• 한국운동역학회지
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• 제34권1호
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• pp.25-33
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• 2024

Objective: The purpose of this study was to compare the lower extremity muscle activity and knee joint load according to movement speed conditions during the barbell back squat. Method: Nine males with resistance training experience participated in this study. Participants performed the barbell back squat in three conditions (Standard, Fast, and Slow) differing movement speed. During the barbell back squat, muscle activity of the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris long head (BFL), semitendinosus (ST), gluteus maximus (GM), gastrocnemius (GCN), and tibialis anterior (TA) was collected using an 8 channel wireless EMG system. The peak flexion angle of the lower extremity joints and the peak resultant joint force in each direction of the knee joint were calculated using eight motion capture cameras and ground reaction force plates. This study was to used the Friedman test and the Wilcoxon signed rank test, to compare lower extremity muscle activity and peak resultant joint force at knee joint according to movement speed conditions during the barbell back squat, and the statistical significance level was set at .01. Results: In the downward phase of the barbell back squat, the RF and TA showed the higher muscle activity in the fast condition, and in the upward phase, RF, VL, VM, BFL, ST, GM, and TA showed the higher muscle activity in the fast condition. As a results, analyzing of the load on the knee joint, in the downward phase, and in the upward phase, the higher peak compressive force of the knee joint was showed in the fast condition. Conclusion: The barbell back squat with fast movement speed was more effective due to increased muscle activity of lower extremity, but one must be careful of knee joint injuries because the load on the knee joint may increase during the barbell back squat with fast movement speed.

• 생명과학회지
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• 제14권3호
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• pp.484-489
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• 2004

인공관절은 21세기 정형외과 발전의 주요변화들 중의 하나이다. 1997년이래 전 세계적으로 무릎인공관절(Total Knee Arthroplasty: TKA)을 사용하는 사람들이 해마다 약 600,000명씩 증가하고 있는 추세이고 미국에서만 인공관절을 사용하고 있는 사람들이 210,000명에 달하고 있으며 그 시장은 대략 $5 billion을 넘고 있다(7). 무릎인공관절은 일상생활에서 의자에 앉았다 일어날 때 계단을 올라 갈 때 등, 무릎의 근 모멘트가 적당한 활동을 해서 무릎관절 근육에 지레와 같은 작용을 하게 하고, 완전한 무릎으로 정상인의 무릎과 같은 기능을 오랫동안 유지하게 한다. 이러한 목적을 달성하기 위해서는 무릎인공관절 디자인 시 정상적인 무릎 회전축(normal knee's axes of rotation)들의 정확한 위치를 파악하는 것은 중요하다. 인공관절 수술 후 무릎관절의 신전과 굴곡 운동을 하는 동안 하나의 회전축(single-axes)을 가진 하나의 회전 반경(single-radius)을 알아보는 것은 여러 축(multi-axes)으로 움직이게 된다는 다축 회전반경(multi-radius)을 분석하기에 앞서 중요한 연구이다. 따라서 본 연구에 서는 무릎이 신전운동과 굴곡 운동 시 신전과 굴곡 모멘트를 만들어내는 대퇴 사두근(quadriceps muscle)과 무릎 오금근 (hamstring)의 역할을 알아보았고, 또한 모멘트와 대퇴 사두근의 iEMG 형태를 파악하였다. 본 연구를 수행하기 위해 무릎인공관절 수술을 받고 1년과 3년이 지난 정상적인 생활을 하는 피검자(1년2명, 3년2명)를 대상으로 Isometric 테스트를 위한 KIN-COM III을 사용하여 60$^\circ$, 30$^\circ$의 무릎굴곡 측정을 하였고, Isokinetic concentric 테스트를 위해서 무릎굴곡각도의 $10^\circ$-80$^\circ$까지 움직임을 측정하였다 또한 15$^\circ$-75$^\circ$까지의 신전운동(sit-to-stand movement)과 굴곡운동(stand-to-sit movement)을 실시하여 시간의 차이, 내전과 외전의 차이 그리고 iEMG의 차이를 알아보았다. 본 연구의 데이터는 여러 번의 실험을 통하여 가장 일반적인 수치를 사용하였다. 이 때 16-channel BTS TELEMG를 사용하여 대퇴사두근과 무릎오금근의 근육활동모양을 알아보았다. 본 연구결과는 시술 후 3년이 지나면서 TKR (Total Knee Replacement)의 대퇴 사두근 토큐가 약해지는 것으로 나타났고, iEMG 실험에서는 N-TKR (Non-Total Knee Replacement)의 대퇴 사두근이 TKR의 대퇴 사두근 보다 근 수축력이 더 크게 발휘되는 것으로 밝혀졌다. 단축회전반경의 굴곡과 신전의 $10^\circ$-80$^\circ$까지의 각 속도는 굴곡동작이 1.19s, 신전 동작이 1.68s로 나타났다. 굴곡과 신전동작에서 다리의 외전(abduction)의 각도변화는 굴곡 시 5.5$^\circ$, 신전 시 5.2$^\circ$로 나타났고, 내전(adduction)의 각도변화는 굴곡 시 7.2$^\circ$, 신전 시 6.1$^\circ$로 나타났다. 대퇴 사두근의 iEMG변화에서는 15$^\circ$-60$^\circ$까지 vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF) 모두 굴곡동작에서 큰 값으로 나타났고, 61$^\circ$-75$^\circ$사이에서는 신전동작에서 iEMG가 큰 값으로 나타났다. 이와 같은 결과들은 인공관절 수술자들의 다축회전 반경을 분석하기에 앞서 중요한 선행연구가 될 것으로 생각된다.

• 대한물리의학회지
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• 제15권1호
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• pp.113-121
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• 2020

PURPOSE: The study examined the effects of non-elastic taping on the knee and ankle joints of stroke patients to increase muscle activity, balance and gait ability. METHODS: In this study, 10 stroke patients were assigned to experimental group (knee and ankle joint non-elastic taping and PNF technique) and control group (PNF technique). The experimental group applied the PNF technique for 30 minutes after attaching the inelastic tape, and the control group performed the PNF technique for 30 minutes. five times a week for a total of four weeks (20 times). RESULTS: The muscle activity of Vastus Medialis and Tiblialis Anterior showed significant differences between the experimental and control groups. BBS and 10MWT also showed significant differences between the experimental and control groups. CONCLUSION: In this study, the muscle activity, balance and walking on the paraplegic side of stroke patients using inelastic taping, and applied inelastic taping on two joints in a different way from the previous study, Therefore, it will have the advantage of increasing paralysis side muscle activity and improving balance and walking ability.

• 한국운동역학회지
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• 제22권3호
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• pp.295-304
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• 2012

This study, through biomechanical analysis, conducts a risk assessment of injury occurrence in ballet dancers while they perform running and jumping movements. The participants were nine female collegiate students majoring in ballet(age: $20.89{\pm}1.17years$; height: $160.89{\pm}7.01cm$; mass: $48.89{\pm}3.26$). Descriptive data were expressed as $mean{\pm}standard$ deviation(SD) for all variables. An independent t-test was conducted to determine how the following variables differed: duration time, position of the center of gravity, angle of the hip, torque of the hip, and muscle activity. All comparisons were made at the p<0.05 significance level. The results show that the jump time was two times longer than the run time in the duration time. The jump length was also longer than the run. The angle of the hip and the torque at the hip were higher in the right. The vastus medialis muscle was most frequently used. These findings demonstrate that participants' jumps may require more biomechanical variables for performance of better and more correct $jet{\acute{e}}$.

• 한국운동역학회지
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• 제16권4호
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• pp.1-12
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• 2006

This research was to know EMG tendency on increasing record in snatch weightlifting. In order to perform this research, we choiced 3 man national weightlifters, EMG analysis were executed on 8 major muscle(Latissimus Dorsi, Trapezius, Anterior Deltoid, Posterior Deltoid, Gastrocenemius, Vastus Medialis, Erector spinae, Abdominal). First trial record of athletics is 80% of each maximal record and increase the $5{\sim}10kg$ gradually. In this study, EMG signal scale of all muscle except posterior Deltoid muscle don't increased according to increasing the barbell weight, This showed a difference between general recognition and experiment result. In posterior Deltoid muscle, EMG signal scale increased according to increasing the barbell weight. It was assumed that EMG signal of protagonist shows possibility of linear increasing if motion have a consistency. It was assumed that In present, In order to increase one's record to $5{\sim}10kg$, Motion consistency training is more effective training method than increasing the muscle force.

• The Journal of Korean Physical Therapy
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• 제26권2호
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• pp.68-73
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• 2014

Purpose: The purpose of this study was to investigate the effect of closed kinetic chain exercise using EMG-biofeedback for selective training of the vastus medialis oblique on functional ability and Q-angle in subjects with patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included in this study. Participants were randomly allocated to the control group (Group I, n=10), closed kinetic chain exercise group (Group II, n=10), and closed kinetic chain exercise using EMG-biofeedback group (Group III, n=10). Intervention was performed in three groups, three times per week, for a period of six weeks. Kujala patellofemoral score and Q-angle were measured before and after the experiment. Results: Some significant differences in kujala patellofemoral score were observed in group II and group III, compared with group I (p<0.01). There was no significant difference on in Q-angle at knee flexion angle $0^{\circ}$. However, some significant differences in Q-angle at knee flexion $60^{\circ}$ were observed in group III, compared with group I (p<0.01). Conclusion: Closed kinetic chain exercise using EMG-biofeedback that provides real-time biometric information on selected muscles in order to increase the efficiency of treatment may be helpful in improvement of functional ability and Q-angle in patellofemoral pain syndrome.

• 대한물리의학회지
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• 제9권3호
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• pp.255-262
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• 2014

PURPOSE: This study was to investigate the effectiveness of TENS on balance in stroke patients by analyzing some components such as foot pressure, limit of stability and velocity sway after providing somatosensroy input using TENS. METHODS: Twenty five subjects participated and were randomly divided into two groups, TENS group (n=13) and control group (n=12) by the computer program. Interventions were given to subjects 5 days a week for four weeks. TENS group were treated with TENS for 60 minutes in addition to the conventional therapy which included 30-minute exercise and rehabilitation ergometer training for 15 minutes. Control group performed only conventional therapy. TENS was applied on the skin of soleus, tibialis anterior, tensor fascia latae and vastus medialis in affected side. Foot pressure, limit of stability and velocity sway for balance test were measured using Biorescue. RESULTS: TENS group was significantly increased limit of stability and foot pressure in affected side more than control group. And in eye closed condition, TENS group was significantly decreased velocity sway more than control group. CONCLUSION: The application of TENS is effective to improve the somatosensory input of affected side and to increase the motor function and balance ability.

• 대한물리치료과학회지
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• 제17권3_4호
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• pp.29-39
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• 2010

Purpose: The purpose of this study was to examine the effect of foot position and lifting an object on muscle activity and foot pressure during sit to stand(STS) in hemiparetic patients. Methods: Fourteen patients participated in this study. Surface electromyography was used to collect muscle activity and foot pressure measurement system was used to analyze foot pressure in hemiparetic side. Three different foot position was assumed(anterior, neutral, posterior) in hemiparetic side. The repeated two-way analysis of variance and multiple comparisons were conducted to determine statistical significance with a significance level of 0.05. Results: The results were as follows. 1) Lower extremity muscle activity was significantly higher(p<0.05) in biceps femoris and tibialis anterior muscle during STS without holding an object. With changing positions of the affected foot, muscle activity was significantly increased (p<0.05) in vastus medialis and lateral gastrocnemius when the foot was positioned in posterior. 2) There was no significant difference(p>0.05) in foot pressure during STS with object holding and foot positioning. Conclusion: Muscle activity showed a significant increase when the foot was positioned in posterior in comparison to the muscle activity when the foot was in neutral or anterior position.

• PNF and Movement
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• 제10권4호
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• pp.49-55
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• 2012

Purpose : The purpose of this study was to assess the effects of bridging exercise and combined lifting pattern bridging exercise on the lower extremity muscle activity. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following bridging exercises. Muscle activity was measured by QEMG-4 system(LXM 3204, Laxtha Korea). A paired t test was used to determine the influence of muscle activity for each exercise and descriptive statistics was used to characteristics of the subjects. Results : The biceps femoris, tibialis anterior, gastrocnemius of combined lifting pattern bridging exercise showed significance excepted vastus medialis(p<.05). In the case of men, biceps femoris showed significance in the combined lifting pattern bridging exercise(p<.05). In the case of women, biceps femoris and tibialis anterior showed significance in the combined lifting pattern bridging exercise(p<.05). Conclusion : The combined lifting pattern bridging exercise was more increased than bridging in lower extremity muscle activation. This result will be used for knee joint stabilizing exercises and biceps femoris strength training.

• 대한정형도수물리치료학회지
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• 제26권2호
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• pp.29-36
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• 2020

Background: The purpose of this study was to determine the effects of whole body vibration (WBV) exercise on lower extremity muscle activity and gait ability in stroke patients. Methods: For this study, 30 stroke patients participated in this study and they were divided into WBV exercise group and sham-WBV exercise group, each group in which consisted of 15 patients. WBV group and sham-WBV group was performed by the patients for five times a week, for six weeks. sEMG was used to measure lower extremity muscle activity. Changes in the activities of the muscles, such as the vatus lateralis (VL), vastus medialis (VM), bicep femoris (BF), gastrocnemius (GCM) muscle, were analysis. Motion analysis system was used to measure gait ability. Gait ability measured the stride length (SL) and walking velocity (WV). Results: According to the results of the comparisons between the groups, after intervention, lower extremity muscle activity of VL (p<.01), VM (p<.01), GCM (p<.01). SL, WV was significant between the group (p<.01). Conclusion: This study showed the WBV exercise is effective for improving increase of muscle activity and gait ability in stroke patients.