• Physical Therapy Korea
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• v.22 no.3
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• pp.71-80
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• 2015

Hip muscle activation and strengthening exercise programs are often used to prevent and treat various lower extremity injuries. Common exercise programs include squat exercises. The purposes of this study were to investigate gluteus medius (GMED) and tensor fasciae latae (TFL) muscle activity, and to assess the GMED/TFL ratio during squat exercises involving different isometric hip contraction conditions. Different types of isometric hip contraction were standard squat without hip contraction, squats with isometric hip adduction, and squats with isometric hip abduction. Twenty (10 males and 10 females) healthy subjects ($23.7{\pm}2.8$ years old) were recruited. Subjects performed the squat exercises with the back supported by a wall and knees flexed to $60^{\circ}$. Surface electromyography (EMG) was used to measure GMED and TFL activity. One-way repeated analysis of variance was used to compare GMED and TFL muscle activity and the GMED/TFL ratio. GMED and TFL EMG activity was significantly higher during squats with isometric hip adduction and abduction compared with the standard squat without hip contraction (p<.05). Between the isometric hip adduction and abduction contraction conditions, only the TFL EMG activity was significantly higher during squats with isometric hip adduction than isometric hip abduction (p<.05). The GMED/TFL ratio was significantly higher during squats with isometric hip adduction than isometric hip abduction (p<.05). Squats with isometric hip adduction and abduction improved GMED and TFL muscle activity. Furthermore, the GMED/TFL ratio was higher during isometric hip adduction than isometric hip abduction. Our data indicate that squat exercises involving isometric hip adduction enhance GMED muscle activity.

• Physical Therapy Korea
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• v.30 no.3
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• pp.237-244
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• 2023

Background: The external rotation (ER) exercise in performed at a 90° abduction of the shoulder joint is an effective to strengthen the infraspinatus. However, failure of the humeral head to control axial rotation during exercise can be increased the posterior deltoid over activity. Biofeedback training is an effective method of promoting motor learning and control it could look forward to activate the infraspinatus selectively by controlling the humeral head during exercise. Objects: The aim of this study was investigated that whether biofeedback for axial rotation was effective to activate selectively the infraspinatus during ER exercise. Methods: The 15 healthy males participated, and all subjects performed both ER exercise in a sitting position with shoulder abducted 90° under conditions with and without axial rotation biofeedback. Exercise was performed in a range of 90° ER, divided into three phases: concentric, isometric, and eccentric. The infraspinatus and posterior deltoid muscle activity were observed using surface electromyography. Results: Both infraspinatus activity (p < 0.01) and infraspinatus to posterior deltoid activity ratio (p = 0.01) were significantly higher with biofeedback however, posterior deltoid activity was significantly lower with biofeedback (p = 0.01). The infraspinatus muscle activity and muscle activity ratio were the highest in the isometric contraction type, and there were significant differences for all contraction types (p < 0.05). Whereas, the posterior deltoid activity was the lowest in the isometric contraction type, and showed a significant difference between isometric and other two contraction types (p < 0.05), but no significant different between concentric and eccentric contraction. Conclusion: Our results indicate that the axial rotation biofeedback during sitting ER exercise might be effective method to activating selective infraspinatus muscle and recommended to enhance the dynamic stability of the shoulder joint.

• Physical Therapy Korea
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• v.2 no.1
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• pp.36-43
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• 1995

The purpose of this study was to determine whether the vastus medialis oblique muscle(VMO) had greater electrical activity than the vastus lateralis muscle(VL) when hip adduction and knee extension exercise were performed. Electrical activity of the VMO and VL was measured on 42 healthy subjects (28 men, 14 women) during maximal voluntary isometric contractions of hip adduction and knee extension by an EMG-BIOFEEDBACK. The results showed that the electromyographic activity of the VMO was significantly greater than that of the VL during the hip adduction exercise. Differences noted with knee extension by performing hip adduction exercises. Isometric hip adduction exercises, therefore, may be advisable in the treatment of patients with patellofemoral pain.

• Physical Therapy Korea
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• v.16 no.3
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• pp.32-41
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• 2009

The purpose of this study was to suppose basis data the influence of different chair type and pelvic control on quadriceps muscle activity and strength during knee joint extension isometric exercise in hemiplegic patients. This research were investigated in ten healthy adults and tens hemipelgic patients. Surface electromyography (EMG) and Biodex system were used to collect kinematic data and muscle activity, respectively. Independent t-test, paired t-test and one-way repeated ANOVA were used to determine a statistical significance. The results showed as follows: (1) Posterior pelvic angles in healthy group and hemiplegic group were significantly different on isokinetic equipment (p<.05). (2) Different chair type and pelvic control on quadriceps muscle activity and strength were significantly different in hemiplegic patients (p<.05). From the result of this research, posterior pelvic angle control during knee joint extension isometric exercise in hemiplegic patients on isokinetic equipment is necessary to increase quadriceps muscle strength in hemiplegic patients.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.147-153
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• 2005

The purpose of this study were to compare the differences of isometric lumber extension strength and subjective pain degrees between obesity patients group and normal body fat group in disc surgical operated patients. The research purposed to indicate how isometric lumbar extension exercise for 12 weeks affected to lumbar strength and visual analogue scale of patients suffered by chronic back pain. The subjects were 65 low back pain patients(male 30, female 35)who had disease on lumbar in W hospital. The lumbar extension strength was measured at seven degrees of angles, which were $0^{\circ}$ $12^{\circ}$ $24^{\circ}$ $36^{\circ}$ $48^{\circ}$ $60^{\circ}$ and $72^{\circ}$ before and after the exercise program. We got the results of subjective pain degree using the modified visual analogue scale(VAS) of Lawlis et al(1989) and measured the maximal isometric lumbar strength of all subjects using MedX lumbar extension machine. Results were as follows; After the exercise, the lumbar extension strength of normal body fat patients groups included males and female were greater than that of the obesity patients groups in all angles(p<.05). The visual analogue scale of chronic back pain patients was decreased significantly after the exercise(p<.05). The results showed the significance between the lumbar extension strength and the visual analogue scale of chronic back pain patients and showed that the isometric lumbar extension exercise decreased the subjective pain degrees of visual analogue scale with and increased lumbar extension strength. The correlation between the visual analogue scale and the %body fat of chronic back pain patients was no significant after exercise. Therefore, the lumbar extension strength exercise is needed for improvement of back strength, decrease of %body fat.

• Physical Therapy Korea
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• v.8 no.3
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• pp.27-34
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• 2001

Physical therapists have been using biofeedback training to induce improvements in various circumstances. The purpose of this study was to compare the effects of visual and tactile feedback using electrical stimulation on quadriceps strength. Nineteen women without known impairment of the neuromusculoskeletal system volunteered for this study. Subjects were randomly allocated into three groups: visual feedback, tactile feedback, and control group. The torque of isometric knee extension force was measured. Subjects were asked to exert the maximal isometric contraction force of quadriceps over a 30 second period. The resting period of 10 minutes was given after the maximal isometric contraction to avoid the muscle fatigue. In between groups comparison, significant differences of the peak torque and the torque area were found on the performance of the maximal isometric contraction of quadriceps (p<.05). The values peak of torque and torque area were significantly higher during visual feedback than tactile feedback. The results of this study suggest that visual feedback is more powerful than tactile feedback (p<.01).

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.455-464
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• 2011

Purpose : This study is to investigate difference in the isometric muscular function of knee joints according to the time of participation in rehabilitation exercise in patients who had anterior cruciate ligament reconstruction. Methods : The subjects of this study were patients by sports injury or accident in the sports rehabilitation center of G hospital. The early exercise program group (n=7) started functional ability exercise from 2 weeks after the surgery and the late exercise program group (n=7) from 6 weeks after the surgery. Statistical analysis was used repeated measure ANOVA to test mean difference by using SPSS 18.0 for windows. Results : First, as to quadriceps femoris muscle according to the time of participation in exercise program, significant difference was observed according to interaction and time. Second, as to hamstring muscle according to the time of participation in exercise program, significant difference was observed in muscle strength according to time. Conclusion : This results suggest that if the effect of exercise program is similar between the early starting group and the late starting group, it is not necessary to have a long period of fixation as in the late exercise program group but is desirable to start functional ability exercise early in order to relieve pains in the knee joints.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.19-31
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• 2001

The twenty one individuals with total knee replacement who were admitted to Kang-Dong Hospital for comprehensive physical therapy were studied in order to demonstrate the effectiveness of an isokinetic test program using the Cybex 6000 machine. The subjects were divided into three groups with the isometric exercise group receiving isometric exercise. the isokinetic eccentric exercise group, and isokinetic eccentric exorcise group receiving isokinetic exercise(eccentric. concentric) to knee flexors and extensors muscles for a six weeks period using the Cybex 6000. The results were follow :1 . The peak torque was increased significantly in the flexors and extensors of the isokinetic conccentric exorcise among three groups(p<.05). 2. The progress of peak torque was increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<.05). 3. The total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<.05). 4. The progress of total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<;.05). 5. The ratio of endurance was not increased significantly in all three groups. 6. The extensors in the peak torque was likely to recover rapidly than the flexors. 7.The average R.O.M in the pre-exercise and post-exercise was not different significantly in all three groups. According to the above results, In the muscle strength recovery for total knee replacement patients, isokinetic concentric exercise group was significantly greater than the isokinetic eccentric and isometric exercise groups after a six weeks training.

• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.537-549
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• 2001

The isometric torque of the elbow flexor and extensor muscles were measured for 6 seconds at a joint angle of 90$^{\circ}$ , in 10 normal subjects (control group) and 10 hemiplegic subjects(patient group), using the Cybex NORMTM System. The peak torque, the time to peak torque were measured for each exercise. In addition, heart rate and blood pressure were recorded simultaneously at rest and immediately following exercise completion at 1 and 3m mutes. Statistical analysis was performed using SPSS 8.0 for Windows software and mean and standard deviations were calculated. The results are as follows. 1) In the patient involved group. the isometric values for flexors and extensors were significantly lower than in the normal nondominant group(p<.05). 2) The extensor to flexor strength ratio in the isometric mode was 121.0% in the patient involved group compared with 78.7%in the normal nondominant group, a significant difference(p<.05). 3) The mean increment ratio was increased 19.0% for systolic blood pressure and 25.2% for disatolic blood pressure in the patient group. 4) The mean increment ratio was increased 36.0% heart rate in the patient group.

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.103-109
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• 2020

Objective: The purpose of this study is to compare the muscle activity by electrode location in the biceps brachii during the arm curl isometric exercise and to provide the basic data needed to develop the proper electrode location of the biceps brachii based on the study results comparing the muscle activity by the angle of the elbow joint. Method: 17 adult males (Age: 21.50±4.63 yrs, height: 175.29±5.97 cm, weight: 63.79±15.31 kg, upper-arm length: 30.10±1.22 cm) participated in the study. In the arm curls isometric exercise, the experiment was divided into 1st and 2nd steps to compare muscle activity according to electrode location in the biceps brachii and muscle activity according to elbow angle change. In the first experiment, the surface electrode was attached at one-third point on the line from medial acromion to cubital fossa, according to the measurement method indicated by SENIAM. The elbow angle was set to 90°. In the second experiment, according to the proposed method of this study, the electrodes were separated at one finger's width in the left and right direction at one-third point on the line from medial acromion to cubital fossa, attached at the long head and short head. From the long head electrode, in about a width of two fingers in proximal direction, a total of three electrodes were attached at the myotendinal junction of the long head. The elbow angles were set as 70°, 90°, and 110°, and the isometric exercise (100% MVC) for 5 seconds was maintained with keeping the forearm and the rope to be 90° for the first and second experiments. Results: During the arm curl isometric exercise, there was no significant difference in SH and SENIAM proposition location proposed by this researcher. LH was shown to be lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.01) differences. MJ appeared lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.001) differences. The muscle activity by the elbow joint angle of SH in the biceps brachii was shown in large order of 70°<90°<110°, but there was no significant difference. The muscle activity by the elbow joint angle of LH was shown in large order of 90°<70°<110°, but there was no significant difference. The muscle activity by the elbow joint angle of MJ was shown in large order of 110°<90°<70°, but there was no significant difference. Conclusion: During the arm curl isometric exercise of the biceps brachii, it is judged appropriate to attach surface electrodes to the location proposed by SENIAM.