• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.411-416
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• 2013

Purpose: The purpose of the present study was to determine the effects of activation of gluteus maximus (Gmax) and abdominal muscle using EMG biofeedback on lumbosacral and tibiocalcaneal angles in standing position. Methods: Fourteen healthy subjects with normal feet participated in the present study. Electromyographic (EMG) biofeedback using visual cue was used to activate the external oblique (EO) and Gmax. The lumbosacral and tibiocalcalcaneal angles were measured by electronic goniometers. All the subjects were instructed to activate the Gmax and EO monitoring increasing amounts of the muscle activities in each muscle. The lumbosacral and tibiocalcaneal angles were collected in three trials during resting and activation of each muscle using EMG biofeedback in standing position. The mean value of three trials was used in the data analysis. A paired-t test was used to compare the lumbosacral and tibiocalcaneal angles between resting and activation of the Gmax and EO using EMG biofeedback. Results: The lumbosacral and tibiocalcaneal angles were significantly less in the resting compared to activation using EMG biofeedback (p<0.05). Conclusion: The activaition of Gmax and abdominal muscles using EMG biofeedback play role to control the pronation of subtalar joint during the weight-bearing.

• The Journal of Korean Physical Therapy
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• v.10 no.1
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• pp.127-138
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• 1998

This study was carried out tn invstigate and compare biomechanical characteristics during free speed gait in hemiplegic patients after stroke who took therapeutic exercise by analyzing kinematic and kinetic data in the sagital plane and electromyographic data. Six patients($41\~69$ years old) and age-matched six volunteers in good health(51-61 years old) wire studied. The patients were sorted into two groups, depending on their self-speed of walking : fast speed group(3 patients) and slow speed group(3 patients). The results were as fellows. : 1. In spatio-temparal parameters, affected and unaffected side of fast group showed symetry but blew group showed asymetry of single limb support, opposite foot contact and stance phase (p<0.05). Compared with normal group, patient group showed slower velocity, shoter stride length and longer double limb support (p<0.05). 2. In the pelvic anterior tilt, patient group showed lower valued than normal group. It. In the ground reaction force-vertical force, fast group showed similar double peak gragh compared with normal group, butvslow group showed lower values without double peak (p<0.05).

• 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 Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.114-120
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• 2018

In this paper we implemented an EMG sensor system for wearable devices to obtain and analyze of EMG signals. The performance of the implemented sensor system is evaluated by the correlation analysis of muscle fatigue and muscle activation to clinical EMG system and compared with power consumption of the measured power of our system and commercial systems. In experiments with biceps and triceps brachii of 5 objects, The correlation values of muscle fatigue and muscle activation between our system and the clinical EMG system is 1.1~1.4 and about 1.0, respectively. And also the power consumption of our system is 25~50% less than that of some commercial EMG sensor systems.

• Physical Therapy Korea
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• v.17 no.4
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• pp.8-15
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• 2010

This study was designed to investigate the effect of different hand positions on scapulothorcic muscle activities during push-up plus exercises. Fourteen healthy males performed push-up plus exercises under three conditions (neutral, $90^{\circ}$ internally rotated, and $90^{\circ}$ externally rotated hand positions), during which the activities of the serratus anterior, pectoralis major, and upper trapezius muscles were recorded using surface electromyography. The statistical significance at three different hand positions was tested by repeated one-way ANOVA. The mean activities of the serratus anterior increased and the mean activities of the pectoralis major decreased in the order of neutral hand position, internally rotated hand position, and externally rotated hand position. There was a significant difference during push-up plus between neutral and externally rotated hand positions as well as in the serratus anterior/pectoralis major activity ratio (p<.0.5). However, no significant differences were found in the activity of the upper trapezius muscle or the serratus anterior/upper trapezius activity ratio. We suggest that the push-up plus exercise performed in the externally rotated hand position could a beneficial strategy for selective strengthening of the serratus anterior muscle, while minimizing the activity of the pectoralis major muscle.

• Physical Therapy Korea
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• v.21 no.2
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• pp.28-36
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• 2014

The purpose of this study was to evaluate the changes in the electromyographic (EMG) activity of the trunk and the lower limb muscles during quiet standing on an unstable surface while wearing low-heeled shoes (3 cm), high-heeled shoes (7 cm) and without footwear (0 cm) in 20 young healthy women. The subjects stood on an unstable surface for 30 seconds. We examined the differences in the EMG data of the erector spinae, rectus abdominis, biceps femoris, rectus femoris, tibialis anterior, and the gastrocnemius medialis muscle. A one-way repeated analysis of variance was used to compare the effects of shoe heel height on the EMG activity with the level of significance set at ${\alpha}=.05$. The EMG activity of the erector spinae and the rectus femoris were significantly increased (p<.05) in the subjects who wore elevated heel height, while the tibialis anterior and the gastrocnemius medialis were significantly decreased (p<.05). However, the rectus abdominis and the biceps femoris exhibited no significant difference among the three conditions. The above results indicate that wearing high-heeled shoes may change the postural strategy. The findings of this study suggest that excessive heel height could contribute to an increased fall risk during quiet standing.

• Physical Therapy Korea
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• v.20 no.3
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• pp.27-35
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• 2013

The aim of this study was to compare the electromyographic (EMG) activity levels of the scapular upward rotators [upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA)] and other scapular muscles [posterior deltoid (PD), levator scapulae (LS), and infraspinatus (IS)] during isometric lower trapezius exercises. Twenty males with no medical history of shoulder pain or upper extremity disorders were recruited for this study. EMG activity was recorded from the UT, LT, SA, PD, LS, and IS while subjects performed three different exercises: Prone arm lift (PAL), Backward rocking diagonal arm lift (BRDAL), Modified Prone Cobra (MPC). One-way analysis of variance (ANOVA) was used to determine any significant differences among the three exercises. A lower relative activation of UT, LT, and SA was seen with the MPC than with the other exercises (p<.05). The relatively lower activation of the UT identified, the MPC exercise as the preferred choice for preferential strengthening the LT (p<.05). However, a higher activation in the PD, LS, and IS occurred with the MPC than with the other exercises (p>.05). The recruitment pattern of synergist varied depending on the exercise posture. These findings suggest that exercise posture is an important factor in the selection of strengthening exercise for weak muscle.

• The Journal of Korean Physical Therapy
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• v.25 no.2
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• pp.81-87
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• 2013

Purpose: The purpose of the current study was to examine the effects of electromyography (EMG)-biofeedback training on lower extremity muscle activity and balance of patients with total knee replacement (TKR). Methods: Subjects were randomly allocated to two groups: experimental and control group. Subjects in the experimental group (n=10) were provided with quadriceps setting exercise by EMG-biofeedback (QSE+BF) and those in the control group were provided with QSE. Subjects in both groups were provided with the respective training programs for 20 minutes per session, five times per week, for a period of six weeks. To test significance, data analysis was performed using repeated-ANOVAs. Results: Statistically significant differences in muscle activity of the rectus femoris muscle and the vastus lateralis, and dynamic balance ability were observed in the experimental group, compared with the control group. In comparison of the muscle activity of the rectus femoris muscle and the vastus lateralis, and dynamic balance ability between different training periods within the groups, both groups showed statistically significant differences. Conclusion: EMG-biofeedback training is effective in improving lower extremity muscle activity and balance ability of patients with TKR, and should be effective in patients with other diseases.

• Journal of International Academy of Physical Therapy Research
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• v.1 no.2
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• pp.185-191
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• 2010

Background: This study investigated effective posture for gluteus medius rehabilitation training and effects of isometric muscle activity by electrophysiology through EMG while performing dynamic isotonic behavior of weight placed differently on upper limbs. Method: 16 healthy male subjects 20 to 29 years of age volunteered for the study. Lateral stabilizer right gluteus medius activity was assessed using EMG while the right lower extremity maintains single limb support, and the left upper extremity elevation movement maintains 5 seconds without load, 1RM to 1 repetition, 5RM to 5 times, 10RM to 10 times, 5RM and 10RM maintain 5sec. Results: Comparison of the mean value of EMG data showed a statistically more significant difference in upper extremity elevation movement on opposite upper extremity added weight than one that was not added on a single limb weight bearing posture(p>.05). Weight supported side gluteus medius activity for 1RM, 5RM, 10RM weight difference and movement repetition did not differ(p>.05). Comparison in maximum value showed statistically significant differences in not adding weight on upper limb elevation exercise and 1RM, 5RM, 10RM repeated behavior. Elevation behavior and repetition appeared over 70% of MVIC. Conclusion: Unilateral weight bearing stance added weight in the opposite upper limb elevation movement was an indirect exercise to effectively stimulate gluteus medius activity. Applying various added weight will have effective exercise on the early stages of rehabilitation because activity gluteus medius did not differ through added weight.

• Physical Therapy Korea
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• v.17 no.2
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• pp.67-74
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• 2010

The purpose of this study was to examine the acute effects of nerve mobilization, static stretching, and hold-relax on the flexibility of hamstring muscles and their surface electromyographic (EMG) responses to passive stretches in poststroke hemiparesis. This study was a randomized cross-over trial. Fourteen subjects received three treatment sessions in random order with each consisting of ten repetitions. The treatment sessions included nerve mobilization, static stretching, and hold-relax. The treatment sessions were held at least 24 hours apart to minimize any carryover effect. The outcome was measured by the distance between the greater trochanter and lateral malleolus and hamstring EMG activity during passive knee extension stretching. Repeated-measures analysis of variance showed significant changes in hamstring flexibility and EMG activity in main effect of time pre, post and followup (p<.05). However, no significant differences occurred among the three stretching techniques. No technique was consistently found to be superior. The three stretching techniques in this study make it difficult to determine the most effective technique. Therefore, clinicians use nerve mobilization of effective stretching techniques with other stretching techniques.