• Journal of the Korean Academy of Clinical Electrophysiology
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• v.2 no.2
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• pp.25-37
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• 2004

To provide reflection diagnostical basic-data by ultrasonography intended for 38 male/female students used by ultrasound imaging system and dynamometer, compared the MVIC and muscle thickness take an accurate measurement of elbow flexor and knee extensor of thickness and MVIC, in confirmity with distinction of sex and then analysised of correlation in muscle thickness-MVIC, MVIC-weight, weight-muscle thickness, it shows statiscally significant difference MVIC and muscle thickness according to sex. Also there is a high interrelation between two. As well as it shows that there is a different between sex in the MVIC of same thickness and MVIC of same weight. This difference will be related with preportions of muscle fiber type in view of the results by preceded research, it needs to be prerequisite analysis of difference in sex with a great variety of ways hereafter.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.83-88
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• 2020

The purpose of this study was to investigate the optimal position among three manual muscle tested positions for upper trapezius in which to obtain an isolated upper trapezius EMG signal for the normalization of upper trapezius muscle EMG activity. A total of 28 healthy adult men participated in the experiment. The UT (upper trapezius) and LS (levator scapulae) muscle activities were measured using the TeleMyo 2400T and analyzed using MyoResearch software. The muscle activity of the US and LS was measured by performing three manual muscle test positions for the upper trapezius. The UT/LS ratio during the S-MVIC was 80.25 and was significantly higher than that during the T-MVIC (76.50; p = 0.011) and the C-MVIC (60.95; p < 0.001). And, the UT/LS ratio during the T-MVIC and was significantly higher than that during the C-MVIC (p < 0.001). Based on the results of present study, we suggest a switch from T-MVIC to S-MVIC for the independent normalization reliability of upper trapezius EMG activity. The UT muscle strength or normalization test using S-MVIC will be able to measure muscle strength or activity of UT compared to previous measurement methods.

• Journal of the Korean Society of Physical Medicine
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• v.3 no.2
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• pp.89-96
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• 2008

Purpose : The study was to evaluate the effect of joint therapy and active exercise on balance and lower foot and ankle muscle MVIC in supination foot. Methods : The subjects of this study were 20. Subjects were 20 to 25($22.20{\pm}1.54$) completed the study and participated three times a week for 4 weeks. Subjects were assessed by utilizing two different EMG MVIC. Results : The change in peroneus longus MVIC significant on pre-test and post test (p<.05). The not change in tibialis anterior, tibialis posterior, peroneus brevis MVIC on pre-test and post-test(p<.05). Conclusion : The study suggest that subtalar joint therapy and active exercise have a increase peroneus longus MVIC for supination foot. Therefore, the subtalar joint therapy and active exercise recommended for supination foot.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.93-101
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• 2006

This study examined whether there is a transfer effect to other joint angles and the angular specificity of muscle fatigue after 6 weeks of isometric training of the vastus medialis. Twenty subjects were randomly assigned to 30° and 90° knee flexion groups and were trained at 80% maximal voluntary isometric contraction(MVIC) three times a week for 6 weeks. The pre-and post-training values of the 80% holding time(endurance time) of MVIC, the Fatigue Index(FI), and the MVIC at 30°, 60°, and 90° were compared. After isometric training for 6 weeks, in the 30° knee flexion group, FI decreased significantly(p<0.05) only at 30°, which was the training angle; there was no change at other angles. By contrast, in the 90° knee flexion group, FI decreased significantly(p<0.05) at both the trained angle and at the other angles, indicating a transfer effect of training. MVIC did not increase significantly(p<0.05) at any trained angle in either the 30° or 90° knee flexion groups after 6 weeks of isometric training, neither did the 80% holding time of MVIC differ significantly compared with pre-training in either group. These findings suggest that training at 90° of knee flexion is more effective than training at 30° of knee flexion for obtaining a training transfer effect on muscle fatigue in the vastus medialis.

• The Journal of Korean Physical Therapy
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• v.18 no.3
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• pp.37-45
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• 2006

Purpose: This study analyzed changes in spinal neuron and action potential of motor unit depending on voluntary contraction on spinal neuron adaptation. Methods: It selected 80 university students in their twenties and divided into experimental groups of 25% MVIC (I), 50% MVIC (II), 75% MVIC (III) and 100% MVIC (IV) depending on maximum voluntary isometric contraction (MVIC) and performed isometric exercise of plantar flexor muscle to each experimental group with given contraction for 20 times. It measured Mmax, H/Mmax, Hmax latency, V/Mmax, V wave latency before and after exercise, compared method and volume of contraction. Results: H/Mmax ratio showed significant difference in comparison among groups (p<0.01) and there was difference in I and IV groups. V/Mmax ratio showed significant difference in comparison among experimental groups (p<0.05) and there was difference in I and IV groups. When voluntary contraction level was maximum, changes were greatest. However, no significantly difference was to Mmax, H latency and V wave latency. Conclusion: These results suggest that amplitude changes of voluntary contraction level, spinal neuron and supra-spinal neuron had a dose connection that the more contraction level, the better central activation seem to decrease highly for a short time.

• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.37-44
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• 2011

Purpose: The aim of this study was to investigate the effects of an exercise program using a virtual reality game and a gait exercise program using a treadmill on % maximum voluntary isometric contraction (%MVIC) and static and dynamic balancing capabilities. Methods: A total of 26 elderly women were included in the study. 13 women were assigned to an exercise program using a virtual reality game, and 13 to a gait exercise program using a treadmill. The subjects performed the exercise for 40 min per session, three sessions per week, for eight weeks. Results: The %MVIC of the vastus medialis was significantly increased from $28.91{\pm}2.03%$ to $32.98{\pm}2.6%$ in the virtual reality game exercise group (p<0.00). The %MVIC of the vastus lateralis was significantly increased from $27.17{\pm}1.93%$ to $31.50{\pm}2.18%$ (p<0.00) in the gait exercise program group. The whole path length with both feet on the floor and eyes open was significantly decreased from $1570.92{\pm}820.6mm$ to $1343.62{\pm}242.41mm$ (p<0.00). The whole path length with both feet on the floor and eyes closed was significantly decreased from $1819.85{\pm}361.14mm$ to $1581.05{\pm}285.11mm$ (p<0.00). The length of a functional reach was significantly increased from $25.2{\pm}4.23cm$ to $27.68{\pm}4.04cm$ (p<0.00). Conclusion: The exercise program using a virtual reality game is effective for improving the %MVIC and static and dynamic balancing capabilities in elderly women aged 65 years and more.

• The Journal of Korean Physical Therapy
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• v.22 no.5
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• pp.25-31
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• 2010

Purpose: The purpose of this study is to provide an efficient and scientific basis for muscle activity (%MVIC) of RA, EO, VL, HS muscles and balance in soccer players through dynamic lumbar stability exercise and static lumbar stability exercise. Methods: This study included 23 soccer players belonging to D University of J province who attended the program for 30 minutes at a time and three times a week for 4 weeks. Of these 13 attended the dynamic lumbar stability exercise (DLSE) program and 10 the static lumbar stability exercise (SLSE) program. The differences between the effects of the dynamic lumbar stability exercise program and static lumbar stability exercise program were analyzed. Results: To increase muscle activity (%MVIC) and balance (WPL), the dynamic lumbar stability exercise program was more effective than was the static lumbar stability exercise program. 1) The %MVIC of trunk muscle (RA &EO) and lower extremitys muscle (VL & HS) increased from before training to after training in the case of the participants who performed the dynamic lumbar stability exercise. 2) The whole path length (WPL) decreased from before the training to after the training. The 2 groups significantly differed in this regard. Conclusion: Dynamic lumbar stability exercise program helps to improve the balancing ability and muscle activity in a soccer players who requires both muscle activity and balance than does any other players.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.4
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• pp.25-35
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• 2013

Purpose : The purpose of this study was to compare the muscle activities of infraspinatus, serratus anterior, upper trapezius, and triceps brachii in different supporting surface intervals during push-up exercise. Method : Subjects of the study were 18 healthy male students without any orthopedic or neurological injuries including neck and shoulder surgeries and can perform a push-up exercise required for the study. EMG was used to measure the muscle activities of four muscles. Result : There were statistically significant differences of all the muscles in three different supporting surface intervals(p<0.5). Muscle activity of upper trapezius was the highest(MVIC 39.40%) in the narrowest width and the lowest in the widest width. In infraspinatus, muscle activity was the highest(MVIC 36.23%) in the narrowest width and the lowest in the widest width. In serratus, muscle activity is the highest(MVIC 58.04%) in the widest width and the lowest in the narrowest width. In triceps brachii, muscle activity is the highest(MVIC 68.51%) in the widest width and the lowest in the narrowest width. Conclusion : Muscle activities are at the highest with the narrowest width in the upper trapezius and the infraspinatus. In the serratus and triceps brachii, however, muscle activities are at the highest with widest width.

• The Journal of Korean Physical Therapy
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• v.25 no.2
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• pp.56-63
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• 2013

Purpose: This study was conducted in order to examine how an effective rehabilitation exercise program influences the activity of shoulder muscles, and to help the clinical application of a rehabilitation program, for prevention and relief of pain, adhesion, and joint stiffness of patients who undergo rotator cuff repair. Methods: Nine test subjects were placed randomly into each group for a total of 27 subjects and exercise program interventions according to the group were conducted for six weeks, after which maximum voluntary isometric contraction (%MVIC) value was re-measured for supraspinatus muscle, infraspinatus muscle, serratus anterior muscle, and middle deltoid muscle in all groups in order to compare changes in muscle activity before and after the experiment in order to perform comparative analysis of changes in muscle activity between groups, based on which four experimental hypotheses were confirmed. Results: Changes in muscle activity according to %MVIC showed a statistically significant difference (p<0.01) (p<0.001) in all muscles, except the middle deltoid muscle, and post-verification results showed that changes in muscle activity according to %MVIC were greater in test groups I and II, compared with the control group, for the supraspinatus muscle, infraspinatus muscle, and serratus anterior muscle. Conclusion: Therefore, rehabilitation through use of the methods described above should be applied efficiently in clinical settings and more research in development of much more efficient rehabilitation program interventions must be conducted.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.141-146
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• 2008

The purpose of this study is to develop the algorithm which can control muscle power assist robot especially for elderly. Recently, wearable robots for power assistance are developed by many researchers, and its application fields are also variable such as for medical or military equipment. However, there are many technical barriers to develop the wearable robot. This study suggest a control method improving performance of a wearable robot system by using a EMG signal of major muscles and a force sensor signal as command signal of system. The result of the robot Prototype efficiency experiment, the case of Maximum Isometric motion it suggest 100% power of muscle, the man need only 66% of MVIC(Maximum Voluntary Isometric Contraction) to lift 5kg dumbbell without robot assist. However the man needs only 52% of MVIC to lift 5kg dumbbell with robot assist. Therefore 20% muscle power increased with robot assist. Also, we designed light weight robot mechanism that extract the command signal verified and drive the wanted motions.