• International Journal of Contents
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• v.6 no.1
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• pp.41-46
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• 2010

The aim of this study was to investigate the effect of different shoe-heel heights on the surface electromyographic (EMG) activity of vastus medialis (VM) and vastus lateralis (VL) during treadmill walking in female patients with patellofemoral pain (PFP). Nineteen women with PFP participated in this research. EMG signals were recorded from the VM and VL of both sides and were compared during the treadmill walking. The subjects walked on a treadmill wearing shoes of three different heel heights: 1 cm, 3 cm and 7 cm. Each subject walked on a treadmill for five minutes at a speed of 2 km/hour with three minutes resting intervals between consecutive trials. The data were analyzed by one-way repeated-measures analysis of variance. The results of the present study indicate that EMG data of the VM and VL of female patients with PFP did improve with an increase in the height of the shoe heel, which were statistically significant. Additionally, the EMG activity of VM increased more dramatically than that of VL associated with the task of walking with high-heeled shoes on the treadmill. This study suggests that the type of high-heeled shoes is related to the VM and VL muscle activation patterns contributing to knee joint pathologies in female patients with PFP.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.25-29
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• 1991

In the field of prosthesis arm control, tile pattern classification of the EMG signal is a required basis process and also the estimation of force from col looted EMG data is another necessary duty. But unfortunately, what we've got is not real force but an EMG signal which contains the information of force. This is the reason why he estimate the force from the EMG data. In this paper, when we handle the EMG signal to estimate the force, spatial prewhitening process is applied from which the spatial correlation between the channels are removed. And after the orthogonal transformation, which is used in the force estimation process the transformed signal is inputed into the probabilistic model for pattern classification. To verify the different results of the multiple channels, SNR(signal to noire ratio) function is introduced.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.2
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• pp.135-143
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• 2011

Purpose: The purpose of this study was to investigate onset timing of vastus medialis oblique(VMO) relative to vastus lateralis(VL) the VMO/VL electromyographic(EMG) ratio according to heel height Methods: A repeated measures design was used. Fifteen healthy female college students with no known knee musculoskeletal dysfunction were recruited this study. They carried out a standardised stair acent activity under 4 conditions; barefoot, and with heel height of 1, 3, 7 cm. Muscle activity was measured by surface EMG (Myosystem 1400A, Noraxon Inc., U.S.A). Data were analysed using $1{\times}4$ repeated measures ANOVA. Results: Onset timing differed with heel height(p<.05). However, the VMO/VL EMG ratio was not significantly difference between conditions. Conclusion: We found that 7 cm heel height delayed in VMO onset compared with 3 cm heel height during stair ascent, but no change in the relative EMG intensity of VMO and VL as measured by th VMO/VL ratio. The findings indicate that high-heeled shoes may have disadvantages in knee stability because of delayed onset of VMO. Due to a lack of knee joint stability, wearing of high heeled shoes should be avoided.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.380-388
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• 2004

This study proposed an improved spike detection algorithm which automatically detects suitable spike threshold on the amplitude of surface electromyography(SEMG) signal during isometric contraction. The EMG data from the low back muscles was obtained in six channels and the proposed signal processing algorithm is compared with the median frequency and Gabriel's spike parameter. As a result, the reliability of spike parameter was inferior to the median frequency. This fact indicates that a spike parameter is inadequate for analysis of multi-channel EMG signal. Because of uncertainty of fixed spike threshold, the improved spike detection algorithm was proposed. It automatically detects suitable spike threshold depending on the amplitude of the EMG signal, and the proposed algorithm was able to detect optimal threshold based on mCFAR(modified Constant False Alarm Rate) in the every EMG channel. In conclusion, from the reliability points of view, neither median frequency nor existing spike detection algorithm was superior to the proposed method.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.147-154
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• 2007

This study's purpose is to investigate the effects on leg muscle activity caused by perturbation, using a trapdoor system during the support phase of gait for healthy adults (n = 6, height $177.5{\pm}5.5cm$, weight $81.0{\pm}9.5kg$, age $30.0{\pm}3.3yrs$). The trapdoor had the functional ability of causing inversion or eversion. The release time for the trapdoor was specified for two times, 0.3 and 0.5 seconds after heel contact. While altering these variables, EMG was recorded for the leg muscles (rectus femoris, biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius, soleus). The following conclusions were derived. The steptime was longer for the 0.5s eversion than 0.3s inversion condition. So in order to regain stability after the perturbation the unsupporting leg reached forward rapidly. This quick reflex can be observed through the center of pressure (COP) and its rapid change in direction. The gastrocnemius was activated throughout the total experiment. There was a low amount of activity recorded in the rectus femoris, vastus lateralis and tibialis anterior except for the condition of inversion 0.3s. For most of the conditions, the highest average EMG peak values were recorded during the condition of inversion 0.3s. The iEMG patterns were similar for the conditions of inversion 0.3s and eversion 0.3s. To cope with the rapid change in these conditions, the biceps femoris was activated. During the experiment except for the condition of normal gait, the activity of the soleus and gastrocnemius was relatively high. Therefore, to prevent injury from perturbation of the lower leg strengthening of the soleus and gastrocnemius is required. Likewise to prevent injury to the thigh strengthening for the biceps femoris.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.383-386
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• 1997

In the EMG evaluation, the neuropathy may be diagnosed by a detection of denervation potentials in the group of muscles. These abnomal potentials might be confused with normal endplate spikes. In this paper we present the software algorithm in C, which automatically detects spontaneous activity such as denervation potentials and endplate potentials and distingushes between those potentials. Parameters with statistically significant differences were used for this automated algorithm. It was concluded that the algorithm established in this study will improve accuracy in EMG diagnosis.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.37-44
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• 2005

Gait control capacity for most trans-femoral prostheses is significantly different from that of a normal person, and training is required for a long period of time in order for a patient to walk properly. People become easily tired when wearing a prosthesis or orthosis for a long period typically because the gait angle cannot be smoothly adjusted during wearing. Therefore, to improve the gait control problems of a trans-femoral prosthesis, the proper gait angle is estimated through surface EMG(electromyogram) signals on a normal leg, then the gait posture which the trans-femoral prosthesis should take is calculated in the neural network, which learns the gait kinetics on the basis of the normal leg's gait angle. Based on this predicted angle, a postural control method is proposed and tested adaptively following the patient's gait habit based on the predicted angle. In this study, the gait angle prediction showed accuracy of over $97\%$, and the posture control capacity of over $90\%$.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.559-563
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• 1990

A new speed improvement method for quantitative superimposed EMG signal analysis to diagnose the neuromuscular dysfunction is described. The improvement is achieved through the use of efficient software and hardware signal processing techniques. The software approch is composed of the MANDF filter and HRWA algorithm which provides the optimal set and time delays of-selected templates. The hardware employs a TMS32OC25 DSP chip to execute the intensive calculation part. The purposed method is verified through a simulation with real templates which are obtained from needle EMG. As a results, the proposed method provides an overall speed improvement of 32-40 times.

• PNF and Movement
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• v.10 no.1
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• pp.35-41
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• 2012

Purpose : This study was conducted to identify the effects of high heel shoes on surface electromyography(EMG) activities fo tibialis anterior(TA), soles(S), and gastrocnemius(G) in 12 healthy women. Methods : Subjects were composed of three group(sports shoes, 5cm heel height shoes, and 9cm heel height shoes). The muscle activity of the TA, G, S in the lower leg were measured using a surface EMG. Results : Results of one way repeated measures ANOVA of the after waling 30minutes standing task duration among the sport shoes, 5cm, and 9cm heel height conditions. The comparison of the muscular activities showed significant differences in the G muscles among the high heel shoes. Conclusion : Wearing high heel shoes for hours will bring inappropriate alignment of the lower limbs and cause postural changes or abnormal sensation and several other problems in the body, resulting in exposure to ankle sprain or fall injuries.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.85-95
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• 2008

This study is analyzing about application of taping by movement about shoulder joint's isometric contraction. M. college students take part in experiment. WEMG-8 and HUMAC system are used. Findings were as follows: EMG of muscle's MVIC at each angle before and after taping. 1. In flexion, EMG with taping is effective for supra spinatus at $0^{\circ}{\cdot}45^{\circ}{\cdot}90^{\circ}$, anterior deltoid at $0^{\circ}{\cdot}45^{\circ}$ and biceps brachii at $0^{\circ}{\cdot}90^{\circ}$. 2. In extension, EMG with taping is effective for triceps brachii at $0^{\circ}$, latissimus dorsi at $90^{\circ}$ and posterior deltoid at $45^{\circ}{\cdot}90^{\circ}$. 3. Each angle viewpoint, EMG of latissimus dorsi in extension can be arranged in its high order as $90^{\circ}<45^{\circ}$, $0^{\circ}$ without taping and $90^{\circ}<0^{\circ}$ respectively. EMG of posterior deltoid in extension is in its high order as $90^{\circ}<45^{\circ}<0^{\circ}$ without taping and $90^{\circ}<0^{\circ}$.