• Journal of the Ergonomics Society of Korea
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• v.31 no.6
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• pp.741-747
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• 2012

Objective: The purpose of this study is to compare the EMG activities of the trunk muscles when carrying a backpack with belts and without belts. Background: This research aimed to explore the influence of carrying a backpack with belts on the trunk muscles activity and to suggest a desirable method of wearing backpacks. Method: Seventy five adolescents participated in this study. The EMG activities of upper trapezious, cervical erector spinae and rectus abdominis were collected. One way ANOVA was used to analyze the collected data. LSD was used for post-hoc test. Results: The EMG data from treadmill walking showed significant differences between carrying a backpack with belts and without belts for the cervical erector spinae and upper trapezious(p<.05) in all group(A Group: no belt, B Group: lumbar belt, C Group: lumbar-chest belt). In descending walking, significant difference were found for the cervical erector spinae and rectus abdominis in all group. In ascending walking, there were no significant differences in all group. LSD showed that the muscle activity of the trunk muscles decreased significantly when the lumbar belt and lumbar-chest belt were worn. Conclusion: The trunk muscles activities were decreased when the subjects were wearing a backpack with belts, comparing with wearing a backpack without belts. Application: These results can be used to provide useful information on how wearing a backpack in adolescent.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.235-243
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• 2013

The purpose of this study was to analyse scientific according to period of rehabilitation training of ACL patients. ACL patients seven subjects participated in this study. Gait (1.58 m/sec) analysis was performed by using a 3-D Cinematography, a Zebris system and a electromyograph system. The data were analyzed by paired t-test. The joint angles were recorded from the ankle, knee, hip joints. Peak max dorsi-flexion and peak max plantar-flexion identified significant differences (p<0.05). Another angles were no significant difference. Vertical force (Fz) and max pressure variables improved 6 month RTP better than 3 month RTP. EMG were collected from 4 muscles (rectus femoris, biceps femoris, gastrocnemius, tibialis anterior) with surface electrides in gait system. EMG signals were rectified and smoothed data. EMG signas were no significant difference but they also improved 6 month RTP better than 3 month RTP. More research is necessary to determine exactly what constitutes optimal rehabilitation training period for ACL patients.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2209-2212
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• 2003

In this paper, we propose the method to extract the important frequency bands from the EMG signal, and for generation of feature vector using the important frequency bands. The EMG signal is measured with 4 sensor and is recorded as 4 channel’s time series data. The same frequency bands from 4 channel’s frequency components are selected as the important frequency bands. The feature vector is calculated by the function formed using the combination of selected same important frequency bands. The EMG signals acquired from seven wrist motion type are recognized by changing into the feature vector formed. Then, the extraction and generation is performed by using the double combination of the genetic algorithm (GA) and the neural network (NN). Finally, in order to illustrate the effectiveness of the proposed method, computer simulations are done.

• ETRI Journal
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• v.36 no.1
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• pp.99-105
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• 2014

This paper presents a new locomotion mode recognition method based on a transformed correlation feature analysis using an electromyography (EMG) pattern. Each movement is recognized using six weighted subcorrelation filters, which are applied to the correlation feature analysis through the use of six time-domain features. The proposed method has a high recognition rate because it reflects the importance of the different features according to the movements and thereby enables one to recognize real-time EMG patterns, owing to the rapid execution of the correlation feature analysis. The experiment results show that the discriminating power of the proposed method is 85.89% (${\pm}2.5$) when walking on a level surface, 96.47% (${\pm}0.9$) when going up stairs, and 96.37% (${\pm}1.3$) when going down stairs for given normal movement data. This makes its accuracy and stability better than that found for the principal component analysis and linear discriminant analysis methods.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.338-349
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• 2000

Neck muscle forces and spinal loads at the C4/5 level were estimated that result from isometric voluntary ramp efforts gradually developing to maximums in flexion, extension, left lateral bending and right lateral bending. Electromyographic (EMG) activities, a three-dimensional anatomic data of the neck and a hybrid model, EMG-assisted optimization (EMGAO) model, were used. The model computed the cervical loads at 25%,50%,75%, and 100% of peak moments. The highest model-predicted C4/5 joint compressive forces occurred during flexion; $361\;({\pm}164)\;N,\;811\;({\pm}288)\;N,\;1207\;({\pm}491)\;N\;and\;1674\;({\pm}319)\;N$ in 25%, 50%, 75% and 100% of peak moment respectively. Variations in load distribution among the agonistic muscles and co-contractions of antagonistic muscles were estimated during ramp efforts. Results suggest that higher C4/5 joint loads than previously reported are possible during isometric, voluntary muscle contractions. These higher physiological loads at C4/5 level must be considered possible during orthopedic reconstruction at this level.

• The Journal of Korean Physical Therapy
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• v.25 no.3
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• pp.143-148
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• 2013

Purpose: The purpose of this study was to investigate whether changes in electromyography (EMG) activations of spinal stability muscles with respiratory demand change were due to changes in respiratory demand or in postural demand. Methods: Forty healthy subjects (19male, 21female, $20.8{\pm}1.9$years old) performed quiet breathing and four different forced respiratory maneuvers (FRM) (Pulsed Lip Breathing, Diaphragmatic Breathing, Combination breathing, and respiratory muscle endurance training breathing) while in sitting and standing positions. EMG data for four muscles (TrA/IO, EO, RA, and ES) were collected and filtered using a band pass filter (20~200Hz) and a notch filter (60, 120, 180Hz). Results: There were no significant differences on percentage of change on %MVIC between QB and FRM (PLB, CB, DB, and RMET) between positions (all p>0.05).

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.305-316
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• 1994

All physical data in the real world are nonstationary signals that have the time varying statistical characteristics. Although few algorithms suitable to process the nonstationary signals have ever been suggested, these are treated the nonstationary signals under the assumption that the nonstationary signal is a piece-wise stationary signal. Recently, statistical analysis algorithms for the nonstationary signal have concentrated so much interest. In this paper, nonstationary EMG signals are mapped onto the orthogonal wavelet transform domain so that the eigenvalue spread of its autocorrelation matrix could be more smaller than that in the time domain. Then the model in the wavelet transform domain and an algorithm to estimate the model parameters are suggested. Also, an test signal generated by a white gaussian noise and the EMG signal are identified, and the algorithm performance is considered in the sense of the mean square error and the evaluation parameters.

• Journal of Oral Medicine and Pain
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• v.26 no.1
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• pp.75-85
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• 2001

This study was performed to investigate the effect of mandibular midline shift and difference of mandibular height between both sides on the electromyo- graphic(EMG) activity of the masticatory muscles on clenching or gum chewing movement. For this study, 105 patients with temporomandibular disorders(TMD) were selected and panoramic radiograph were taken. Amount and side of the midline shift and height of the mandible from antegonial notch to the top of the condylar head were measured on panoramic view. $BioEMG^{(R)}$ (Bioresearch Inc., Milwaukee, USA) was used for recording of EMG activity(${\mu}V$) of the anterior temporalis and the superficial masseter on clenching or gum chewing movement. EMG activity on clenching during 533msec period were measured for activity of the starting point and the one second-after activity as the early EMG and the maximum EMG, respectively. EMG activity on gum chewing movement were measured for activity of the first and the second chewing stroke. The data collected were analysed by SPSS windows program, and the results of this study were as follows : 1. Height of the mandible was 8.06cm on right side and 8.03cm on left side, and showed no difference by age, but significantly differed by sex with higher in male subjects. 2. Mean value of the midline shift was 0.1mm with range of 0~5mm on both sides. The amount and side of the midline shift did not related with height difference of the mandible and/or the EMG activity of the masticatory muscles on clenching. 3. Prevalence of higher right side and higher left side of the mandible were almost same, and the EMG activity of higher side was not higher than that of the other side. 4. In the subjects with height difference of more than 5mm between both sides of the mandible, the early EMG activity on clenching were differed for the anterior temporalis, but the maximum activity were differed for the superficial masseter. 5. In the subjects with height difference of more than 5mm between both sides of the mandible, EMG activity of the anterior temporalis of the gum chewing side was not higher than that of the other side when chewing on the side of lower height, but in the subjects with height difference of less than 5mm, the EMG activity was higher than that of the other side.

• Journal of Korean Institute of Industrial Engineers
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• v.11 no.2
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• pp.87-99
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• 1985

The purpose of this study is to analyze the changes in centers-of-gravity (COG), acceleration and body posture and their associated effects both on EMG and on the maximum capability of weight lifting during Clean & Jerk and Snatch motions. Displacement, velocity, acceleration of joints were obtained from film analysis. Also levels of exertions on 11 major muscle groups were obtained from EMG analysis during a lifting cycle. The EMG data were measured from Telemetry System which is useful in field experiments. Magnitude and direction of force, change in center-of-gravity were extracted from COG data which were measured from force platform. The results of this study can be to be useful both to coaches and to athletes in weight-lifting.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.219-233
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• 2004

The purpose of this study was to compare the EMG activities of four-forearm muscles during Kumdo head striking. The four skilled and unskilled Kumdo club members were selected from D university in B city. Investigated muscles were left brachioradialis, right brachioradialis and left flexor carpi radialis, right flexor carpi radialis. Raw EMG data were collected during the head striking motions and the average EMG were calculated by the frame width of 0.05s, and then the average %MVC were calculated. The average %MVC values of each muscle in each group were compared. The results are as follows. 1) In each group, there were no significant statistical differences between every muscle over the all phases. 2) There were significant differences, however, between skilled group and unskilled group. The former got higher average %MVC at left flexor carpi radialis and the latter at right brachioradialis in the ready phase and in the impact phase.