• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.160-163
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• 1995

An optimal EEG and artifact classifier is proposed using neural network operating characteristics. The neural network operating characteristics are two dimensional parametric representations of the right and false identification probabilities of the network classifier. Since the EEG and EP signals acquired from multi -channel electrodes placed on the head surface are often interfered by other relatively large physiological signals such as electromyogram (EMG) or electroculogram (EOG), the removal of the artifact-affected EEGs is one of the key elements in neuro-functional mapping. Conventionally this task has been carried out by human experts spending lots of examination time. Using the neural-network based classification, human expert's efforts and time can be substantially reduced. From experiments, the neural-network based classification performs as good as human experts: variation of decisions between the neural network and human expert appears even smaller than that between human experts.

• Physical Therapy Korea
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• v.14 no.4
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• pp.50-57
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• 2007

The purpose of this study was to investigate the relationship between delays in initiation and termination of tibialis anterior contraction through surface electromyographic (sEMG) analysis in adults with hemiplegia and healthy subjects and clinical assessment of lower-limb mobility. EMG activity of 6 long-term survivors of stroke and 5 healthy subjects was recorded during maximal isometric ankle dorsiflexion in 3 seconds beeper signals. It must be done as fast and forcefully as possible. Lower limb mobility was assessed with Modified Emory Functional Ambulation Profile (mEFAP). Delay in initiation and termination of muscle contraction was significantly prolonged in the affected lower limb relative to the unaffected limb. Termination of muscle contraction in the hemiplegic lower limb was significantly delayed than the initiation on the affected sides. Delay in initiation and termination of muscle contraction correlated significantly with a few range of mEFAP. Abnormally delayed initiation and termination of muscle contraction may contribute to hemiparetic lower limb mobility in hemiparetic patients. Consequently, this study showed that abnormal delay of initiation and termination of muscle contraction may contribute to hemiparetic lower limb mobility in adults with hemiplegia. Further studies are needed to demonstrate a treatment effect.

• Physical Therapy Korea
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• v.13 no.1
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• pp.38-46
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• 2006

The purposes of this study were to investigate the median frequency (MDF) between initiation and termination of muscle contraction through surface electromyographic (sEMG) analysis and to propose the basis of clinical treatment for movement problems in early hemiparetic upper limbs. Thirteen patients who had stroke with onset less than 3 months prior to the study and seven control subjects participated in the study. The median frequency in initiation and termination of muscle contraction was recorded from wrist flexor and extensor muscles using the sEMG, with 3 second beeper signals, during maximal isometric wrist flexion and extension. Flexion and extension must be done as quickly and forcefully as possible. The results of the study were as follows: 1. The MDF of the onset and offset sections were significantly lower on the paretic than the nonparetic and control sides. 2. The MDF of the offset section significantly decreased on the paretic and nonparetic sides. Consequently, this study showed that the lowering of the MDF was due to the hemiparetic wrist motor impairment and muscle weakness. These results are also related to Fugl-Meyer motor assessment (FMA) scores in hemiparetic upper limbs. This study also suggests that since muscle weakness of early stroke patients affects the functional decrease of upper limbs, further studies must focus on the treatment to improve muscle agility and muscle fiber recruitment efficiency that can induce the functional recovery correlated to motor control.

• Physical Therapy Korea
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• v.24 no.4
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• pp.77-83
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• 2017

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. Although the side-lying wiper exercise (SWE) is the most effective shoulder external rotation exercise to maximize infraspinatus activity, the effect of adduction force on the infraspinatus and posterior deltoid has not been demonstrated. Objects: This study was conducted to investigate whether horizontal adduction force increases infraspinatus activity and decreases posterior deltoid activity. Methods: Twenty-eight healthy subjects (male: 21, female: 7; $age=23.5{\pm}1.8years$; $height=170.1{\pm}7.4cm$; $weight=69.4{\pm}9.6kg$) were recruited. Subjects were asked to perform the SWE under two conditions: (1) general SWE and (2) SWE with adduction force using pressure biofeedback. Surface electromyography (EMG) signals of the infraspinatus and posterior deltoid were recorded during SWE. Paired t-tests were used to compare the EMG activity of the infraspinatus and posterior deltoid between the two conditions. Results: Posterior deltoid muscle activity was significantly decreased following SWE with adduction force ($7.53{\pm}4.52%$) relative to general SWE ($11.68{\pm}8.42%$) (p<.05). However, there was no significant difference in the infraspinatus muscle activity between the SWE with adduction force ($28.33{\pm}12.16%$) and the general SWE ($26.54{\pm}13.69%$) (p>.05). Conclusion: Horizontal adduction force while performing SWE is effective at decreasing posterior deltoid activity.

• The Journal of Korean Physical Therapy
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• v.24 no.3
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• pp.216-222
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• 2012

Purpose: Weight-bearing exercise is a type of physical exercise that is widely performed for rehabilitation after acquiring nervous-system diseases or sports-related injuries. It is one of the most commonly prescribed rehabilitation programs for strengthing of the lower extremities. Weight-bearing exercise is important for the conduct of such activity of daily living (ADLs) as walking, and up and down the stairs. The purpose of this study was to investigate the muscle activities during one-leg standing and one-leg squatting, the two most representative weight-bearing exercises. Methods: A total of 43 elderly (60~70 years old) males who could perform weight-bearing exercises were included in the study. During the one-leg standing and one-leg squatting, the electromyographic (EMG) signals were quantified as maximum voluntary isometric contraction (%MVIC) using surface EMG, and then the muscle activities of the lower extremities during the two exercises were compared. For statistical analysis, an independent sample t-test and one-way ANOVA were performed. Results: The results of the study are as follows: (1) in the one-leg standing, the activity of the gluteus medius was the greatest among the vastus medialis, vastus lateralis, bicep femoris, (2) in the one-leg squatting, the activity of the vastus medialis was the greatest; and (3) the activity was greater in the one-leg squatting than in the single-leg standing exercise. Conclusion: The one-leg standing and squatting exercises are suitable for strengthening the muscles for the prevention of and recovery from lower-extremity injury, and for functional ADL in elderly people. In addition, dynamic exercise was shown to be more effective than static exercise for strengthening the muscles.

• Physical Therapy Korea
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• v.13 no.4
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• pp.39-46
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• 2006

The purpose of this study was to determine the effects of slump sitting postures on the masticatory, neck, shoulder, and trunk muscles associated with work-related musculoskeletal disorders (WRMD). Eleven healthy adults (age, $23.3{\pm}2.7$ yrs; height, $174.0{\pm}4.1$ cm; weight, $61.4{\pm}6.6$ kg) participated in this study. The participants were free of injury history and neurologic deficits in the masticatory, neck muscles and upper extremities at the time of participation. The subjects were asked to perform erect and slump sitting postures under the guidance of physical therapists. The surface electromyography (EMG) was recorded from the anterior temporalis, masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique, gluteus maximus muscles of 11 adults as they performed visual terminal display work, which are known as the weakened and tightened muscles owing to WRMD. The recorded signals were averaged and normalized to the mean amplitude of the EMG signal obtained during submaximal reference voluntary contractions. The results of study were as follows: The masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique muscles significantly differed in the slump sitting posture (p<.05). The muscle activities of the serratus anterior, middle trapezius muscle, and external abdominal oblique were significantly lower and that of the masseter, upper trapezius, L3 paraspinal muscles were significantly higher. Further research is needed to assess the motor control problems and the function of the deep muscles in posture stability of patients with WRMD.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.99-111
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• 2023

PURPOSE: This study examined the effects of pelvic compression methods on the muscle activities of the trunk muscles during plank exercises in individuals with and without low back pain. METHODS: Individuals who experienced back pain for three or more days within the last six months (low back pain group, LBPG; n = 15) and those who did not (non-experienced low back pain group, NLBPG; n = 15) were instructed to perform plank exercise without pelvic compression or while wearing a ReaLine or Com-pressor belt. The electromyography (EMG) data was measured during each session of exercise. Surface EMG signals were collected for the rectus abdominis (RA), external oblique (EO), erector spinae (ES), and gluteus maximus (GM) muscles. The data were collected during three 5-s exercises with a 1-min rest period between the three sets. RESULTS: During the plank exercise, the muscle activity of the RA in the LBPG was significantly higher than that in the NLBPG (p < .05), and greater muscle activity was observed in the LBPG even when two pelvic compression methods were applied (p < .05). The muscle activity of RA was decreased significantly during pelvic compression according to the pelvic compression methods in both groups (p < .05). No significant interaction was observed between the groups or the pelvic compression methods for the RA, EO, ES, or GM muscle activities during plank exercises. CONCLUSION: Both pelvic compression methods reduced the RA muscle activity during plank exercises in individuals who had not experienced back pain within the last six months.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.3
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• pp.289-294
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• 2013

PURPOSE: The purpose of this study was to examine differences in erect spinae activities at different height of table during ultrasound therapy in order to propose a optimum work environment. METHODS: Twenty five healthy adult males and females volunteered to participate in this study. EMG signals of both erector spinae(T10, T12, L2, L4) were recorded throught the surface electromyography system at different height of table(45cm, 56.2cm, 67.5cm) during ultrasound therapy work. RESULTS: The higher table heights was, the lower %RVC of the T10, T12, L2, L4 erect spinae at both sides. The left and right T10, T12 and the left L4 showed significant differences. The lower the spinal level was, the higher %RVC of both erect spinae at 45cm, 56.2cm, 67.5cm. The left erect spinae at 56.2cm, right erect spinae at 45cm, 67.5cm showed significant differences. CONCLUSION: The muscle activities of both erect spinae decreased at higher table height and increased lower spinal level. We identified lower table height are risk factor of spine work related musculoskeletal disorders.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.3
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• pp.236-241
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• 2006

Monitor height is one of the key factors in the VDT workstation design. Most of the previous studies have focused on traditional VDT workplace where the operators performed data entry or word processing tasks using single monitor. This study aimed to suggest proper monitor height when the main task was monitoring information from different number of information sources. Twelve male students participated in three experiments: single information source (one monitor), two information sources (one monitor and one CCTV), and three information sources (one monitor, one CCTV and a window). Subjects performed monitoring tasks for 10 minutes with 3 different monitor center heights : 89.0 cm (Low), 111.3 cm (Middle), and 124.8 cm (High). Surface EMG signals of five neck muscles, subjective discomfort ratings, preference, and working postures were recorded. Results indicated that the middle height was proper for one monitor condition, but the low monitor height was recommended for more than two information sources.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.1
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• pp.39-45
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• 2014

Background: The purpose of this study is to identify effects of neuro-muscular control training on vastus medialis oblique (VMO) after menisectomy of the knee. Methods: The subjects of this study are women aged 42 and 39 each who did menisectomy. Case 1 was applied quadriceps setting exercise and neuro-muscular contrlol training and case 2 was applied quadriecps setting. Intervention was done 5 times a week for 2 weeks. Measurement of muscle activity on VMO and vastus lateralis (VL) was standardized signals of each muscle to %RVC using surface EMG. Results: On comparison of exercise before and after on VMO and VL, VL activation of case 2 was increased more than case 1. Conclusion: Quadriecps-setting exercise and selective neuro-muscular control training of VMO is effective intervention on VMO activity and muscle activity ratio of VMO to VL.