• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.239-244
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• 2019

The purpose of this study was to determine the correlation between upper limb muscle power and bat swing speed in elementary school baseball players. This study subjects were 32 subjects. Upper extremity muscle strength was measured in the Both Shoulder joints extensor flexor abductor adductor, Both elbow joints extensor flexor and bat swing speed. The correlation between upper extremity muscle strength and bat swing speed was analyzed using pearson's correlation analysis. There was a significant correlation between dominant upper extremity muscle strength and bat swing speed in the order of shoulder adductor, shoulder abductor, elbow flexor, and shoulder flexor and in correlation between non-dominant upper extremity muscle strength and bat swing speed in the order of shoulder adductor, elbow flexor, shoulder abductor, shoulder extensor, elbow extensor, and shoulder flexor. From these results, it can be seen that the stronger the upper extremity muscle strength, the bat swing speed is the more positive correlation.

• Journal of Biomedical Engineering Research
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• v.33 no.3
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• pp.135-140
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• 2012

Previous investigators have shown that the frequency compression is related to the muscle fatigue and the decreasing conduction velocity of muscle fibers. The aim of the present study was to investigate the relationship between endurance times and frequency parameters such as mean power frequency and median frequency in the surface EMG signal during isotonic contractions. Eight healthy subjects performed voluntary isotonic contractions of biceps Brachii muscle until their endurance times which were determined when the subject could no longer follow the contraction cycle. The regressive slopes of mean power frequency and median frequency were used to describe the frequency compression of the surface EMG signal, and to test the predictability of endurance time. As results of experiment, significant correlations were found between endurance time and the regressive slopes of mean power frequency and mean frequency computed over 50%Tend of endurance time.

• Biomedical Engineering Letters
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• v.8 no.4
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• pp.345-353
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• 2018

This study suggested a new EMG-signal-based evaluation method for knee rehabilitation that provides not only fragmentary information like muscle power but also in-depth information like muscle fatigue in the field of rehabilitation which it has not been applied to. In our experiment, nine healthy subjects performed straight leg raise exercises which are widely performed for knee rehabilitation. During the exercises, we recorded the joint angle of the leg and EMG signals from four prime movers of the leg: rectus femoris (RFM), vastus lateralis, vastus medialis, and biceps femoris (BFLH). We extracted two parameters to estimate muscle fatigue from the EMG signals, the zero-crossing rate (ZCR) and amplitude of muscle tension (AMT) that can quantitatively assess muscle fatigue from EMG signals. We found a decrease in the ZCR for the RFM and the BFLH in the muscle fatigue condition for most of the subjects. Also, we found increases in the AMT for the RFM and the BFLH. Based on the results, we quantitatively confirmed that in the state of muscle fatigue, the ZCR shows a decreasing trend whereas the AMT shows an increasing trend. Our results show that both the ZCR and AMT are useful parameters for characterizing the EMG signals in the muscle fatigue condition. In addition, our proposed methods are expected to be useful for developing a navigation system for knee rehabilitation exercises by evaluating the two parameters in two-dimensional parameter space.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.76-81
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• 2004

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

• Journal of Mechanical Science and Technology
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• v.18 no.8
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• pp.1388-1400
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• 2004

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.974-979
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• 2004

The fluidic muscle cylinder consist of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. In this study, we carried out the finite element modelling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.

• Journal of Korean Physical Therapy Science
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• v.24 no.2
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• pp.17-26
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• 2017

Purpose: The importance of core exercise on muscle activation of the lower extremity has been studied. This study investigated the effects of core exercise using pressure biofeedback unit on muscle strength of lower extremity. Method: Fourteen healthy young adults (7 males and 7 females) were recruited. They were randomly separated two groups and performed core exercise using pressure biofeedback unit of one set for three minutes, 10sets per day for three weeks. Result: The mean of muscle strength of lower extremity, maximum power of muscle and peak TQ/BW in core exercise group significantly increased after core exercise using bio feedback unit (p<.05). Conclusion: These findings suggest that core exercise using pressure biofeed-back unit may help improving of muscle strength of lower extremity in young adults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.162-169
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• 2020

This study was conducted from November 25 to December 4, 2019, to unmask differences in physical fitness based on the weight class of high school Ssirum elite-players. A total of 28 high school Ssirum elite-players were compared and analyzed by measuring physical factors (muscle strength/power, agility, anaerobic power, aerobic ability, flexibility, and isokinetic muscle function) by weight class. Data were analyzed using SPSS ver. 23.0. One-way ANOVA was used for comparison between groups. There was no difference by weight class in terms of grip strength, sit-ups, sergeant jump, long jump, flexibility, side step, and reaction time. Evaluation of back muscle strength revealed that the group with more than 100 kg had greater strength than lower weight categories, whereas it was lower in the sit-ups, 20 m shuttle run and the relative values anaerobic power. Considering isokinetic muscle function, no difference was observed between the groups of back muscle strength and knee joint. The results of this study indicate that amongst the high school Ssirum elite-players, there is no difference in muscle power, flexibility, agility, and anaerobic average power per body weight, isokinetic trunk strength, and knee flexion strength, when evaluated according to weight class.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.272-279
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• 2018

This study was conducted to compare the muscle strength, muscle power, and H/Q ratio according to energy system contribution in athletes participating in various sports. Subjects of the study were assigned into an Anaerobic Exercise Group (AEG, n=60; Short-Distance, Weight Lifting, Jumping, Throwing, Bowling, Golf) and an Endurance Exercise Group (EEG, n=60; Modern Pentathlon, Field Hockey, Handball, Cycle, Boxing, Rowing) groups. Isokinetic peak torque/body weight% and flexor/extensor ratio at 60, 180 deg/sec of knee extension and flexion were measured using an cybex 770. Data analysis was conducted using an independent t-test and one-way ANOVA. Based on the results of this study, there was higher extension, flexion strength and flexion power in the AEG than the EEG (p<0.05). We also confirmed higher muscle strength and muscle power in short distance and jumping athletes than other athletes participating in other events (p<0.05). However, there was no significant difference within the endurance exercise group. The HS ratio was within a stable range of 50% to 60% in all events. Collectively, the outcomes of this study indicate that routine physiological and performance testing can provide measurable benefits for elite athletes and their coaches.

• Journal of Korean Academy of Nursing
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• v.36 no.1
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• pp.5-14
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• 2006

Purpose: This study was done to analyze the effects of an exercise program on body composition and physical fitness of obese female college students. Method: Data was collected from September 29, 2003 to December, 29, 2003. The research design was arandomized control group pretest-posttest experimental design. The subjects were college nursing students at K University. Forty four students, 20 in the experimental group and 24 ina control group, with more than $30\%$ body fat were randomly assigned. The subjects in the experimental group participated in an exercise program for 12 weeks, sixty minutes per session, five times per week. Body composition and physical fitness was measured by a body composition analyzer, cardiovascular endurance, muscle endurance, muscle strength(grip strength, back strength), flexibility, balance, agility(whole body reaction time) and power(standing long jump). Result: Body weight(F=4.76, p=0.035), body fat(kg)(F=5.68, p=0.022) and body mass index(F=5.73, p=0.021) of the experimental group were significantly different from the control group, but there were no significant differences in body fat($\%$), lean body mass, muscle mass and WHR. Back strength(F=6.50, p=0.015), flexibility(F=14.62, p=0.000), muscle endurance(F=7.98, p=0.007), power(F=5.76, p=0.02l) and balance(F=2.46, p=0.018) of the experimental group were significantly different from the control group, but there were no significant differences in cardiovascular endurance, grip strength or agility. Conclusiton: The exercise program was effective in improving body weight, body fat(kg), body mass index, back strength, muscle endurance, flexibility, balance and power of obese female college students.