• 대한정형도수물리치료학회지
• /
• 제26권1호
• /
• pp.47-54
• /
• 2020

Background: This study examined the changes in the leg muscle activities of 30 healthy subjects according to different pressures caused by isometric hip adduction during squat exercise. Methods: With their knee flexed at 60°, the subjects performed isometric hip adduction with a pressure of 0, 20, 40, and 60mmHg. Surface electromyography was used to measure their muscle activities. Changes in the activities of the muscles, such as the gluteus maximus (GMAX), Gluteus medius (GM), vastus medialis oblique (VMO), vastus lateralis oblique (VLO), biceps femoris (BF), and Tensor fasciae latae (TFL) muscles, were analyzed. Results: The activities of the VMO, VLO, GM, BF, and GMAX muscles were significantly different after exercise compared to that before exercise (p<.05). The activities of all the leg muscles measured were highest at a pressure of 60mmHg during isometric hip joint adduction. Conclusion: The pressure produced by isometric hip joint adduction during squat exercise increased the leg muscle activities of the subjects. These results will provide basic data on effective squat exercise to alleviate knee joint diseases.

• PNF and Movement
• /
• 제15권2호
• /
• pp.177-183
• /
• 2017

Purpose: This study compared and analyzed the effect of the proprioceptive neuromuscular facilitation (PNF) arm extension pattern and leg flexion pattern on the contralateral lower extremity muscles when the patterns were applied to the same subject. Methods: In the study, 35 healthy men and women who understood the PNF patterns were selected as participants. The participants completed the PNF arm extension-abduction-internal rotation pattern and leg flexion-adduction-external rotation with knee flexion pattern in the supine position. While the patients' completed each pattern, the contralateral leg muscle activity was measured to examine the irradiation effect. The maximum isometric contraction time of the muscles to be measured was kept for 5 seconds, and the mean value was obtained by repeating the pattern three times. Results: When the leg flexion-adduction-external rotation with knee flexion pattern was completed, the muscle activity in the vastus lateralis, vastus medialis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity was significantly greater than that found in the PNF arm extension-abduction-internal rotation pattern. Conclusion: The PNF leg flexion pattern showed greater muscle activity on the contralateral lower extremity than the arm extension pattern. Thus, the PNF leg extension pattern is more effective in the activation of the muscles associated with weight-bearing activity.

• 한국응용과학기술학회지
• /
• 제36권3호
• /
• pp.1028-1040
• /
• 2019

본 연구는 내리막 달리기(downhill running, DR) 후 초음파 영상분석을 이용해 대퇴사두근 무리(quadriceps group, QG) 내 근손상의 국소화 여부를 검증하고, DR 동안 운동 강도가 운동유발성 근손상(exercise-induced muscle damage, EIMD) 및 근육 반향세기 변화에 미치는 영향을 규명하려는 목적으로 수행되었다. 규칙적인 신체활동이 없는 건강한 남성 11명이 무작위 교차설계에 따라 서로 다른 강도[low-intensity DR session($50%HR_{max}$), LDR; high-intensity DR session($70%HR_{max}$), HDR]의 DR 운동을 수행하였다. DR 후 EIMD의 심각성은 혈청크레아틴 키나아제(creatine kinase, CK) 활성 수준 변화와 함께 신경근 기능 지수로서 무릎 신전근의 최대 수의적 등척성 수축(maximal voluntary isometric contraction, MVIC) 및 관절가동범위(range of motion, ROM) 변화를 통해 결정되었다. 회색조 분석을 적용한 근육 반향세기 평가는 DR에 따른 QG 내 국소 근육별(rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; vastus intermedius, VI) 손상 양상을 탐지하기 위해 활용되었다. 모든 세션에서 혈청 CK 활성 수준과 VL 및 VM의 근통증 정도는 운동 후 24시간째(RF의 경우 각각 LDR 24시간째와 HDR 48시간째) 최대에 이르렀으며, 혈청 CK 수준에서 운동 강도에 따른 유의한 차이(p<.05)가 나타난 반면 근통증에서 세션 간 통계적 차이는 없었다. 무릎 관절을 이용한 MVIC 및 ROM과 같은 신경근 기능 지표 및 VM을 제외한 모든 QG 근육 반향세기는 운동 직후 극적으로 감소 또는 증가 후 72시간까지 점진적 회복 양상을 나타내었다. 그러나 신경근 기능 지표에서 운동 강도에 따른 통계적 차이는 없었으나 RF 및 VL 반향세기에서 세션 내 및 세션 간 유의한 차이(p<.01)를 나타내었다. 본 연구의 결과로 ECC를 함유한 DR 운동 시 운동 강도는 DOMS 및 신경근 기능 지표에 부분적으로 영향을 미칠 가능성이 있으며, 특히 혈청 CK 수준과 함께 RF 및 VL의 근육 반향세기는 운동 강도의 영향을 직접적으로 반영한다는 사실을 알 수 있다. 또한, 현재 연구결과는 DR 동안 ECC를 겪는 QG 내 국소 근육 간 근손상 정도가 다를 수 있으며 초음파 근육 반향세기가 국소 근육의 EIMD 심각성을 차별화할 수 있는 유용한 평가기법임을 뒷받침하고 있다.

• The Journal of Korean Physical Therapy
• /
• 제28권3호
• /
• pp.212-216
• /
• 2016

Purpose: The current study seeks to identify the relationship between torque values of the quadriceps and muscle activity during isometric and isokinetic exercises. Methods: The subjects of the study included 29 healthy individuals 17 men and 12 women) who took part in isometric and isokinetic exercises that utilized the quadriceps. The isometric exercises were performed three times each at 4 different angles (0, 30, 60, and 90 degrees). For the isokinetic exercises, concentric contraction and eccentric contraction were undertaken three times each at two angular velocities (30 and 60 degrees). Results: The muscle activity of the quadriceps during the isometric exercises showed significant differences at the 30, 60, and 90 degree angles. During the concentric contractions and eccentric contractions, muscle activity at the peak torque of the quadriceps indicated significant differences in vastus medialis, vastus lateralis, and rectus femoris at angular velocities of 30 and 60 degrees. Conclusion: When applied clinically based on the biomechanical analysis of the current study, it is possible to anticipate and selectively strengthen muscles with isometric and isokinetic exercises for not only healthy adults and professional athletes, but also for those who experience limited knee movement for long periods following knee surgeries.

• 한국전문물리치료학회지
• /
• 제26권1호
• /
• pp.75-83
• /
• 2019

Background: A tight iliotibial band (ITB) may lead to lateral patellar maltracking, compression, and tilt, and dominant vatus lateralis (VL) muscle activation relative to vastus medialis oblique (VMO) can laterally displace the patella, which leads to anterior knee pain. Therefore, an effective management technique is needed to stabilize the patella in individuals with tight ITB. Increased stability during the modified Thomas test has the potential to decrease compensatory motion and thus to selectively stretch the ITB. Objects: The purpose of this study was to determine the effects of ITB stretching in the modified Thomas test position on ITB flexibility, patellar translation, and muscle activities of the VMO and VL during quadreceps-setting (QS) exercise in individuals with tight ITB. Methods: Twenty-one subjects with tight ITB were recruited. Digital inclinometer was used to measure the hip adduction angle during the modified Ober test. Universal goniometer was used to measure the hip abduction angle during the modified Thomas test. Ultrasonography was used to measure the patella-condylar distance. Electromyography was performed to collect data of muscle activities. Paired t-test was used to determine the statistical significance between pretest and posttest. Results: The range of hip adduction in modified Ober test increased (p=.04) and the range of hip abduction in the modified Thomas test decreased after ITB stretching (p<.01). There was no difference between lateral patellar translation (p=.18). VMO muscle activity significantly increased after ITB stretching during QS (p<.01). VL muscle activity had no difference after stretching. Conclusion: The ITB stretching in the modified Thomas test position can be suggested as a management method for improving ITB flexibility and VMO muscle activity in individuals with tight ITB.

• 대한의용생체공학회:의공학회지
• /
• 제10권2호
• /
• pp.109-111
• /
• 1989

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients.

• 감성과학
• /
• 제13권1호
• /
• pp.207-214
• /
• 2010

본 연구에서는 근전도 신호를 활용하여 정상인의 보행과 관련된 상지와 하지 근육의 신호를 확인하고 저항센서를 이용하여 정상적인 보행 패턴을 확인하였다. 대학생 15명을 대상으로 정지해 있을 때와 평지를 보행할 때, 상지의 4부위(대흉근과 승모근)와 하지의 10부위(대퇴직근, 대퇴이두근, 내측광근, 외측광근, 반막양근, 반건양근, 가자미근, 장비골근, 내비복근과 외비복근)에 전극을 부착하여 근전도를 측정하였다. 저항센서는 양측 발바닥의 8부위에 센서를 부착하여 보행시 발에 가해지는 압력을 측정하였다. 그 결과, 근전도 신호는 정지상태에 비하여 보행 시에 허벅지의 외측광근과 반건양근을 제외하고 모든 근육에서 유의하게 높은 진폭을 가졌다. 또한 보행주기의 두 단계인 입각기와 유각기와 관련된 근육을 확인하였다. 저항 센서의 신호 분석 결과, 평균 보폭 주기 동안 크게 입각기와 유각기의 두 주기와 세부적으로 여덟 단계 - 초기 접지기, 하중 반응기, 중간 입각기, 말기 입각기, 전 유각기, 초기 유각기, 중간 유각기, 말기 유각기 - 의 보행 주기를 확인할 수 있었다.

• The Journal of Korean Physical Therapy
• /
• 제32권5호
• /
• pp.273-276
• /
• 2020

Purpose: The purpose of this study was to investigate the effects of the resistance conditions on the electromyography (EMG) activity ratio of vastus medialis oblique (VMO) and vastus lateralis (VL) muscle during partial lunge exercise in healthy subjects in order to suggest the basic data of exercise intervention for such as patients with patellofemoral pain syndrome (PFPS). Methods: The participants of this study were healthy twenty two people with no knee pain, limitation of motion and past history of operation at lower extremity. The participants performed three types of lunge 1) no resistance, 2) anterolateral 45° resistance and 3) lateral 90° respectively. The EMG activity of the VMO and VL were recorded by surface EMG and the measured data normalized by the %MVIC value was analyzed by repeated measured ANOVA. Results: The results showed that the VMO/VL EMG activity ratio during lunge with anterolateral 45° resistance was significantly higher than with no resistance and lateral 90° resistance (p<0.05). There was no significant difference in VMO, VL, and VMO/VL muscle activity between male and female subjects (p>0.05). Conclusion: This study suggests that partial lunge exercise with anterolateral 45° resistance can increase the VMO/VL muscle activity in healthy subjects. This result could be used as basic data to develop therapeutic exercise programs such as PFPS patients.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1492-1495
• /
• 2008

As a prerequisite of developing muscle biofeedback system which can simulate analogous isokinetic exercise, the purpose of this study was to study the effects of frequency and amplitude of whole-body vibration on the difference in sEMG on lower extremities during leg press exercise with/without vibration. The amplitude of vibration was set to 20, 50, 80 and the frequency of vibration was set to 10, 20, 30, and 50 Hz. EMG were measured at Vastus lateralis muscle and Vastus medialis muscle. MP100 EMG module(BIOPAC system Inc., USA) was used for EMG measurement. The result showed that the combination of frequency of 30Hz and amplitude of 50 had more activated EMG than other combination with relatively small work load (30kg). It is necessary to experiment the frequency between 20 and 40Hz in detail, and to normalize sEMG using maximal voluntary contraction (MVC).

• 대한물리의학회지
• /
• 제16권1호
• /
• pp.41-48
• /
• 2021

PURPOSE: The purpose of this study was to provide fundamental clinical data to be used in therapeutic approach to patients with patellofemoral pain syndrome by administrating the squat exercise combined with whole body vibration exercise to them and investigating the effect of such exercise to leg muscle activity and muscle fatigue. METHODS: The patients with patellofemoral pain syndrome were randomly assigned to experimental group I (n = 9) where only squat exercise was administered and experimental group II (n = 9) where the squat exercise combined with whole body vibration exercise was provided. The intervention program was administered for two weeks, four days a week, one session a day, three set a session, and 20 reps a set. The pre- and post-test were performed to measure muscle activity and muscle fatigue of vastus medialis and vastus lateralis. RESULTS: The muscle activity significantly changed in both group (p < .05, p < .01, respectively) and the muscle fatigue showed significant change only in group I (p < .05). In addition, there was significant difference between groups in change of muscle fatigue of both muscles (p < .05) but not in change of muscle activity. CONCLUSION: The results showed that both exercise are effective in improving muscle activity, however, that the squat exercise combined with whole body vibration exercise is more effective in preventing muscle fatigue.