• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.127-133
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• 2020

PURPOSE: The study examined the relationship between the knee function score and knee strength and muscular endurance of an elite female handball athletes according to their position in the team. METHODS: Thirty handball athletes participated on the study: 12 front positions, 12 back positions, and five goalkeepers. The knee function score consisted of symptoms, pain, daily activity, sports and recreation, and quality of life. In addition, CSMI (Cybex, USA) was used to measure the strength and muscular endurance of the knee. The muscular strength and muscular endurance were measured at an angular velocity of 60°/s and 180°/s, respectively. RESULTS: The overall items of the knee function score showed a significant difference (p = .017), and goalkeepers had significantly higher scores than the back positions. In addition, significant differences were observed in all five items depending on the position (p ≤ .05). On the other hand, both the flexor and extensor muscles of the knee strength and muscular endurance were not significant. Moreover, there was no correlation between the knee function score and the knee strength and muscle endurance. CONCLUSION: Elite female handball athletes have different knee functions score depending on their position in the team, but the, strength and muscular endurance of the knee were similar for each position. Furthermore, the knee function score showed no correlateion with the strength and muscular endurance of the knee.

• Journal of Life Science
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• v.22 no.5
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• pp.665-670
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• 2012

This study investigated the effect of endurance exercises on blood pressure, angiogenesis, and the vascular endothelial growth factor (VEGF) expression in the skeletal muscle of spontaneously hypertensive rats (SHR). Five week old SHRs and Wistar-Kyoto rats (WKY) were randomly divided into 3 groups: Wistar-Kyoto rats (WKY, n=9), SHR control (SHR-C, n=9), and SHR endurance exercise training (SHR-E, n=9). Endurance exercise training was performed on a treadmill (12-20 m/min, 0% grade, 60 min/day, 5 days/week, 16 weeks). Systolic blood pressure was monitored with the tail-cuff method. The expression of VEGF protein and capillary density were identified using western blotting and H&E staining in the soleus muscle, respectively. Systolic blood pressure was reduced by endurance exercise in SHR ($p$ <0.05). The capillary density of skeletal muscles in SHR-C was lower than in WKY ($p$ <0.05), but it was recovered by endurance exercise training (SHR-E) compared to SHR-C ($p$ <0.05), and VEGF protein was also increased by endurance exercise training compared to SHR-C ($p$ <0.05). These data suggest that the enhancement of capillary density via an increase of VEGF expression in skeletal muscles by endurance exercise training could be an important factor to inhibit blood pressure elevation in SHR.

• Korean Journal of Occupational Health Nursing
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• v.8 no.1
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• pp.5-21
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• 1999

The purpose of this study is to evaluate the physical fitness status and health promoting life styles of the workers. For the purpose, 108 workers who attended the exercise program in Inchon branch of KISCO were selected as the subjects. From Oct. 20th to Nov. 30th, in 1998, they were firstly assessed their physical fitness. The items include cardio-respiratory endurance, flexibility, muscular strength, muscular endurance, agility, power, balance, body composition, etc. Secondly, the health promoting life styles were asked by questionnaires about daily life and dietary habits. Both of them were evaluated by 5 or 3 levels as A(very good) to E(very poor) or A (good) to C(poor). Those data were analyzed percentile, mean, standard deviation by SAS program. Major findings are as follows ; 1. The health promoting life styles were generally good, but 43.5% of the subjects didn't exercise at all. Most of them(93.5%) thought about their physical fitness status as lower than average level. About half of them(48.1%) didn't drink alcohol, non smokers were 70.4% of them. But they had poor dietary habits(lower than average level : 79.6%), females were a little bit better than males. The aged group had the poor body compositions, 21.4% of females and 10.0% of males were obese. 2. Physical fitness status of the workers were assessed as two areas, one is health related, the other is physical function related area. In the health related area, females were better than males, in view of age, forties aged group had the highest scores of all items except cardio-respiratory endurance. Among 'A' and 'B' level, muscular endurance was showed most frequently, followed by muscular strength, flexibility, cardiorespiratory endurance. In physical function related status, balance was ranked highly in the portion of over 'B', followed by power, agility. In view of sex, males were better than females for all items except balance, and there were various figures in the status by age groups. 3. Comprehensive assessment scores were poor(under 'D' leves were most frequent), females were better than males, and teenage group had the worst scores. In ages of the physical fitness, generally they had 1 year under their real ages, and females were better than males. In view of age, forties aged group was ranked highly and teenagers had lowest scores.

• Journal of the Korean Society of Safety
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• v.22 no.3 s.81
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• pp.1-6
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• 2007

In order to evaluate fatigue endurance for the rocker arm of a diesel engine, stress measurements were performed using the strain gages attached near the neck, where is one of the most critical region in the rocker arm, in variation of the engine speed. The fatigue life experiments were carried out on miniature specimens from the rocker arms. For evaluating the fatigue endurance of the rocker arm, the S-N data were compared with the stress analysis results through FEM analysis of the rocker arm. The effective stress of the neck region was determined 17.7MPa through FEM analysis of the rocker arm. Conclusively, on the basis of fatigue limit, the rocker arm has a safety factor of 2.8 or 3.4 from the stress measurement or FEM results, respectively.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.05a
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• pp.88-88
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.829-835
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• 2016

Electro-Mechanical Actuator installed on the aircraft plays a key role in an aircraft's flight control through flight control computer. Reliable prediction of the actuator is important for the aircraft. To estimate the lifetime of a product, it is necessary to test full target life. However, it is very difficult to perform it due to the long life time of actuator but short period of development time with increasing cost. Therefore, accelerated life test has been used to reduce the test time for various reasons such as reducing product's development cycle and cost. In this paper, to predict the lifetime of the actuator, we analyzed the flight profile of aircraft and adapted the method of accelerated life test in order to accelerate failure modes that might occur under user conditions. We also set up an endurance test equipment for validating the demanded lifetime of an actuator and performed accelerated life test.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.379-389
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• 2009

The purpose of this study was to investigate the influence of physical self-efficacy by a participation of sport leisure activity on general self-efficacy and life satisfaction for women based on the survey data from 174 women participating in swimming program in indoor pools at the area of Daegu and Gyongbuk. With the empirical analysis of the data, this study found the following conclusion. First, physical self-efficacy were significant on all general self-efficacy factors. Thus physical self-efficacy were influenced on pride, interpersonal relations, overcome difficulties, endurance. Second, physical self-efficacy was significant on life satisfaction. thirdly, general self-efficacy was partly significant on life satisfaction. Thus pride, interpersonal relations were not influenced on life satisfaction but influenced on overcome difficulties, endurance. Fourth, in case of the women over 40 years of age, physical self-efficacy was not significant on life satisfaction, and only endurance of general self-efficacy factors was influenced on life satisfaction. Whereas in case of the women under 40 years of age, physical self-efficacy was significant on life satisfaction, and overcome difficulties, endurance general self-efficacy factors were influenced on life satisfaction.

• Journal of Life Science
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• v.21 no.8
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• pp.1127-1133
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• 2011

Exercise has been shown to positively influence quality of life for elderly men with a wide variety of medical illnesses. Tai chi exercise, a slow and graceful form of exercise and meditation, has especially been offered as the ideal exercise for elderly men with diverse conditions, such as people suffering from chronic heart failure or breast cancer survivors. In one recent study, Tai Chi was found to improve exercise capacity, sleep stability, and quality of life in heart failure patients including elderly men. The purpose of the study was to examine the effects of 16 weeks of Tai Chi exercise (3 times/week, 60 min/trial, 40-50% HRR) on physical and physiological changes. Sixty four healthy volunteers without any particular disease between the ages of 65 and 79 years participated in the study. The results were as follows; Significant changes of cardiac endurance, strength, muscle endurance, flexibility and balance were observed following 16 weeks of Tai Chi exercise (p<0.05). In addition, significant changes of diastolic blood pressure, body fat and fat-free mass were observed following 16 weeks of Tai Chi exercise (p<0.05). These findings suggest that a brief period of Tai Chi exercise is beneficial, particularly to elderly men. It is especially beneficial for body composition, and physical fitness factors such as cardiopulmonary endurance, muscle endurance, flexibility, and balance. Further study is needed in this area for specific disease patients.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.114-123
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• 2007

We are going to propose equations for stable static and endurance strength design of driveshafts. It is very important to decide the contact normal stress of internal components of CV joints. We can estimate the strength, torque capacity, endurance life of CV joints from contact normal stress by presented equation in this paper. Besides it can be shown the equation for shaft design.

• Journal of Power System Engineering
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• v.18 no.2
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• pp.31-36
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• 2014

In this paper, pneumatic valve which consists of valve body, valve controller, nozzle and a multi-bender PZT actuator was suggested and fabricated. The fabricated pneumatic valve was experimented for performance evaluation. From the experimental results, we know that the flow rate of the suggested valve is 23 lpm at the pressure difference of 1bar and the maximum flow rate is 30 lpm at the pressure difference of 4 bar. The flow rates after endurance test of 9.8 million were 22.57 lpm and 28.62 lpm at the pressure difference of 1bar and 4bar, respectably. Finally, it was verified that the B10 life of the suggested pneumatic valve is over 50 million.