• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.585-596
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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 concentric exercise group receivind isokinetic exercise(eccentric, concentric) to knee flexors and extensors muscles for a six weeks' period using the Cybex 6000. The results are follow: 1. The extensors were increased significantly at all groups after 6 weeks training(p<.05). The flexors were increased significantly at isokinetic eccentric and isokinetic concentric group but no significantly differences at isometric group(p>.05) 2. At the effect of extensors and flexors after 6 weeks training. higher to 30$^{\circ}$ /sec of isokinetic concentric exercise, lower to 120$^{\circ}$ /sec of isometric exercise. 3. The peak torque was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 4. The total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 5. The ratio of peak torque to body weight were more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 6. The average power was more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 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.

• Journal of Korean Physical Therapy Science
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• v.10 no.1
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• pp.74-82
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• 2003

The purpose of this study is to provide guideline of muscle strengthening exercise for preparing ambulation by presenting suitable ratio of muscle power of agonist & antagonist, and that of concentric & eccentric contraction on behalf of amputee's normal ambulation training and it's strenthening as well. 7 Subjects who have femur amputee for experimental group were able to ambulate naturally without inconvenience and 20 adult subjects of comparison group for comparison were considered to be free from disturbance of ambulation. The method of study was to measure the muscle power of hip pint, was to figure out the ratio of agonist & antagonist, concentric contraction & eccentric contraction, and was to find out mean and standard deviation of each measurement. Every numerical value of comparison was tested by Mann-whitney and comparison group's comparison between left & right value was done with t-test. Results are as followings : 1) Extension force was stronger than flexor force and had no remarkable difference(p<0.05) 2) For normal adults, adduction farce was stronger than abduction force and for amputees, abduction force was stronger while adduction force was the same as the normal without showing remarkable difference(p<0.05) According the result above, I make an assumption that maintaining a proper ratio of muscle power on strengthening exercise for amputee's ambulation training & rehabilitation and finally bring out an improvement of transfer and ambulation.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.3
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• pp.2147-2154
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• 2020

Background: Improperly conducted exercise may lead to worsening of musculoskeletal complications. Such may worsen due to increased repetition and intensity during exercise. In addition, different responses may show different needs for training program. Objectives: To compare kinematics of symmetric concentric and eccentric motions during increased repetitions and intensities for men and women. Design: Quasi-randomized trial. Methods: A total of ten men and eleven women participated in this study. Concentric and eccentric motions of the lateral raises were observed for initial positions of abduction and adduction. Low and high exercise intensities were applied, and 15 repetitions were conducted for both intensities. Initial, 3 inbetween repetitions, and last repetition were recorded for comparisons. Results: The concentric or abduction motions showed no significant differences for all comparisons. However, eccentric or adduction motions showed greater significant differences as the exercise intensity increased for both men and women. Such significant differences were most prevalent during the first and last repetitions with greatest differences during the initial repetitions. Conclusion: Kinematic difference between men and women during increased repetitions and intensity indicate the need for more individualized exercise intervention and consideration between men and women. Individualized interventions may prevent exercise-induced postural abnormality and corresponding musculoskeletal dysfunction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2475-2482
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• 2002

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.412-418
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• 2001

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is corrected using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could corrected the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for correction of the error due to hole eccentricity in hole-drilling method.

• 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.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.489-493
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• 2013

Purpose: This study was to investigate peripheral vision and provide people with macular degeneration with a guideline for eccentric viewing training. Methods: 30 adult subjects with normal vision took part in this study. The lateral area of $20^{\circ}$ eccentricity from the fovea of right eye was only used to measure the physiological summation. The target was sinusoidal vertical gratings within a circular aperture. The critical points in spatial and temporal summation was found to compare each other for 0.7 cpd and 3.0 cpd, respectively. Results: Critical duration and contrast sensitivity for 0.7 cpd were 540 ms and 1.1, and 315 ms and 0.98 for 3.0 cpd respectively. The critical degrees and contrast sensitivity for 0.7 cpd were $11.3^{\circ}$ and 2.8, and $5^{\circ}$ and 2.63 for 3.0 cpd respectively. Conclusions: The critical point in peripheral vision reaches relatively faster than the one in central vision. It is recommended to train the peripheral retina under the lower spatial frequency more frequently for a short time than constantly for a long time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.723-728
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• 2003

The physical restoration technology for lower limb amputees is being advanced as the biomechatronics is being applied to the area of rehabilitation. As the advanced prosthetics for lower limb amputees are introduced, a suitable prescription of biomechanical rehabilitation training becomes important to utilize the advanced full features of the devices. Since lower limb amputation significantly affects biomechanical balance of mosculoskeletal system for gait, an appropriate and optimal biomechanical training and exercise should be provided to rebalance the system before wearing the prostheses. Particularly, biomechanical muscular training for hip movements in the both affected and sound lower limbs is important to achieve a normal-like ambulation. However, there is no study to understand the effect of hip muscle strength on the gait performance of lower limb amputees. To understand the hip muscle strength characteristics for normal and amputated subjects, the isokinetic exercises for various ratios of concentric contraction to eccentric contraction were performed for hip flexion-extension and adduction-abduction. As a results. biomechanical isokinetic training protocols and performance measurement methodologies for lower limb amputees were developed in this study. Using the protocols and measurement methods, it has been understood that the appropriate and optimal biomechanical prescription for the rehabilitation process for lower limb amputees is important for restoring their gait ability

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.111-119
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• 2020

Objective: The purpose of this study is to apply exercise learning effect to various subjects through training effect and information accumulation based on verification of the effect on dumbbell curl exercises applied with virtual reality. Method: To analyze the effect on the dumbbell curl exercise in the virtual environment, a total of 20 persons with 10 males and 10 females who does not have orthopedics diseases were selected. The dumbbell weight of the subjects was set to a weight of 70% strength of 1RM. At this time, the virtual environment situation was set to four types; presence/absence of virtual environment, preferred colors, and unfavorable colors to perform dumbbell curl exercise. The anaysis of muscle activity was conducted by adhering four surface electrodes (Biceps Brachii, Triceps Brachii, Brachioradialis Muscle, Extensor Carpi Radialis Longus Muscle) on the right upper limbs. Independent sample t-test using SPSS (24.0) program was carried out to analyze average values and standard deviations for each variable depending on the presence/absence of virtual environments and changes in color (preferred colors, unfavorable colors) and the level of significance was set to a=.05. Results: In the eccentric contraction, males showed high muscle activity in the Biceps Brachii under virtual reality. On the other hand, females had high muscle activity in the Biceps Brachii in the absence of virtual reality. Also, in case of a change of colors in the virtual environment, females had the high muscle activity in the unfavorable color in the eccentric contraction. Conclusion: During the dumbbell curl exercise, results of different exercises present depending on gender. When males put VR on and performs a basic dumbbell curl exercise, the effect of Biceps presents Brachii for them while exercising in unfavorable colors. However, since it is the basic research data of muscle exercise using virtual reality, it is necessary to verify whether or not it is effective for myopachynsis through long-term training rather than unity.

• 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.