• Korean Journal of Exercise Nutrition
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• v.25 no.3
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• pp.8-15
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• 2021

[Purpose] Excessive reactive oxygen species (ROS) induced by prolonged high-intensity exercise can cause structural and functional damage. Antioxidant polyphenol supplementation, which reduces ROS levels, may improve high-intensity exercise performance. We evaluated the effect of lychee fruit extract, which contains high levels of low-molecular-weight oligomerized polyphenols, on high-intensity exercise performance. [Methods] Ten male athletes were included in an open-label trial that consisted of control and intervention phases, with a 7-day washout period between phases. The participants were administered oligomerized lychee fruit extract for seven days, whereas no intervention was given in the control phase. High-intensity intermittent exercise and the Wingate test were performed. The power output, blood lactate levels, reactive oxygen metabolite levels, biological antioxidant potential, heart rate, and rate of perceived exertion were measured. [Results] The average power output was significantly higher in the intervention phase than in the control phase (P < 0.01), while the change in blood lactate levels was significantly lower in the intervention phase than in the control phase (P < 0.05). The average heart rate was significantly higher in the intervention phase than in the control phase (P < 0.05), without changing the rate of perceived exertion. Although there was no difference in reactive oxygen metabolite levels between the phase, the change in biological antioxidant potential was larger in the intervention phase than in the control phase (P = 0.06). The Wingate test showed no significant differences between the phase. [Conclusion] Short-term loading with oligomerized lychee fruit extract may increase performance during high-intensity intermittent exercise by improving metabolism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1128-1135
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• 2011

The purpose of this study was to identify the effects of field athletes' self-management on their psychological happiness. The subjects of the study were 184 athletes (male=82, female=102) who participated in the 91th National Athletes Meeting. All statistical analyses and description methods were computed by SPSS window 18.0. The discriminant analysis was used to find effects of self-management on their psychological happiness, ANOVA and Multiple regression. The results of this study were as followings: Frist, there was not significant difference to The Relationship between social-demographical variables and self-management, their psychological happiness. Second, self-management had a significant effect on psychological happiness. Based on the results, Field athletes's self-management has a positive effect on their psychological happiness.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.67-79
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• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.311-325
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• 2003

A relation between the movement range of arms and arising moment has been studied to find out efficient movement range to minimize impact concerning arm landing in sports aerobics. Four male athletes who won top three in national-level sports aerobics competition were chosen for the experiment. They were allowed to jump in between two force platform so that the right hand and the right leg could land onto the front and rear force platform, respectively. The sampling frequency was 200 Hz. The main conclusions based on the analysis of the angle and joint moment parameters of wrist, elbow, and shoulder are as follows: 1. The wrist moment was small when its angle was small, indicating that the dorsi-flexion of the wrist joint offered a positive influence to reduce wrist moment. 2. The elbow angle increased as wrist angle decreased and vice versa. This means that the movement range of the wrist joint affects that of the elbow joint. The darsi-flexion of the wrist is the position to absorb the impact of the elbow effectively rather than to absorb the impact of the wrist itself. The impact is absorbed by the flexion of wrist joint rather than the wrist. 3. The degree of moment transfer of the shoulder joint, having absorbed the impact from the elbow and elbow joint, became dependent on the efficiency of the fore-joints impact absorption.

• Korean Journal of Exercise Nutrition
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• v.25 no.1
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• pp.1-6
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• 2021

[Purpose] We determined the effect of partial sleep deprivation (PSD) after an exercise session on exercise performance on the following morning. [Methods] Eleven male athletes performed either a normal sleep trial (CON) or a PSD trial. On the first day (day 1), all subjects performed an exercise session consisting of 90 min of running (at 75% ${\dot{V}}O_{2max}$) followed by 100 drop jumps. Maximal strength (MVC) was evaluated before and after exercise. In the CON trial, the sleep duration was 23:00-7:00, while in the PSD trial, the sleep duration was shortened to 40% of the regular sleep duration. On the following morning (day 2), MVC, the metabolic responses during 20 min of running (at 75% ${\dot{V}}O_{2max}$), and time to exhaustion (TTE) at 85% ${\dot{V}}O_{2max}$ were evaluated. [Results] On day 2, neither the MVC nor ${\dot{V}}O_2$ during 20 min of running differed significantly between the two trials. However, the respiratory exchange ratio was significantly lower in the PSD trial than in the CON trial (p = 0.01). Moreover, the TTE was significantly shorter in the PSD trial than in the CON trial (p = 0.01). [Conclusion] A single night of PSD after an exercise session significantly decreased endurance performance without significantly changing muscle strength or cardiopulmonary response.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.281-288
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• 2020

The objective of the study was to identify the structural relationship between adolescent athletes'positive thinking and coping flexibility, burnout. In order to achieve such research goal, male and female athletes'from physical education middle and high schools across the nation were recruited; using a convenience sampling method, a total of 333 samples were selected as the final effective samples. The data went through a goodness-of-fit test for the whole model using SPSS 20.0 and AMOS 20.0 and a hypothesis test. The result is as follows: first, positive thinking was revealed to have significant influence on coping flexibility. second, repertories and flexible a subfactor of coping flexibility, had significant negative (-) effects on burnout, whereas reflective had no significant effects on it. Third, positive thinking was revealed to have no significant influence on burnout. In conclusion, although positive thinking is a variable that is based on internal information, positive thinking did not directly affect psychological burnout, but coping flexibility can be used to prevent burnout.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.4
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• pp.85-93
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• 2021

PURPOSE: This study aimed to examine the evaluation of muscle activity, muscle fatigue and balance in male high school Taekwondo athlete with a deformity of the medial longitudinal arch. METHODS: The 20 male high school Taekwondo athletes participated in the study they have been measured radiographic a medial longitudinal arch and divided into a medial longitudinal arch group (higher than 18.8°; MLA group, n = 12) and control group (lower than 18.8°; CON group, n = 8). All subjects were measured muscle activity (TA, PT, PL and PB), muscle fatigue (TA, PT, PL and PB) and balance (A-, AL-, L-, PL-, P-, PM-, M-, AM-direction and composite score; CS). RESULTS: The muscle activity of TP was significantly higher in MLA group compared to CON group (p = 031) and the muscle fatigue of TA was significantly lower in MLA group compared to CON group (p = .043). However, balance did not show significant differences between the groups. CONCLUSION: These results confirmed that male high school Taekwondo athlete with a deformity of medial longitudinal arch increase TP and decrease TA, but there was no difference on balance.

• Journal of Sport and Applied Science
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• v.7 no.4
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• pp.7-12
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• 2023

Purpose: The purpose of this study is to compare and analyze power and agility, which are factors that affect performance, by dividing adult fin swimmers into groups by male and female careers, and use them as basic data for improving performance during fin swimmer guidance and training. Research design, data, and methodology: Accordingly, 21 fin swimmers were selected and they were divided to four groups by gender and career to conduct experiments. Power and agility, which are factors related to performance of fin swimmers, were measured. Independent sample T-Test was conducted to verify differences between groups. Results: As a result of this study, there was no statistically significant difference in power and agility by the careers of male and female athletes. Conclusion: The results of this study can be used as basic data for organizing training programs suitable for the gen-der of fin swimmers and basic data for the guidance and training of fin swimmers. In future follow-up studies, based on the results of this study, it is expected that follow-up studies should be con-ducted to improve detailed performance according to age, fin swimming events, and gender. Further implications were discussed.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.155-161
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• 2021

Objective: There is a lack of studies using the 3D-2D image registration techniques on the mechanism of a shoulder injury for ice hockey players. This study aimed to analyze in vivo 3D glenohumeral joint arthrokinematics in collegiate ice hockey athletes and compare shoulder scaption with or without a hockey stick using the 3D-2D image registration technique. Method: We recruited 12 male elite ice hockey players (age, 19.88 ± 0.65 years). For arthrokinematic analysis of the common shoulder abduction movements of the injury pathogenesis of ice hockey players, participants abducted their dominant arm along the scapular plane and then grabbed a stick using the same motion under C-arm fluoroscopy with 16 frames per second. Computed tomography (CT) scans of the shoulder complex were obtained with a 0.6-mm slice pitch. Data from the humerus translation distances, scapula upward rotation, anterior-posterior tilt, internal to external rotation angles, and scapulohumeral rhythm (SHR) ratio on glenohumeral (GH) joint kinematics were outputted using a MATLAB customized code. Results: The humeral translation in the stick hand compared to the bare hand moved more anterior and more superior until the abduction angle reached 40°. When the GH joint in the stick hand was at the maximal abduction of the scapula, the scapula was externally rotated 2~5° relative to 0°. The SHR ratio relative to the abduction along the scapular plane at 40° indicated a statistically significant difference between the two groups (p < 0.05). Conclusion: With arm loading with the stick, the humeral and scapular kinematics showed a significant correlation in the initial section of the SHR. Although these correlations might be difficult in clinical settings, ice hockey athletes can lead to the movement difference of the scapulohumeral joints with inherent instability.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.97-105
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• 2022

The purpose of this study was to analyze the effects of flossing band exercise on the range of motion and vertical jump for taekwondo demonstration athletes with ankle functional instability. The subjects of this study were 21 male Taekwondo Demonstration Team athletes enrolled at D University. They were divided into functional ankle instability group(FAIG, n=7), mild ankle instability group(MAIG, n=7), and ankle stability group(ASG, n=7). All groups performed a acute flossing band exercise program. The results of this study are as follows; dorsi flexion(p<.01), inversion(p<.01), eversion(p<.05) and vertical jump(p<.01) were significantly increased in the FAIG. Flossing band exercise of Taekwondo demonstration team with FAI increased joint range of motion and vertical jump. Therefore, it was confirmed that it could be an intervention that can improve performance and reduce the risk of ankle injury.