• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.329-340
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• 2006

The purpose of this research is to know the influence of high school students' activities of Marine Sports on the development of their sociality by comparing students in this activities with those who are not in this activities. The objects of this research are high school students who live in Busan at present. The total number of the object is 146, including 74 students who participated in this organization and 72 students who didn't participate in this organization. We have reached the following conclusion after analyzing the materials according to the methods and procedures of the research. In the domain of activity, the students who are in Marine sport activities are statistically different from those who are not. In the domain of stability, the students who are in Marine sport activities are meaningfully different from those who are not. In the domain of ascendancy, the students who are in Marine sport activities are meaningfully different from those who are not. In the domain of sociability, the students who are in Marine sport activities are meaningfully different from those who are not. In the domain of self-control, the students who are in Marine sport activities are meaningfully different from those who are not.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.477-487
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• 2016

This study examines the relationship between ego-resilience, mattering and school life adjustments of elementary students participating in physical activity after school. The number of subjects for this study were 429 who were participating in the physical activity after school in Gyeonggi-do. The reliability and validity test of the questionnaire and descriptive analysis, factor analysis, correlation were conducted by using SPSS 20.0 and structural equation model was conducted by using AMOS 20.0 program. The results are as follows; First, ego-resilience of elementary students participating in physical activity after school affects their mattering. Second, mattering of elementary students participating in physical activity after school affects their school life adjustments. Third, ego-resilience of elementary students participating in physical activity after school affects their school life adjustments. Lastly there is a causal relationship between ego-resilience, mattering and school life adjustments of elementary students participating in physical activity after school.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2690-2696
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• 2012

The purpose of this research was to investigate effects of participation in family leisure activity on school adjustment of middle school students. A total of six hundred questionnaires were distributed to the subjects, but only 587 questionnaires were collected. After excluding 12 questionnaires, 575 questionnaires were used for the analysis. An analysis of variance and independent t test were conducted using SPSS 18.0 for Windows and all comparisons were made at the p<.05 level of significance. The results showed that gender did not affect on school adjustment. There were significant differences in school adjustment by academic grades and family leisure activity participation(p<.05). It was concluded that participating in family leisure activity may be beneficial for middle school students to adapt their school life better.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.347-353
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• 2016

This study aims to analyze how parents and their children participating in sports after school hours positively affects their communication and behavior based on the stratified sampling of 189 students (fifth and sixth graders) in Cheongju city C-province. The result from the exploratory factor and the structural analysis using SPSS18.0 showed that participating in sports improved parent-child communication including increasing their motivation, self-confidence, and self-esteem, and reducing children's problematic behavior such as anxiety, feeling insecure, insubordination, and aggressiveness. In order to improve the children's mental health, it would be essential to set various programs of after school sports and more importantly validate its quality.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.457-465
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• 2012

The purpose of study was to exploring on the educational values in after school physical programs. The participants were students in grades 5 (3), after school parents who are interested in sports activities (3), after school sports activities led by experienced teachers in three of were selected as study participants. The data were collected through in-depth interviews, collected data were transcribed and coded for domain analysis, classification analysis. The analysis of the results were as follows. After school physical activities, educational significance of the various values of physical activity experiences, meeting with school physical education and sport, educational welfare: the elimination of educational disparities, physical culture, introductory appeared.

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.10-16
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• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• Korean Journal of Applied Biomechanics
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• v.31 no.4
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• pp.308-313
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• 2021

Objective: The purpose of this study was to investigate the effect of different kettlebell mass (30%, 40%, and 50% of the body mass) on kinematics and kinetic variables of kettlebell swing. Method: Total of 16 healthy male who had at least 1 year of kettlebell training experience were participated in this study (age: 31.69 ± 3.46 yrd., height: 173.38 ± 4.84 cm, body mass: 74.53 ± 6.45 kg). In this study, a 13-segments whole-body model (upper trunk, lower trunk, pelvis, both side of forearm, upperarm, thigh, and shank) was used and 26 reflective markers were attached to the body to identify the segments during the movement. A 3-dimensional motion analysis with 8 infrared cameras and 4 channeled EMG was performed to find the effect of kettlebell mass on its swing. To verify the kettlebell mass effect, a one-way ANOVA with a repeated measure was used and the statistical significance level was set at 𝛼=.05. Results: Firstly, in all lower extremity joints and thoracic vertebrae, a statistically significant change in angle was shown according to an increase in kettlebell mass during kettlebell swing (p<.05). Secondly, in both the up-swing and down-swing phases, the knee joint and ankle joint ROM showed a statistically significant increase as the kettlebell mass increased (p<.05) but no statistically significant difference was found in the hip joint and thoracic spine (p>.05). Lastly, the hamstrings muscle activity was statistically significantly increased as the kettlebell mass increased during up-swing phases (p<.05). Also, as the kettlebell mass increased in P4 of the down swing phase, the gluteus maximus showed a statistically significantly increased muscle activation, whereas the rectus femoris showed a statistically significantly decreased muscle activation (p <.05). Conclusion: As a result of this study, hip extension decreased and knee extension increased at 40% and 50% of body mass, and the spine also failed to maintain neutrality and increased flexion. Also, when kettlebell swings are performed with 50% of body mass, synergistic muscle dominance appears over 30% and 40% of body mass, which is judged to have a risk of potential injury. Therefore, it is thought that for beginners who start kettlebell exercise, swing practice should be performed with 30% of body mass. In addition, even in the case of experienced seniors, as the weight increases, the potential injury risk may increase, so it is thought that caution should be exercised when performing swings with 40% and 50% of body mass. In conclusion, it is thought that increasing the weight after sufficiently training with 30% of the weight of all subjects performing kettlebell swing is a way to maximize the exercise effect as well as prevent injury.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.75-81
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• 2017

Objective: The purpose of this study was to compare and analyze the kinematic variables and electromyography (EMG) findings that change with varying characteristics of crouch start and feedback provision, and to provide the fundamental data for record improvement in 400 mH. Method: Four short-distance runners participated in the experiment. The analyzed variables were elapsed time per interval, stride length, and muscle activities in three lower limb muscles. These variables were analyzed by using Kwon3d XP and Noraxon Myoresearch. The participants were subjected to three conditions, including two conditions that relate to the thrusting foot on the rear block and another condition pertinent to feedback provision. Results: In terms of a one-step interval, the elapsed time in condition A was longer than that in condition B, and the one after the feedback was the longest. The stride length of a one-step interval was the longest in condition A. The stride length of a two-step interval was the shortest in condition A. The muscle activity during a one-step interval showed differences in vastus medialis and medial gastrocnemius, with condition A being the highest. Conclusion: When the non-dominant left foot was located at the back, negative results were observed in terms of elapsed time and stride length. Moreover, an imbalance in muscle activity was observed between the left and right feet when the left foot was placed at the back. As a result, significant differences in elapsed time, stride length, and muscle activity were observed depending on the foot placed on the rear block. In conclusion, we identified the characteristics of crouch start in 400 mH, and a specialized program must be suggested.

• IMMUNE NETWORK
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• v.14 no.5
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• pp.255-259
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• 2014

Physical activity could be considered one of the factors that affect the immune system status and function. To find the relation between exercise and cytokines, we examined the possible effects of an 8-week endurance training program on the serum levels of cytokines, including tumour necrosis factor-alpha (TNF-${\alpha}$) and interferon-gamma (IFN-${\gamma}$) in sedentary men. A total of 30 healthy young male volunteers were randomly divided into an endurance training group and a control group. The training group followed a specific exercise protocol (running on a treadmill for 15~30 min at 50~70% maximal heart rate) for 8 weeks and the control group did not participate in any exercise program. Venous blood samples were collected from both the groups 24 h before and 24 h and 48 h after the exercise. Repeated ANOVA was used for statistical purposes. The serum levels of TNF-${\alpha}$ and IFN-${\gamma}$ were determined by ELISA. Significant (p<0.05) and non-significant (p>0.05) decreases were observed in the serum levels of IFN-${\gamma}$ and TNF-${\alpha}$, respectively, after the 8-week endurance training program. Our findings indicated that an 8-week endurance exercise may affect the serum levels of some inflammatory cytokines, suggesting the beneficial role of this training protocol in elderly population and people with certain conditions (inflammation of the vertebrae or other inflammatory diseases).

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.105-111
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• 2012

The purpose of this study was to investigate the effect that difference in forefoot of shoe flexibility during the quick lunge from a jump smashing on the lower limbs and the plantar pressure distribution. For this 10 elite badminton players with over 10 years experience and right handed participated. Two kinds of badminton shoes were selected and tested mechanical testing for the forefoot flexibility. Motion analysis, ground reaction forces and plantar pressure distribution were recorded. It was required to conduct lunge movement after jumping smashing as possible as high. Photo sensor was located in 3 meter away from standing position and its height was 40 cm. Subjects were conducted to return original position after touching the sensor as under clear movement as possible as fast. Forefoot stiffness had an effect on shoe peak bending degree and peak bending angular velocity in propulsion phase. Forefoot flexibility had an effect on ankle plantar flexion and knee flexion moment. It appears that joint power on lower limb and peak plantar pressure were not influenced by the flexibility of shoes.