• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.185-198
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• 2023

The purpose of this study is to obtain information necessary for the development of patient clothes that can reduce physical fatigue of caregivers by quantitatively measuring the muscle load and fatigue. The patient clothes used in this study can be broken down into three types: A type (back center zipper open suit), B type (top-to bottom separated patient clothes), and C type (front zipper open suit). The EMG measurement sites are as follows: hand muscle (brachioradialis), upper arm (biceps, triceps), shoulder (anterior deltoid, medial deltoid, posterior deltoid, upper trapezius), and waist (erector spinae); additionally, the EMG signals were measured. Through this experiment, muscle load, muscle energy consumption, and muscle fatigue generation tendency were analyzed. The results of the study revealed that the C type patient clothes required the most strength in the muscles of the shoulders, upper arms, hands, and back when being put on and taken off compared to other patient clothes. The A type clothes required a relatively large force in opening the zipper. In terms of muscle energy consumption, B type generally called for more strength when it came to the zip-up and putarmsup motions. With regard to the cover the body and put legs/hips up motions, C type used the highest amount of muscle energy, whereas A type used relatively little energy. In terms of the occurrence of muscle fatigue during the putting on and taking off of the patient's clothing, there was a difference in the area and degree of muscle fatigue in the A, B, and C types, and there was also a tendency for muscle fatigue to occur when performing repetitive movements.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.541-547
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• 2013

Objective: The aim of this study is to find the influence on muscle fatigue by changing an angle of neck while Shaker exercise. Background: Shaker exercise is commonly applied to dysphagia patients for strengthen suprahyoid muscle(SHM) and relaxing upper esophageal sphincter. Method: Experiments were conducted by measuring muscle fatigue with surface electromyography(SEMG) in case of neck $15^{\circ}$ and $50^{\circ}$ flexion, in addition to original method. For the study 30 undergraduate students were participated as subjects. Muscle fatigue was measured with variations of median frequency(MF) and median frequency slope(MFS) by attaching SEMG to 3 muscles. At the same time, perceived exertion was measured by using Borg's rating of perceived exertion(RPE). Results: A MF was increased when low angle in SHM, both male and female. It means that muscle fatigue was significantly decreased(p<.05). RPE was significantly increased when low angle(p<.01). Perceived exertion explained 15.2% of the variation of MF in SHM. And regression equation was, MF in SHM = 59.918 + (4,910 * RPE). Conclusion: The outcome shows that it is possible to use the efficient method which makes muscle fatigue decrease by reducing the angle of neck flexion. Application: The results might contribute to develop the effective Shaker exercise method.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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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.

• Journal of the Ergonomics Society of Korea
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• v.27 no.3
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• pp.15-22
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• 2008

The purpose of this study was to define the effects of noise and background music on the trunk muscle fatigue during dynamic lifting and lowering tasks. Six healthy male subjects with no prior history of low back disorders participated in this study. The participants were exposed to two levels of background noise such as 40dB noise and 90dB noise and three levels of background music such as no music, slow music, and fast music. Six different combinations of background noise and background music were played while the participants were performing the lifting task at 15% level of Maximum Voluntary Contraction. Electromyography signals from six muscles were collected and fatigue levels were analyzed quantitatively. In results, the 90dB noise increased trunk muscle fatigue and slowed down the recovery. The trunk muscle fatigue was the lowest when the fast music was played for as background. After recovery, the 90dB noise increased trunk muscle fatigue. The trunk muscle fatigue was the lowest when the slow music was played for as background. The results can be useful to manage the cumulative fatigue of trunk muscles due to background noise and music during repetitive lifting and lowering tasks in industry.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.349-356
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• 2012

This study aimed to assess the effects of progressive lumbar stability exercises and lumbar stability exercises on changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index in soccer players. Ten subjects were assigned to undergo training in each of the 2 groups, namely, the progressive lumbar stability exercise group and lumbar stability exercise group. Each intervention session lasted for 30 min, and 4 sessions were conducted in a week for 6 weeks for soccer players of S. University in Jeonnam, Korea. Changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index were measured using ultrasound and surface electromyogram. The results of the ultrasound measurement for the transversus abdominis muscle thickness indicated that progressive lumbar stability exercises were more effective than lumbar stability exercises. The results of the lower extremity muscle fatigue index measurements using surface electromyogram indicated that the fatigue index decreased in the progressive lumbar stability exercise group. Progressive lumbar stability exercise is believed to have put more workload during the shaking of the limbs, leading to increased stability and increased efficiency of the lower extremity muscle, thereby decreasing the fatigue index. Therefore, progressive lumbar stability exercises can be an effective measure for preventing injuries and improving the game performance of sports players by increasing the transversus abdominis muscle thickness and decreasing the lower extremity muscle fatigue index.

• Journal of International Academy of Physical Therapy Research
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• v.3 no.2
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• pp.422-428
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• 2012

The present study purposed to examine the effects of transcutaneous electrical nerve stimulation, self-stretching and functional massage on the recovery of muscle contraction force for muscle fatigue caused by sustained isotonic contraction. The subjects of this study were 45 healthy students. They were divided into transcutaneous electrical nerve stimulation group(n=15), self-stretching group(n=15) and functional massage group(n=15), and using Primus RS. We observed the pattern of changes in maximal voluntary isometric contraction force(MVIC) after causing muscle fatigue in quadriceps femoris muscle through sustained isotonic contraction. Maximal voluntary isometric contraction force(MVIC) were greatly increased after transcutaneous electrical nerve stimulation, self-stretching and functional massage. In the comparison of recovery rate of muscle contraction force for muscle fatigue caused by sustained isotonic contraction among the treatment groups, it did not show any significant differences. However, it showed that each treatment may be effective in recovery of muscle fatigue caused by sustained isotonic contraction.

• Journal of Biomedical Engineering Research
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• v.44 no.3
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• pp.218-224
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• 2023

This study aimed to analyze the coordination of muscle and muscle fatigue between biceps, lateral deltoid, and anterior deltoid during dumbbell side lateral raise using bio-signal. One male subject performed dumbbell side lateral raise with 3% of 1RM dumbbell at the rate of 30bpm until failure (8 minutes). While performing, ECG were recorded to observe the participant's performance. EMG were recorded from biceps, lateral deltoid, and anterior deltoid for observing coordination and fatigue. ECG were analyzed in time and frequency domain to observe Heart rate, normLF, normHF. Changes in heart rate, normLF, and normHF indicate that the sympathetic nervous system is activated, while changes in median frequency (MDF) indicate the occurrence of muscle fatigue. Moreover, the coordination relationship of muscle changed. The correlation of MDF between each muscles indicated that lateral deltoid is associated with biceps and anterior deltoid. These results showed that our study can contribute to improving understanding of muscle fatigue and muscle coordination relationships.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.656-658
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• 1999

This paper presents musculotendon model to show the decline in muscle force during functional electrical stimulation (FES). It represent muscle activation and contraction concepts including muscle fatigue. A muscle fatigue term in activation dynamics as a function of the intracellular acidification and the pulsewidth of stimulation pulses change activation to decline muscle force. The computer simulation shows that muscle force decline in stimulation time.

• The Journal of Korean Physical Therapy
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• v.19 no.3
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• pp.11-17
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• 2007

Purpose: The purpose of this study were to analyze fatigue patterns of the rectus femoris muscle by isometric contraction. Methods: Twenty healthy subjects(10 male, 10 female) participated in this study. Maximal voluntary isometric contraction(MVIC) was measured by the dynamometer. Muscle activity was recorded from the rectus femoris muscle. During the experiment, the subject was seated in the chair. The measured items, median frequency(MDF) and root mean square (RMS), were collected from the surface EMG. All data were analyzed using repeated measures ANOVA. Results: There was significant difference of MVIC between male and female. Endurance time was significant difference by the level of MVIC but no significant in the main effect(sex) and interaction effect. The MDF and fatigue index were significant differences in the interaction effect. The RMS was not significant difference in both of main and interaction effect. The muscle fatigue patterns of female was greater than male after 60% MVIC. Conclusion: This study showed that sex differences of muscle fatigue were started from 60% MVIC.

• Textile Coloration and Finishing
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• v.26 no.3
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• pp.181-186
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• 2014

This paper surveys improvement characteristics in muscle fatigue with bio-activity material imbedded fabric. For this purpose, the subjects wear the garment which is covered by bio-activity materials all over every day during 2 weeks of experimental period. After 2 weeks period, VAS(Visual Analogue Scale) index evaluation regarding muscle fatigue and pain has been conducted in comparison between before wearing and after so that we can evaluate the effect on muscle fatigue improvement. The effectiveness survey for testing products consists of improvement on krunkle, muscle fatigue and exercise capacity. As a result, 100% of test subject group completes a questionnaire with positive answer as above normal in every question. In addition the preference of testing products is researched in wearing comfort, activity and convenience. And it is marked above normal by 100% of test subject group as well. Moreover any kind of unusual skin reaction has not been detected in safety evaluation. Therefore this testing products is being judged as a beneficent product for improvement on muscle fatigue without any skin irritation.