• The Journal of Korean Society for Neurotherapy
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• v.22 no.3
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• pp.31-36
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• 2018

Purpose The purpose of this study was to investigate the effects of contact handorientation response(CHOR) during sit-to-stand(STS) in people with stroke. Methods The subjects of the study were Thirty hemiplegia participated (Rt. hemiplegia/Lt. hemiplegia: 15/15, mean age: $65.82{\pm}8.53$) in this study. The analysis of muscles activation (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) distribution was conducted by the EMG, and the analysis of foot pressure distribution was conducted by the resistive pressure sensor. Hemiplegic stroke patients were instructed to perform STS three times with the non-affected side hand and affected side hand on the table. Results There was a significant positive correlation between rectus femoris, tibialis anterior muscle activation and affected side hand contact during STS(p<0.05). The STS correlated with the foot pressure in the affected side hand contact(p<0.05). Conclusion AS a result, CHOR during STS is related to muscle activation and the characteristics of foot pressure. This information was observed in the affected side hand contact on the table, suggestion that rehabilitation programs should be implemented.

• PNF and Movement
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• v.19 no.1
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• pp.1-8
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• 2021

Purpose: The purpose of this study was to determine how the position of tibial rotation affects peak force and hamstring muscle activation during isometric knee flexion in healthy women. Methods: Seventeen healthy women performed maximum isometric knee flexion at 30˚ with three tibial rotation positions (tibial internal rotation, neutral position, and tibial external rotation). Surface electromyographic (EMG) activity was recorded from the medial hamstring (MH) and lateral hamstring (LH) muscles. The strength of the knee flexor was measured with a load-cell-type strength-measurement sensor. Data were analyzed using one-way repeated analysis of variance. Results: The results showed that MH and LH activities and peak force were significantly different among the three tibial rotation conditions (p < 0.01). The post-hoc comparison revealed that the MH EMG activity in tibial neutral and internal rotation positions were significantly greater than tibial external rotation (p < 0.01). The LH activity in tibial external rotation was significantly greater than the tibial neutral position and internal rotation (p < 0.01). The peak force of the knee flexor was also greater in the external tibial rotation position compared with the tibial neutral and internal rotation positions (p < 0.01). Conclusion: Our findings suggest that hamstring muscle activation could be changed by tibial rotation.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1638-1641
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• 2004

Many walking stands, and assisting tools have been developed for the people with low-limb disability to prevent diseases from bedridden state and to help them walk again. But many of those equipments require user to have some physical strength or balancing ability. In our last research, we developed walking assist system for the people with lower-limb disability. With the system, user can be assisted by actuators, and do not have to worry about falling down. The system adapted the unique closed links structure with four servomotors, three PICs as controller, and four limit switches as HMI (human man interface). We confirmed the adaptability of the system by the experiment. In this research, Muscle Stiffness Sensor was tested as the advanced HMI for walking assist system, and confirmed the adaptability by the experiment. As Muscle Stiffness Sensor can attain the muscle activity, user can interface with any device he want to control. Experimental result with Muscle Stiffness sonsor showed that user could easily control the walking assist system as his will, just by changing his muscle strength.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.3
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• pp.253-259
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• 2017

Conventional upper extremity rehabilitation paradigm after brain injury has several shortcomings that is monotonous, simple, and repetitive in exercises over a long period of time, thereby causing training efficiency to decline as a consequence of low interest and participation. To resolve this issue, this paper proposes a new rehabilitative program integrating a wearable device integrated with EMG and motion sensor and a mobile game for the upper limbs' rehabilitative training. The developed wearable device is manufactured in the form of band, making it easy to wear. The mobile game is designed to enable rehabilitative training through games reflective of flexion, extension, abduction, and adduction identified by motion sensors along with grasp motion recognized by EMG signals measured from the wearable device. It also provides a tailored rehabilitative environment suitable for individual patients based on difficulty adjustments. As a consequence of applying the developed program to 14 brain injury in need of the upper limb rehabilitation and taking surveys on the utility of the developed rehabilitative program, the responses indicated that the developed rehabilitative program is far much more interesting and fun than the conventional rehabilitative program, further to the desire of those surveyed to reuse the developed program in the future.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.133-140
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• 2021

Purpose: This study aimed to compare the relative muscle activity on the erector spinae, gluteus maximus, and hamstring, using a non-visual feedback bridge exercise and a visual feedback bridge exercise with a tension sensor and clinometer. Methods: Twenty-two healthy subjects participated in this study. The study subjects performed bridge exercises without visual feedback, bridge exercises using a tension sensor, and bridge exercises using an inclinometer in the supine position, and the muscle activity of the left and right erector spinae, gluteus maximus, and hamstring muscles was measured while maintaining isometric contraction during the bridge movement. Muscle activity was measured by using surface an electromyography equipment. To standardize the measured action potential of each muscle, the maximum voluntary isometric contraction was measured. The bridge exercise was repeated 3 times for 5s each. Using repeated analysis of variance, we compared the significant difference in EMG activity for each muscle between the three experiments, and all statistical processing was performed using SPSS version 26. The statistical significance level was set at α = 0.05. Results: During bridging exercises, the asymmetry of the muscle activity of the erector spinae and gluteus maximus during visual feedback guiding was lower than that during no visual feedback. However, there was no significant difference. Moreover, the asymmetry of the muscle activity of the hamstring muscles was significantly lower during tension sensor visual feedback than that during no visual feedback (p<0.05). Conclusion: These findings suggest that bridge exercise with visual feedback using a tension sensor and an inclinometer is effective in inducing symmetrical movement. When it is necessary to symmetrically adjust the weight load of both feet during the bridge exercise, it is effective to apply visual feedback using a tension sensor.

• Journal of Life Science
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• v.14 no.3
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• pp.484-489
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• 2004

Artificial joint replacement is one of the major surgical advances of the 21th century. The primary purpose of a TKA (Total Knee Arthroplasty) is to restore normal knee Auction. Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from a chair or climbing stairs;(b) allow the same range of motion as an complete knee; and (c) provide adequate knee joint stability. Four individuals (2 peoples after surgery one year and 2 peoples after surgery three years) participated in this study. All they were prescreened for health and functional status by the same surgeon who performed the operations. Two days of accommodation practice occurred prior to the actual strength testing. The isometric strength (KIN-COM III) of the quadriceps and hamstring were measured at 60$^\circ$ and 30$^\circ$ of knee flexion, respectively. During isokinetic concentric testing, the range of motion was between 10$^\circ$ to 80$^\circ$ of knee flexion (stand-to-sit) and extension (sit-to-stand). for a given test, the trial exhibiting maximum torque was analyzed. A 16-channel MYOPACTM EMG system (Run Technologies, Inc.) was used to collect the differential input surface electromyographic (EMG) signals of the vastus medialis (VM), vastus lateralis(VL), rectus femoris (RF) during sit-to-stand and stand-to-sit tests. Disposable electrodes (Blue SensorTM, Medicotest, Inc.) were used to collect the EMG signals. The results were as follows; 1. Less maximum concentric (16% and 21% less for 1 yew man and 3 years mm, respectively) and isometric (12% and 29%, respectively) quadriceps torque for both participants. 2.14% less maximum hamstrings concentric torque for 1 year man but 16% greater torque for 3 years mm. However, 1 year man had similar hamstring isometric peak torque for both knees. 3. Less quadriceps co-contraction by 1 year man except for the VM at 10$^\circ$-20$^\circ$ and 30$^\circ$-50$^\circ$ range of knee flexion.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.738-743
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• 2007

In this paper, a muscle motion sensing system and an artificial arm control system are studied. The artificial arm is for the people who lost one's forearm. The muscle motion sensing system detect the intention of motion from the upper arm's muscle. In sensing system we use flex sensors which is electrical resistance type sensor. The sensor is attached on the biceps brachii muscle and coracobrachialis muscle of the upper arm. We propose an algorithm to classify the one's intention of motions from the sensor signal. Using this algorithm, we extract the 4 motions which are flexion and extension of the forearm, pronation and supination of the arm. To verify the validity of the proposed algorithms we made experiments with two d.o.f. artificial arm. To reduce the control errors of the artificial arm we also proposed a fuzzy PID control algorithm which based on the errors and error rate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.799-807
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• 2017

In this paper, a new method is proposed for estimating pedestrians' walking velocity based on lower-limb kinematics and wearable inertial measurement unit (IMU) sensors. While the soles and ground are not in contact during the walking cycle, the walking velocity can be estimated by integrating the acceleration output of the inertial sensor mounted on the pelvis. To minimize the effects of acceleration measurement errors caused by the tilt of the pelvis while walking, the estimated walking velocity based on lower-limb kinematics is imposed as the initial value in the acceleration signal integration process of the pelvis inertial sensor. In the experiment involving outdoor walking for six minutes, sensor drift due to error accumulation was not observed, and the RMS error in the walking velocity estimation was less than 0.08 m/s.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.47-51
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• 2017

The purpose of this study was to investigate the effect of wearable sensor wear on the muscle contraction of cervical erector spinae and upper trapezius causing the forward head posture induction in order to reduce the stress induced by the use of smartphone. This study was to investigate the muscle activity of healthy adults in the 20th to 30th generations by dividing them into the control group using the smartphone, the non-wearing group conscious the posture of the head posture, and the wearing group wearing the wearable sensor. There were no differences in muscle activity between cervical erector spinae and upper trapezius compared to the control, non - wearing, and wearing groups. In addition, the changes in muscle activity of cervical erector spinae muscles were increased in all groups, but the muscle activity of upper trapezius muscles were in the wear group compared to the non-wear group and the control group, but there was no statistical significance. That is, wear of the wearable sensor may be effective in controlling the conscious posture, but it may cause the compensation of another part.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.181-189
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• 2015

Powered prosthesis is used to assist walking of people with an amputated lower limb and/or weak leg strength. The accurate gait phase classification is indispensable in smooth movement control of the powered prosthesis. In previous gait phase classification using physical sensors, there is limitation that powered prosthesis should be simulated as same as the speed of training process. Therefore, we propose EMG signal based gait phase recognition method to classify stairs ascending and stairs descending into four steps without using physical sensors, respectively. RMS, VAR, MAV, SSC, ZC, WAMP features are extracted from EMG signal data and LDA(Linear Discriminant Analysis) classifier is used. In the training process, the AHRS sensor produces various ranges of walking steps according to the change of knee angles. The experimental results show that the average accuracies of the proposed method are about 85.6% in stairs ascending and 69.5% in stairs descending whereas those of preliminary studies are about 58.5% in stairs ascending and 35.3% in stairs descending. In addition, we can analyze the average recognition ratio of each gait step with respect to the individual muscle.