• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.7 no.1
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• pp.79-86
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• 2003

A myoelectric signal, under sustained isometric contraction of muscle the modelled as the output of a linear time-varying system whose input is constant number of pulse train. The proposed model considered localized muscle fatigue by metabolic by-products during sustained fatiguing contraction. To characterize muscle fatiguing model of myoelectric signal, We calculated median frequency of generated signal as fatiguing index of muscle during sustained isometric contraction.

• Physical Therapy Rehabilitation Science
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• v.7 no.3
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• pp.127-133
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• 2018

Objective: The purpose of this study was to investigate the effects of foam roller (FR) stretching, kinesiotaping (KT), and dynamic stretching (DS) on gait parameters after inducing muscle fatigue in the ankle joint. Design: Cross-sectional study. Methods: The subjects were thirty healthy young adults between the ages of 20 and 31 years at Baekseok University who voluntarily participated in this study. The participants were randomly assigned to either the FR group, KT group, or the DS group after inducing muscle fatigue of the ankle joint. Fatigue induction of the ankle joint muscles was performed by alternating a heel up and down exercise with the standing posture on the ground. The speed was maintained at 40 beats/minute using a metronome. Subsequently, the respective intervention was applied to each group. Gait parameters were measured before and after ankle muscle fatigue induction, and after intervention using the GAITRite system. One-way ANOVA was used to compare gait parameters among groups, while repeated measures ANOVA was used to compare gait parameters within each intervention group. Results: The FR group increased significantly in velocity, step length, and stride length except for cadence after intervention compared to after ankle muscle fatigue induction (p<0.01). Furthermore, the KT group showed significant increases in velocity, cadence, step length, and stride length after intervention, especially in cadence group (p<0.05). All intervention groups showed significant increases in stride length after intervention, especially the DS group (p<0.05). Conclusions: Therefore, we suggest that KT, FR, and DS can be an effective intervention on gait parameters when the ankle joint is unstable and injured.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.1
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• pp.15-24
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• 2023

PURPOSE: This study examined the effects of lowintensity resistance exercise combined with blood flow restriction on muscle activity and muscle fatigue to determine if such a combination may be an alternative to high-intensity resistance exercise in maintaining the muscle mass and strength and preventing degenerative loss of skeletal muscle and to provide basic data for presenting the effectiveness of exercise. METHODS: The interventions were provided for five weeks, four sessions a week, once a day, 60 minutes a session to Experimental group I (n = 13), in which low-intensity resistance exercise was applied by combining blood flow restriction with the biceps curl and experimental group II (n = 12), in which only high-intensity resistance exercise was applied. As a pre-test, the biceps brachii muscle activity and fatigue were measured by surface electromyography, and the hemodynamic variables, such as blood pressure and heart rate, were measured. The post-test was performed identically to the pre-test and compared and analyzed with the pre-test. RESULTS: A significant difference within-group was observed in the biceps brachii muscle activity and fatigue in experimental group I and only in biceps brachii activity in experimental group II. No significant differences were observed between the two groups. CONCLUSION: Since the low-intensity resistance exercise combined with blood flow restriction has similar effects to high-intensity resistance exercise, it is considered an alternative for improving muscle function in groups unable to perform high-intensity resistance exercise.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.181-190
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• 2007

The purpose of this study was to analyze the muscle fatigue for lower limbs during the level and downhill running. The subjects were 6 males of twenties who have no experience to get the injury in the lower limbs and required to run on the level and downhill which was -7% grade treadmill at 8.3km/h. EMG signal was gained by ME3000P8 Measurement Unit and computed the Median Frequency(MF) with the power spectrum analysis in the Megawin software. Rectus femoris(RF), Vastus lateralis(VL), Gluteus medius(GLU), Biceps Femoris(BF), gastrocnemius medial head(GM), gastrocnemius lateral head(GL), Tibialis anterior(TA) were selected. The result of this study were as follows: The MF of RF decreased in the downhill running than level running in length of time but, the MF of VL was opposite. The MF of BF decreased in the level and downhill running, but, the MF of BF decreased much in the level than downhill running. The MF of GLU decreased much in the downhill running but, almost no change in the level running. The MF of TA decreased in the level running than downhill running. The MF of GL decreased in the level running but, the MF of GM decreased in the downhill running in length of time. This study analyzed the muscle fatigue of the lower limbs with the median frequency on the basis of an assumption that the impact force for the flexion and extension of the joint and the body mass may be much in the eccentric contraction such as the downhill running than level running. RF and GM showed the muscle fatigue in the downhill running than level running. BF and GL showed the muscle fatigue in the level running than downhill running.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.377-382
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• 2004

In the present study, thirteen healthy volunteers performed lumbar extension exercises at 48$^{\circ}$/s, loaded by 40, 50, 60kg(about 44, 55, 66％ of maximum voluntary contraction). During the whole period of exercises, electromyographic(EMG) signal was measured in the erector spinae muscle in order to determine muscle fatigue. Using the wavelet transform, EMG signal was separated by various frequency ranges in the time-frequency domain, and muscle fatigue was analyzed, comparing with the results based on the median frequency(MDF). MDF shifted toward the lower frequency ranges with the muscle fatigue, showing a single characteristic frequency. On the other hand, wavelet transform of EMG signals resulted in increased power amplitude in lower frequency ranges(0-125Hz), and decreased power amplitude in higher frequency ranges(375-468Hz). This study reveals that the muscle fatigue during dynamic movement is explained better by wavelet analysis.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.175-182
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• 2023

In this paper, we propose a study compared and analyzed the CPR results and muscle fatigue of the three groups. There is a group that counts loudly when compressing the mannequin's chest (Group A), a group that breathes autonomously without counting (Group B), and a group that breathes abdominally without counting (Group C). Twelve people were assigned to each group, and after performing chest compressions for 5 minutes, the results of CPR were analyzed using a program connected to the mannequin, and the muscle fatigue of the performers was analyzed using wireless electromyography. The most efficient method was found to be group B. If we only look at the speed and depth of compression within the normal range, Group C would be more efficient, but Group B showed significantly lower muscle fatigue, and Group A did not reach the normal range in depth of chest compression and muscle fatigue was the highest. Group B was also found to be the most accurate in hand positioning accuracy, and was also found to be the most efficient in maintaining concentration on chest compressions.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.59-66
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• 2014

The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on shock absorption during single-leg landing of adult women. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. Both the normal weight group and the overweight group showed that use soft landing and ankle dominant strategy. The peak vertical ground reaction force, the knee joint absorption power, and eccentric work done, as the increase of knee joint muscle fatigue level, showed a decrease. And the hip joint absorption power and eccentric work done, as the increase of weight, was less than the overweight group showed the normal weight group. In conclusion, the accumulation of the knee joint muscle fatigue and the increase of body weight may lead to an increased risk of injury during landing.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.115-121
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• 2011

This study was to investigate the change of muscle fatigue through maximum contraction during flexion and extension of knee joint before and after the isometric trunk exercise was implemented on elderly Hansen's disease. 18 subjects exercised for 60 minutes twice a week for 12 weeks. The subjects were divided into normal sensory group, group with sensory loss in left sole, group with sensory loss in right sole, and group with sensory loss in both soles, according to the sensory condition on their soles. We obtained following results. Muscle fatigue in normal sensory group, there were significant differences in left right hamstring, left rectus femoris(p<.05), in group with sensory loss in left sole, there were significant differences in left right hamstring(p<.05), in group with sensory loss in right sole, there were significant differences in left right hamstring, right rectus femoris and group with sensory loss in both sole, there were significant differences in right hamstring(p<.05). The differences of muscle fatigue according to the sensory condition on their soles, there were significant differences in left hamstring between normal sensory group and group with sensory loss in both sole(p<.05).

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.1-9
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• 2020

PURPOSE: This study examined the effects of muscle fatigue on proprioception in the type of taekwondo training, causing injury to taekwondo athletes. METHODS: The subjects were divided into Taekwondo Kyorugi athletes (n = 14) and Taekwondo Poomsae athletes (n = 14). After inducing muscle fatigue to the subjects, the joint position sense (JPS) and the force reproduction sense (FRS) were measured before and immediately after the induction of muscle fatigue. RESULTS: Studies have shown no significant impact on the JPS and FRS caused by muscle fatigue induced by Poomsae and Kyorugi (p > .05). The JPS, however, showed a significant difference before and after Kyorugi (p < .05). The FRS showed significant differences before and after Poomsae (p < .05). Through this study, the injuries to taekwondo athletes appear to be influenced by the joint position and force reproduction. Moreover, the injury appears to affect the joint position sense in Kyorugi athletes and the force reproduction sense in Poomsae athletes. CONCLUSION: The results will contribute to injury prevention and athlete protection. In addition, the information can be used as basic data for the development of sports injuries prevention and rehabilitation programs for Taekwondo athletes. Research is needed on the customized management of sports methods and self-care to prevent sports damage, considering the athletic characteristics of the taekwondo athletes in the future.

• Asian Oncology Nursing
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• v.10 no.2
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• pp.171-179
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• 2010

Purpose: The purpose of this study was to evaluate the effects of progressive muscle relaxation on nausea, vomiting, fatigue, anxiety, and depression in cancer patients undergoing chemotherapy. Methods: This study was a quasi-experimental research using non-equivalent control group pretest-posttest design. Data were collected from outpatients in a university hospital from April to August, 2009. There were 74 participants, 39 in the experimental group and 35 in the control group. The experimental group was given daily the progressive muscle relaxation for 20 min during three weeks. The structured questionnaire was used to measure nausea, vomiting, fatigue, anxiety, and depression. Data were analyzed using the SPSS/WIN 12.0 program, $x^2$-test, Fisher's exact test, t-test and ANCOVA were conducted to examine the homogeneity and the research hypotheses. Results: There were statistically significant decreases in anxiety and depression in the experimental group compared to the control group. However, there were no significant differences in nausea, vomiting, and fatigue between the groups. Conclusion: In this study, progressive muscle relaxation was effective in alleviating anxiety and depression of cancer patients undergoing chemotherapy. Therefore, progressive muscle relaxation can be usefully utilized as a nursing intervention that enhances psychological function of cancer patients.