• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.63-68
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• 2019

The purpose of this study was to investigate the effect of hyper-extended knee and asymmetric standing posture on knee joint position and lower extremity muscle activity. Thirty-three voluntary participants participated and included sixty legs in the study. The sixty legs were divided into two groups: hyper-extended knee and normal group. The muscle activity and knee extension angle were measured. In the asymmetric standing posture, the knee joint extension angle and the muscle activity of the gastrocnemius were statistically significant between the normal group and the hyper-extended knee group. Based on the results, we confirmed that the asymmetric standing posture increases the hyper-extended knee. Therefore, it will contribute to the establishment of therapeutic guide for the subjects with hyper-extended knee to maintain the symmetrical standing posture, and future studies need to be conducted including the effects of the hip joint and ankle joints.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.336-337
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• 2017

본 논문에서는 이처럼 중요한 역할을 하는 무릎의 굽힘(flexion)과 폄(extension)에 대하여 측정을 한다. 무릎과 엉덩이를 펴고 골반을 중립상태로 두고 엎드려 무릎을 구부리고 편다. 일반인의 도수 측정 각도는 구부렸을 때 $110^{\circ}$에서 $135^{\circ}$ 사이의 값이 나온다. 여기서 구부렸을 때 고통을 호소하면 무릎 관절 및 근육에 이상이 있는 것이다.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.463-471
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• 2019

The purpose of this study was to investigate the effect of muscle imbalance on motion of back squat. The isokinetic muscle strength of the 8 subjects was recorded for the knee flexion/extension by the cybex 770 dynamometer. Each subject performed 3 back squats with the long barbell with an intensity of 25% body weight(BW), 50%BW, 100%BW, 125%BW. During the back squat through the recorded kinematic data the subjects' maximum flexion and extension knee angle, center of mass displacement and V-COP were calculated for evaluation of the stability of the movement. For the statistical analysis independent t-test was used. Knee flexion angle and COM displacement are dominated by the reciprocal muscle ratio. V-COP factor was dominated by bilateral extension deficit. Based on the results we can know that as the intensity of the squat increased to a level control was difficult because the muscles' imbalance influenced the movement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4395-4403
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• 2014

The purpose of study was to compare the effectiveness of sling exercise on the muscle strength and range of motion in female patients who received a total knee replacement. The participants were allocated randomly into 2 groups: sling exercise group (n=15) and control group (n=15). The subjects were evaluated using the Biodex system for the muscle strength test and a goniometer for the range of motion test. The data was analyzed using a paired t-test and independent t-test to determine the statistical significance. As a result, the sling exercise group before and after intervention showed a statistical significance difference in the flexion angle, quadriceps femoris, and hamstring muscle strength. The control group before and after the intervention revealed a statistically significant increase in the flexion & extension angle, quadriceps femoris, and hamstring muscle strength. Muscle strength test and flexion range of motion test in the sling exercise group showed statistical significance differences compared to the control group (p<.05). Therefore, the sling exercise group has a positive influence on the muscle strength and ROM in patients with a total knee replacement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.538-546
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• 2017

The purpose of this study was to investigate the effect of neuromuscular electrical stimulation (NMES) and transcutaneous electrical nerve stimulation (TENS) on muscular strength, pain, range of motion and fear-avoidance in anterior cruciate ligament reconstruction (ACLR) patients. The subjects of this study who received ACLR after arthroscopic injury were divided into two groups: NMES (n=14) and TENS (n=14). Each group received intervention after routine physical therapy. Each electrotherapy intervention was applied regularly for a total of 12 times, 3 times a day (30 minutes) for 4 weeks. The evaluation by intervention method included isokinetic muscle strength in flexion and extension of the knee joint, pain, range of motion of the knee joint, and fear-avoidance beliefs. The results showed significant improvement in pain, range of motion, and fear-avoidance beliefs in both groups (p<0.05). However, there was a significant improvement in isokinetic knee flexion and extension strength only in the NMES group (p<0.05). There was no significant difference between the two electrotherapy methods in muscle strength, pain, range of motion, and fear-avoidance beliefs. These study results suggest that NMES and TENS can be effective intervention methods for pain, range of motion, and fear-avoidance response in patients with ACLR, but to improve muscle strength NMES may be more effective.

• PNF and Movement
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• v.18 no.3
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• pp.375-382
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• 2020

Purpose: The purpose of this study was to investigate the muscle contraction onset time characteristics of the gluteus maximus, semitendinosus, and biceps femoris muscles at different knee flexion angles in individuals with shortened or over-lengthened hamstrings performing prone hip extension. Methods: Twenty-six participants were divided into a hamstring shortened group (n = 12) and hamstring lengthened group (n = 14). Wireless surface electromyography was used to verify the muscle onset time of the gluteus maximus, semitendinosus, and biceps femoris when performing prone hip extension at different knee flexion angles. Results: There were significant differences in the muscle onset times of the semitendinosus and biceps femoris between the hamstring shortened group and hamstring lengthened group (p < 0.05). In addition, there was a significant difference in the muscle contraction onset times among of the gluteus maximus, semitendinosus, and biceps femoris muscles when performing prone hip extension at a knee flexion of 90° in the hamstring shortened group (p < 0.05) and a knee flexion angle of 0° in the hamstring lengthened group (p < 0.05). Conclusion: In all groups, there was no effect on the onset time of the gluteus maximus muscle according based on the knee angle. In addition, the knee flexion angles affected the onset time of the muscle contraction of the gluteus maximus muscle in the hamstring shortened group and hamstring lengthened group with an abnormal length of the hamstring muscle.

• Science of Emotion and Sensibility
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• v.20 no.3
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• pp.141-150
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• 2017

The purpose of this study was to analyze the effect of the shape and attached position of E-textile-based stretchable sensors on motion-sensing performance and to investigate the requirements for the optimal structure of clothes for sensing limb motions. An experimental garment was prepared with different sensor shapes, and attachment positions. A child subject, wearing the experimental garment, performed arm and leg bending and extension motions at $60^{\circ}$, $90^{\circ}$ and $120^{\circ}$ motion angles, at a rate of 60 deg/sec. The changes in voltage triggered by the stretching and contracting of the fabric-sensor were measured, and an acceleration sensor was utilized to verify that the experimental motions were correctly performed. Dummy arms and legs of a child were manufactured to perform an identical test, in order to compare the dummy results with the actual human body experiment results. The analysis showed that the reproducibility and reliability of the rectangular sensor, showing uniform and stable were higher than those of the boat-shaped sensor, in both the dummy and the human body experiments. The attachment position of the sensor was more reproducible and reliable when placed on 4 cm below the elbow and knee joints in the dummy test, when placed in the joints of the elbow and knee, in children experiment. The appropriate shapes and attached positions of the sensor for sensing the motions were analyzed, and the results proved that motion-sensing of the human body is possible by utilizing flexible fabric-sensors integrated into clothes.