• Physical Therapy Korea
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• v.27 no.3
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• pp.171-177
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• 2020

Background: The flexion-relaxation phenomenon (FRP) refers to a sudden onset of activity in the erector spinae muscles that recedes or fades during full forward flexion of the trunk. Lumbar spine and hip flexion are associated with many daily physical activities that also impact trunk flexion. Shorter hamstring muscles result in a reduction of pelvic mobility that eventually culminates in low back pain (LBP). Many studies have explored the FRP in relation to LBP. However, few studies have investigated the influence of hamstring muscle length on the FRP in relation to the erector spinae muscles during trunk flexion. Objects: This study aimed to investigate the influence of hamstring muscle length on the FRP in relation to the erector spinae muscles during trunk flexion. Methods: Thirty subjects were divided into three groups according to hamstring length measured through an active knee extension test. The 30 participants consisted of 10 subjects who had a popliteal angle of 20° or less (Group 1), 10 subjects who had a popliteal angle of 21°-39° (Group 2), and 10 subjects who had a popliteal angle of 40° or more (Group 3). A one-way analysis of variance was used to compare the difference in muscle activity of the erector spinae muscles during trunk flexion. Results: The subjects with a shorter hamstring length had significantly higher muscle activity in their erector spinae muscles during trunk flexion and full trunk flexion (p < 0.05). The subjects with a shorter hamstring length also had a significantly higher flexion-relaxation ratio (p < 0.05). Conclusion: The results of this study demonstrate that differences in hamstring muscle length can influence the FRP in relation to the erector spinae muscles. This finding suggests that the shortening of the hamstring might be associated with LBP.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.11-16
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• 2015

Objective: Prone bridge exercise is one of the core strengthening exercise for improving abdominal, lower and upper extremity muscles. In addition, coactivation of the trunk muscles and extremities is important for treatment of low back pain. This study aimed to investigate the correlation between the thickness, cross-sectional area of the target muscle, and endurance during prone bridge exercise. Our hypothesis was that an increase in muscle thickness is positively related to the hold time for the static prone bridge exercise. Design: Cross-sectional study. Methods: Fourteen healthy university students (8 men and 6 women) voluntarily participated in the study at Sahmyook University. Hold time for the prone bridge with one and both legs was measured. The resting and contracted thickness of the lateral abdominal, rectus femoris, and triceps muscles was measured using rehabilitative ultrasound imaging. The correlation between muscle thickness and endurance for maintenance time was evaluated. Results: The prone bridge with both legs and the contraction thickness of the triceps muscle showed a positive correlation (r=0.692, p<0.05); the prone bridge with one leg and the contraction thickness of the internal oblique and transversus abdominis muscles showed a positive correlation (r=0.545, 0.574, p<0.05, 0.05, respectively). Conclusions: Endurance for the prone bridge exercise with a stable support surface is correlated with the contraction thickness of arm muscles; the prone bridge exercise with an unstable support surface is correlated with the contraction thickness of the deep abdominal muscles.

• Investigative Magnetic Resonance Imaging
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• v.20 no.4
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• pp.224-230
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• 2016

Purpose: The purpose of this study was to compare the grade of fatty degeneration and atrophy of rotator cuffs on immediate postoperative MRI to those on preoperative MRI in patients with rotator cuff tears. Materials and Methods: Seventy patients were included in this study, who received arthroscopic rotator-cuff repair and underwent both preoperative magnetic resonance imaging (MRI) and immediate postoperative MRI in our institution. Fatty degeneration of rotator cuffs and the atrophy of supraspinatus muscles were evaluated with T1 oblique sagittal images in the Y-shaped view. Fatty degeneration was evaluated using a Goutallier classification system, and the atrophy of supraspinatus muscles was evaluated using a modified tangent sign and a visual occupation ratio. Results: From 70 patients, a total of 100 tendons were repaired: 18, 69, and 13 tendons were treated for subscapularis, supraspinatus, and infraspinatus, respectively. The Goutallier grades (P = 0.012), modified tangent signs (P = 0.000), and visual occupation ratios (P = 0.000) of supraspinatus muscles were significantly decreased in immediate postoperative MRIs when compared to preoperative MRIs. In immediate postoperative MRIs, the Goutallier grades of supraspinatus muscles were decreased by one grade in 18.8% (n = 13) of the patients, and the atrophy of supraspinatus muscles was improved by one grade in 26.1% (n = 18) for modified tangent signs and 21.7% (n = 15) for visual occupation ratios. However, fatty infiltration by the Goutallier grades of subscapularis (P = 1.000) and infraspinatus (P = 0.157) muscles were not significantly changed after arthroscopic surgery. Conclusion: Immediate postoperative MRIs showed a significant improvement of fatty degeneration and muscle atrophy in supraspinatus muscles when compared to preoperative MRIs.

• Journal of the Korea Computer Graphics Society
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• v.16 no.3
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• pp.21-30
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• 2010

We present a real-time simulation method for muscles which are actuated by skeletal structure based on anatomical properties of the muscles. Muscles are designed by their two endpoints attached to either bones or other muscles and their volume are preserved approximately during the deformation. Skin deformation animation is obtained by a simple skinning due to the muscle deformation. We present also the performance data for a human-like multi-linked character which has bones, muscles, and skin. According to our experimental result, we can get skin deformation animation with a few tens of muscles in real-time. The method proposed in this paper can be applied to obtain skin deformation animation for multi-linked characters appear frequently in real-time environments such as games.

• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.2
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• pp.115-127
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• 2016

Shoulder pain, injury and discomfort are public health and economic issues world-wide. The function of these joints and the stresses developed during their movement is a major concern to the orthopedic surgeon to study precisely the injury mechanisms and thereby analyze the post-operative progress of the injury. Shoulder is one of the most critical joints in the human anatomy with maximum degrees of freedom. It mainly consists of the clavicle, scapula and humerus; the articulations linking them; and the muscles that move them. In order to understand the behavior of individual muscle during abduction arm movement, an attempt has been made to analyze the stresses developed in the shoulder muscles during abduction arm movement during the full range of motion by using the 3D FEM model. 3D scanning (ATOS III scanner) is used for the 3D shoulder joint cad model generation in CATIA V5. Muscles are added and then exported to the ANSYS APDL solver for stress analysis. Sensitivity Analysis is done for stress and strain behavior amongst different shoulder muscles; deltoid, supraspinatus, teres minor, infraspinatus, and subscapularies during adduction arm movement. During the individual deltoid muscle analysis, the von Mises stresses induced in deltoid muscle was maximum (4.2175 MPa) and in group muscle analysis it was (2.4127MPa) compared to other individual four rotor cuff muscles. The study confirmed that deltoid muscle is more sensitive muscle for the abduction arm movement during individual and group muscle analysis. The present work provides in depth information to the researchers and orthopedicians for the better understanding about the shoulder mechanism and the most stressed muscle during the abduction arm movement at different ROM. So during rehabilitation, the orthopedicians should focus on strengthening the deltoid muscles at earliest.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.2
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• pp.233-243
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• 2010

Purpose : This study aimed to examine the effects of sling exercise therapy on the relief of low back pain and the cross-sectional area change of lumbar muscles by CT analysis for chronic low back pain patients. Methods : Forty-one patients with diagnosis of chronic low back pain was divided sling exercise therapy group(SEG) 19 subjects and conservative physical therapy group(CPG) 22 subjects. we randomized and treated them(subjects) for 12 weeks. As using visual analogue scale(VAS), we evaluated recovery accuracy of pain, and for investigating cross-section area change of lumbar muscles for before and after treatment we used computed tomography(CT). Results : This study were summarized as follows : 1) As treatment period, in each compared testing on VAS of SEG and CPG, the both group was significantly different(p<.05). 2) Compared testing on VAS of between-subject groups(SEG and CPG) were not significantly different(p>.05). 3) At SEG of before and after treatment, in compared testing on cross-section area size of lumbar muscles, All muscles of psoas major, quadratus lumborum, erector spinae and multifidus were significantly different(p<.05). At CPG, psoas major was significantly different(p<.05). But other muscles were not significantly different(p>.05). Conclusion : From this result, both sling exercise therapy and the conservative physical therapy are effect on decrease of pain for chronic low back pain patients. but Increasing of the cross-section area being proportioned with muscular strengthening of low back muscle is noticeable difference in SEG. Therefore, sling exercise therapy have affect both decreasing of pain for chronic low back pain patients and lumbar muscles strengthening.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.4
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• pp.91-100
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• 2018

Purpose : The study investigated the effects of Pilates exercise on strengthening trunk muscles of females who perform such exercise for the purpose of comparing activation of trunk muscles that contact while performing Pilates motions between females with or without at least 8 weeks of Pilates experience. Methods : The study investigated 10 females with at least 8 weeks of Pilates experience in the past 6 months (experienced group) and 10 healthy females without Pilates experience (non-experienced group). The study used basic Pilates postures involving hip abduction, lift, and leg swing motions as the measurement postures in comparing the activation of muscles used for stabilization, such as the rectus abdominis, external oblique abdominal, and transverse abdominis & internal oblique abdominal muscles. Surface electromyography was used for measuring muscle activation, and the measurements targeted activation of the rectus abdominis, external oblique abdominal, transversus abdominis, and internal oblique abdominal muscles. Results : The study results showed that, as compared to the non-experienced group, the experienced group had significantly higher muscle activation in the transverse abdominis and internal oblique abdominal muscles during hip abduction (p<.05) and significantly higher muscle activation in the rectus abdominis, external oblique abdominal, and transverse abdominis & internal oblique abdominal muscles during lift and leg swing motions (p<.05). Conclusion : Pilates exercise performed over a long period can be recommended as an effective exercise method that can increase the activation of trunk muscle, and especially, repeated performance of highly difficult motions can increase muscle activation even more, which can help promote spinal stabilization, prevent pain, and improve performance of activities of daily living.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.189-195
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• 2019

Purpose : The purpose of this study was to investigate the effects of chin tuck exercise (CTE) on the craniovertebral angle (CVA), strength and endurance of deep cervical flexor (DCF) muscles in subjects with forward head posture(FHP). This study was performed on 30 subjects with FHP. Method : Thirty subjects were divided into two groups; modified CTE (n=15), conventional CTE (n=15). Both of the group performed the exercise 4 times a week for 6 weeks. The subjects performed CTE in two different methods; modified CTE, with device designed that help keep cervical lordois curve, and coventional CTE, without using device. The CVA was measured using Image software version. A pressure biofeedback unit was used to measure the strength and endurance of the DCF muscles. The data was analyzed by the paired t-test for comparing before and after changes of variables in each group and the independent t-test for comparing the between groups. Result : There was statistically significant difference of before and after strength and endurance of DCF muscles in modified CTE (p<0.05). There was statistically significant difference of before and after only endurance of DCF muscles in conventional CTE (p<0.05). There was statistically significant difference of between the two group in strength of DCF muscles (p<0.05). Conclusion : Muscle strength to stabilize the spine plays an important role in maintaining a good posture. Therefore, we suggest that the application of CTE with a device designed to maintain the lordotic curvature in the neck is likely to yield better outcomes in FHP subjects in future studies.

• Food Science of Animal Resources
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• v.39 no.4
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• pp.655-667
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• 2019

The present study aimed at investigating the effects of dry- and wet-aging methods on flavor compounds and sensory properties of low fat Hanwoo beef muscles. All the beef samples were obtained from 2-grade carcasses of Hanwoo cows. The beef samples used in the dry- and wet-aging methods were prepared in the forms of quarter beef (bone-in) and cuts (boneless), respectively. The dry-aging was carried out at $2^{\circ}C-4^{\circ}C$ and humidity of 65%-85%, while the wet-aging was done at $1^{\circ}C$ for 0, 20, 40, and 60 d. At each aging time, three muscles: longissmus thoracis (LT), glutaeusmedus (GM) and semimembranosus (SM) were taken from the corresponding quarters and cuts, and used for the flavor compounds and sensory analyses. Results showed that both aging methods significantly increased the concentrations of flavor compounds and total amount of all classes of the flavor compounds as the aging time increased (p<0.05). In the dry-aging method, the GM and SM muscles presented significantly higher total amounts of pyrazines and sulfur-containing compounds compared to the LT muscle (p<0.05). Both the aging methods improved the eating quality attributes, indicating by increased scores of sensorial attributes with increased aging time for all the muscles studied (p<0.05). However, compared to the wet-aging, the dry-aging method resulted in significantly higher scores of tenderness and flavor for the GM and SM muscles after 40 to 60 d. Thus, postmortem aging, especially the dry-aging method could be used to improve eating quality attributes (tenderness and flavor) of low fat beef muscles such as GM and SM.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.167-174
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• 2021

Objective: Single leg bridge exercise (SLBE) improves trunk muscle activation and provides muscle stability by aligning joints related to posture. This preliminary study aimed to investigate the effects of SLBE on abdominal muscle activation in subacute stroke patients. Design: Cross-sectional study. Methods: Fifteen subacute stroke patients (9 males, 6 females) voluntarily participated in this study. SLBE was performed on the affected side. Each individual patient performed an SLBE ten times in three sets and was asked to hold their position for 5 s. Muscles activity was recorded using a surface electromyography (EMG) system before and after the SLBE. A surface EMG system was used to analyze the muscle activity during general bridge exercise, including the rectus abdominis (RA), internal oblique (IO), and external oblique (EO) abdominal muscles. Results: Muscle activity of both EO and IO on the affected side significantly increased (p<0.05), whereas the muscle activity of the RA and the three muscles on the unaffected side did not show a significant difference. In addition, improvement in muscle asymmetry of the EO and IO showed a significant change after SLBE (p<0.05). Conclusions: SLBE is effective in activating the abdominal muscles of stroke patients on the affected side and is a helpful exercise intervention that activates the muscles to transform asymmetric abdominal muscles into symmetric patterns.