• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.11-20
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• 2005

This study has a purpose on contributing to apprehend safe and right way to stop to the inline skate beginners and to the instructors who teaches line skating on the basis for the result of the kinematical analysis on Heel brake stop movement of the inline skate, focusing on the displacement on COG, angle displacement of ankle joint, angle displacement of knee joint, angle displacement of hip joint, using a 3D image method by DLT. To achieve this goal, we analysed the kinematical factor of the 3 well-trained inline skating instructors and obtained the following results. 1. During the movement of heel-brake stop, when strong power was given to a stable and balanced stop and the lower limbs, if the physical centroid is lowered the stability increases, and if it is placed high from the base surface, as the stability decreases compared to the case of low physical centroid, we should make a stop by placing a physical centroid in the base surface and lowering the hight of physical centroid. 2. To make a stable and balanced stop and to provide a strong power to the lower limbs, it is advisable to make a stop by decreasing an angle displacement of ankle joint during a "down" movement. In case of the left ankle joint, in all events and phases the dorsiflexion angle showed a decrease. Nevertheless, in the case of the right ankle joint, the dorsiflexion angle shows an increase after a slight decrease. The dorsiflexion angle displacement of ankle joint can be diminished because of the brake pad of the rear axis frame of the right side inline skate by raising a toe, but cannot be more decreased if certain degree of an angle is made by a brake pad touching a ground surface. To provide a power to a brake pad, it is recommended to place a power by lowering a posture making the dorsiflexion angle of the left ankle joint relatively smaller than that of the right ankle. 3. To make a stable and balanced stop and to add a power to a brake pad, the power must be given to the lower limbs in lowering the hight of physical centroid. For this, it is recommended to make a down movement by decreasing the flexion angle of a knee joint and it is necessary to make a down movement by a regular decrease of the angle displacement of knee joint rather than a swift down movement in every event and phase. 4. The right angle displacement of hip joint is made by lowering vertically the hight of physical centroid as leaning slightly forward. If too narrow angle displacement of hip joint is made by leaning forward too much, the balance is lost during the stop by placing the center in front. To make a stable and balance stop and to place a strong power to the lower limbs, it is recommendable to make a narrow angle by lower the hip joint angle. However, excessive leaning of the upper body to make the angle too narrow, can cause an instable stop and loss of physical centroid. After this study, it is considered to assist the kinematical understanding during the heel brake stop movement of the inline skate, and, to present basic data in learning a method of stable and balanced stop for the inline skating beginners or for the inline skate instructors in the present situation of the complete absence of the study in inline skating.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.103-111
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• 2020

Performance indicators have often investigated and developed in order to identify foundational elements and factors for an enhancement of performance in sports. In order to identify the valid performance indicators it is important that the indicators used within a performance analysis system discriminate between the winning and losing performances within a match (Hughes and Bartlett, 2002). However, the performance indicators proposed in research studies on basketball performance have not been used for real-time analysis and feedback within a coaching context. Such real-time support for the coach and players has been described within research on other sports (Choi et al., 2004; O'Donoghue, 2001; Palmer et al., 1997). Within the process of real-time feedback, the identification of relevant performance indicators that distinguish winning and losing performances should be the first stage of the development of a real-time analysis system. Therefore, this study investigated the differences between winning and losing teams in terms of a set of performance indicators gathered during the analysis of 10 English National Basketball League matches. Winning and losing teams were compared using whole match data (N=10) as well as individual quarters (N=40). A series of Wilcoxon Signed Ranks tests was used to identify the relevant performance indicators that discriminate between winning and losing performers within whole matches and individual quarters. The tests found that 3 point shots made (p<0.05) and Assists (p<0.05) were significantly different between winning and losing teams within matches. However, 2 point shots made (p<0.05), 2 point shots attempted (P<0.05), percentages of 2 point shots scored (p<0.05), 3 point shots made (p<0.05), Defensive Rebounds (p<0.05) and Assists (p<0.05) were significantly different between winning and losing performance within quarters. The analysis task should be based on relevant performance indicators which explain the current performances to performance analysts and coaches. Within a real-time analysis and feedback scenario, this will have the additional benefit of supporting a decision based on immediate performance within the most recent quarter. Consequently, the real-time analysis system would use performance indicators which have the property of construct validity to support the decisions of the coach.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.395-407
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• 2016

This study aims to apply the G-theory for estimation of reliability of evaluation scores between raters on Taekwondo Poomsae rating categories. Selecting a number of game days and raters as multiple error sources, we analyzed the error sources caused by relative magnitude of error variances of interaction between the factors and proceeded with D-study based on the results of G-study for optimal determination of measurement condition. The results showed below. The estimated outcomes of variance component for accuracy among the Taekwondo Poomsae categories with G-theory showed that impact of error was the biggest influence factor in raters conditions and in order of interaction in subjects and between subjects, also impact of variance component estimation error on expression category was the major influence factor in interaction and in order of the between subjects and raters. Finally, the result of generalizability coefficient estimation via D-study showed that measurement condition of optimal level depend on the number of raters was 8 persons of raters on accuracy category, and stable reliability on expression category was gained when the raters were 7 persons.

• Journal of Life Science
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• v.16 no.6
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• pp.960-963
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• 2006

The purpose of this study is to evaluate the different type of exercise training on the changes of blood variables and leptin in SD rats. For this study, SD rats were divided into three groups: control group (CG: n=10), swim trained group (SG: n=10), and treadmill trained group (TG: n=10). The animals were housed in a pathogen-free animal facility ($22-24^{\circ}C$, 50-60% relative humidity, 08:00-20:00 lighting hours) at D university animal center, Pusan, Korea). Food and water were available ad libitum. The trained rats underwent a 8-wk endurance swim training (5 times/wk) in water at $26-29^{\circ}C$ (SG) and treadmill training (5 times/wk) in DAEJONG treadmill for 60 min. All data were expressed as mean and standard deviation by using SPSS package program (ver 10.0). The result through the statistical analysis of this data were summarized as follows: 1. In the weight changes, there were significant differences among CG, SG and TG(p<.05) after regular swim and treadmill training. TG showed the lowest weight than the other groups. 2. In the epididymal & perirenal adipose tissue levels, there were significant differences among CG, SG and TG(p<.05) after regular swim and treadmill training. TG showed the lowest adipose tissue levels than the other groups. 3. In the triglyceride changes, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG showed the lowest triglyceride levels than the other groups. 4. In the insulin hormone, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG showed the lowest insulin levels than the other groups. 5. In the leptin changes, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG was the lowest than the other groups. Based on the results, Regular swim and treadmill training decrease body weight, epididymal & perirenal adipose tissue levels significantly, this is caused but by decreased triglycerides, insulin, and leptin hormone levels not by the other factors. Regular treadmill training decreased insulin hormone levels compare to swim training, however there was no direct insulin effect on the weight changes. and it might be the direct effect of leptin hormones.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.388-397
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• 2012

The tennis was one of the most popular sport in the general physical education lesson. However there are many problems such as difficult of improvement tennis skill, lack of class days and so many students in a class. These reasons could ultimately damage the overall quality of class. The purpose of this research was to beginner students was fun and easy to learn. The tennis lesson using tools were 1.selective hitting ball, 2. high net hitting ball, 3. hitting orange ball. Scores of the experimental group(n=23) and the control group(n=21) were compared. In order to verify course content was the same 15 weeks, conducted a tennis teaching methods to take advantage of the tools. And tools to take advantage of the students who participated in a class analysis of the qualitative data (interviews, documents, questionnaires, observations, journals). As a result, the satisfaction scores of the experimental group were higher than those of the control group. The tennis lesson using tools to take positive effect(meaning, improved skill, easy, fun/curious/confident) and negative effect(difficulties of adaptation, a high challenge level) was induced. In summary of the quantitative/qualitative data 'Orange Ball' has a positive impact on the girls than boys and teaching methods using tools gave generally positive influence to students.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.279-286
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• 2022

The purpose of this study is to examine the mediating effect of physical activity in the relationship between generalized anxiety disorder and overdependence on smartphones in adolescents. To find a way for solving the problems caused by the over-use of smartphones during adolescence, we tried to find the importance of a health promotion program through physical activities. For the purpose of the study, the 2020 Youth Health Behavior Survey data conducted by the Ministry of Education, the Ministry of Health and Welfare, and the Korea Centers for Disease Control and Prevention were used as analysis data for this study. As a result of the study, firstly, generalized anxiety disorder has a negative (-) relationship with physical activity, and physical activity also has a negative (-) relationship with overdependence on smartphones. Secondly, as a result of analyzing the mediating effect of physical activity in the relationship between generalized anxiety disorder and smartphone overdependence experience, the physical activity was found to be a significant factor. Thirdly, it was confirmed that the physical activity has a partial mediating effect in the relationship between generalized anxiety disorder and smartphone overdependence experience. Increasing physical activity through team sports rather than individual sports may help reduce smartphone use.

• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.49-56
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• 2014

This study aims at providing basic data for product planning to design smart clothing and to develop applications, focusing on consumers by satisfying their emotions through analyzing emotional factors on smart clothing, comparing emotional differences between conventional clothing and it, reviewing changes of consumers' emotion by integrating the product and clothing and researching differences of preference and purchase intention between smart clothing and traditional one. As the results of the study, emotional factors for smart clothing were analyzed with total 6 including 'technical', 'comfort', 'aesthetic', 'modern', 'fun' and 'multiple' factors. Among them, except for 'comport', five emotional factors showed emotional factors between conventional sport-casual clothing and smart clothing. That is, emotional factors of 'technical', 'aesthetic', 'modern', 'fun' and 'multiple' were emphasized more in smart clothing than conventional ones, indicating that they should be considered in planning products of smart clothing. Though there was no significant difference of preference between smart clothing and conventional clothing, in case of comparison of averages, that of smart clothing was a little higher. For purchase intention, smart clothing was lower than the conventional clothing. So preference seems to be not directly related to consumers' immediate purchase. To make consumers' interests and preference to result in purchase, it is necessary to develop smart clothing with more various applications and to prepare commercializing strategies. As the results of the analysis on free-descriptive questionnaire survey, consumers were interested in development of smart clothing to help diet with functions including energy harvesting from body motion, calorification and perspiration, measurement of motion and calory consumption as well as health-care type smart clothing to measure heartbeat and ECG. Reflecting these requirements from the consumers, they should be utilized as guidance to develop smart clothing in the future.

• Journal of Industrial Convergence
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• v.22 no.1
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• pp.105-115
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• 2024

This study aimed to analyze the impact of mental strength on the competitive performance of student Taekwondo sparring athletes. A total of 343 middle school, high school, and university students registered as Taekwondo sparring athletes with the Korea Taekwondo Association were conveniently sampled. The Mental Toughness Test developed by Loehr was utilized after expert consultations. Data analysis involved t-tests and one-way ANOVA to assess the levels of mental strength sub-factors based on general characteristics, followed by post hoc tests using the Schéffe method for intergroup comparisons. Correlation analysis and multiple regression were conducted to examine the relationship between sub-factors of mental strength and competitive ability. The results indicated significant differences in mental strength sub-factors-confidence, level of awakening regulation, visualization and mental imagery regulation, motivation level, positive energy, and attitude control-based on gender and age among Taekwondo sparring student athletes. In terms of perceived competitive ability, significant differences were found based on age and sports experience. Consequently, beyond psychological training, the study revealed that age and diverse experiences positively influence specific aspects of mental strength among Taekwondo sparring student athletes. Therefore, coaching and training for these athletes, particularly during middle and high school years, should incorporate psychological aspects alongside diverse competition experiences and training to help overcome performance evaluation anxieties during matches.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.179-195
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• 2002

The purpose of this research is to provide a proper model by analyzing the sports biomechanical of physical movements on the basis of the two patterns(open-stance and cross-stance) at the ready-to-start pose. The subjects for this study are composed of five male handball players from P university and five female shooting players from S university. Three-way moving actions at start(right, left, and forward) are recorded with two high-speed video cameras and measured with two Force platforms and a EMG system. Three-dimensional action analyzer, GRF system, and Whole body reaction movement system are used to figure out the moving mechanisms at the start pose. The analytic results of the moving mechanism at the start pose were as follows. 1. Through examining the three-way moving actions at start, I have found the cross-stance pose is better for the moving speed of body weight balance than the open-stance one. 175 degree of knee joint angle at "take-off" and 172 degree of hip joint angle were best for the start pose. 2. The Support time and GRF data shows that the quickest center of gravity shift was occurred when cross-stanced male subjects started to move toward his lefthand side. The quickest male's average supporting time of left and right foot is 0.19${\pm}$0.07 sec., 0.26${\pm}$0.06sec. respectively. The supporting time difference between two feet is 0.07sec. 3. Through analyzing GRF of moving actions at start pose, I have concluded that more than 1550N are overloaded on one foot at the open-stance start, and the overloaded force may cause physical injury. However, at the cross-stance pose, The GRF are properly dispersed on both feet, and maximum 1350N are loaded on one foot.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.361-373
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• 2019

Falls are a threat to the physical health of the elderly as well as to their overall quality of life. The purpose of this study was to identify which type of exercise is effective for improving the balance of the elderly, and to obtain the basic data for developing the falls prevention exercise intervention program for the elderly. We compared to the differential effects between rhythmic step exercise and core muscle strengthening exercise in terms of functional balance test and self-reported balance test. Women older than 65 years and under 80 years of age were assigned to one of the step exercise group(21), core muscle exercise group(20), and control group(21), and for 8 weeks, twice per week, 20-30 minutes of exercise were treated. All participants performed one foot static balance test with open and closed eyes. And they responded to self-reported balance test, such as Fall Efficacy Scale(FES) and Activities-specific Balance Confidence(ABC) Scale. The results of statistical analysis are summarized as follows. First, rhythmic stepping exercise was more effective in improving functional balance than core muscle strengthening exercise. In particular, the effect of step exercise was obvious in the one-foot static balance test with open eyes. Second, the self-reported balance test showed better step exercise than core muscle exercise. Specifically, rhythmic step exercise was more effective in enhancing fall efficacy than core muscle exercise. In conclusion, the rhythmic step exercise was more effective in improving the balance ability of the elderly than the core muscle exercise. The rhythmic step exercise is more related to the lower extremity muscles, and especially since the rhythmic step exercise is performed in various ground changes, it seems to have a high similarity to the fall occurrence situation. For future research, we recommended the development of task-oriented ankle proprioceptive exercise intervention program and exercise equipment based on the specific motion situation in which the fall accident occurs in the elderly.