• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.11-18
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• 2020

PURPOSE: This study was to investigate examined the differences in the autonomic nervous functions of elite female judo athletes according to their performance by measuring the heart rate variability (HRV). METHODS: Sixteen elite female judo players participated in this study. The participants were divided into a high performance and low performance group according to the results of their competitions. The HRV (mean heart rate, SDNN, RMSSD, TP, LF, HF, LF/HF ratio) was measured in the resting status. A t-test was used to compare the two groups, and bivariate logistic regression analysis was performed to determine the HRV elements that affect performance. The data were analyzed using IBM SPSS Statistics ver. 24.0 (IBM Co., Armonk, NY, USA). RESULTS: The mean heart rate was higher in the high performance group (72.88) than in the low performance group (64.75) (p=.049). The LF/HF ratio was higher in the high performance group (3.43) than in the low performance group (0.83), and the results were significant (p=.038). No HRV elements having a significant effect on the performance were observed. CONCLUSION: This study showed that the activity of the sympathetic nervous system was dominant in the high performance group in the resting status than in the low performance. The high performance group is believed to be in the overtraining status who experience more stress.

• Proceedings of the KSCN Conference
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• 2003.11a
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• pp.1048-1048
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• 2003

The purpose of this study was to investigate dietary behaviors, body image, hematological index and nutrient intake of female athletes in Incheon. The subjects were 112 female athletes (field and track: n=32, firing: n=27, fencing: n=29, swimming: n=14, badminton: n=10) from middle and high schools in Incheon. This cross-sectional study was conducted by a self-administered questionnaire. Fasting blood samples were obtained and analyzed for hemoglobin (Hb), hematocrit(Hct), ferritin, serum iron, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), unsaturated iron binding capacity (UBC), total iron binding capacity (TIBC) and transferrin saturation (TS). Nutrient intakes collected from 3 day-recalls were analyzed by the Computer Aided Nutritional Analysis Program. Statistical analysis was conducted using SPSS 10.0 program. The results are summarized as follows: Average age of field and track athletes, firing, fencer and swimmer was 14 years and that of badmintoner was 17 years. Most of female athletes had dietary problems such as unbalanced meals, skipping meals, and preference of processed foods. More than 60% of female athletes skipped breakfast. As for perception of body image, most of female athletes perceived themselves fatter compared to normal body image. Especially, field and track athletes were more significantly experienced weight control compared to the other athletes (p<0.05). As for physical burden during exercise, 56.3% of swimmer and 31.3% of field and track athletes answered “very hard”, which showed a significant difference (p<0.001) More than 80% of female athletes had experienced a vertigo during exercise (p<0.01). Also, more than 50% of female athletes except badmintoner had experienced an irregular menstruation (p<0.05). Average serum iron level (p<0.05) and TS (p<0.05) of field and track athletes were significantly lower compared to the other athletes. Serum ferritin of badmintoner, field and track athletes and fencer was significantly lower compared to firing and swimmer (p<0.05). Nutrient intakes of female athletes except vitamin B6, niacin and phosphorus were lower than the Korean RDA. Especially, calcium and iron intakes of female athletes were under the 50% of the Korean RDA. Therefore, proper nutrition education and supplementation are required for female athletes to encourage desirable food habits as well as to improve their nutritional status and exercise performance.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.199-204
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• 2021

Objective: The purpose of this study was to present a new idea of methodology to evaluate Poomsae performance using inertial measurement unit (IMU) sensors in terms of signal processing techniques. Method: Ten collegian Taekwondo athletes, consisting of five Poomsae elite athletes (age: 21.4 ± 0.9 years, height: 168.4 ± 11.3 cm, weight: 65.0 ± 10.6 kg, experience: 12 ± 0.7 years) and five breaking demonstration athletes (age: 21.0 ± 0.0 years, height: 168.4 ± 4.7 cm, weight: 63.8 ± 8.2 kg, experience: 13.0 ± 2.1 years), voluntarily participated in this study. They performed three different black belt Poomsae such as Goryeo, Geumgang, and Taebaek Poomsae repeatedly twice. Repeated measured motion data on the wrist and ankle were calculated by the methods of cosine similarity and Euclidean distance. Results: The Poomsse athletes showed superior performance in terms of temporal consistency at Goryeo and Taebaek Poomsae, cosine similarity at Geumgang and Taebaek Poomsae, and Euclidian distance at Geumgang Poomsae. Conclusion: IMU sensor would be a useful tool for monitoring and evaluating within-subject temporal variability of Taekwondo Poomsae motions. As well it distinguished spatiotemporal characteristics among three different Poomsae.

• Journal of the Korean Data and Information Science Society
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• v.23 no.3
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• pp.475-485
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• 2012

The purpose of this study was to examine the impact of the Sport Talent Development Environment on the Achievement Goal in Sport of college athletes. The Sport Talent Development Environment (Martindale et al., 2010) had seven factors, but only four factors (long-term development, lack of quality preparation, communication, lack of understanding) were used after exploratory factor analysis. The Achievement Goals in Sport (Wang et al., 2007) was composed of four factors (mastery approach, mastery avoidance, performance mastery, performance avoidance). The results showed that 1)long-term development factor and communication factor of male athletes were significantly higher than female athletes while lack of understanding factor of female athletes were significantly higher than male athletes, 2)mastery avoidance factor of female athletes was significantly higher than male athletes, and 3)factors of development environment accounted for 27.8% to 34.5%-male athletes and for 13.2% to 22.7%-female athletes variance in the four achievement goals. Therefore, it is important for coaches and sport administrators to take these results into consideration when designing an effective talent development program.

• Korean Journal of Community Nutrition
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• v.24 no.1
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• pp.47-59
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• 2019

Objectives: Young athletes require adequate nutrition to maintain their athletic performance, growth and health. This study examined the status and needs of nutrition management and meal services for student athletes among the athlete's parents. Methods: The subjects were parents of elementary, middle, and high school athletes (n=323) from 18 schools participating mainly in the Sports Food Truck. The questionnaire included general characteristics, status and needs on nutrition management and meal service for student athletes, and satisfaction with the Food Truck. The survey was done during 2018. The data were analyzed according to the school groups using a ${\chi}^2-test$ or ANOVA. Results: Approximately 45% of subjects had difficulty in the nutrition management of athletes, and 87.1% had not received nutrition education. Approximately 74% wanted nutrition education held for athletes, and mainly wanted topics on nutrition management for health and eating for athletic performance. The preferred methods were lectures and cooking activity. The responses on the necessity of nutrition education for athletes, desired education topics, and desired times for education differed significantly according to the school groups (p<0.05). Most subjects also wanted nutrition information mainly through SNS. In the athlete's meal, breakfast and snacks were highlighted as the meal to supplement. Approximately 90.3% responded that providing a meal service is necessary. The subjects preferred snacks before/after exercise and dinner if a meal service was provided. They preferred Korean food, followed by snacks, and a dish meal. As the meal type, the subjects wanted the Food Truck and packed meal. The responses on necessity of a meal service (p<0.05), preferred food (p<0.001), and meal type (p<0.001) in the meal service differed significantly according to the school groups. Approximately 43% were satisfied with the Food Truck and 50.8% responded as average. They made suggestions for the Food Truck in terms of foods, operations and frequency. Conclusions: Based on the study results, nutrition education and meal service may support nutrition for student athletes considering the needs of the parents according to the school groups.

• Nutrition Research and Practice
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• v.17 no.4
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• pp.762-779
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• 2023

BACKGROUND/OBJECTIVES: Mediterranean diet is an environmentally friendly and healthy diet model. The diet offers many vegetables, fruits, nuts, and olive oil to consumers. In addition, it provides moderate amounts of fish and chicken, smaller quantities of dairy products, red meat, and processed meat. The Mediterranean diet has a high anti-inflammatory and antioxidant content, and it causes many physiological changes that can provide a physical performance advantage. This study examined the effects of a 15-day menu, which was planned using foods with a low acid load within the Mediterranean diet rules, on the exercise performance, lactate elimination, anthropometric measurements, and body composition. SUBJECTS/METHODS: Fifteen professional male athletes between the ages of 13 and 18, who were engaged in ski running, were included in the experimental study. Dietary intervention was applied for 15 days. The athlete performances were evaluated by applying the vertical jump test, hand grip strength, 20 meters shuttle run test, and Borg fatigue scale. After the shuttle run test (every 3 min for 30 min), blood was drawn from the finger, and the lactate elimination time was calculated. Performance and lactate measurements, body analysis, and anthropometric measurements were taken before and after dietary intervention. RESULTS: The vertical jump height and hand grip strength increased after the intervention (P < 0.05). The test duration, total distance, the number of shuttles, and maximum oxygen consumption parameters of the shuttle run test increased (P < 0.05). After the intervention, the athletes' perceived fatigue scores decreased in several stages of the shuttle run test (P < 0.05). The lactate elimination time and athlete's body composition were similar in repeated measurements (P > 0.05). In the last measurements, the upper middle arm circumference decreased while the height of the athletes increased (P < 0.05). CONCLUSIONS: These results show that the Mediterranean diet is a safe and feasible dietary approach for aerobic performance and strength increase.

• Biomedical Science Letters
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• v.11 no.2
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• pp.227-235
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• 2005

It has been reported that endurance performance is influenced by various environmental and genetic factors. In view of an important role of human mitochondrial DNA (mtDNA) as a candidate for endurance performance, this study focused on the relationships between $VO_{2max}$ value as a measure of endurance performance or other associated phenotypes and four mtDNA restriction fragment length polymorphisms (RFLPs) (Bam HI, Hinc II1, Hinc II2 and Nci I) in the NADH dehydrogenase subunit 5 and one (Kpn I) in the D-loop region of mtDNA. MtDNA was purified from buffy coat in human peripheral blood, and PCR-RFLP analysis was performed to estimate the allele frequencies of each polymorphism in the mtDNA. There were no significant differences in allele distributions of all polymorphisms studied between male athletes and controls, respectively (P>0.05). However, the Kpn I polymorphism was significantly associated with diastolic blood pressure level in male athletes, respectively (P<0.05). Therefore, our results suggest that this polymorphism might be one of the factors modifying inter-individual difference in cardiovascular risk. Further studies using larger sample size will be required to generalize these results from the study described herein.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.535-546
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• 2017

The purpose of The purpose of this study is to empirically investigate the relationships among achievement goal-orientation, sports confidence, and exercise commitment in university student-athletes. To fulfill this purpose, data were collected from 347 student-athletes enrolled in universities located in Seoul and the Gyeong-In area, and analysis thereof was carried out. Conclusion drawn from the performance of this study is as follows: First, university student-athletes' achievement goal-orientation has significant effects on their sports confidence. Second, university student-athletes' sports confidence has significant effects on their exercise commitment. Third, university student-athletes' achievement goal-orientation has significant effects on their exercise commitment. Fourth, sports confidence has indirect mediation effects on the relationship between achievement goal-orientation and exercise commitment in university student-athletes, and it was found that these factors had causal relationships. Therefore, the findings of this study show that university student-athletes' achievement goal-orientation plays an important role for their effective commitment to exercise, in the process of which sports confidence plays the role of a mediator, suggesting that psychological support as well as motor skill cultivation is necessary to enhance university student-athletes' performance.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.370-378
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• 2015

BACKGROUND/OBJECTIVES: Athletes generally desire changes in body composition in order to enhance their athletic performance. Often, athletes will practice chronic energy restrictions to attain body composition changes, altering their energy needs. Prediction of resting metabolic rates (RMR) is important in helping to determine an athlete's energy expenditure. This study compared measured RMR of athletic and non-athletic adolescents with predicted RMR from commonly used prediction equations to identify the most accurate equation applicable for adolescent athletes. SUBJECTS/METHODS: A total of 50 athletes (mean age of $16.6{\pm}1.0years$, 30 males and 20 females) and 50 non-athletes (mean age of $16.5{\pm}0.5years$, 30 males and 20 females) were enrolled in the study. The RMR of subjects was measured using indirect calorimetry. The accuracy of 11 RMR prediction equations was evaluated for bias, Pearson's correlation coefficient, and Bland-Altman analysis. RESULTS: Until more accurate prediction equations are developed, our findings recommend using the formulas by Cunningham (-29.8 kcal/day, limits of agreement -318.7 and +259.1 kcal/day) and Park (-0.842 kcal/day, limits of agreement -198.9 and +196.9 kcal/day) for prediction of RMR when studying male adolescent athletes. Among the new prediction formulas reviewed, the formula included in the fat-free mass as a variable [$RMR=730.4+15{\times}fat-free\;mass$] is paramount when examining athletes. CONCLUSIONS: The RMR prediction equation developed in this study is better in assessing the resting metabolic rate of Korean athletic adolescents.

• Korean Journal of Applied Biomechanics
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• v.26 no.2
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• pp.143-151
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• 2016

Objective: The purpose of this study was to investigate the effect of fatigue induction on ground reaction force (GRF) components, postural stability, and vertical jump performance in Taekwondo athletes. Method: Ten Taekwondo athletes (5 men, 5 women; mean age, $22.30{\pm}2.62years$; mean height, $174.21{\pm}9.20cm$; mean body weight, $67.28{\pm}12.56kg$) participated in this study. Fatigue was induced by a short period of strenuous exercise performed on a motorized treadmill. The analyzed variables included vertical jump performance, static stability (mediolateral [ML], center of pressure [COP], anteroposterior [AP] COP, ${\Delta}COPx$, ${\Delta}COPy$, and COP area), postural stability index values (ML stability index [MLSI], AP stability index [APSI], vertical stability index [VSI], dynamic postural stability index [DPSI]), and GRF components (ML force, AP force, peak vertical force [PVF], and loading rate). To analyze the variables measured in this study, PASW version 22.0 was used to calculate the mean and standard deviation, while a paired t-test was used to evaluate the pre- versus post-fatigue results. Pearson's correlation coefficients among variables were also analyzed. The statistical significance level was set at ${\alpha}$ = .05. Results: Vertical jump performance decreased significantly after the induction of fatigue, while AP COP, ${\Delta}COPx$, COP area, APSI, VSI, and DPSI increased significantly. PVF and loading rate increased significantly after the induction of fatigue, while the postural stability variables (AP COP, ${\Delta}COPy$, COP area, APSI, VSI, DPSI) were similarly correlated with GRF components (PVF, loading rate) after fatigue was achieved (r = .600, $R^2$ = 37%). Conclusion: These results suggest that the induction of fatigue can decrease postural stability and exercise performance of Taekwondo athletes during training and competition sessions.