• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.5
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• pp.338-347
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• 2005

A computer-based low back muscle evaluation system was designed to simultaneously acquire, process, display, quantify, and correlate electromyographic(EMG) activity with muscle force, and range of motion(ROM) in the lumbar muscle of human. This integrated multi-channel system was designed around notebook PC. Each channel consisted of a time and frequency domain block, and T-F(time-frequency) domain block. The captured data in each channel was used to display and Quantify : raw EMG, histogram, zero crossing, turn, RMS(root mean square), variance, mean, power spectrum, median frequency, mean frequency, wavelet transform, Wigner-Ville distribution, Choi-Williams distribution, and Cohen-Posch distribution. To evaluate the performance of the designed system, the static and dynamic contraction experiments from lumbar(waist) level of human were done. The experiment performed in five subjects, and various parameters were tested and compared. This system could equally well be modified to allow acquisition, processing, and analysis of EMG signals in other studies and applications.

• The Journal of Korea Robotics Society
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• v.13 no.4
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• pp.265-271
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• 2018

The recent prosthetic technologies pursue to control multi-DOFs (degrees-of-freedom) hand and wrist. However, challenges such as high cost, wear-ability, and motion intent recognition for feedback control still remain for the use in daily living activities. The paper proposes a multi-channel knit band sensor to worn easily for surface EMG-based prosthetic control. The knitted electrodes were fabricated with conductive yarn, and the band except the electrodes are knitted using non-conductive yarn which has moisture wicking property. Two types of the knit bands are fabricated such as sixteen-electrodes for eight-channels and thirty-two electrodes for sixteen-channels. In order to substantiate the performance of the biopotential signal acquisition, several experiments are conducted. Signal to noise ratio (SNR) value of the knit band sensor was 18.48 dB. According to various forearm motions including hand and wrist, sixteen-channels EMG signals could be clearly distinguishable. In addition, the pattern recognition performance to control myoelectric prosthesis was verified in that overall classification accuracy of the RMS (root mean squares) filtered EMG signals (97.84%) was higher than that of the raw EMG signals (87.06%).

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.21-26
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• 2015

NUI (Natural User Interface) system interprets the user's natural movement or the signals from human body to the machine. sEMG (surface electromyogram) can be observed when there is any effort in muscle even without actual movement, which is impossible with camera and accelerometer based NUI system. In sEMG based movement recognition system, the minimal number of electrodes is preferred to minimize the inconvenience. We analyzed the decrease in recognition accuracy as decreasing the number of electrodes. For the four kinds of movement intention without movement, extension (up), flexion (down), abduction (right), and adduction (left), the multilayer perceptron classifier was used with the features of RMS (Root Mean Square) from sEMG. The classification accuracy was 91.9% in four channels, 87.0% in three channels, and 78.9% in two channels. To increase the accuracy in two channels of sEMG, RMSs from previous time epoch (50-200 ms) were used in addition. With the RMSs from 150 ms, the accuracy was increased from 78.9% to 83.6%. The decrease in accuracy with minimal number of electrodes could be compensated partly by utilizing more features in previous RMSs.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.487-497
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• 2002

The fatigue process of the triceps surae was evaluated during a standing heel-rise test, comparising of pre-fatigue and post-fatigue. Sixteen healthy subjects with a mean age of 22.88 years participated. The heel-rise test was performed until exhaustion, and electromyographic activity expressed as mean value and root mean square of the gastrocnemius and soleus muscles were calculated. The average number of heel-rise performed was 63.69$\pm$26.10. The result of this present study indicate that the EMG signal is sensitive to the different muscle fatigue. Mean value and RMS decreased significantly in after fatigue. Significant difference were found between the pre-fatigue and post-fatigue in the total subjects. But there were no significant changes in mean and RMS between the male and female during standing heel-rise test. The present results, showing decreased EMG signal in the triceps surae, could be used as reference when testing the fatigue process in different clinical conditions. Recommendations for standardization of a heel-rise test are given.

• Journal of Life Science
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• v.16 no.5
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• pp.773-779
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• 2006

Eight of the individuals had a unilateral S-RAD TKA and Multi-Radius TKA ($Scorpio^{TM}$ PS, Howmedica-Osteonics, Inc.). The instrument were used Peak Motion Measurement $System^{TM}$, $MYOPAC^{TM}$EMG System, KIN-COM $III^{TM}$ System. The Figure 3 shows that the average time for the S-RAD group to accomplish the sit-to-stand movement was 1.59 s, which was 0.19 s less than the M-RAD group (p= 0.033). In Figure 5, the S-RAD TKA group tended to have $7^{\Omega}{\cdot}S^{-1}$ less trunk flexion velocity than that of the M-RAD group (p= 0.058). The Figure 6 shows that the S-RAD TKA limb tended to have less ADD displacement (p = 0.071) than that of the M-RAD TKA limb. We failed to find significant differences for ABD and ADD displacements between the S-RAD and M-RAD N-TKA limbs (p= 0.128 and 0.457, respectively). The VM of the S-RAD TKA limb demonstrated significant less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $15^{\Omega}$ of knee flexion (p 0.05). The VL of the S-RAD TKA limb also demonstrated significant less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $45^{\Omega}$ of knee flexion (p 0.05). Similar to the VM and VL, the RF of the S-RAD TKA limb showed less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $30^{\Omega}$ of knee flexion (p 0.05).

• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.84-90
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• 2018

Objective: To assess the correlation between surface electromyography (SEMG) and conventional EMG in patients with facial nerve palsy. Additionally, compare the discomfort and the time required by the patients in two methods. Method: 36 patients with facial palsy were given nerve conduction studies (NCS) via conventional EMG. Then, the peak root mean square (RMS) values were obtained from the SEMG. We also recorded visual analogue scale (VAS), House-Brackmann scale, and the time required for the examination. Results: Pearson's correlation coefficient between the amplitude loss ratio of the RMS values obtained by SEMG compared to the unaffected side (RSEMG) and the amplitude loss ratio of CMAP amplitudes compared to the unaffected side (RCMAP) was 0.567 at the frontalis, 0.456 at the orbicularis oculi, 0.393 at the nasalis, and 0.437 at the orbicularis oris. An increase in RSEMG is positively correlated with an increase in RCMAP. The mean VAS score with conventional EMG was $3.55{\pm}1.42$, whereas that experienced when using SEMG was $0.11{\pm}0.52$ and the mean time required for conventional EMG was $610{\pm}103.84$ seconds, while that required for SEMG was $420{\pm}86.32$ seconds. Conclusion: This study demonstrated a significant positive correlation between facial muscle activities as measured by SEMG and conventional EMG in patients with facial nerve palsy. SEMG has the benefits of being more comfortable and faster when diagnosing facial palsy.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.81-85
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• 2009

Work related musculoskeletal disorders(WMSDs) was a leading cause of sick leave and injuries in the industries of our country. Posture was an important consideration in the design of work method and workplaces, because it affected the ability of workers to use various equipments and influenced how long they could perform their job without feeling discomfort, fatigue, and musculoskeletal disorders. Imbalanced lower limb postures such as a squatting posture were awkward working postures common to the shipbuilding shops, farms, automobiles assembly lines in our country. Different awkward working postures were known to be associated with specific musculoskeletal disorders. Eight postures in lower limb postures divided into balanced and imbalanced postures were evaluated by electromyographic(EMG) activity for lower limb muscles. Twelve male subjects participated in this study. This paper was to analyze the effects of lower limb muscles workload according to lower limb postures(knee angle) and working time. The ANOVA results showed that most EMG root mean square(RMS) values were statistically significant effect according to lower limb postures(knee angle) and working time. Therefore, the results of this study will provide the basis to evaluate workload of lower limb postures correctly adopted by workers in various jobs and the ergonomic reference to prevent WMSDs.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.148-153
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• 2005

Computer dominated jobs and industrial automation have rapidly created work-related musculoskeletal disorders(WMSDs) and WMSDS are expanding to employee of other general industry. Specific risk factors associated with WMSDs include repetitive motion, heavy lifting, forceful exertion, contact stress, vibration awkward posture and rapid hand and wrist movement. The purpose of this paper is to analyze the effects of the neck muscle workload according to posture(joint angle) and load weight. Seven male students participated in this study. To analyze neck muscle workload was studied on electromyographic(EMG) activity for sternocleidomastoid and trapezius, was subjectively rated using a Borg's CR-10 scale. ANOVA showed that the CR-10 ratings and most EMG root-mean-square (RMS) value were statistically significant improvement according to posture(joint angle) and load weight. The results of this study indicate the joint angle and weight of neck muscle workload to provide safe working conditions. To reduce the large number and severity of WMSDs employees have been experiencing, we need to redesign the job in workplace to identify and control hazards that are reasonably likely to be causing or contributing to the WMSDs.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.399-405
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• 2012

The purpose of this study was to compare the shoulder stabilizer muscle activity during a push up plus on a different conditioning surface. Eighteen healthy volunteers were tested. Surface EMG was recorded from the upper trapezius(UT), pectoralis major(PM), and serratus anterior(SA) using surface differential conditions. Measurements were performed for 7 days. The mean root mean square (RMS) of EMG activity was calculated. A one-way repeated measures analysis of variance was performed to compare RMS normalized values. The UT and PM did not show significant differences of electric activation amplitude in relation to different surface conditions(p>.05). However, the SA showed greater mean electric activation amplitude values on the push up plus exercise on a upper and lower unstable surface(p<.05). These results suggest that to improve SA EMG activity is more useful when performed on a upper and lower unstable surface conditions than on a stable surface conditions.

• Journal of Biomedical Engineering Research
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• v.33 no.4
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• pp.194-201
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• 2012

This study was designed to investigate the effect of a combined stimulus which was composed of chiropractic massage and thermotherapy on the relief of mental and physical stress. Fifteen healthy male subjects were treated with three type of stimuli; control (without any stimulus), a single stimulus (only chiropractic) and a combined stimulus. To evaluate the effects of stimuli, visual analogue scale (VAS), trunk extension, electromyogram (EMG) on erector spinae muscle and electrocardiogram (ECG) were measured and analyzed before and after stimuli. In the control group, there were no significant changes in EMG root mean square (RMS) value and low Frequency/high Frequency (LF/HF) ratio (p > 0.05, p > 0.05). However, both stimulus groups showed significant increases in trunk extension and EMG RMS values (p < 0.05, p < 0.05), but significant decreases in LF/HF ratios (p < 0.05). Particularly the decrement rate in LF/HF ratio was significantly higher in the combined stimulus group than that in the single stimulus group (p < 0.05). Also, a significantly lower VAS was recorded after combined stimulus. Our findings indicate that the combined stimulus might not only improve flexibility and strength of muscle, but also active parasympathetic nerve activity. The combined stimulus may thus contribute to relieve the stress and to enhance the muscle function.