• Proceedings of the KOSOMBE Conference
• /
• v.1985 no.06
• /
• pp.5-8
• /
• 1985

This paper describes the use of power spectral densing in the examination of the electromogram (EMG). The EMG signals were obtained with surface electrodes from the biceps brachii muscle. Shifts of the high-energy regions of the power spectra can be inferred from the changes in the mean frequency. This paper is consistent with result that most information of EMG signal is located 10-200 Hz.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.12
• /
• pp.1278-1285
• /
• 2008

An optimization-based real-time joint angle extraction method of human elbow is proposed by processing the biomedical signal of surface EMG (electromyogram) measured at the center point of biceps brachii. The EMG signal is known as non-stationary (time-varying) signal, but we assume that it is quasi-stationary because a physical or physiological system has limitations in the rate at which it can change its characteristics. Based on the assumption, a pre-processing method to obtain pre-angle values from raw EMG signal is firstly suggested, and then an optimization method to minimize the error between the pre-angle and real joint angle is proposed in this paper. Finally, we suggest the experimental results showing the effectiveness of the proposed algorithm.

• Journal of Korean Physical Therapy Science
• /
• v.19 no.4
• /
• pp.41-46
• /
• 2012

Background : The purpose of this study was to investigate the electromyographic(EMG) amplitude of the gluteus medius muscle bilaterally at various hip angles and motions(flexion, extension and abduction). Methods : Thirty young with a mean(SD) age of 21.03(1.69) years performed hip motions(flexion, extension and abduction) while the surface EMG activity of the gluteus medius muscles was recorded bilaterally. Subjects were instructed to use the right lower limb during moving 3 different direction. Differences in EMG amplitudes in according with movement direction and angle were assessed by use of paired t-test analyses of variance for the right and left lower extremities. The alpha level was set at .05. Results : Gluteus medius muscle EMG activities in the both side were significantly greater for abduction at angles of 30 degrees than those for other motions at other angles. Conclusion : Hip abduction at angles of 30 degrees on the standing position may be effective in activating the gluteus medius muscle.

• Journal of Biomedical Engineering Research
• /
• v.22 no.3
• /
• pp.249-257
• /
• 2001

The voluntary contracted EMG signal of spinal cord injured patients is very small because the information from central nervous system is not sufficiently transmitted to $\alpha$ motor neuron or muscle fiber. Therefore the acquisited EMG signal from needle or surface electrodes can not be identified obvious voluntary contraction pattern by muscle movement. In this paper we propose the extraction technique of voluntary muscle contraction and relaxation pattern from EMG signal of spinal cord injured patient whose EMG signal is composed of the linear sum of mo색 unit action potentials with two noise sources, additive noise assumed to be white Gaussian noise and high frequency discharge assumed to be not motor unit action potential but impulsive noise. In order to eliminate impulsive noise and additive noise from voluntary contracted EMG signal, we use the FatBear filter which is a nonarithmetic piecewise constant filter, and multiscale nonlinear wavelet denoising processing, respectively. The proposed technique is applied to the EMG signal acquisited from transverse myelitis patients to extract voluntary muscle contraction pattern.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.4
• /
• pp.77-83
• /
• 2009

In this study, we investigated relationship of muscular activity in thigh muscle and knee joint angle from bicycle exercise. The EMG signals of 16 persons were measured from rectus femoris and vastus lateralis muscles. The experiment was performed in 5 steps according to saddle distance and 60RPM/200W loads were applied for 1 minute at each step. EMG activation of rectus femoris and vastus lateralis muscles and knee joint angle were recorded using surface EMG and motion analysis system, respectively. Experimental results of inter relationship between EMG activation of thigh muscles and knee joint angle showed high correlation from Step 1. The unified EMG activation of two muscles and knee joint angle showed negative correlation(-0.97).

• The Journal of Korean Physical Therapy
• /
• v.27 no.4
• /
• pp.228-233
• /
• 2015

Purpose: Gait is the most basic element when evaluating the quality of life with activities of daily living under ordinary life circumstances. Symmetrical use of the lower extremities requires complicated coordination of all limbs. Thus, this study examined asymmetry of muscle activity quadriceps femoris and tibialis anterior as a baseline for training during over-ground walking and stair walking of stroke patients. Methods: Subjects were 14 stroke patients included as one experimental group. Gait speed used in this study was determined by the subject. Low extremity paretic and non-paretic EMG was compared using the surface EMG system. Results: The low extremity EMG difference was statistically significant during over-ground walking and stair walking (p<0.05). The result of low extremity EMG substituted symmetry ratio formula was compared to EMG symmetry ratio in both legs during over-ground walking and stair walking. The average symmetry ratio of quadriceps femoris during over-ground walking was 0.65, and average symmetry ratio of quadriceps femoris during stair walking was 0.47, with significant difference (p<0.05). Conclusion: EMG data was higher in stair walking than over-ground walking. However, in the comparison of symmetry ratio, asymmetric EMG of quadriceps femoris was significantly increased during stair walking. These findings suggested that application of stair walking for strengthening of both legs can be positive, but the key factor is maintaining asymmetrical posture of both legs. Therefore, physical therapists should make an effort to reduce asymmetry of quadriceps femoris power during stair walking by stroke patients.

• Physical Therapy Korea
• /
• v.8 no.2
• /
• pp.1-16
• /
• 2001

This study was designed to identify the effects of foot position on electromyographic (EMG) activity of the quadriceps femoris during maximum voluntary contraction (MVC) in standing. Twenty young adults who had not experienced any knee injuries were recruited. Their Q-angles were within a normal range. They were asked to stand in five different foot positions ($40^{\circ}$ externally rotated, $30^{\circ}$ internally rotated, neutral, $20^{\circ}$ plantarflexed, and $10^{\circ}$ dorsiflexed foot position). The EMG activities of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis oblique (VMO) were recorded in standing by surface electrodes and normalized by MVC EMG values derived from manual muscle test. The normalized EMG activity levels (%MVC EMG) of muscles in the five foot positions were compared using repeated measures ANOVA. The EMG activity levels of the VL, RF, and VMO were the highest when foot was externally rotated. The EMG activity levels of the VL and RF were significantly different among the foot positions (p<.05). However, EMG activity levels of the VL, RF, VMO, and VMO/VL ratio did not show significant differences in each foot position (p> .05). The results suggest that the quadriceps femoris may be effectively activated by performing MVC at an externally rotated foot position. Therefore, the externally rotated foot position can be considered as an effective foot position for quadriceps femoris strengthening exercise. Further studies are needed to identify whether there are differences in the effects of foot position on muscle strength after MVC exercise of quadriceps femoris in standing.

• Physical Therapy Korea
• /
• v.29 no.2
• /
• pp.106-116
• /
• 2022

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

• Physical Therapy Korea
• /
• v.18 no.2
• /
• pp.60-66
• /
• 2011

Foot posture is important in the development of the musculoskeletal structure in the lower limbs because it can change the mechanical alignment. Although foot orthotics are widely used for the correction of malalignments in the lower extremities, the biomechanical effects of wedges have not yet been cleared. The aim of this study was to investigate whether medial wedges affect the electromyographic (EMG) activity of the knee and hip joints in healthy adults that are performing one leg standing. Seventeen healthy volunteers performed the one leg standing under two foot conditions: A level surface, and a $15^{\circ}$ medial wedge. The subjects' EMG data for the gluteus maximus (Gmax), gluteus medius (Gmed), tensor fasciae latae (TFL), biceps femoris (BF), vastus lateralis (VL), and vastus medialis oblique (VMO) were recorded, along with the surface EMG, and all were analyzed. The EMG activity of the Gmed and TFL had significantly decreased under the medial wedge condition during one leg standing. Further study is needed in order to investigate whether medial wedges influence the EMG activity and kinematic data of the knee and hip joints as well as the ankle joints in adults with flexible flatfoot, while they are performing one leg standing.

• Journal of the Korea Convergence Society
• /
• v.10 no.12
• /
• pp.183-189
• /
• 2019

The aim of this study was to determine the effects of movement control exercise of hip joint using visual EMG biofeedback on hip joint muscles in healthy adults. This study was nonequivalent one group Pre-post test design. Twenty-one healthy adults were participated in the study. all subjects conducted movemnet control exercise(MCE) using electromyography(EMG) biofeedback of hip joint durng 20 min. The outcome measures included surface eletromyography. Surface electromyography data were collected from the Gluteus medius (Gmed), Gluteus maximus (Gmax),and Tensor fasciae latae(TFL), rectus femoris(RF) during small knee bending (SKB) test. There was a significant difference in Gluteus maximus muscle activity between the pre-test and the post-test (p < 0.05). The findings suggest that Movement control exercise using EMG biofeedback for limiting hip internal rotation is effective in activating the hip external rotator muscles. in addition, this study showed that rehabilitation exercise combined with ICT convergence technology could be an effective intervention in clinical practice.