• 한국융합학회논문지
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• 제9권10호
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• pp.371-376
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• 2018

본 연구는 전신진동 자극시 스쿼트의 형태에 따른 하지근육의 근활성 효과의 차이를 분석함으로써 전신진동운동의 효과를 규명하고 효율적인 운동을 위한 과학적 근거를 제시하는데 그 목적이 있다. 본 연구는 정형외과적 질환이 없는 건강한 20대 남성 10명을 대상으로 똑바로 선자세, 슬관절을 90도, 120도 굴곡시킨 일반적인 스쿼트 자세와 뒷꿈치를 들어 올린 혼합 스쿼트 자세의 진동자극 시 근활성도를 측정하였다. 근활성도는 외측비복근, 전경골근, 외측광근, 대퇴이두근에 근전도 전극을 부착한 후 RMS를 구하여 비교하였으며 진동 자극의 강도는 각 자세에서 볼륨 50, 80, 주파수 10, 25, 40Hz를 혼합하여 적용하였다. 분석 결과 외측비복근과 전경골근 외측광근에서 자세별 근활성도의 차이가 나타났고 뒷꿈치를 들어올린 자세에서 근활성 효과가 높음을 확인할 수 있었다. 이와 같은 결과는 전신진동 자극 시 스쿼트 자세와 강도에 따라 근활성 효과에 차이가 있으며, 운동의 효율을 극대화하기 위하여 목표 근육에 따라 다양한 자세와 강도가 적용되어야 함을 의미한다.

• The Journal of Korean Physical Therapy
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• 제31권2호
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• pp.129-133
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• 2019

Purpose: This study aimed to investigate effect of ankle instability on peripheral muscle activation among female ballet dancers to provide information on the development of prevention programs for ankle injury rehabilitation. Methods: 32 female ballet dancers were randomly divided into two groups: experience ankle sprain group (n=16, age, $20.7{\pm}0.8years$, BMI $18.6{\pm}1.2kg/m2$) and non-experience ankle sprain group (n=16, $age=21.0{\pm}0.8years$, BMI $19.6{\pm}2.0kg/m2$). Activation of the peroneus longus, tibialis anterior muscle, and gastrocnemius during vertical landing, half pointe, and gait between the two groups were measured. Body composition analyzer was used to examine skeletal muscle mass and body fat mass. Results: A total of 32 patients were included. In the experience ankle sprain group (n=16: left sprain 14, right sprain 2), average ankle sprain injury occurred 7.5 months before the study. The average age of the dancers in the experience ankle sprain group and non-experience ankle sprain group was $20.7{\pm}0.8$ and $21.0{\pm}0.8years$, major period was $64.5{\pm}23.8$ and $71.6{\pm}25.8months$, BMI was $18.6{\pm}1.2$ and $19.5{\pm}2.0kg/m2$, respectively. No significant differences were found on body composition between the two groups (p>0.05). The experience ankle sprain group showed significantly lower tibialis anterior and peroneus longus muscle activation (p<0.5), while gastrocnemius muscle activation appeared to be significantly higher (p<0.05) during landing, half pointe, and normal gait. Conclusion: Ankle sprain can cause a decline in peripheral muscle activation and coordination, which increased the risk for repetitive ankle sprain in the future. Moreover, ankle peripheral muscle selective strength training, coordination program development, and application need to be considered to prevent ankle sprain.

• The Journal of Korean Physical Therapy
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• 제35권6호
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• pp.167-176
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• 2023

Purpose: Due to the high incidence of shoulder injuries, including shoulder impingement syndrome (SIS), among CrossFit practitioners due to frequent overhead movements, serratus anterior exercises are considered crucial for scapular stabilization in both intervention and prevention. Objective: The objective of this study is to compare the muscle activity and ratios of scapular stabilizing and shoulder girdle muscles between individuals with and without SIS during serratus punch and wall slide exercises, both targeting the serratus anterior muscle, in CrossFit training practitioners. Methods: Surface electromyography was used to compare the muscle activity and activity ratio of scapular stabilizing muscles and shoulder muscles during serratus punch and wall slide exercises in two groups of 20 CrossFit practitioners: ten with SIS and ten without symptoms. Results: The group with SIS showed higher activation of the pectoralis major, upper trapezius, and a higher pectoralis major/serratus anterior and upper trapezius/serratus anterior muscle activation ratio during the serratus punch exercise compared to the group without SIS. Similarly, during the wall slide exercise, the group with SIS exhibited higher activation of the upper trapezius and a higher upper trapezius/serratus anterior muscle activation ratio compared to the group without SIS. However, no significant difference in serratus anterior muscle activation was observed between the two groups. Conclusions: This study highlights the higher activation of the pectoralis major and upper trapezius muscles in CrossFit practitioners with SIS during the serratus anterior exercise, suggesting the importance of minimizing the overactivation of these muscles to prevent impingement syndrome in this population.

• 정형스포츠물리치료학회지
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• 제14권2호
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• pp.55-64
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• 2018

Purpose : The purpose of this study was to investigate the effect of the sprinter and skater combined patterns on muscle contraction onset time and muscle activation of body stabilizing muscles. Method : Our study included young and healthy men in their 20s. The participants used the sprinter and skater combined patterns of the proprioceptive neuromuscular facilitation (PNF) methods to measure muscle activation and muscle contraction onset time of the trunk muscles. To measure muscle contraction onset time and muscle activation, electrodes were attached to the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinalis (ES) regions. Significant differences were identified using a paired t-test and a one-way analysis of variance (ANOVA) analysis. Result : In the sprinter combined pattern, the muscle with the fastest onset time of contraction was the RES, and that with the slowest was the RRA (p<.001). In the skater combined pattern, the muscle with the fastest onset time of contraction was the LES, and that with the slowest was the LRA (p<.001). In the sprinter combined pattern, the REO and LIO presented medium muscle contraction onset times (p<.001). In the skater combined pattern, the LEO and RIO presented medium muscle contraction onset times (p<.001). Conclusions: Based on these results, these patterns could be used as exercise methods for the elderly with delayed proactive response speeds of the body stabilization methods due to imbalances in body stabilizing muscles or limbs movement.

• 대한의생명과학회지
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• 제17권4호
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• pp.273-281
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• 2011

Our previous study demonstrated that the Korean traditional medicine Gyeongshingangjeehwan (GGEx) inhibits obesity and insulin resistance in obese type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. We investigated whether GGEx may affect AMP-activated protein kinase ${\alpha}$ ($AMPK{\alpha}$) since $AMPK{\alpha}$ activation is known to stimulate fatty acid oxidation in skeletal muscle of obese rodents. After OLETF rats were treated with GGEx, we studied the effects of GGEx on $AMPK{\alpha}$ and acetyl-CoA carboxylase (ACC) phosphorylation, and the expression of $AMPK{\alpha}$, $PPAR{\alpha}$, and $PPAR{\alpha}$ target genes. The effects of GGEx on mRNA expression of the above genes were also measured in C2C12 skeletal muscle cells. Administration of GGEx to OLETF rats for 8 weeks increased phosphorylation of $AMPK{\alpha}$ and ACC in skeletal muscle. GGEx also elevated skeletal muscle mRNA levels of $AMPK{\alpha}1$ and $AMPK{\alpha}2$ as well as $PPAR{\alpha}$ and its target genes. Consistent with the in vivo data, similar activation of genes was observed in GGEx-treated C2C12 cells. These results suggest that GGEx stimulates skeletal muscle $AMPK{\alpha}$ and $PPAR{\alpha}$ activation, leading to alleviation of obesity and related disorders.

• The Journal of Korean Physical Therapy
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• 제23권5호
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• pp.1-5
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• 2011

Purpose: This study was designed to investigate the changes of postural sway and muscle activation while standing upright and performing a dual task. Methods: Nine healthy adults were recruited and provided their written informed consent. They performed a balance task with and without a cognitive task on a force flatform (Good balance, Metitur Ltd., Filand). Postural sway was measured as medio-lateral and anterior-posterior distance and the velocity of the center of pressure and muscle activations of the ankle dorsi- and plantar-muscle was measured. The recruits completed three trials and the data was analyzed by a paired t-test. Results: There were significant differences in the medio-lateral and anterior-posterior distance and the velocity of the center of pressure, and significant increases in the muscle activities of the tibialis anterior. Conclusion: These findings revealed that performing a dual task increases postural sway and muscle activation of the ankle when simultaneously maintaining balance and performing another cognitive task. Future studies should focus on balance training with a dual task for patients.

• 대한전기학회논문지:전력기술부문A
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• 제48권8호
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• pp.1046-1053
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• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• 대한물리의학회지
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• 제8권4호
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• pp.647-653
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• 2013

PURPOSE: The purpose of this study was to compare the lower extremities muscle activation between squatting exercise with gym ball and wall for improving muscle strengthening in lower extremities. METHODS: Participants were 21 university students (males 10, females 11) who didn't have any problem with orthopedic surgery. Participants performed squatting exercise with gym ball and wall. Squatting exercise with gym ball were performed using by gym ball behind back, and the gym ball were fixed in back and wall. We asked participants to push back the gym ball slightly to prevent fall of ball. Wall squatting exercise, we ask participants to contact their back in wall slightly in order to prevent trunk flexion during performed squatting exercise. Each squatting exercise had performed until knee joint were flexed at 60 degree, and maintained five seconds. We collected data from E.M.G of Biceps femoris, Gastrocnemius, Vastus medialis and lateralis, Tibialis anterior of lower extremity in isometric phase of knee joint angle 60 degree of each squatting exercise. We analysed data using by ANOVA and independent t-test of SPSS PC ver.20.0 in order to compare the muscle activation between squatting exercise with gym ball and wall. RESULT: All of lower extremities muscle activation showed more higher value in squatting exercise with gym ball than squatting exercise with wall, especially there was significantly difference of muscle activation in vastus medialis, tibialis anterior between squatting exercise with gymball and with wall. CONCLUSION: On comprehensively considering the results of the present study, we suggested that squatting exercise with gym ball was more effective method improving lower extremity muscle strengthening.

• The Journal of Korean Physical Therapy
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• 제21권3호
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• pp.47-52
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• 2009

Purpose: To examine the correlation between the gait speed and muscle activation or foot pressure in stroke patients. Methods: Twenty five functionally ambulant stroke patients (male/female: 15/10, mean age: $57.65\pm2.30$) were enrolled in this study. The patients were asked to walk on a plate at a self-selected and comfortable speed. Three walking trials were obtained and then averaged for data analysis. The gait speed and foot pressure were measured from a RS-Scan system. Activation of the quadriceps femoris muscle and biceps hamstring muscle (%RVC) were recorded using ProComp $Infiniti^{TM}$. Results: There was a significant positive correlation between Hamstring muscle activation (%RVC) and gait speed. The gait speed correlated with the foot pressure of the lateral metatarsal zone (M3-5) in the affected side. There was a correlation between the gait speed and the foot pressure of the lateral metatarsal (M3-5) and heel (medial, lateral) zone in the less-affected side. Conclusion: The gait speed is related to hamstring muscle activation and the characteristics of foot pressure. This information was observed in both the affected and less-affected sides, suggesting that rehabilitation programs should be implemented on both sides.

• The Journal of Korean Physical Therapy
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• 제27권4호
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• pp.264-269
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• 2015

Purpose: The objective of this study was to determine the effects of game based weight-bearing training (GBWBT) on lower extremity muscle activation and balance in stroke patients. Methods: Thirty subjects were randomly divided into two groups: experimental group I (n=15) and control group II (n=15). Each group was provided intervention under two conditions, as follows: in the Game based weight-bearing training (group I), 30 minutes per day, five times per week, with physical therapy for 30 minutes, and in the functional weight-bearing training (group II), 30 minutes per day, five times per week, with physical therapy for 30 minutes The training program was conducted for a period of eight weeks. Subjects were measured on lower extremity muscle (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) by electromyography and balance by Biorescue. ANCOVA was performed for comparison of lower extremity muscle activation and balance between different intervention methods. All patients were evaluated at baseline and at the end of the treatment protocol. Statistical significance was tested between the patients before and after treatment by t-test. Results: Significant difference in lower extremity muscle activation was observed in experimental group I compared with control group II (p<0.05). Significant difference in balance was observed in experimental group I compared with control group II (p<0.001). Conclusion: Findings of this study suggest that game based weight-bearing training may have a beneficial effect on improvement of lower extremity muscle activation and balance in stroke patients.