• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.63-74
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• 2005

J. R. PARK. The Analysis of Electrimyography and Kinematic of Kumdo Player's Head Hitting. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, pp. 63-74, 2005. The purpose of this study were to describe and compare the selected electromyographical muscle activities of arm and kinematic data of kumdo player's head hitting. Using surface electrode electromyography, we evaluated muscle activity in 6 male players during head hitting motion. Surface electrodes were used to record the level of muscle activity in the carpi radialis, deltoid, triceps, biceps muscles during the player's head hitting. These signals were compared with %RVC(Reference voluntary contraction) which was normalized by IEMG(Integrated EMG). The kumdo head hitting motion was divided into two phases: back swing, down swing. we observed patterns of arm muscle activity throughout two phases of the kumdo head hiting The results can be summarized as follows: right elbow angle had decreased and left deltoid muscle's activation had higher than right deltoid muscle's activation, right carpi radialis muscle's activation had higher than left carpi radialis muscle's activation in back swing phase, knee angle had decreased and left triceps muscle's activation had higher than right triceps muscle's activation, right deltoid muscle's activation had higher than left deltoid muscle's activation, right carpi radialis muscle's activation had higher than left carpi radialis muscle's activation in down swing phase

• Physical Therapy Rehabilitation Science
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• v.10 no.3
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• pp.304-310
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• 2021

Objective: This study aimed to investigate effective cueing methods for selective muscle activation of gluteus medius muscles. Design: Cross sectional study design. Methods: Using the inclusion criteria for this study, 20 healthy adults, both males and females were selected for the measurement of muscle activation of gluteus maximus, gluteus medius, and tensor fascia latae muscles while performing clamshell exercise, basic movements in leg raise in side-lying, and 3 different cueing methods. Electromyogram was used to measure muscle activation, and both muscle activation and muscle ratio were compared during the basic movements and different cueing methods. Results: Gluteus medius activation was highest using "try not to make your body rotate" (cueing method 2) in both clamshell exercise and leg raise side-lying (F=5.533, p<0.05, F=7.771, p<0.05), and muscle ratio was highest in clamshell exercise using cueing method 2 (p<0.05) and "don't move your tensor fascia late" (cueing method 1) in leg raise side-lying (p<0.05). This study showed that cueing method 1 in leg raise side-lying and cueing method 2 in clamshell exercise were the most effective cueing methods for selective muscle activation of gluteus medius muscle. Conclusions: The results of this study may be used as basic information for future studies on muscle activation and muscle ratio for different cueing methods and different muscles in various exercises.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.3
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• pp.101-108
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• 2015

PURPOSE: This study researched the effects of the changes of elbow joint angle and of arm position in PNF pattern on muscle activation of the contralateral shoulder muscles while performing PNF pattern exercise. METHODS: The research subjects were 16 male physical therapists who had no neuromuscular or neurological disorders. To measure the muscle activation of the contralateral shoulder muscles, EMG electrodes were attached to the muscle valley of the middle and posterior areas of the deltoid and triceps muscles of the arm. Muscle activation while performing the ulnar thrust PNF pattern exercise was measured with the elbow joint positioned at angles of $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$. Resistance points were at the initial, middle, and end ranges of PNF pattern exercise. RESULTS: Muscle activation of the middle and posterior portions of the deltoid muscle increased significantly according to the changes of elbow joint angle. In each resistance point the middle range was significantly higher than at other points. A significant difference on muscle activation was demonstrated throughout each range depending on the type of muscle. Muscle activation of the middle and posterior portions of the deltoid muscle was higher than muscle activation of the triceps. CONCLUSION: The results of this study demonstrate that the PNF pattern exercising method used in this study is a selective exercising method focusing on the deltoid muscle over the triceps muscle. In order to increase the muscle strength to the maximum level, it is necessary to provide the maximum level of resistance in the middle range of the elbow joint.

• Journal of Korean Physical Therapy Science
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• v.19 no.4
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• pp.53-59
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• 2012

Background : The purpose of the study was: to investigate muscle activation of upper arm according mouse shape. Methods : Twenty person(mean age : 23. 7) who have healthy condition was participated this study, we collected data of muscle activation using by EMG from upper trapezius(Tr), deltoid middle fiber(De), extensor digitorum(Ed), first dorsal interosseous(Di) during participants was performed click and drag according various mouse. Mouse shape was divided 4 level as follow shape 1 was very small, 2 was small, 3 was moderate, 4 was large. Data was analyzed ANOVA, independent t-test using by SPSS ver18.0. Results : There was significantly difference of muscle activation among each muscle according mouse shape in drag and click. In shape 1, 4, there was significantly difference of muscle activation of Tr, De, Ed between drag and click except Di. In shape 2, 4, there was significantly difference of muscle activation of all muscle between drag and click. Conclusion : We knew that extensor digitroum showed more higher muscle activation than other muscle in drag, first dorsal interoseous showed more higher muscle activation that other muscle in click. We suggest that mouse shape was very important factor in order to prevent skeletal muscular disorder for computer user, and mouse shape can reduce muscle fatigue during computer work.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.65-70
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• 2016

Purpose: The aim of this study was to determine the effects of electromyographic (EMG)-Biofeedback using closed kinetic chain exercise (EB-CKCE) on quadriceps angle (Q-angle) and quadriceps muscle activation and muscle activation ratio in subjects with patellofemoral pain syndrome and to provide fundamental information on rehabilitation exercise in patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included. The subjects were randomly divided into three groups: control group (Group I, n=10), semi-squat exercise group (Group II, n=10), and EMG-Biofeedback using closed kinetic chain exercise group (Group III, n=10). Intervention was provided to each group for eight weeks (three times per week; 30 minutes per day). Subjects were measured on Q-angle and quadriceps muscle activation. Results: Significant difference in Q-angle and quadriceps muscle activation was observed in groups II and III compared with control group I (p<0.01). Results of post-hoc analysis showed a significant difference in Q-angle and quadriceps muscle activation in on group III compared with groups I and II. Conclusion: Findings of this study suggest that closed kinetic chain exercise using EMG-Biofeedback that provides real-time biofeedback information on muscle contraction may have a beneficial effect on improvement of Q-angle and quadriceps muscle activation in patellofemoral pain syndrome.

• The Journal of Korean Physical Therapy
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• v.27 no.3
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• pp.129-134
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• 2015

Purpose: The purpose of this study was to determine the influence of WBV exercise on CMJ and quadriceps muscle activation according to different frequency of vibration in soccer player and also to find effective frequency for leading appropriate treatment reaction. Methods: Thirty three subjects were randomly divided into three groups: the three groups are WBV group using 20 Hz frequency, WBV group using 30 Hz frequency and squat exercise group according to training method. The exercise program was conducted for six weeks. Subjects were measured on CMJ and quadriceps muscle activation. Results: Significant difference in CMJ was observed in the group I, II compared with the group III (p<0.05). Results of post-hoc, showed a significant difference in CMJ in on group I, II compared with the group III, but no a statistically significant difference between group I and II. Significant difference in quadriceps muscle activation was observed in the group I, II compared with the group III (p<0.05, p<0.01). Results of post-hoc, significant difference in quadriceps muscle activation in on group I, II compared with the group III and significant difference between group I and group II. Conclusion: This research intervened WBV for soccer players and compared the differences of CMJ and quadriceps muscle activation; as a result of the effective frequency for improving performance, there is a significant difference in CMJ and quadriceps muscle activation of WBV group with comparison of control group; and it was proved that WBV is effective using 30 Hz frequency for improving quadriceps muscle activation.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.249-253
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• 2014

PURPOSE: This study intends to examine the effects of change of anatomical position of the ankle joint in open kinematic chain, an appropriate position for selective muscle training, on vastus lateralis obliques, rectus femoris, vastus medilais obliques, and rectus abdominalis muscle activation and to present an effective method of muscle training for patients and normal people. METHODS: The participants of this study were Korean healthy adult in their 20s. The 8 channel surface electromyography was used to measure muscle activation while the subjects raised their legs under each condition. Under each condition, while the subjects raised the leg to hip joint flexion at $60^{\circ}$ along the arch. RESULTS: The analysis result of muscle activation by each section and position during leg rising. There were significant differences. CONCLUSION: For independent strengthening of each muscle, muscle activation was measured according to leg raising angles and the result differed according to each section and position. If this study result is applied to muscle training for patients who need selective muscle training, more effective muscle strengthening will be made possible.

• Physical Therapy Korea
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• v.31 no.1
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• pp.18-28
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• 2024

Background: Lateral instability of the ankle is one of the most common causes of musculoskeletal ankle injuries. The peroneus longus (PL) and peroneus brevis (PB) contribute to ankle stability. In early rehabilitation, isometric exercises have been selected for improvement of ankle stability. To effectively train the peroneal muscles during eversion, it is important to consider ankle and body posture. Objects: This study aimed to compare activation of the PL, PB, and biceps femoris (BF) muscles during eversion in different ankle postures (neutral [N], plantarflexed [PF]) and body postures (sitting and side-lying). Methods: Thirty healthy individuals with no history of lateral ankle sprains within the last 6 months were included in the study. Maximal isometric strength of eversion and muscle activation were measured simultaneously. Muscle activation at submaximal eversion was divided by the highest value obtained from maximal isometric eversion among the four postures (percent maximal voluntary isometric contraction [%MVIC]). To examine the differences in muscle activation depending on posture, a 2 × 2 repeated measures analysis of variance (ANOVA) was conducted. Results: There were significant interaction effects of ankle and body postures on PL muscle activation and evertor strength (p < 0.05). The PL muscle activation showed a significantly greater difference in the side-lying and PF conditions than in the sitting and N conditions (p < 0.05). Evertor strength was greater in the N compared to the PF condition regardless of body posture (p < 0.05). In the case of PB and BF muscle activation, only the main effects of ankle and body posture were observed (p < 0.05). Conclusion: Among the four postures, the side-lying-PF posture produced the highest muscle activation. The side-lying-PF posture may be preferred for effective peroneal muscle exercises, even when considering the BF muscle.

• The Journal of Korean Physical Therapy
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• v.18 no.4
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• pp.51-60
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• 2006

Purpose: This study was to compare the effect of center of pressure(COP) displacement and muscle activation onset during expected and unexpected sudden limb loading in subjects with low back pain and healthy control subjects. Most studies of COP displacement and muscle activation onset on postural task focused on sudden trunk loading or gross limb movements. Investigation of the COP displacement and muscle activation onset during expected and unexpected sudden upper limb loading deserves similar attention. Methods: For this study, 14 subjects with low back pain and 12 healthy control subjects are participated. Force plate and surface EMG measures were used to determine COP displacement and muscle activation onset under expected and unexpected sudden upper limb loading. Results: COP displacement and muscle activation onset under unexpected sudden upper limb loading were similar in subjects with low back pain and healthy control subjects. However, COP displacement and muscle activation onset under expected sudden upper limb loading were shortened in healthy control subject but not among the subjects with low back pain. Conclusion: The results provide evidence for impaired feed-forward control in subjects with low back pain.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.323-330
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• 2010

Purpose : The purpose of this study was to evaluate the effects of muscle activation of neck, lumbar and low limb by using baby carrier with arms during walking. Methods : Twenty healthy and young females who brought up infants and had no musculoskeletal disorders of neck, lumbar and low limb were recruited for this study. They were instructed to perform muscle activation of neck, lumbar and low limb using the baby carrier with and without arms during walking. ProComp $infiniti^{TM}$ (Thought Technology Ltd., Canada) was used to measure the muscle activity of neck, lumbar and lower extremity muscles. Results : Activation of neck paraspinalis muscle was significantly increased using baby carrier with arms and there was a significant increase on erector spinae muscle activation by using anterior baby carrier. Conclusion : These results indicate that the muscle activation was changed by arms assist and the position of using baby carrier. Therefore, it could be considered relationship of muscle activation and musculoskeletal demage as carrying baby.