• 대한물리의학회지
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• 제16권1호
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• pp.41-48
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• 2021

PURPOSE: The purpose of this study was to provide fundamental clinical data to be used in therapeutic approach to patients with patellofemoral pain syndrome by administrating the squat exercise combined with whole body vibration exercise to them and investigating the effect of such exercise to leg muscle activity and muscle fatigue. METHODS: The patients with patellofemoral pain syndrome were randomly assigned to experimental group I (n = 9) where only squat exercise was administered and experimental group II (n = 9) where the squat exercise combined with whole body vibration exercise was provided. The intervention program was administered for two weeks, four days a week, one session a day, three set a session, and 20 reps a set. The pre- and post-test were performed to measure muscle activity and muscle fatigue of vastus medialis and vastus lateralis. RESULTS: The muscle activity significantly changed in both group (p < .05, p < .01, respectively) and the muscle fatigue showed significant change only in group I (p < .05). In addition, there was significant difference between groups in change of muscle fatigue of both muscles (p < .05) but not in change of muscle activity. CONCLUSION: The results showed that both exercise are effective in improving muscle activity, however, that the squat exercise combined with whole body vibration exercise is more effective in preventing muscle fatigue.

• 산업경영시스템학회지
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• 제41권4호
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• pp.1-8
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• 2018

Whole body fatigue detection is an important phenomenon and the factors contributing to whole body fatigue can be controlled if a mathematical model is available for its assessment. This research study aims at developing a model that categorizes whole body exertion into fatigued and non-fatigued states based on physiological and perceived variables. For this purpose, logistic regression was used to categorize the fatigued and non-fatigued subject as dichotomous variable. Normalized mean power frequency of eight muscles from 25 subjects was taken as physiological variable along with the heart rate while Borg scale ratings were taken as perceived variables. The logit function was used to develop the logistic regression model. The coefficients of all the variables were found and significance level was checked. The detection accuracy of the model for fatigued and non-fatigues subjects was 83% and 95% respectively. It was observed that the mean power frequency of anterior deltoid and the Borg scale ratings of upper and lower extremities were significant in predicting the whole body fatigued when evaluated dichotomously (p < 0.05). The findings can help in better understanding of the importance of combined physiological and perceived exertion in designing the rest breaks for workers involved in squat lifting tasks in industrial as well as health sectors.

• 한국운동역학회지
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• 제24권2호
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• pp.111-119
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• 2014

The purpose of this study was to investigate the effects of localized muscle fatigue and whole body fatigue on postural control during single-leg stance after impairment induced by heel raise and the Harvard step test. Thirty-eight university students (19 men: age, $20.1{\pm}0.2$ yrs; height, $175.0{\pm}5.23cm$; weight, $66.8{\pm}5.6kg$; body mass index, $21.8{\pm}1.7kg/m^2$, 19 women: age, $20.6{\pm}1.1yrs$ ; height, $163.6{\pm}6.7cm$; weight, $58.8{\pm}4.6kg$; body mass index, $22.0{\pm}2.2kg/m^2$) were participated in this study. Subjects performed a series of single-leg postural tasks prior to, following, and 24 hours after completing: heel raise or the Harvard step test. This study showed that the root mean squared distance and velocity in the anteroposterior and mediolateral planes of the center of pressure decreased significantly due to heel raise exercise-induced fatigue. Furthermore, the root mean squared distance in the anteroposterior and mediolateral planes, and the 95% confidence ellipse area of the center of pressure also decreased significantly 24 hours after completing the Harvard step test. In conclusion, this study showed that both heel raise exercise- and Harvard step exercise-induced fatigue affects postural control during single-leg stance in AP and ML planes. Furthermore, this study suggests that changes in the postural control strategy may have occurred after the fatigue protocols during single-leg stance. Also vision can attenuate the postural deficits associated with the fatigues. In order to clarify these results, further studies using other equipment and variables are necessary.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.242-249
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• 1999

Spot welding is very important and useful technology in fabrication of an automobile body structure. Because fatigue strength of the spot welding point is however considerably lower than parent metal due to stress concentration at the nugget edge, accurate stress analysis and fatigue stength evaluation of spot welded lap joint are very important to valuate the reliability and durability of automobile body structure and to establish a criterion of long life fatigue design. Many invetigators have studied so far onsystematic fatigue strength evaluation with various methods. It is however necessary to verify their reliability and abailability for practical application to fatigue design of spot welded structure, Thus,in this study, fatigue strength evaluation methods of spot welded lap joint. which are the maximum principal stress method. the fracture and availability with the Weibull probability distribution. From the results, it was found that reliability and availability withe the Weibull probaility distribution. From the results, it was found that reliability and availability of the suggest fatigue strength estimation methods methods were higher than $\Delta$P-$N_f$ relation. However, among them , reliability of the maximum pricipal stress method was the highest.

• 여성건강간호학회지
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• 제26권3호
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• pp.231-239
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• 2020

Purpose: The purpose of this study was to investigate factors affecting premenstrual symptoms among nursing students, focusing on depression, fatigue, and body esteem. Methods: The participants were 145 nursing students at a university located in Changwon, Korea. Data were collected from November 2 to November 30, 2019 using self-reported structured questionnaires, and analyzed using descriptive statistics, independent t-test, analysis of variance, Pearson correlation coefficients, and multiple regression analysis. Results: The mean item score for premenstrual symptoms was 2.52±0.92, indicating a low level. The mean score for depression was 16.05±7.72, and 15.2% of participants were found to be moderately depressed and 9.7% severely depressed. The mean item score for fatigue was 4.84±0.84, indicating a moderate level, and body esteem was 2.94±0.44, indicating a moderate level. The premenstrual symptoms of nursing students showed a statistically significant correlation with depression (r=-.58, p<.001), fatigue (r=.33, p<.001), and body esteem (r=-.28, p<.001). Factors impacting premenstrual symptoms of nursing students were depression (β=.47, p<.001), dysmenorrhea (β=-.18, p=.009), menstrual cycle irregularity (β=.17, p=.013), and body esteem (β=-.14, p=.038). The total explanatory power of these variables was 41.0%. Conclusion: Findings from this sample of nursing students suggest that intervention programs to relieve premenstrual symptoms should focus on depression, menstrual cycle irregularity, dysmenorrhea, and body esteem.

• 재활간호학회지
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• 제8권2호
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• pp.139-148
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• 2005

Purpose: This study was to examine the effects of foot reflexology on ADL and fatigue in stroke patients. Method: The subjects were 31 stroke patients hospitalized in the Oriental Medicine Hospital of D University from June to November, 2002. Foot reflexology was applied to the experimental group twice a week for 6 weeks, 40 minutes each. For the data analysis, $x^2$-test was conducted to verify the homogeneity of general characteristics and clinical characteristics, and t-test was done to verify the homogeneity of ADL and fatigue. To examine the relative efficacy of the intervention, ANOVA and ANCOVA were conducted. Results: After foot reflexology, the subjects in the experimental group showed significant improvement in ADL. They also had less physical, psychological, and neurosensory fatigue, which are three areas of fatigue. Conclusion: The results suggest that foot reflexology is an effective intervention that helps the body work efficiently, eases stress and strain, and enhances the homeostasis of the body through stimulating the reflex zone of internal organs in the body. Therefore, it is necessary to develop foot reflexology as an unique nursing intervention.

• 한국생산제조학회지
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• 제20권4호
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• pp.427-433
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• 2011

Chassis part in automotive body is affected by fatigue load at driving on the ground. Universal joint on this part is influenced extremely by the fatigue load. Fatigue life, damage and natural frequency are analyzed at universal joint under nonuniform fatigue load. The york part at universal joint is shown with the maximum equivalent stress and displacement of 60.755 MPa and 0.21086 mm as strength analysis. The possible life in use in case of 'SAE bracket' is the shortest among the fatigue loading lives of 'SAE bracket', 'SAE transmission' and 'Sine Wave'. The damage at loading life of 'SAE transmission' is the least among 3 types. The frequency of damage in case of 'Sine Wave' is 0.7 with the least among 3 fatigue loading life types but this case brings the most possible damage as 80% at the average stress of 0. Natural vibration at this model is analyzed with the orders of 1'st to 5'th and maximum frequency is shown as 701.73 Hz at 5'th order. As the result of this study is applied by the universal joint on chassis part, the prevention on fatigue damage in automotive body and its durability are predicted.

• 대한기계학회논문집A
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• 제31권2호
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• pp.166-173
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• 2007

Fatigue fracture behavior of a hybrid bolted joint was evaluated in comparison to the case of static fracture. Two kinds of specimens were fabricated for the mechanical tests; a hybrid bolted joint specimen for the shear test and a hybrid joint part specimen applied in the real tilting car body for the bending test. Characteristic fracture behaviors of those specimens under cyclic toads were obviously different from the case under static loads. For the hybrid bolted joint specimen, static shear loading caused the fracture of the bolt body itself in a pure shear mode, whereas cyclic shear loading brought about the fracture at the site of local tensile stress concentration. For the hybrid joint part specimen, static bend loading caused the shear deformation and fracture in the honeycomb core region, while cyclic bend loading did the delamination along the interface between composite skin and honeycomb core layers as well as the fracture of welded joint part. Experimental results obtained by static and fatigue tests were reflected in modifications of design parameters of the hybrid joint structure in the real tilting car body.

• 대한통합의학회지
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• 제8권2호
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• pp.139-147
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• 2020

Purpose : Proprioceptive position sense plays a key role in providing joint stability, and multiple factors are related to proprioceptive position sense. Thus, this study aimed to determine the effects of body composition, particularly skeletal muscle mass on proprioceptive position sense following muscle fatigue. Methods : Healthy female subjects agreed to have their body composition analyzed. Only subjects who had 18.5-22.9 kg/㎡ of BMI (body mass index) were included in this study, and the participants were divided into two groups by skeletal muscle mass level. The experimental group had a level of skeletal muscle lower than the standard level (n=9), while the control group showed a standard or high level of skeletal muscle mass (n=11). To determine the change in proprioceptive position sense of the knee joint, the absolute angle error (AAE) was evaluated following muscle fatigue on low extremity. The muscle fatigue was induced by isokinetic resistance exercise program of Biodex system. AAE was measured by the Biodex system and compared the result before and after muscle fatigue. Results : The experimental group showed a significant AAE difference between before (3.16±2.48 °) and after (5.40±2.61 °) muscle fatigue. In addition, there was a AAE difference between the experimental (5.40±2.61 °) and control groups (3.53±1.67 °) after fatigue; however, there was no significance. Those results indicated that low level of skeletal muscle mass might influence the proprioceptive position sense of the knee joint after muscle fatigue. Conclusion : Thus, maintaining the proper level of skeletal muscle mass is pivotal to reduce the risk of injury following muscle fatigue in ADL or sport activities.

• Journal of Ginseng Research
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• 제46권4호
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• pp.543-549
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• 2022

Background: In physical activity or labor, the human body is in a state of high intensity stress, and all parts or physiological functions of the body respond positively to maintain or balance the need for movement. The human body has many physiological changes in the process of movement, and fatigue is the external manifestation of various complex changes inside the human body. Fatigue is also a physiological mechanism of self-protection after the body reaches a certain level of activity, which can prevent the occurrence of life-threatening excessive functional failure. The generation of fatigue is a very complex process, and its mechanism has not been concluded yet. Therefore, it is an important work to search and screen the effective components of natural plants that have anti-fatigue effect and to explore their mechanism. Methods: This was a 8-week, randomized, double-blind, placebo-controlled clinical trial. A total of 110 subjects who passed physical examination were included according to the scheme design, and randomly divided into a test group which was given KRG and a placebo control group. The calculation is carried out according to the standard of sub-high-intensity exercise test. Results: There was no adverse effect on safety index of subjects after taking red ginseng capsule. After KRG treatment, subjective strength grade is significant lower than placebo treatment. Blood lactic acid content is significantly get lower after trial in KRG group, and significant lower than placebo group. Creatine phosphokinase(CK) content is significantly get lower after trial in KRG group, and significant lower than placebo group. Conclusion: According to the criterion in the test scheme, the result shows that KRG is helpful on relieving physical fatigue.