• 한국전문물리치료학회지
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• 제11권3호
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• pp.85-90
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• 2004

The purpose of this study was to find the difference in muscle firing rate between each muscle according to the knee angle with the quadriceps femoris which is a representative action muscle of the lower extremity. Seven normal healthy subjects were recruited. The median frequency (MDF) of muscle contraction was recorded from vastus lateralis, vastus medialis, and rectus femoris muscles using the surface EMG, in 5 seconds, during maximal isometric knee extension. The data were analyzed by the two-way repeated ANOVA. The results of the study were as follows: 1) median frequency of muscle contraction was significantly higher at the vastus lateralis, vastus medialis, and rectus femoris in descending order. 2) median frequency of muscle contraction was significantly higher at the $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ in descending order. Consequently, muscle recruitment at the knee decreases the EMG activity of the lengthened muscle. This study suggests that the change in EMG activity at different muscle lengths resulted in affecting the muscle firing rate during the knee extension.

• 한국임상수의학회지
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• 제34권5호
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• pp.366-369
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• 2017

A 30 kg, 6-year-old spayed female Samoyed dog was referred with a history of intermittent weight-bearing lameness in her right hindlimb for 3 weeks. The patient hadsurgery to correct a medial patellar luxation in the same limb 3 years prior. Based on the physical examination and radiographic findings, MPL and CCLR of the right hindlimb were diagnosed. Pre-surgical arthroscopy examination was performed, revealing a complete rupture of the cranial cruciate ligament, medial caudal meniscal tears and fibrotic cartilagechanges on the trochlear groove. An arthroscopy-assisted partial meniscectomy was used to repair themedial caudal meniscus. To correct the tibial plateau angle and medial patellar luxation, a tibial plateau leveling osteotomy (TPLO) was performed. A tibial tuberosity transposition (TTT) was performed to realignthe quadriceps mechanism with the trochlear block recession followed by soft tissue reconstruction. The post-surgical recovery was uneventful, and the patient was weight-bearing with normal ambulation on the repaired limb. There were no complications, and the implants were well positioned at the last follow-up. The clinical outcome of the caseindicates that combining TPLO with TTTis a good surgical option for treatingconcurrent CCLR and MPL.

• 대한정형도수물리치료학회지
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• 제19권2호
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• pp.55-60
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• 2013

Background: The purpose of this study was to determine if there is a difference in activation of the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris when performing normal free squat with standinding position and free squat with $30^{\circ}$ flexed hip joint. Methods: Electromyograph surface electrodes were placed on the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris of 19 healthy college students. The participants performed standing bilateral squats and standing bilateral squats with $30^{\circ}$ flexed hip joint with EMG measures taken upon initiation of muscle activity as confirmed by an electronic goniometer. Participants completed one trial with the EMG time measurements on each type. Results: There was a significant difference between normal squats(standing squats) and normal squats with $30^{\circ}$ flexed hip joint. The normal squat exercise was statistically higer than normal squat exercise with $30^{\circ}$ flexed trunk except for semitendinosus and biceps femoris that shown slightly high. Conclusions: As a result of this study, there were increases of muscle activity in both ways. In particular, it may be more beneficial for knee joint stabilization to perform normal squat exercise with standing position relatively.

• 대한관절경학회지
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• 제4권2호
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• pp.128-133
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• 2000

목적 : 전방 십자 인대 재건술후 슬개-대퇴 관절의 문제중 슬개건의 길이 변화, 슬개-대퇴 관절의 선열의 변화 및 환자의 주관적 증상으로 비교 하였고 슬개건의 침습이 없는 동종 이식술과 슬개건을 침습한 자가 이식술을 비교하여 슬개건의 침습이 슬개-대퇴 관절에 미치는 영향을 분석하였다. 대상 및 방법 : 전방 십자 인대 재건술을 시행 받은 환자 중 1년 이상 추시 가능했던 환자 87명을 대상으로 하였으며 자가 골-슬개건-골을 이용해 재건술을 시행한 환자 52예를 제 1군, 동종 골-슬개건-골과 동종 아킬레스건을 이용해 재건술을 시행한 환자 35예를 제 2군으로 하였다. 수술 전, 후 단순 방사선 사진상에서 Blackburne-Peel 방법, 일치각(Congruence angle), 외측 슬개-대퇴 각(Lateral patellofemoral angle), 환자의 주관적 증상에 기초를 두어 결과를 판정하였다. 결과 : 시상면에서 슬개골 위치는 제 1군에서 술전 0.86에서 술후 0.80으로 유의할 만하게 감소하였으며, 제2군에서 술전 0.87에서 술후 0.83로 감소하였지만 통계적 유의성은 없었다. 외측 슬개-대퇴 각은 양군에서 유의할 만한 차이는 없었으며, 일치각은 제 1군에서 술전 $-1.43^{\circ}$에서 술후 $-5.43^{\circ}$로 $4^{\circ}$내측으로 전위되었고 제2군에서 술전 $-1.53^{\circ}$에서 술후 -3.65로 약 $2.12^{\circ}$내측으로 전위되었다. 결론 : 전방 십자 인대 재건술후 슬개-대퇴 관절의 선열은 변하며 이러한 변화는 자가 이식건의 채취, 십자 인대 재건술 자체, 대퇴 사두근 약화등 여러 가지 요소에 의한 것으로 사료된다.

• 재활복지공학회논문지
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• 제6권2호
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• pp.43-48
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• 2012

본 논문에서는 Electromyogram(EMG) 신호와 허벅지 각도 측정 장치, 발바닥 저항 센서를 이용하여 보행의 단계를 판단하는 방법을 제시한다. 신호의 측정을 위하여 건강한 성인 남성 5명을 대상으로 실험을 실시하였고 정상 보행에서의 EMG, 허벅지 각도, 발바닥 저항 센서를 통한 변화를 측정 하였다. EMG 신호의 획득을 위하여 실험자의 대퇴 사두근, 대퇴 이두근, 전경골근, 장딴지근에 Ag/AgCl 표면 전극을 부착하였으며, 양측 발뒤꿈치와 앞꿈치에 저항센서를 부착 하였다. 허벅지 각도 측정 장치는 굴곡 25도, 신전 20도 까지 범위를 가지며 이를 통하여 허벅지의 각도를 측정 하였다. 실험 결과 보행 시 입각기와 유각기를 명확히 판단 할 수 있었으며 세부적으로 8단계의 보행 상태를 판단 할 수 있었다.

• Physical Therapy Rehabilitation Science
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• 제8권1호
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• pp.45-51
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• 2019

Objective: The purpose of this study was to investigate the muscle activity ratio of the lower limb according to changes in straight leg raise (SLR) test angles on hamstring muscle shortening during squat exercises. Design: Randomized controlled trial. Methods: The subjects were 14 healthy adults who were informed of and agreed to the method and purpose of the study. The participants were classified into SLR groups according to two angles (over $80^{\circ}$ or under $80^{\circ}$) assessed using the SLR tests. After training and practicing the wall squat posture to be applied to the experiment, electromyography (EMG) was used to measure changes in muscle activity during the performance of a wall squat. After stretching, a sequence of pre-stretch tests were performed again, and the active and passive SLR tests were also reconducted; thereafter, a wall squat was performed again by attaching EMG electrodes. The EMG results before and after stretching were compared. Results: The muscle activity of the vastus lateralis oblique muscle increased in both groups. The muscle activity of the vastus medialis oblique muscle decreased in over both group. Rectus femorus activity increased in the under 80-degree groups but decreased in the over 80-degree group. The muscle activity of the biceps femoris muscle decreased after stretching in the over 80-degree group and increased in the under 80-degree group, and the semitendinosus muscle activity after stretching was decreased. The quadriceps-to-hamstring muscle (Q:H) ratio before and after stretching between groups showed that the hamstring muscle ratio decreased after stretching in both groups. Conclusions: The results of this study showed that the Q:H ratio before and after stretching between groups was not significantly different.

• 한국운동역학회지
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• 제17권2호
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• pp.113-121
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• 2007

The purpose of this study was to determine the effect of three different plates($0^{\circ}$, $10^{\circ$}, $20^{\circ}$)under heels on the lower limb muscles and erector spinae during squat exercise. Ten high school korean traditional wrestling players(age: $18.5{\pm}0.7$, weight: $1972.2{\pm}128.5N$, height: $177.8{\pm}6.0cm$, weight of barbell: $1004.5{\pm}132.4N$) performed squat exercise using three different tilting plates under heels at a cadence of 40beats/sec with 80% one repetition maximum load. Surface electrodes were placed on the participants' left and right erector spinae, and rectus femoris, vastus medialis, vastus lateralis, tibialis anterior, biceps femoris, medial gastrocnemius, and lateral gastrocnemius in the right lower extremity. One S-VHS camcorder(Panasonic AG456, 60fields/s) was placed 10m to the side of the participant. To synchronize the video and EMG data, a synchronization unit was used for this study. Average and Peak IEMG values were determined for each participant. For each variable, a one-way analysis of variance was used to determine whether there were significant differences among three different tilting plates under heels. When a significant difference was found in plates type, post hoc analyses were performed using the Tukey procedure. A confidence level of p<.05 was used to determine statistical significance. As a result of this study, maximum nEMG values of the tibialis anterior in $0^{\circ}$ plates was significantly higher than the corresponding values for the other plates during the knee extension. This increased activation in the tibialis anterior muscle indicates an increase in displacement of center of gravity of body. It is very likely that additional muscle activation are needed to stop the forward and backward movement. The results also showed that muscular activities of quadriceps femoris and erector spinae were decreased with increasing angle of plates. This suggests that increasing angle of plate may help to sustain the balance and posture of squat exercise. It is considered that very few significant differences were found among three different plates($0^{\circ}$, $10^{\circ}$, $20^{\circ}$) since elite players with much experience in squat exercise, were chosen as a participant of this study. In order to obtain meaningful results regarding the tilting angle of heel plates in squat exercise, kinetic and 3D kinematic analysis will be needed in the future study.

• 한국전문물리치료학회지
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• 제11권3호
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• pp.1-9
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• 2004

Most exercise for Patellofemoral pain syndrome (PFPS) has focused on selectively strengthening the vastus medialis oblique muscle (VMO). Although open chain knee extension exercises are effective for increasing overall quadriceps strength, they are not always indicated for PFPS rehabilitation. This study was designed to identify the effect of combined posture of lower extremity on Electromyographic (EMG) activity of the vastus lateralis muscle (VL) and VMO during static squat exercises. The subjects were twenty young adult males who had not experienced any knee injury and their Q-angle was within a normal range. They were asked to perform static squat exercises in five various postures using their lower extremities. The EMG activity of the VL and VMO were recorded in five exercises by surface electrodes and normalized by %MVC values derived from seated, isometric knee extensions. The normalized EMG activity levels (%MVC) of the VL and VMO for the five postures of the lower extremities were compared using one way ANOVA with repeated measures. Results of repeated measures of ANOVA's revealed that exercise 3 and exercise 5 produced significantly greater EMG activity of VMO/VL ratios than exercise 1 (p<.05). When the static squat exercise was combined with hip adduction and toes pointed outwardly, the EMG activity of VMO/VL rates was increased. The EMG activity of VMO/VL ratio was highest during static squat exercises performed on a decline squat. These results haveimportant implications for progressive and selective VMO muscle strengthening exercises in PFPS patients.

• 한국운동역학회지
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• 제15권1호
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• pp.197-206
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• 2005

The purpose of this study was to quantify the maximum EMG levels and determine if there are differences in these EMG levels with respect to different knee flexion angles. Eight university students with no known musculoskeletal disorders were recruited as the participants. The maximum voluntary isometric knee extensions and flexions were taken from each participant sat on the isokinetic exercise machine (Cybex 340) at five different knee flexion angles ($10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$, $90^{\circ}$) After surface electrodes were attached to rectus femoris, vastus medialis, vastus laterlis, biceps femoris, and semitendinosus, maximum EMG levels at five different knee flexion angles were measured. The results showed that there was no significant difference in maximum EMG levels among five different knee flexion angles. Although there was no significant difference in EMG levels and were some variations among different knee flexion angles, the EMG signals of quadriceps in extension and biceps femoris in flexion were the greatest at $30^{\circ}$. It seems that different joint angles or relative locations of body segments might affect the magnitude of EMG levels. Because the maximum EMG levels could change with a different knee flexion angle, an attempt should be made to more accurately measure these values. If then, %MVIC measure provides more reliable data and is most appropriate for EMG normalization.

• 한국전문물리치료학회지
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• 제23권4호
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• pp.9-15
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• 2016

Background: Squatting is one of the best functional exercises to strengthen the quadriceps muscle in independent gait and activities of daily living. Although the use of a gym ball during squat exercise is the most common way of strengthening the vastus medialis oblique (VMO) muscle, published data on this subject are limited. Objects: The purpose of this study was to compare the sequential muscle activation of the VMO and vastus lateralis (VL) muscles during squat exercise using a gym ball at different knee flexion angles. Methods: Forty healthy adults were randomly divided into experimental (squat exercise using a gym ball) and control (squat exercise alone) groups, in which squats were performed at $45^{\circ}$ and $90^{\circ}$ knee flexion. Electromyographic (EMG) activity data were collected over 10 seconds under the 2 angles of knee flexion ($45^{\circ}$ and $90^{\circ}$). Results: There was significant group and time interaction effect for VMO and VL muscle activation at $45^{\circ}$ knee flexion. This was similarly demonstrated at $90^{\circ}$ knee flexion. No significant group main effect and time main effect for VMO and VL muscle activation were noted at $45^{\circ}$ knee flexion, respectively. In contrast, there was significant group main effect and time main effect for VMO and VL muscle activation at $90^{\circ}$ knee flexion. These significant differences were demonstrated through two-way analysis of variance over repeated measurements, suggesting that the EMG activity of the VMO muscle during squatting with a gym ball showed remarkable improvement compared to that of the VL muscle. Conclusion: This research suggests that squat exercise using a gym ball may be more beneficial in improving the activity of VMO than of the VL muscle at both $45^{\circ}$ and $90^{\circ}$ of knee flexion, respectively. We highly recommend squat exercises with a gym ball for selective strengthening of the VMO muscle in knee rehabilitation.