• Journal of Sport and Applied Science
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• v.5 no.3
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• pp.1-5
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• 2021

Purpose: The purpose of this study is to examine the relationship between the leadership style and performance of university athletes' leaders. Research design, data, and methodology: This study utilizes survey items constructed by reserach variables. Data were collected from college athletes of universities in Seoul and Gyeonggi-do, where sports teams are located. A convenient sampling method was used of non-probability sampling methods. A total of 314 responses were computed at statistic program, spss version 21.0. In specific, the study employed correlation, exploary factor analysis, mulple-regressions to test the effects of ledership types on performance. Results: As a result of an empirical analysis to examine the relationship between the leader's leader-ship style and the athletic performance of college athletes, it was found that the leader's leadership style had a significant effect on the college athletes' performance. Conclusions: A leader's leadership style is a very important factor for college athletes who enter the professional world after graduating from college. Therefore, coaches maintain a horizontal relationship with the players rather than a vertical one, and if a leadership style suitable for the players is applied, the players' performance will be better, and the development potential of players and teams will increase. Suggestions for future studies were discussed.

• Korean Journal of Exercise Nutrition
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• v.25 no.2
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• pp.20-25
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• 2021

[Purpose] The aim of this review was to discuss the effects of vitamin D on physical performance and musculoskeletal injuries in athletes and provide information on the field applications of vitamin D. [Methods] A systematic review was conducted to identify studies on vitamin D in athletes that assessed serum vitamin D levels, vitamin D and physical performance, vitamin D and musculoskeletal injuries, and practical guidelines for supplementation of vitamin D. [Results] Several studies reported that a high proportion of athletes had vitamin D insufficiency or deficiency. Low serum levels of vitamin D in athletes were more pronounced in winter than in other seasons, and indoor athletes had lower serum vitamin D levels than outdoor athletes. Low vitamin D levels have been demonstrated to have negative effects on muscle strength, power, and endurance; increase stress fractures and other musculoskeletal injuries; and affect acute muscle injuries and inflammation following high-intensity exercises. Therefore, periodic assessment and monitoring of vitamin D levels are necessary in athletes; the recommended serum level of 25(OH)D is > 32 ng/mL and the preferred level is > 40 ng/mL (-1). In those with low levels of vitamin D, exposure to sunlight and an improved diet or supplements may be helpful. Particularly, 2000-6000 IU of supplemental vitamin D3 can be consumed daily. [Conclusion] Vitamin D is a potential nutritional factor that can significantly affect physical performance and musculoskeletal injuries in athletes. The importance and role of vitamin D in athletes should be emphasized, and the current levels of vitamin D should be assessed. Therefore, it is essential to periodically evaluate and monitor serum vitamin D levels in athletes.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.545-553
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• 2016

The purpose of this study is finding out the effect of self-confidence and stress on University Judo Athletes performance. For this study, 249 participants of University Judo team athletes were sampled using convenient sampling method. To process data, AMOS 23.0 and SPSS PC+23.0 Version statistical program for WINDOWS were used and frequency analysis, confirmatory factor analysis, reliability, correlations and structural equation model analysis were conducted. Through such processes and method of the study as above, the results of this study are as follows. Firstly, it was discovered that self-confidence had static influence to athletes performance. Secondly, the stress did not affect the athletes performance.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.142-151
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• 2023

The purpose of this study is to verify the research model and identify the causal relationship among leader's super leadership, self-leadership, psychological empowerment, sport commitment and performance perceived by Taekwondo athletes. The subjects of the study were middle and high school Taekwondo athletes registered in the Korea Taekwondo Association in 2020 and 2021, and data from 454 people were used as final effective samples through convenience sampling. The collected data used the SPSS 23.0 version and the Amos 21.0 version to verify the hypothesis. As a result, the following conclusions were obtained. First, we discovered that the leader's super leadership had a positive impact on the athlete's self-leadership, psychological empowerment, and sport commitment. Second, we found that the athlete's self-leadership had a positive effect on psychological empowerment, sport commitment, and performance. Third, we found that athlete's psychological empowerment had a positive effect on sport commitment and performance. Fourth, we found that the athlete's sport commitment had a negative effect on performance. Therefore, this study has reminded us about importance of psychological empowerment and sport commitment for explaining the relationship between leadership type and performance perceived by Taekwondo athletes, and might contribute to the theoretical discussion of variables related to athletes' performance.

• Journal of Nutrition and Health
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• v.34 no.1
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• pp.79-88
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• 2001

Management of nutrient intakes through behavior-mordification can be important for improving exercise performance in athletes. The purpose of this study was to determine the effectiveness of nutritional counseling for improving exercise performance capability in athletes. The subjects were seven golfers and fourteen ju-do athletes from Hoseo university, and they have nor received professional hel[ from dieticians. Prior to nutritional counseling, their dietary intakes, lifestyles and dietary habits were evaluated. Nutritional counseling sessions were conducted by a trained dietician every 2-3 weeks for 3-4 month. After 5 counseling sessions, nutrient intakes, lifestyle and dietary habits were re-evaluated. Exercise performance capability was measured by maximal exercise stress test using treadmills. Individual data were assessed as quality index represents the better nutritional status. The common dietary and lifestyle problems were overeating binging, overeating, snacking and drinking alcohol prior to the nutritional counseling. After counseling sessions, the quality index of dietary habits seemed to decrease, especially in ju-do athletes, representing nutritional problems were resolved. Body fat and body mass index decreased in ju-do athletes, but not in golfers. Both athletes have shown to increase oxygen uptake at anaerobic threshold and maximal oxygen uptake status, which represents that the athletic performance capacity was improved after counseling sessions. Their respiratory quotients were decreased. In conclusion, nutritional counseling sessions over five times are an effective and efficient approach to change dietary habits to improve exercise performance capacity. Furthermore, clients can have good dietary habits and learn how to manago muscle strength by behavior modification through multiple nutritional counseling sessions. (Korean J Nutrition 34(1):79-88, 2001)

• Nutritional Sciences
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• v.5 no.1
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• pp.34-39
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• 2002

The objective of tole study was to compare nutritional knowledge, attitudes and food practices of competitive athletes, recreational athletes and non-participants. All students enrolled at the University of Nebraska in an Introductory Nutrition course in which sports nutrition was stressed, were asked to participate in the study. The course was typical of many introductory nutrition courses ; about two thirds of the students were from the Department of Health, Physical Education and Recreation, and most of the students were encouraged to take this course by their advisers. The students were divided into three groups : 20 competitive athletes (mostly runners, swimmers, basketball players and football players for the University), 14 recreational athletes (who were involved in a planned exercise program at least 2 hours per week), and 19 non-participants. At the beginning of the semester, students completed a food frequency questionnaire, and a 24-hour food record based on the Food Guide Pyramid. A nutrition knowledge and attitude questionnaire was formulated specifically for this study, covering normal nutrition and sports nutrition. The results showed that consumption of foods from all Food Guide Pyramid food groups except the fats/oils/sweets group was not significantly different among the three student groups. Regarding the fats/oils/sweets group, competitive athletes consumed significantly more numbers of servings than recreational athletes, while the recreational athletes consumed significantly more than non-participants (p<0.01). The total mean scores from the nutrition attitude and knowledge questionnaire were not significantly different among the three student groups. However, combined athletes (competitive athletes and recreational athletes) obtained significantly higher scores on some of the nutrition attitude questions (p<0.05). The results of the study indicate that athletes, significantly lower scores on some of the nutrition knowledge questions (p<0.05). The results of the study indicate that athletes, whether competitive or some of the nutrition knowledge questions (p<0.05). The results of the study indicate that athletes, whether competitive or recreational, had a very positive attitude regarding the effects of nutrition on their sports performance and health: however, these athletes did not appear to apply scientific principles of sports nutrition to their diet. In conclusion, advising athletes to simply increase or decrease their intakes of certain foods is too simplistic an approach for maintenance of good health and for better sporting performance. Athletes and non-athletes need continuous nutrition education to help with improving their competitive edge and food choices.

• Korean Journal of Exercise Nutrition
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• v.25 no.3
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• pp.23-27
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• 2021

[Purpose] Functional beverages are intended to support those who want to maintain optimal physical condition and improve their quality of life through the enhancement of heart health, immunity, and digestion. The purpose of this study was to investigate the performance of top-level athletes consuming immune-strengthening conditioning nutritional drinks. [Methods] A total of 107 top-level athletes (baseball (56 players), pro volleyball (17), athletics (16), cycling (8), golf (6), and fencing (6)) participated in the experiment. They consumed an immune-enhancing functional beverage once a day for 8 weeks and responded to a survey before, during, and after drinking the beverage. [Results] Three total aspect-based subfactors were drawn from 24 questions in the factor analysis: physical, satisfaction with mental stability, and activity in performance. The physical, mental stability and performance changes of athletes significantly increased in period 2 (4 weeks after intake) and period 3 (after 8 weeks of intake). [Conclusion] We evaluated the efficacy of a new conditioned beverage containing Lactobacillus B240 and protein in improving the performance and physiological utility of top athletes. This functional drink may gain popularity among those seeking health benefits and improved exercise performance.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.253-264
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• 2003

This study aims at finding the structure of spike technique by analysing comparatively the spike action by excellent and by non-excellent players throughout the section from a flying jump to the time of landing for the correct analysis of spike action and tries to help athletes and coaches to execute a scientific training. For the objected person of this study, six of H College athletes three of excellent athletes and three of non-excellent athletes, presently registered as athlete with the Korea Volleyball federation) were chosen, and the factors of analysis were analysed upon performance time of action by section, human body centered displacement, change of articulation angle, speed change of articulation of the upper limbs, uniformity of the articulation of the upper limbs upon impact, etc. The conclusion of this study is as follow: 1. In the time required for taking action, it shows to take $1.067{\pm}0.057$ seconds for the group of excellent athletes and $1.034{\pm}0.033$ seconds for the group of non-excellent athletes. Although there was not big difference between two groups in the performance time of action, it showed that the group of excellent athletes takes longer compared to the group of non-excellent athletes. And it was found by the result of this study that the group of excellent athletes stays longer in the duration of flight. 2. In the displacements of horizontal movement and vertical movement, it was found that the group of excellent athletes have moved more than the group of non-excellent athletes in the horizontal movement of the center of human body 3. In the angles of wrist and knee, it was found that the excellent athletes have shown little than the non-excellent athletes in the entire sections, but that in the angle of elbow, the non-excellent athletes have shown bigger than the excellent athletes.. 4. In the speed of the articulation of the upper limbs upon impact, it was found that the group of excellent athletes have shown bigger than the group of non-excellent athletes, and that in the maximum value of the articulation of the upper limbs, the maximum value for the hand was indicated upon impact and that forearm and upper arm have shown the maximum value just before the impact. 5. In the uniformity of articulation of the upper limbs at the time of impact, the group of excellent athletes showed bigger than the group of non-excellent athletes in all the articulations.

• Korean Journal of Applied Biomechanics
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• v.28 no.2
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• pp.79-85
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• 2018

Objective: This study aimed to create a strategic training method to enhance optimal athletic ability using information from 1H to 10H rhythmic units. Method: Top three world class athletes and three national winners of 110-m hurdle finals from the 2010 Daegu International Athletics Competition and 2017 National Athletics Championship, respectively, were selected. To analyze the kinematic variables, Dartfish 9.0 was used for two-dimensional analysis. Results: Regarding the interval time from the start to the finish line, the national athletes took less time during the pure acceleration phase (start to 1H) than the foreign athletes. The horizontal velocity increase was slower after 1H; the national athletes showed a lack of ability to accelerate at the interval phases. Moreover, the hurdle clearance time between phases was longer in the national athletes than in the foreign athletes and lacked consistency. Conclusion: The national athletes lacked the ability to accelerate at the transition, maximum rhythm, rhythm maintenance, and re-acceleration phases and showed a longer hurdle clearance time. If technical improvements and strategic training methods using rhythmic units are applied for hurdling motions, the national athlete's hurdling abilities, performance, and consistency could improve.

• Korean Journal of Exercise Nutrition
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• v.23 no.3
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• pp.29-38
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• 2019

[Purpose] Effective nutritional intervention can help reduce the risk of nutritional problems and improve athletic performance in adolescents. The five A's (assess, advise, agree, assist, and arrange) model is widely used as the theoretical framework for advice on nutrition, smoking, drinking, and physical activity and it recommends that practitioners in primary health care promote behavior change to facilitate positive outcomes. This model has also been useful in understanding the underlying processes of behavior change. This study aimed to develop both a novel evidence-based nutritional intervention protocol, rooted in sound nutritional theory, and a customizable nutritional intervention program to support sustainable healthy eating, enhance nutrient intake, and improve athletic performance in adolescent athletes. [Methods] In this study, we adapted the 5 A's behavioral change model and motivational interview to develop a theoretical framework to help adolescent athletes change their behavior and achieve their goals. [Results] During each step of the 5 A's protocol, a customized nutritional intervention protocol was developed by nutrition experts for each of adolescent athletes. Each plan was developed to improve the eating habits of adolescent athletes through group education and counseling. All nutritional counseling sessions were designed to enable participants to apply nutritional knowledge and practical action plans to their training and competition conditions to enable each of them to achieve individual athletic goals and facilitate self-management. [Conclusion] A theoretical and evidence-based nutritional intervention protocol was developed to identify and address obstacles to healthy dietary habits in adolescent athletes. This could be used as the basis for further studies aimed at improving nutrient intake and athletic performance in adolescent athletes.