• 대한정형외과스포츠의학회:학술대회논문집
• /
• 2004.09a
• /
• pp.7-7
• /
• 2004

• Korean Journal of Applied Biomechanics
• /
• v.21 no.2
• /
• pp.141-152
• /
• 2011

The purpose of this study was to investigate the projectile factors and biomechanical characteristics of men's hammer throwing during turning phases. Four national leveled athletes including Korea national record holder participated in this study. After full warm-up, each participant performed 6 trials of hammer throwing with their best. The best recorded trial was selected from each participant and they were analyzed for this study. Three-Dimensional motion analysis using a system of 5 video cameras at a sampling frequency 60Hz was performed for this study. As the number of turns increased, athletes revealed following characteristics. 1) The single and double support time decreased. 2) The rotation foot was closed to axis foot and it revealed greater medio-lateral displacement than that of horizontal one. 3) At the transition point from double support to single support, ball was in front of rotation foot so that not much angular velocity obtained. For the projectile factors, projectile angle did not show differences while projectile height and velocity revealed differences among the participants. It may indicated that each athlete has different fitness and skill level to resist centrifugal force which become larger as the number of turn increased.

• Proceedings of the Korean Nutrition Society Conference
• /
• 2003.05a
• /
• pp.318.2-318.2
• /
• 2003

• Korean Journal of Human Ecology
• /
• v.4 no.1
• /
• pp.51-61
• /
• 1995

The purpose of this study was to find out the characteristics of the adolescent consumers related to the attitudes toward TV advertisements on and purchasing behaviors of the sport beverages, and to test the role of the atitudes toward TV advertisements between the consumer characteristics and the purchasing behaviors of the sport beverages. The qusetionnaire method was utilized to 549 female and male junior and senior high school students in urban and rural areas. The results showed that the attitudes toward TV advertisement on sport beverage was related to the residentiae years in school, whom to buy, level of interests in sports, and level of knowledges of the beverages; purchasing behaviors of the sport beverages, whom to buy, gender, level of knowledges of the beverages, size of the allowance, and the residentiae years in school. The attitudes toward TV advertisements seemed to the intervenning role between the consumer characteristics and the purchasing behaviors among adolescent consumers.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.3
• /
• pp.201-207
• /
• 2014

This study investigated the center of mass and lower extremity kinematic patterns between carved and basic paralell turn during alpine skiing. Six experienced skiers (age: $20.67{\pm}4.72yrs$, body mass: $72.67{\pm}7.15kg$, height: $171.00{\pm}5.51cm$) participated in this study. Each skier were asked to perform carved and basic paralell turn on a $22.95^{\circ}$ groomed slope. Each turn was divided into the initiation phase, steering phase 1 and 2. The results of this study show that the carved turn spent significantly less running time than basic paralell turn at all three phases (p<.05). Also vertical displacement of the center of mass was significantly greater in carved turn at all three phases, whereas inward leaning angle of the center of mass was significantly greater in carved turn at the steering phase 1 and 2 (p<.05). Bilateral knee and hip joint angle were significantly greater in basic paralell turn at the initiation phase and the steering phase 2 (p<.05). On the other hand, left knee and hip joint angle were significantly greater in basic paralell turn at the steering phase 1 (p<.05). In order to perform successful carved turn, we suggest that skiers should coordinate bilateral knee and hip joint angles to adjust the center of mass, depending on three ski turn phases.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.2
• /
• pp.173-180
• /
• 2014

The purpose of this study was to investigate the effect of combined exercise on injury risk factors of lower extremity during landing. Ten sports talented athletes participated in this study. Sports talented athletes participated in a combined exercise (sports talented exercise, coordination) for 16 weeks. A three-dimensional motion analysis was performed using eight infrared cameras (sampling rate of 100 Hz), one force plate, and electromyography system (sampling rate of 1000 Hz) during landing. Kinetic, and kinematics analysis including average impulsive force, angle of lower extremity, vertical stiffness, onset of muscle activation were calculated by Matlab2009a software. Paired t-test was performed at alpha=.05. The average impulsive force in landing phase was not statistically significant (t=-.748, p=.474). The hip joint angle was more decreased in post test compared to pre test (E1: t=2.682, p=.025, E2: t=5.609, p=.000, E3: t=2.538, p=.032). The knee joint (E1: t=-.343, p=.739, E2: t=1.319, p=.220, E3: t=.589, p=.570) and ankle joint (E1: t=.081, p=.937, E2: t=.784, p=.453, E3: t=.392, p=.704) angle were tended to decrease after combined exercise. The vertical stiffness was tended to decrease after combined exercise (t=1.972, p=.080). Onset of quadriceps femoris (t=.698, p=.503) and medial gastocnemius (t=1.858, p=.096) were tended to be faster than biceps femoris (t=-.333, p=.747) after combined exercise. Although thses findings were not statistically significant except on a hip joint angle, risk factors of lower extremity such as joint angle, vertical stiffness and onset of quadriceps femoris, medial gastrocnemius were positively changed after the combined exercise but an additional training for improved onset of biceps femoris would be required in the future.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.2
• /
• pp.189-196
• /
• 2011

The purpose of this study was to verify the difference in biomechanical variation and pattern of the lower limb between planned and unexpected termination, which is related to the prevention of fatal fall in the elderly. Therefore, selected twenty subjects for each group which composed of females(age: $73.5{\pm}4.63$ year, height: $153.2{\pm}6.46$ cm, body mass: $58.98{\pm}5.82$ kg) and women(age: $23.4{\pm}2.5$ year, height: $164.65{\pm}3.9$ cm, body mass: $58.47{\pm}5.53$ kg) in their twenties. As a result, lower limb's extension moment and power were increased significantly in statistics(p<.05). Also, knee joint power showed instant changes from concentric contraction to eccentric contraction and hip joint power from eccentric contraction to concentric contraction. During unexpected termination there were dramatical increase in eccentric contraction and power(p<.05). In both planned and unexpected termination, ankle joint moment were higher in young group, but the moment of the hip joint were higher in the elderly group(p<.05). In contrast to younger group, there were no changes in knee extension moment in elderly group(p<.05). but showed relatively higher hip joint extension moment and power(p<.05).

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

• BMB Reports
• /
• v.37 no.4
• /
• pp.416-421
• /
• 2004

The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy-pyridine ($PyH_2$), were evaluated in vitro. NADH was found to be oxidized by the peroxyl radical derived from 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH) decomposition, in a pH-dependent manner. Both NADH and $PyH_2$ inhibited the peroxidation of egg yolk lecithin (EYL) liposomes, although $PyH_2$ was more effective than NADH when 2,2'-azobis-4-methoxy-2,4-dimethyl-valeronitrile (methoxy-AMVN) was employed to induce EYL liposome peroxidation. The antioxidant activities of NADH and $PyH_2$ were also evaluated by measuring their influences on 1,3-diphenylisobenzofuran (DPBF) fluorescence decay in the presence of peroxyl radicals. NADH and $PyH_2$ were much more effective at inhibiting DPBF quenching in Triton X-100 micelles than in liposomes. These results indicate that NADH can inhibit lipid peroxidation despite being hydrophilic. Nevertheless, membrane penetration is an important factor and limits its antioxidant activity.

• The Journal of the Korea Contents Association
• /
• v.12 no.9
• /
• pp.434-446
• /
• 2012

The purpose of this paper was to analyze a social discourse on the enactment of School Sport Promotion Law produced in the media. For this purpose, 73 articles related to the law collected from portal sites such as 'Daum', 'Naver' and 'Yahoo' as well as 'KINDS' were utilized for data analysis. Therefore, it was concluded that a social discourse's feature related to the enactment of the law is a social 'support' discourse calling for the enactment of the law, a 'denunciation' discourse after the rejection at the regular session of the National Assembly, a 'opposition' discourse concerned about the regression of elite sport and a 'wish' discourse expecting the leap and vitalization of school sport. From the holistic point of view, a dominant discourse is the appropriateness and necessity of the enactment of the law. However, smaller but stronger voices of dissent concerning about the decline in the development of elite sport (especially elite sporting success) were raised.