• The Journal of Korean Physical Therapy
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• 제28권3호
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• pp.205-211
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• 2016

Purpose: This study investigated the influence of muscle activity of the trunk and lower limb during a bridge exercise using a unstable surface and during one-legged bridge hip abduction in healthy adults. Methods: Nineteen healthy participated in this study (12 males and 7 females, aged $29.0{\pm}5.0$). The participants were instructed to perform the bridge exercises under six different conditions. Trunk and lower limb muscle activation, such as the erector spinae (ES), gluteus maximus (GM), external oblique (EO), and internal oblique (IO), was measured using surface electromyography. The six different bridge exercise conditions were conducted randomly. Data analysis was performed by using the mean scores after three trials of each condition. Results: On the ipsilateral side, muscle activity of the IO, EO, and ES during the hip abduction condition (Single-legged hip abduction bridge, Bridge with use of a ball and single-leg hip abduction, Bridge with use of a sling and single-leg hip abduction) was significantly higher than those during Unstable surface (Bridge with use of a ball, Bridge with use of a sling) and General bridging exercise (p<0.05). In the contralateral side, activities of the GM and EO during Single-legged hip abduction bridge, Bridge with use of a ball and single-leg hip abduction and Bridge with use of a sling and single-leg hip abduction was significantly higher than that during Bridge with use of a ball, Bridge with use of a sling and General bridging exercise (p<0.05). Conclusion: This study demonstrated that performing a bridge exercise with use of a sling and single-leg hip abduction had an effect on trunk and gluteal muscle activation. The findings of this study suggest that this training method can be clinically effective for unilateral training and for patients with hemiplegia.

• 대한통합의학회지
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• 제7권1호
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• pp.19-26
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• 2019

Purpose : The aim of this study was to investigate the effects of the abdominal draw-in (ADI) exercise on the onset times of the gluteus maximus (GM) and erector spinae (ES) as well as the pelvic anterior tilt angle during prone hip extension (PHE). Methods : A total of 24 female adults were divided into two groups: those with normal abdominal muscles (n=12) and those with weak abdominal muscles (WAM; n=12). Before the intervention, the onset times of the GM and ES along with the pelvic angle during PHE were measured. Subsequently, the participants conducted the ADI exercise for 10 minutes. After conducting the ADI exercise, the onset times and the pelvic angle were re-measured. Results : In the pre-intervention comparison between the two groups, the WAM group showed faster ES onset times and higher pelvic angle than the normal group (p<0.05). In the WAM group, the ES onset times were significantly delayed after the ADI exercise (p<0.05). In both groups, the pelvic angle was significantly decreased after the ADI exercise (p<0.05). The decrease in the pelvic angle was significantly greater in the WAM group than in the normal group (p<0.05). The GM onset time was found to be not significant in all comparisons (p>0.05). Conclusion : Therefore, it can be concluded that after performing the ADI exercise, the pelvic anterior tilt during PHE is decreased in normal women and those with WAM, especially in the WAM group, suggesting that the ADI exercise can reduce the compensatory pelvic anterior tilt more effectively by delaying the ES onset times.

• 대한물리의학회지
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• 제13권4호
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• pp.123-129
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• 2018

PURPOSE: This study was conducted to investigate the influence of hip abduction angle on the muscle activity of the Gluteus Maximus (GM), Biceps Femoris (BF) and Tensor Fascia Lata (TFL) during Knee Flexed Prone Hip Extension exercise. METHODS: The subjects of this study were 42 healthy individuals. All participant consented to participate in this study. Subjects performed exercise, using the Knee Flexed Prone Hip Extension exercise in three hip abduction position $0^{\circ}$, $15^{\circ}$ and $30^{\circ}$. Subjects rested two minutes, between changing hip abduction position. Data were analyzed using a Noraxon MR-XP 1.08 Master Edition EMG to determine average amplitude, for each angle and muscle. All data were processed by Multivariate analysis of variance (MANOVA). There were a total of three groups. the GM muscle, BF muscle, TFL muscle. RESULTS: GM muscle activity was greatest in the $30^{\circ}$ hip abduction position (p<.05), followed by $0^{\circ}$. Between $0^{\circ}$ and $30^{\circ}$ has significant difference in muscle activity. However, the BF and TFL amplitude were greatest at $0^{\circ}$ hip abduction position followed by $30^{\circ}$. Moreover, the TFL differed significantly between $0^{\circ}$ and $30^{\circ}$, but, BF did not (p<.05). CONCLUSION: Hip abduction at $30^{\circ}$ was found to be the most appropriate position for GM muscle activity.

• 대한정형도수물리치료학회지
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• 제27권2호
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• pp.27-36
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• 2021

Background : Prone hip extension (PHE) is commonly used for exercises and tests in patients with low back pain. Previous studies have shown that pelvic compression belts (PCB) and non-elastic taping (NET) contribute greatly to improvements in lumbopelvic stability. This study aimed to compare the effect of two lumbopelvic stability methods such as PCB and NET on the trunk and hip extensor muscle activities during PHE tests. Methods: Subjects who experienced low back pain (low back pain group, LBPG; n=20) and those who did not experience low back pain (non-LBPG; n=20) participated in this study. The subjects were instructed to perform PHE with and without a PCB and NET. PHE tests were performed in the condition wherein the two stabilization methods were applied, and the actions of the muscles at that time were measured using surface electromyography (EMG). EMG data were collected from the hamstring, gluteus maximus, erector spine (ES), and multifidus (MF) muscles. The data were collected three times for 5 s with a 1-min rest between each of the three sets. Results: In the LBPG, EMG of the ES muscle was significantly reduced when NET or a PCB was applied (p<.05). There was no difference in the change in the ES muscle activity when NET and a PCB were applied. The ratio of MF/ES muscleactivity showed a significant increase in the LBPG with NET (p<.05). Conclusion: Both NET and PCB applied to subjects who experienced low back pain significantly reduced the ES muscle activity during PHE exercises and helped control the balance of the superficial and deep trunk extensor muscles.

• PNF and Movement
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• 제10권1호
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• pp.61-70
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• 2012

Purpose : The purpose of this study was to investigate thigh muscle-bone CSA and leg strength during low-intensity exercise program with leg blood flow restriction by external compression to reduce muscle outflow. Methods : Eighteen health students gave informed written consent to participate in this investigation. An occlusion cuff was attached to the proximal end of the leg so that blood flow was reduced during the training. The training was conducted one times a day, three times a week, for 8 weeks using one sets of 30 minutes. The training program performed to squat with standing, lunge with standing and heel raise with one leg standing. Measurements of thigh muscle-bone CSA(cross-sectional area) and leg strength were evaluated pre and post-training. Statistical evaluation of these data was accomplished utilizing a paired t-test by SPSS 12.0 program for windows. Significance level was set at p <.05. Results : All data are reported as means and standard deviations(SD) for all variables. The result of the study is followed; After the training, muscle-bone CSA, gluteus maximus m, quadriceps m, hamstring m of both legs were significantly improved but not calf muscle(p<.05). There was no significant difference of change quantity between muscle-bone CSA and leg strength in Lt. and Rt. side. But the variation in leg muscle strength of Rt. leg(dominant) was much more increased than Lt. leg(non-dominant) after 8 weeks training. Conclusion : Low-intensity training with leg blood flow restriction offers a potentially useful method for improving leg muscle strength.

• 한국운동역학회지
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• 제30권4호
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• pp.285-291
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• 2020

Objective: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Method: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Results: In vastus lateralis muscle Activation, Type 55 were significantly higher for Type 50 and X (p=0.019, p=0.045). In Gluteus Maximus muscle activation, Type 55 was significantly lower for type 50 (p=0.005). In loading late, Type 55 and X were significantly higher for type 45 (p=0.008, p=0.006). Conclusion: The components of a shoe are very complex, and there can be many differences in manufacturing as well. Although some differences can be found in the biomechanical variables of the high elastic midsole, it is difficult to interpret the performance enhancement and injury prevention.

• 한국운동역학회지
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• 제32권2호
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• pp.43-48
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• 2022

Objective: The purpose of this study was to verify the effectiveness among simulating ski jumping trainings by comparing with actual ski jump. Method: Three healthy youth national athletes were recruited for this study (age: 13.70 ± 0.9 yrs, height: 169.30 ± 0.9 cm, jumping caree: 5.3 ± 0.9 yrs). Participants were asked to performed ski jumping with 3 simulating and one actual situation. A 3-dimensional motion analysis with 5 channels of EMG was performed in this study. Muscle activations of Rectus Femoris [RF], Tibialis Anterior [TA], Thoracis [TH], Gluteus maximus [GM], and Gastronemius [GL] were achieved with sampling rate of 2,000 Hz during each jump. Results: In the case of S1 in the actual jumping motion, the deviation of the muscle activity peak did not appear each trial, and the jump timing was consistent. For S2, the timing of the muscles peak activation which can maintain the posture of the upper body and ankles appeared at the beginning. In the case of S3, the part maintaining the ankle posture at the beginning appeared, but it could be expected that it would progress in the vertical direction due to the activation of GL at the time of jumping. Conclusion: The muscle activation peak before the take-off point showed a different pattern for each athlete, and individual differences were large. In addition, it was attempted to confirm the actual jump with simulation jump, and it was found that not only the difference in patterns but also the fluctuations in the timing of each muscle activation peak were large.

• 한국운동역학회지
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• 제32권2호
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• pp.49-55
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• 2022

Objective: This study aims to verify the front squat motions using by two different surfaces, thereby elucidating the grounds for effective training environment that can minimize the risk of injury. Method: Total of 10 healthy male crossfit athletes were recruited for this study (age: 32.30 ± 3.05 yrs., height: 173.70 ± 5.12 cm, body mass: 82.40 ± 6.31 kg, 1RM: 160 ± 13.80 kg). All participants are those who know how to do front squats well with more than five years of crossfit athlete experience. All participants have sufficient experience in front squats on two types of surface which are soft surface (SS) and hard surface (HS). In each surface, participant perform 10reps of the front squat with 80% of the pre-measured 1RM. A 3-dimensional motion analysis with 8 infrared cameras and 2 channels of EMG was performed in this study. Paired sample t-test was used for statistical verification between two surfaces. The significant level was set at α=.05. Results: The significantly decreased rectus femoris muscle activation was found in SS compared with that of HS on phase 1 (p<.05). Also, ROM of ankle joint was significantly increased in the SS compare with that of HS on phase 1 (p<.05). The muscle activity ratio of gluteus maximus/rectus femoris showed a significant difference only in SS compared with that of HS on phase 1 (p<.05). Conclusion: In conclusion, Korean crossfit boxes should consider the use of hard surface, which has a relatively less risk of injury than soft surface, in selecting flooring materials. For the Crossfit athletes, they are also considered appropriate to train on a relatively hard surface.

• 한국전문물리치료학회지
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• 제29권3호
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• pp.215-224
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• 2022

Background: The presence of the lumbopelvic-hip neuromuscular chain is essential for dynamic spinal stabilization; its therapeutic effects on dynamic movements of the distal extremity segment and underpinning motor mechanism remain unknown and warrant further study on participants with low back pain (LBP). Objects: We aim to compare the effects of the broken chain exercise (BCE) and connected chain exercise (CCE) on electromyography (EMG) amplitude and onset time in participants with and without LBP. Methods: Randomized controlled clinical trial. A convenience sample of 40 nonathletic participants (mean age: 24.78 ± 1.70) with and without LBP participated in this study. All participants underwent CCE for 30 minutes, 30-minute daily. We measured EMG amplitude and onset times on bilateral erector spinae (ES), gluteus maximus (GM), hamstring (HAM), transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) during the prone hip extension (PHE) test before and after the BCE and CCE. We used multivariate analysis of variance (MANOVA) to analyze the amplitude and onset time difference between exercises (BCE and CCE) and Pearson's correlations to determine any synergistic relationship among the HAM, GM, bilateral TrA/IO, and ES muscles. The statistical analyses were used at p < 0.05. Results: MANOVA showed that CCE was more decreased on EMG amplitude in HAM and bilateral ES, while increased GM and contralateral TrA/IO than BCE (p < 0.05). MANOVA EMG onset time data analyses revealed that the main effect of the conditions was significant for all HAM, GM, and bilateral ES muscles, whereas the main effect for the group was significant only for GM and contralateral ES in healthy and LBP groups. Pearson's correlation coefficient was computed to assess the relationship between BCE and CCE on dependent variables. In most of the muscles, there was a strong, positive correlation between the two variables, and there was a significant relationship (p < 0.001). Conclusion: CCE produced more effective and coordinated core stabilization and motor control mechanism in the lumbopelvic-hip muscles in participants with and without LBP during PHE than BCE.

• 대한물리의학회지
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• 제18권3호
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• pp.99-111
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• 2023

PURPOSE: This study examined the effects of pelvic compression methods on the muscle activities of the trunk muscles during plank exercises in individuals with and without low back pain. METHODS: Individuals who experienced back pain for three or more days within the last six months (low back pain group, LBPG; n = 15) and those who did not (non-experienced low back pain group, NLBPG; n = 15) were instructed to perform plank exercise without pelvic compression or while wearing a ReaLine or Com-pressor belt. The electromyography (EMG) data was measured during each session of exercise. Surface EMG signals were collected for the rectus abdominis (RA), external oblique (EO), erector spinae (ES), and gluteus maximus (GM) muscles. The data were collected during three 5-s exercises with a 1-min rest period between the three sets. RESULTS: During the plank exercise, the muscle activity of the RA in the LBPG was significantly higher than that in the NLBPG (p < .05), and greater muscle activity was observed in the LBPG even when two pelvic compression methods were applied (p < .05). The muscle activity of RA was decreased significantly during pelvic compression according to the pelvic compression methods in both groups (p < .05). No significant interaction was observed between the groups or the pelvic compression methods for the RA, EO, ES, or GM muscle activities during plank exercises. CONCLUSION: Both pelvic compression methods reduced the RA muscle activity during plank exercises in individuals who had not experienced back pain within the last six months.