180.6{\pm}6.2cm$, body mass: $75.9{\pm}8.9kg$, career: $9.2{\pm}2.9yrs$.) and 10 healthy male non-athletes (age: $26.3{\pm}2.6yrs$, height: $174.2{\pm}4.8cm$, body mass: $72.8{\pm}7.7kg$) participated in this study. Subjects performed maximum isometric knee extension at knee joint angles of $40^{\circ}$, $60^{\circ}$, $80^{\circ}$, and $100^{\circ}$ (the full knee extension was set to $0^{\circ}$) with the hip joint angles of $0^{\circ}$ and $80^{\circ}$ (the full extension was set to $0^{\circ}$). During the contractions, knee extension torque using an isokinetic dynamometer simultaneously with muscle activities of the rectus femoris (RF), and the vastus lateralis (VL) and vastus medialis (VM) using surface electromyography were recorded. Based on the torque values at systematically different knee-hip joint angles, the joint torque-angle relationships were established and then the optimal joint angle for the knee extensor was estimated. Results : The results of this study showed that the isometric knee extension torque values were greater for the Taekwondo athletes compared with the non-athlete group at all hip-knee joint angle combinations (p<.05). When the hip joint was set at $80^{\circ}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($313.61{\pm}36.79Nm$ and $221.43{\pm}35.92Nm$, respectively; p<.05) but the estimated optimum knee joint angles were similar ($62.33{\pm}5.71^{\circ}$ and $62.30{\pm}4.67^{\circ}$ for the Taekwondo athletes and non-athlete group, respectively). When the hip joint was set at $0^{\circ}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($296.29{\pm}45.13Nm$ and $199.58{\pm}25.23Nm$, respectively; p<.05) and the estimated optimum knee joint angle was larger for the Taekwondo athletes compared with the non-athlete group ($78.47{\pm}5.14^{\circ}$ and $67.54{\pm}5.77^{\circ}$, respectively; p<.05). Conclusion : The results of this study suggests that, compared with non-athletes, Taekwondo athletes have stronger knee extensor strength at all hip-knee joint angle combinations as well as longer optimum muscle length, which might be optimized for the event-specific required performance through prolonged training period.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.407-415
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• 2002

Athletic products must meet the needs of athletes and the demands imposed by sports through innovative design. These needs of athletes and requirements of sports are performance, protection and comfort related. In depth knowledge of anatomy and physiology, etiology of commonly reported injuries, and lower extremity mechanics form the basis of product creation/engineering. Game analysis which entails time and frequency surveys of the skills performed during a game, interviews with athletes and coaches, and discussions with medical staffs are used to identify the skills that are critical to the needs of athletes. In lab full biomechanical analyses of these skills and/or physiological responses of the athletes lead to clear functional criterions that serve as guidelines to be met by the design team. The concepts created by the design team are in turns subjected to the same battery of biomechanical analyses. The learning gathered through this pluridisciplinary process is used to further evolve design concepts. The evolution-testing loop is repeated until biomechanical and/or physiological, mechanical and perceptual tests indicate that the design concept meets the established functional design criterions. At that time, the design concepts is ready for manufacturing research and development. Additional biomechanical and physical tests are performed through that phase to confirm that the manufacturing processes preserve the functionality of the design concept. Durability and long term performance of production samples are evaluated through a final three month long weartest program. A rigorous research/testing program is crucial to create and engineer sport products that meet the performance, protection.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.148-152
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• 2022

The purpose of this study was to investigate whether there is a difference in self-reflection and insight according to the performance level of college athletes. A total of 395 (210 male, 185 female) college athletes from 6 universities were sampled. The level of performance was divided into upper, middle, and lower groups based on the results of matches played in the past 1 year. To measure self-reflection and insight, THE SELF-REFLECTION AND INSIGHT SCALE developed by Grant et al. [4] was used. As a result, there was a statistically significant difference according to the level of performance, and as a result of post-hoc(scheffe) analysis, the upper group of performance was higher than that of the middle group and the lower group.

• Journal of Sport and Applied Science
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• v.6 no.4
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• pp.11-23
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• 2022

New insights into the aetiology of anaemia in athletes have been discovered in recent years. From hemodilution and redistribution, which are thought to commit to so-called "sports anaemia," to iron deficiency triggered by higher requirements, dietary requirements, decreased uptake, enhanced losses, hemolysis, and sequester, to genetic factors of different types of anaemia (some related to sport), anaemia in athletes necessitates a careful and multisystem methodology. Dietary factors that hinder iron absorption and enhance iron bioavailability (e.g., phytate, polyphenols) should be considered. Celiac disease, which is more common in female athletes, may be the consequence of an iron deficiency anaemia that is unidentified. Sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis are all ways iron is lost during strength training. In training, evaluating the iron status, particularly in athletes at risk of iron deficiency, may work on improving iron balance and possibly effectiveness. Iron status is influenced by a healthy gut microbiome. To eliminate hemolysis, athletes at risk of iron deficiency should engage in non-weight-bearing, low-intensity sporting activities.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.260-268
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• 2022

The purpose of this study is to investigate the effect of social support of table tennis players on exercise stress and athletic performance. To clarify the purpose of this study, middle and high school table tennis players registered with the Korea Table Tennis Association in 2020 were targeted. After that, a total of 300 subjects (150 males and 150 females) were selected using the convenient sampling method. The survey tool consisted of a questionnaire on a 5-point scale. Also, the collected data were statistically processed using SPSS version 20.0. The results obtained through this research procedure are as follows. First, it was found that the social support of athletes partially affected the exercise stress. Second, it was found that the social support of athletes partially affected athletic performance. Third, exercise stress of athletes was found to have a partial effect on athletic performance.

• Korean Journal of Community Nutrition
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• v.3 no.1
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• pp.94-106
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• 1998

Nutrient supplements are often used by athletes as ergogenic aids. This study was done to investigate the use of nutrient supplements, nutritional knowledge and nutrient intakes of athletes. Subjects of this survey consisted of 195 national team athletes. The prevalence of nutrient supplement use among all subjects was 30.3%, and the frequency of use, by decreasing order, was weight lifting, taekwondo and badminton athletes. Sport drinks were the type of nutrition supplement used most frequently and vitamin C was the second one. Major reasons for nutrient supplement use were to improve training performance and to recover from fatigue, to supplement fluid and to control weight. The average score of nutritional knowledge was $19.9\pm{2.5}$ for nutrient supplement users, and $19.8\pm{3.6}$ for nutrient supplement nonusers. Intakes of protein, calcium and niacin of the user were higher than those of the nonuser. This information provided by this study can help sport nutritionists identify nutrient supplement most often consumed by national elite athletes and can aid counselors as they guide athletes towards more healthful nutrition practices.

• The Korean Journal of Physiology
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• v.1 no.1
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• pp.91-101
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• 1967

The maximal oxygen intake (MOI) was determined in 54 males (23 nonathletes, 10 basketball players, 8 hand ball players, 7 weight lifters and 6 long distance runners) and in 49 females (24 non-athletes, 16 basketball players and 9 volley ball players) by using a treadmill method outlined in Part I of the present investigation and the following results were obtained: (1) The maximal aerobic work capacity varied from the lowest value of 1,008 kg-m/min in female non-athletes to the highest value of approximately 2,000 kg-m/min in male basketball players and long distance runners. Values of other groups varied from 1,400 kg-m/min in male non-athletes and female athletes to 1,800 kg-m/min in male hand ball players. (2) The MOI per unit body weight varied from the lowest value of 41.3 ml/min/kg in female non-athletes to the highest value of 67.6 ml/min/kg in male long distance runners. Values of other groups were in the order of 47 to 55 ml/min/kg. (3) The heart rate during maximal aerobic work performance varied from the lowest value of approximately 180 per min in female basketball players and male long distance runners to the highest value of 190 or above in nonathletes of both sexes. (4) An estimate of oxygen debt as measured during 15 minutes following the maximal work was 3.841 in female non-athletes, 4.681 in female athletes, 5.561 in male non-athletes and 6.321 in male athletes. These results indicate that the MOI per unit body weight as well as the oxygen debt of Korean non-athletes were comparable to, while corresponding values of Korean athletes were considerably lower than, those of other countries such as Japan, the United States of America and Europe.