• Journal of Biomedical Engineering Research
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• v.32 no.1
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• pp.1-6
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• 2011

An active training system has been developed to assist the upper extremity function in patients with spasticity. We also evaluated the performance of the developed assistive system in five normal subjects and one hemiplegic patient. The maximum voluntary contraction (MVC) tests for biceps brachii and triceps brachii were performed and the relationship between linear enveloped EMG signal and the elbow joint torque was found. In order to implement an active training, our system was designed to allow isokinetic movement only when the subject generates elbow joint motion larger than the pre-fixed threshold level. The proposed EMG-feedback control method could provide active exercises, resulting in better rehabilitation protocol for spastic patients.

• Journal of the Ergonomics Society of Korea
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• v.22 no.2
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• pp.57-69
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• 2003

This study was performed to investigate the isometric endurance time as percentages of maximum voluntary contraction. Electromyogram(EMG) and Borg's CR-I0 value were measured by push-pull-up-down tasks for 10 healthy males. The normalized EMG value and the MPF(mean power frequency) were used to estimate the muscle recruitment pattern and the development of muscle fatigue. The subjects exerted and maintained 5 levels of %MVC(maximum voluntary contraction) in $90^{\circ}$ shoulder flexion/ 180oelbow extension at sitting posture. The up-task showed the lower endurance time and higher Borg's CR-I0 value than the other task types. Comparing Rohmert's curve with the endurance time of task types. Rohmert's curve overestimated the endurance time of up-task and underestimated the endurance time of push-pull-down tasks. The normalized EMG value showed that muscles recruitment patterns were different from task types. The 4 muscles(biceps brachii muscle, tricep brachii muscle. middle deltoid muscle. trapezius muscle) recruitment patterns of up-task were higher than those of other tasks. The MPF value decreased with the endurance time, and the shift of MPF at up-task was larger than that of the other task types.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.327-333
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• 2013

The purpose of this study was to investigate the effects of different types of attentional focus(internal focus vs. external focus) on the dart throwing mechanics. Seven expert dart throwing athletes were assigned to an internal focus group and other seven athletes were assigned to an external focus group. Each group was asked to throw dart either under verbal instruction or without instruction. During dart throwing, accuracy(radial error), consistency(bivariate variable error), dart velocity, acceleration, elbow joint ROM, elbow joint angular velocity, EMD(electromechanical delay), iEMG of biceps brachii and triceps brachii, and CI(coactivation index) were collected and analyzed. Nither instruction type nor instruction itself affected in accuracy and consistency. However, in dart velocity and acceleration, there was an interaction between instruction and attentional focus types. Velocity and acceleration increased in the internal condition, where as they decreased in the external condition. The ROM of elbow joint did not affected by instruction and attention type. However, similar to dart velocity and acceleration, angular velocity increased in internal focus group, while it decreased in external focus group. EMG showed no difference with any condition. In conclusion, internal focus is better than external focus for dart throwing.

• International Journal of Contents
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• v.16 no.1
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• pp.57-64
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• 2020

We sought to compare upper extremity muscle activity between handwriting on paper and touchscreen with dominant and non-dominant hands in younger adults (age 23.90±1.12) and the elderly (age 75.55±5.76). Muscle activity (percent of maximum voluntary contraction) in the biceps brachii muscle, triceps brachii muscle, flexor carpi ulnaris muscle, and extensor carpi ulnaris muscle was measured using an electromyography device. As a result, our data indicate that muscle activity is lower in younger adults than the elderly. Besides, muscle activity is lower in the dominant versus non-dominant hand, and lower when writing using a touchscreen than on paper. These results can be used to support recommending touchscreens in the elderly. Also, they can be used as baseline data for comparing the performance of non-paretic side and paretic side in patients relative to the central nervous system.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.145-153
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• 2022

Objective: The purpose of this study was to evaluate the Electromyography (EMG) of the upper limb during reaching tasks according to two heights in the sitting position. Design: Cross sectional design Methods: Fifteen hemiplegia, fifteen elderly, and fifteen healthy subjects have participated in this study. The targets (90% length of the subject's arm) were located at the two heights (the eye and xiphoid process). We have recorded EMG signals of seven upper limb muscles (anterior deltoid (AD), posterior deltoid (PD), pectoralis major (Pec), infraspinatus (Inf), supraspinatus (Sup), biceps brachii (Bi), triceps brachii (Tri)). The dependent variables were movement time(s), modulation ratio, working ratio, and the co-contraction ratio of the hemiplegia, elderly, and healthy at the reaching task. Two-way repeated-measures ANOVA (2-heights) was analyzed with the LSD post hoc test. Results: The study results were as follows: (1) The movement time to the target during reaching movement was significantly longer for the hemiplegia and elderly groups compared to the healthy group. (2) The modulation rate was significantly higher at eye height than the xiphoid height in AD, PD, Pec, Inf, Bi muscles, and the hemiplegia group and elderly group were significantly lower than the healthy group. Additionally, the modulation ratio showed a significant interaction between heights and groups. Conclusions: It is expected that the variables using the muscle contraction characteristics, the evaluation method of this study, can be used as an electromyography-based feedback method that can be objectively evaluated and quantified in clinical practice.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.2
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• pp.39-48
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• 2023

Background: The position of pitcher requires a lot of repetitive motion, and because of this, it is known that not only professional baseball players, but also middle and high school players are frequently exposed to injuries in baseball. The purpose of this study is to examine the differences in upper extremity muscle activity during repeated pitching and the activity of each muscle during repeated pitching by analyzing middle and high school pitchers, divided into groups by age. Methods: Twenty participants (10 middle school male students and 10 high school male students) were recruited for this research. The outcome measures included neuromuscular motor control, including the upper trapezius (UT), triceps brachii (TB), deltoid (DT), latissimus dorsi (LD), biceps brachii (BB), pectoralis major(PM), extensor carpi radialis(ER), and flexor carpi radialis (FR). Results: The two-way analysis of varaince (ANOVA) was used to compare the muscle activity variables between the middle school and high school students. The one-way ANOVA was used to compare the muscle activity variables within time differences each groups. Conclusion: Our results provided promising clinical evidence that guide for upper extremity muscles to increase pitching efficiency in middle and high school base ball players.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3109-3116
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• 2011

We studied the effects of vibration stimulation method on upper limbs spasticity in patients with brain lesion. 21 patients with spasticity of the upper limbs selected and divided randomly 3 groups. And then vibratory stimulation was applied to the triceps brachii muscle in group I(n=7), to biceps brachii muscle in group II (n=7), and to both muscles in group III (n=7). Using Neuro-EMG_Micro to investigate the changes in spinal neuronal excitability, F-waves were measured at before and directly after stimulation, and 10 minutes later and 20 minutes later after stimulation especially. MAS(Modified Ashworth Scale) test for muscle tone and MFT(Manual Function Test) for the upper extremity motor function were performed before stimulation and 20 minutes later after stimulation for the purpose of clinical evaluation. In our study, MAS was significant decreased in all groups, F wave and F/M ratio parameters were decreased in all groups and more decreased specially in group III. MFT was increased in group II and III, and more increased specially in group III. Vibration stimulation reduced the neuronal excitability of spinal cord and also muscle tone, and improved the motor function of the upper extremity. These results suggested that vibration stimulation giving to both muscles(triceps and biceps brachii muscle) at the same time was more efficiency in reducing the neuronal excitability of spinal cord and improving the motor function of the upper limbs.

• Journal of Korean Physical Therapy Science
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• v.2 no.3
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• pp.599-608
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• 1995

If a controlled sensory stimulation is given to the specific receptors, a reflex movement and motor engrams is achieved by the principle of neurophysiology. Based on this theoretical background, we choose 80 healthy person(male 40,female 40) and compare chronaxie of before stimulation with after stimulation. Also we measured chronaxie with same method. Stimulation was applied to the muscle belly by tapping. The results are summarized as follows; 1. The mean value of rheobase measured from the proximal part of upper extremity is 3. 56mA for male, 4.04mA for female. 2. The mean value of rheobase measured from the lower extremity is 4.19mA for male, 4. 37mA for female, which is higher than that of upper extremity for both male and female. 3. The mean value of chronaxie from the proximal part of upper extremity is 0.91msec for male, 0.87 msec for female, which means male is higher than female, and the average is 0.82msec. 4. The mean value of chronaxie from the proximal part of lower extremity is 1.04msec for male, 1.14msec for female, which means female is higher than male. 5. The decrease of rheobase after stimulation is prominent at the triceps brachii for male, biceps brachii for female. 6. The decrease of rheobase after stimulation is prominent at the tibialis anterior for both male and female. 7. The decrease of chronaxie after stimulation is prominent for both male and female at the triceps brachii from upper extremity and at the tibialis anterior from lower extremity for both male and female.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.241-250
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• 2022

It is known that chronic pain and injury of upper limb joint tissue in manual wheelchair users is usually caused by muscle imbalance, and the propulsion speed is reported to increase this muscle imbalance. In this study, kinematic variables, electromyography, and ultrasonographic images of the upper limb were measured and analyzed at two different propulsion speeds to provide a quantitative basis for the risk of upper extremity joint injury. Eleven patients with spinal cord injury for the experimental group (G_E) and 27 healthy adults for the control group (G_C) participated in this study. Joint angles and electromyography were measured while subjects performed self-selected comfortable and fast-speed wheelchair propulsion. Ultrasound images were recorded before and after each propulsion task to measure the acromiohumeral distance (AHD). The range of motion of the shoulder (14.35 deg in G_E; 20.24 deg in G_C) and elbow (5.25 deg in G_E; 2.57 deg in G_C) joints were significantly decreased (p<0.001). Muscle activation levels of the anterior deltoid, posterior deltoid, biceps brachii, and triceps brachii increased at fast propulsion. Specifically, triceps brachii showed a significant increase in muscle activation at fast propulsion. AHD decreased at fast propulsion. Moreover, the AHD of G_E was already narrowed by about 60% compared to the G_C from the pre-tests. Increased load on wheelchair propulsion, such as fast propulsion, is considered to cause upper limb joint impingement and soft tissue injury due to overuse of the extensor muscles in a narrow joint space. It is expected that the results of this study can be a quantitative and objective basis for training and rehabilitation for manual wheelchair users to prevent joint pain and damage.

• Journal of the Korean Institute of Navigation
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• v.20 no.4
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• pp.81-98
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• 1996

The purpose of this study was analysis of the muscle action in physical exercise in the rolling machine. The rolling machine moved by eletric power-driven was made to keep the constant cycle and size of rolling. The subjects of this study consist of 4 seaman(SM) and 4 landman (LM). The experiment analyzed the muscle power of lower and upper limbs by Intergrated Electromyogram(IEMG). The measurement was made on the ground, and 6 and 8 degrees of rolling separately. This study concludes as follows ; including analysis of IEMG of heavy exercise in two hands curl, a standstill walking and just standing. 1. IEMG of the lower limbs when standing. 1) In 6 degrees of rolling, for the landman(LM), vastus medialis m.(9.73), vastus lateralis m.(9.55), and rectus femores m.(8.73) acted more. As for the seaman(SM), tibialis anterior m.(5.38), biceps femores m.(5.05), and gastrocnemius m.(4.47) acted more. 2) In 8 degrees of rolling, in common, for both LM and SM, it were vastus medialis m.(11.20 and 8.97), vastus lateralis m.(16.20 and 4.63), and tibialis anterior m.(5.13 and 4.47). 3) It was showed that IEMG of LM was larger than that of SM. 2. IEMG of the lower limbs when walking. 1) On the ground, for the LM, gastrocnemius m.(7.08), vastus medialis m.(6.65), and vastus latralis m.(6.60) acted more. As for the SM, vastus lateralis m.(7.08), vastus medialis m.(6.58) and restus femores m.(5.10) acted more. 2) In both 8 and 6 degrees of rolling, vastus medials m.(14.50 and 11.98), vastus lateralis m.(10.10 and 14.10), and gastrocnemius m.(11.75 and 7.10) acted more in two groups. 3) It was showed that IEMG of LM was larger than that of SM. 3. IEMG of the lower limbs when heavy exercise(two hands curl). 1) On the ground, for the LM, vastus lateralis m.(21.68), vastus medialis m.(16.08), and rectus femores m.(14.08) acted more. As for the SM, tibialis anterior m.(16.08), vastus medialis m.(14.58), and vastus lateralis m.(8.78) acted more. 2) In 8 and 6 dgrees of rolling, it were vastus medialis m.(17.05 and 12.45), vastus lateralis m.(37.98 and 17.08), and tibialis anterior m.(19.83 and 13.20). 3) It was showed that IEMG of LM was larger than that of SM. 4. IEMG of the upper limbs when heavy exercise. 1) On the ground, the brachialis m.(44.30 and 17.80), and biceps brachii m.(13.40 and 25.10) acted more in two groups. 2) In both 6 and 8 degrees of rolling, the brachialis m.(37.60 and 24.35), and biceps brachii m.(11.38 and 7.97) acted more in two groups. 3) It was showed that IEMG of SM was larger than that of LM.