• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.584-590
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• 2009

Since driving include compilcated actions that require a variety of abillity and cause extrme concentration or strain, divers tend to feel tired easiy. However, divers can't recognize fatigue degree by himself and accordingly the methods to measure quantitative fatigue degree exactly is quite difficult to be secured. In this study, the most efficient driving posture was suggested based on the analysis of quantitative muscular strength and fatigue degree according to posture. The driver whom we experimented included 9 commercial bus drivers. We also analyzed quantitative legs' muscular strength according te operating each pedal, left and right then we analyzed muscular strength and muscular fatigue degree according to driving pattern while driving commercial buses. And then we suggested the most efficient driving posture.

• Journal of Korean Physical Therapy Science
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• v.15 no.4
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• pp.19-26
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• 2008

Background: This study examines the changes in muscular strength and muscle fatigue substances when taping treatment is applied in squat exercise and treadmill exercise, in which quadriceps femoris muscles are used frequently so as to clarify the effects of taping as an aid of exercise ability improvement. Methods: 20 healthy male adults in their 20's participated in the study, in which tapes were put on their quadriceps femoris muscles, and various variables as the indicator of muscular strength and muscle fatigue substances were measured by means of the measuring tool before and after exercises. Results: the following conclusion was drawn up: 1. In exercise using muscular strength of the right knee extension, the reduction of muscular strength after exercise of the taping group showed significant statistical difference from that of the non-taping group. 2. In exercise using muscular strength of the lower limbs, the reduction of blood Glaucos after exercise of the taping group showed significant statistical difference from that of the non-taping group. 3. In exercise using muscular strength of the lower limbs, the value of lactic acid after exercise of the taping group showed significant statistical difference from that of the non-taping group. Conclusion: Therefore, the results of this study demonstrate that the application of taping treatment in sports activity or daily life where quadriceps femoris muscles are used a lot can have positive effects on the improvement of muscular strength and relief of muscle fatigue.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.87-96
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• 1993

Spectrum analysis of surface electromyogram (FMG) signals is an effective approach to the study of localized muscular fatigue during isometric contraction. Many investigators have con firmed the frequency of the EMG signals being lowered during sustained contaction. In this study, the cyclic loading tasks were performed, and a comparison was made for the median power frequency shift pattern of the EMG signals with the sustained contraction of the same load. The median power frequency shift of the EMG signals for the cyclic loading task was found to be a part of that for the sustained contraction. Based on this result, a new muscle fatigue index was computed by normalizing the duration of the sustained contraction. A fatigue index was obtained as a function of exertion level and the work/rest schedule. With the proposed fatigue index, it is possible to evaluate or predict the degree of muscular fatigue for a physically demanding task.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.2
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• pp.1774-1778
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• 2019

Background : Methods of wearing a baby carrier have suggested; however, there have been no studies suggesting ideal ways. Objective : To investigate muscular fatigue and balance of the waist during baby carrier are worn on the front, the side, and the back of the body. Design: Randomized controlled clinical trial (single blind) Methods : The subjects of this study were 20 healthy men and women in their 20s, who underwent tests of muscular fatigue and balance of the waist bones based on types of wearing baby carrier. Electromyogram (EMG) patches were attached to the L2 and the L4 for testing muscular fatigue, while a device for measuring proprioceptive senses was used to assess balance ability. The measurements were performed before wearing the baby carrier and after 30 minutes of normal walking. The methods of wearing the baby carrier included wearing on the front, the side, and the back of the body. Results : The time taken to adjust the balance was shorter than other types of wearing during the baby carrier were worn on the side, and the ratio of lumbar flexion and relaxation was shown insignificant. Conclusions : These results suggested that wearing the carriers on the side was most effective on reducing fatigue and enhancing balance ability of the waist.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.1
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• pp.28-38
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• 2008

Purpose: This study was conducted to investigate the muscular strength & stamina improvement and muscle anti-fatigue effects of Morinda officinalis How after long term administration. Methods: 4-6 weeks old ICR mice were used in this study and we administered the water soluble extracts of Morinda officinalis How in the concentration of 1, 10. 100/mg/0.3ml to each 5 mice (ATS group) and same volume of normal saline was administered to 5 mice (control group) once a day for 90 or 120 days. After the administration we performed the swimming exercise test and the grip strength test. And we measured the concentration of glucose and the activity of lactate dehydrogenase in plasma regarded as biochemical indicator related with the muscular fatigue. Results: In swimming exercise test, all ATS groups showed increased time compared with relative control group after 90 days administration. After 120 days adminstration 100/mg/0.3ml ATS groups showed increased results. In grip strength test, all ATS groups showed increased grip strength compared with relative control group after 90 days administration. After 120 days adminstration 10/mg/0.3ml ATS groups showed increased result. All the results of plasma glucose didn't showed statistically significant difference after 90 and 120 days administration. In the plasma concentration of activity level of lactate dehydrogenase, all ATS groups didn't showed statistically significant difference compared after 90 days administration. Conclusion: This study show that Morinda officinalis How can increase the muscular strength & stamina and anti-fatigue effect.

• Journal of Korean Physical Therapy Science
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• v.4 no.2
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• pp.391-397
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• 1997

The purposes of this study were to determine wether knee muscular fatigue affects on one-leg static standing balance. Sixty four healthy subjects were used for this study : 44 men and 20 women, with an average age of 19.52. One leg static standing balance was measured at pre-fatigue and post-fatigue by an instrumented balance assessment system(kinesthetic ability training balance platform) which is commercially available for testing or training balance. Isokinetic exercises were used to evoke muscle fatigue at 180 degree/see by Cybex 1200. One leg static standing balance ability was significantly decreased after knee muscular fatigue. Although these phenomenons were not clearly understood, these results have important implications for rehabilitation in fatigable patients. These results suggest that the excessive fatiguing during rehabilitation in patients with fatigable disease may increase risk of reinjury and falling injury due to balance disturbance. Further studies are required to determine the physiological mechanisms of muscle fatigue that can play in decreasing one-leg static standing balance ability.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1149-1156
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• 2012

In this study, we proposed the most efficient driving posture based on the analysis of quantitative muscular strength and fatigue degree according to posture. Since driving include complicated actions required by a variety of ability and cause by extremes concentration or strain, drivers tend to feel tired easily. However, drivers can't recognize the fatigue degree by themselves. Moreover, the method for measuring the quantitative fatigue degree exactly is quite difficult to be secured. 9 professional bus drivers were participated. We analyzed the quantitative legs' muscular strength when operating each pedal. And then we also analyzed the muscular strength and muscular fatigue degree according to driving pattern during bus driving. Therefore, we suggested the most efficient driving posture.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.27-32
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• 2009

Human physical activity to lead daily life is performed by a variety of muscular activity strategies. These strategies can be influenced by characteristics, difficulty and muscle fatigue of work. Therefore this study examines muscular strengths (grip and back strength) of workers engaged in electronics industry in Korea, compares them to mean value of muscular strength by sex and age, accumulates related data and then aims to develop improvement methods of working environment and prevention/management program.

• Safety and Health at Work
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• v.10 no.3
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• pp.321-326
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• 2019

Background: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. Methods: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a $2{\times}2{\times}3$ within-subject repeated measures analysis of variance. Results: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. Conclusions: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.1-7
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• 2013

According to the frequent use of mobile devices, risk of repetitive strain injury for the finger joints was increasing recently. The purpose of this study was to investigate the difference of muscular endurance limit of the thumb between adults and children. A total of thirty subjects (15 adults: $41.0{\pm}7.9$ years and 15 children: $9.5{\pm}2.7$ years) was recruited for this experiment. Maximum voluntary contraction (MVC) of the thumb was measured for 100 trials for each subject by using a push-pull gauge. From the maximum peak value obtained, three main factors (MVC, endurance limit, and fatigue index) were defined to quantify fatigue characteristics of the thumb flexor muscle. The experimental results showed that the mean of MVC, endurance limit, and fatigue index of the children were approximately 50% compared to the adults (p < 0.001). From the results of Pearson correlation test, the endurance limit was highly correlated with weight, age, hand length rather than height. Based on this study, children are more vulnerable to repetitive task using the thumb such as text/SNS messaging, gaming, and scrolling.