• Physical Therapy Korea
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• v.24 no.4
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• pp.1-10
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• 2017

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under $30^{\circ}$; Group 2-consisted of 13 subjects who had a popliteal angel above $50^{\circ}$. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people's hamstring muscle activity and lumbopelvic kinematics.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.95-108
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• 2003

The purposes of this study were to analyze the muscle activities and the characteristics of muscle recruiting patterns of upper trunk for Ssirum dutguri technique using three top-ranked elite Ssirum players. The EMG technique was used to record muscle activities of both right and left sides of latissimus dorsi, biceps brachii, and erector spinae. Six surface electrodes were placed on the surface of the selected muscles and one ground electrode was also attached on the back of neck(C7). One video camera was also used to record the Ssirum motion to define 4 events and 3 phases for further analysis. The raw EMG data were filtered with band pass filter (50-400 Hz) to remove artifacts and then low pass filtered (4 Hz) to find the linear envelope which resemble muscle tension curve. This filtered EMG data were normalized to MVIC for the purpose of comparion between the subjects. The results were indicated that each subject with different physical characteristics showed very different muscle activity patterns. Although Ssirum dutguri is considered as foot technique the player grasped opponent's satba(belt) with both hands when they play. Because of this reason, activities of upper trunk muscles were relatively high. However, direct comparison between upper and lower body muscles was not possible due to the lack of the data in present study. Interestingly, all threes subjects showed that erector spinae muscle activity was comparatively higher than those of latissimus dorsi and biceps brachii. This implies to reinforce back muscle as a routine of training to improve performance or to prevent back injury.

• Physical Therapy Korea
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• v.26 no.3
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• pp.32-41
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• 2019

Background: Limitations in hip flexion caused by tight hamstrings lead to excessive lumbar flexion and low back pain. Accordingly, many studies have examined how to stretch the hamstring muscle. However, no study has focused on the effect of hamstring eccentric exercise for tight hamstrings on trunk forward bending. Objects: We compared the short-term effect of hamstring eccentric exercise (HEE) and hamstring static stretching (HSS) on trunk forward bending in individuals with tight hamstrings. Methods: Thirty individuals with tight hamstrings participated in the study. The subjects were randomly allocated to either a HEE or HSS group. To determine whether the hamstrings were tight, the active knee extension (AKE) test was performed, and the degree of hip flexion was measured. To assess trunk forward bending, subjects performed the fingertip to floor (FTF) and modified modified Schober tests, and the degree of trunk forward bending was measured using an inclinometer. We used paired t-tests to compare the values before and after exercise in each group and independent t-tests to compare the two groups on various measures Results: The FTF test results were improved significantly after the exercise in both groups, and AKE for both legs increased significantly in both groups. There was no significant difference in the hip angles, mmS test results, or degree of trunk forward bending between groups after the exercise. No test results differed significantly between the two groups at baseline or after the exercise. Both groups increased hamstring flexibility and trunk forward bending. Conclusion: HSS and the HEE groups increased hamstring flexibility and trunk forward bending. However, HEE has additional benefits, such as injury prevention and muscle strengthening.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.957-958
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• 2010

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.1
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• pp.45-51
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• 2015

This study was to verify effect on muscle strength of trunk and body composition for elderly according to spinal stability exercise with three dimension. We recruited forty elderly participants(twenties as training group, the other twenties as control group) over sixty five aged. The participant performed muscle strength estimation to exercise of eight direction using spinal stability training system. Also, we estimated body composition in participants using inbody 720. Trining group performed direction exercise(F, FOR, R, BOR, B, BOL, L, FOL) and multiple exercise with band exercise, strengthening gym and walking during thirty minute. But control group only performed multiple exercise without direction exercise. All training progressed three days a week for eight weeks. The results showed that muscle strength of trunk in training group increased significantly from 79.9 point to 85.6 point with reducement of body weight, body fat and BMI. However, control group showed a few exercise effect with increasement of amount of muscles and reducement of body fat without muscle strength of trunk. These results means that spinal stability exercise could be helped to prevent obey and fall of elderly caused by muscle strengthening and improving body composition. This could be applied to develop rehabilitation program efficiently based these data.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.4
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• pp.147-159
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• 2008

Objectives : In order to investigate the relation of body composition analysis and isokinetic trunk muscle strength for the screening test of low back pain. Methods : This study was carried out with the data from comprehensive medical testing. 75 subject aged 20-59 performed the segmental bioelectrical impedance analysis, isokinetic trunk muscle strength test and questionnaire. Then we analyzed the relationship of data. Results : Low back pain(LBP) prevalence in high obesity index(Body mass index(BMI), Percentage of Body Fat(PBF), Waist Hip Ratio(WHR)) group was higher than LBP prevalence in normal obesity index group(p<0.001). In LBP group, Extension Peak Torque(Ext.PT), Extension Peak Torque per Body Weight(Ext.PT/BW) were significantly lower than Non-LBP group(p<0.001). And 90% of LBP group indicated abnormal Extension-Flexion Ratio(E/F ratio)(1.0 < Normal E/F ratio <1.6). When it comes to analyze relation between obesity index and muscle strength, Ext.PT/BW was significantly decreased according to PBF, WHR score. And correlation coefficient in Flex.PT, Flex.PT/BW, Ext.PT, Ext.PT/BW and PBF showed decreasing function. Conclusions : Results from this investigation showed positive correlation between obesity and LBP prevalence. Decreased muscle strength and inbalanced E/F ratio were shown in LBP. Trunk muscle strength was changed according to body mass composition parameters. This results are expected to contribute to prevent and diagnose LBP by application the clinical index of body composition analysis.

• Journal of the Ergonomics Society of Korea
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• v.31 no.6
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• pp.741-747
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• 2012

Objective: The purpose of this study is to compare the EMG activities of the trunk muscles when carrying a backpack with belts and without belts. Background: This research aimed to explore the influence of carrying a backpack with belts on the trunk muscles activity and to suggest a desirable method of wearing backpacks. Method: Seventy five adolescents participated in this study. The EMG activities of upper trapezious, cervical erector spinae and rectus abdominis were collected. One way ANOVA was used to analyze the collected data. LSD was used for post-hoc test. Results: The EMG data from treadmill walking showed significant differences between carrying a backpack with belts and without belts for the cervical erector spinae and upper trapezious(p<.05) in all group(A Group: no belt, B Group: lumbar belt, C Group: lumbar-chest belt). In descending walking, significant difference were found for the cervical erector spinae and rectus abdominis in all group. In ascending walking, there were no significant differences in all group. LSD showed that the muscle activity of the trunk muscles decreased significantly when the lumbar belt and lumbar-chest belt were worn. Conclusion: The trunk muscles activities were decreased when the subjects were wearing a backpack with belts, comparing with wearing a backpack without belts. Application: These results can be used to provide useful information on how wearing a backpack in adolescent.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.496-508
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• 2020

This study reviews studies on the core stabilization of respiratory muscle training for the elderly health. Previous research data and presenting basic literature data suggest that respiratory activation is an important mechanism for core strengthening via exercise interventions for the elderly. The review found that first, the mechanism of improving the respiratory muscles weakened by aging to address the loss of core function due to old age sarcopenia among the elderly results entails promoting the autonomic nervous system by focusing on the respiratory muscle activation pattern, the core muscle sensation mobilized for body centering. Second, nerve roots, intraperitoneal pressure, and deep muscles in the trunk of the body can be promoted while controlling respiratory stimulation with cognitive feedback. Effortful inspiration increases the activation of respiratory assistive muscles and effortless exhalation can improve the core muscle mobilization by involving abdominal muscles. Third, through respiratory muscle training, the elderly can increase their awareness of spinal centering and improve the ability to control the deep core muscles that must be mobilized for core stabilization. In conclusion, respiratory muscle training to increase the utilization of the trunk muscles seems to be a useful core stabilization exercise for the elderly with chronic tension and joint degeneration.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.91-99
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• 2019

PURPOSE: This study was conducted to evaluate the activity of trunk muscles according to width of the foot and posture of the arm during sit to stand (STS). METHODS: Thirty subjects were recruited and examined for variation in muscle activity of the erector spine, gluteus maximus, gluteus medius and external oblique during different STS conditions; namely, the cross arm basic sit to stand (CBSTS), overhead basic sit to stand (OBSTS), cross arm wide sit to stand (CWSTS), and overhead wide sit to stand (OWSTS). Repeated measures ANOVA (Analysis of Variance) was used for analysis. RESULTS: Erector spinae muscle activity showed a significant increase in the OBSTS condition (p<.05) and external oblique muscle activity showed a significant increase in the OWSTS condition ((p<.05). There was no significant difference in the activity of the gluteus maximus and gluteus medius under any conditions (p>.05). CONCLUSION: During evaluation of the performance of the STS, the CWSTS condition will be useful to decrease the muscle activity of the erector spinae and the OWSTS condition will be useful to increase the muscle activity of the external oblique. The results of this study can be used as an index to find a suitable exercise method for subjects who have back pain or to strengthen the abdomen.

• Journal of Korean Physical Therapy Science
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• v.24 no.1
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• pp.1-13
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• 2017

Purpose: The objective of this study was compare the effect of core muscle strengthening between core exercise on stable surface and core exercise on unstable surface. Methods: Thirty-nine adults participated in this study and were randomly allocated to three groups. The stable surface exercise group and unstable surface exercise groups practiced core muscle training for $3{\times}30minute$ sessions over a 4-week period. The control group did not received therapeutic intervention except pre and post test. The following clinical tools were used to assess core muscle strength and balance: Side Plank Test, Trunk Flexion Test, Balance Error Scoring Test, Core Muscle Stength & Stability Test. Results: The stable surface exercise group showed significant improvement in trunk muscle strength of anterolateral part as revealed by the Side Plank Test and Trunk flexion Test(p<.05). The unstable surface exercise group showed significant improvement in trunk muscle strength of anterolateral part and balance ability as revealed by the Balance Error Scoring Test and Core Muscle Strength & Stability Test(p<.05). Conclusion: The results of this study, both core exercise on stable surface and core exercise on unstable surface induced core muscle strengthening and balance ability. Expecially core exercise on unstable surface more effective to core muscle strengthening and balance ability.