• 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.

• The Journal of Korean Physical Therapy
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• v.30 no.1
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• pp.1-7
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• 2018

Objective: This study aimed to determine the efficacy of flexible pole training combined with lumbar stabilization in improving trunk muscle activities and to investigate the difference according to posture in young adults. Methods: Twenty-five participants were enrolled in this study. The subjects were randomly allocated into either the flexible pole group or the rigid pole group. Participants performed lumbar stabilization exercises on quadruped and curl-up, with the flexible pole or rigid pole. Electromyography was used to assess the percent maximal voluntary isometric contracion (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spine (ES) muscles. All participants completed one 30-minute session per day, 3 days per week, for 6 weeks. The evaluation was performed before and 6 weeks after the training, and follow-up. The data were analyzed using independent t-test and two-way repeated measure analysis of variance to determine the statistical significance. Results: The flexible pole in curl-up showed significant differences in EO and IO muscle activities compared with the rigid pole. The flexible pole in quadruped showed significant differences in IO and ES muscle activities compared with the rigid pole. The RA, EO, IO, and ES muscle activities of both groups were significantly higher after 6 weeks training. Conclusion: The flexible pole in curl-up and quadruped showed an improvement in trunk muscle activation. The flexible pole combined with lumbar stabilization will be useful as an exercise tool to improve activity of trunk muscles.

• The Journal of Korean Physical Therapy
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• v.30 no.1
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• pp.8-13
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• 2018

Purpose: The present study was to investigate effects of scapular position and pain on a trunk stabilization exercise with gym ball for patients with arthroscopic rotator cuff repair. Methods: Subjects were patients after 2 weeks of rotator cuff repairs. Subjects were randomly assigned to conservative treatment group (CTG, n=10) or trunk stabilization with gym ball group (SBG, n=10), and participated one of those groups for 2 weeks. Measurements about pain and scapular position were assessed in before and after treatment programs. Results: Pain reduced in both rest and night in SBG compared to CTG. In the case of scapular position, decreased scapular retraction (increased protraction) was found in CTG and vice versa in SBG. Reduced scapular anterior tilting was also found on SBG. Conclusion: The present study showed that early performed trunk stabilization with gym ball could bring a scapular alignment that increases subacromial space and reduces pain. This suggests early trunk stabilization with gym ball programs to restore shoulder functions for patients with rotator cuff repair.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.1
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• pp.93-101
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• 2011

Purpose : The purpose of this study was to investigate the effects of maximum muscle activation of lower extremity of facility dwelled elderly Hansen's disease after isometric trunk exercise for 12weeks. Methods:18 elderly Hansen's disease who isometric trunk exercise for 12weeks were recruited for this study. They were instructed to perform maximum muscle activation of lower extremity after exercise. and the subjects were divided into normal sensory group, sensory loss in left foot group, sensory loss in right foot group and sensory loss in both feet group, according to the sensory condition ability on their soles. Results : After exercise, Hamstring muscle increased significantly (p<.05), and activation of the rectus femoris muscle decreased with a significance (p<05). In terms of Post-hoc test for examining the difference in MVIC according to sensory condition, there was significant difference in the normal sensory group, sensory loss in right and left foot group of left hamstring muscle before the exercise(p=.01) and the normal sensory group, sensory loss in both feet group of right hamstring muscle before the exercise(p=.04). Conclusion : These results indicate that the maximum muscle activation was changed after isometric trunk exercise. it could be improved maximum muscle activation of lower extremity muscle after the exercise although there was sensory loss.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.4
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• pp.501-507
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• 2012

PURPOSE: This study aims to examine the effects of trunk flexion on the kinetic characteristics of the lumbar according to the degree of hamstring flexibility. METHODS: This study has as its subjects 29 young adults and divides them into the group (NSRTG, n=15) with the normal length of hamstrings according to SRT and the group (SSRTG, n=14) tending to have shortened hamstrings. Sit and Reach Test was conducted to evaluate the degree of hamstring flexibility. And to examine the kinetic difference of the lumbar at the trunk flexion, it was compared and analyzed by using the picture archiving and communication system (PACS). RESULTS: SSRTG showed more significant difference than NSRTG in the analysis on the trunk flexion of NSRTG and SSRTG. CONCLUSION: According to the analysis, the shortening of hamstrings is the factor that affects the dynamic stability of the lower lumbar through the reduction of the pelvic anterior tilt at the trunk flexion.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.307-318
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• 2013

The purpose of this study was to analyze the kinematic variables of glide kip motion on the uneven bars through a two-dimensional cinematography. Three expert female gymnastics players were involved in the data gathering process. The followings were concluded according to the results. The arm, trunk and leg segments were fully extended throughout the kip movement. The whole body center of gravity showed the biggest changes during 66 to 87% of the kip motion. During the kip phase, the horizontal displacement of the leg was greater than the vertical displacement the leg. Glide kip motion should be done in orders of upward movement of leg, forward movement of leg, upward movement of trunk and forward movement of trunk segment. It was found that trunk segment and hip joint movements showed bigger changes than those of leg segment and shoulder joint in the glide kip motion. The largest angular velocity of hip joint was shown in the middle of the kip Phase. In conclusion, effective kip movement could be resulted when the trunk was displaced posterior-upward direction with fast hip joint extension after the leg segment was elevated upward and thrusted forward in advance.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.33-39
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• 2013

Background: The purpose of this study was to find out the effect of trunk stabilization training on the self posture control efficacy, physical self-description and perception stress in high school students. Methods: 92 voluntary students (73 females, 19 males) participated in this study. They received trunk stabilization training for 40 minutes per day and a time per week during 6 weeks period. Trunk stabilization training was an approach of education in proper posture and coordination of movement. In the evaluation, the self posture control efficacy scale (SPCES) was used to measure the posture control efficacy, the physical self-description questionnaire (PSDQ) was used to measure the physical self description and the perception stress scale (PSS) was used to measure the stress. All measurement of each subject were measured before and after stabilization training. Results: The SPCES were significantly different before and after (p<.05). The PSDQ and PSS were no significantly different before and after (p>.05) but the means were increased slightly. Conclusion: Conclusionally these results suggest that the trunk stabilization training increased the self posture control efficacy and would give help to control Students themselves.

• The Journal of Korean Physical Therapy
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• v.27 no.4
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• pp.196-200
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• 2015

Purpose: The purpose of this study was to examine the muscle activity of the trunk muscles during balance exercises on a stable and unstable surface in patients with stroke. Methods: Thirteen subjects (8 males, 5 females) with stroke were enrolled in the study. Muscle activity was recorded using surface EMG electrodes from the affected side of the erector spinae, external oblique, and internal oblique muscles. The exercise was performed under three conditions. For the first condition for balance exercise, subjects were instructed to sit on an exercise mat with legs extended. The second condition was to sit with legs extended, with a balance pad under their buttocks. The third condition was to sit with legs extended, have a balance pad under the buttocks and a balance cushion under the lower legs. Results: This study showed significant differences in EMG activities during both arm lifting exercise and weight shifting exercise between conditions. This study showed that the EMG activities of the erector spinae, external oblique, and internal oblique muscles were significantly higher when the trunk exercise was performed using the balance pad with balance ball than when using the stable surface. Conclusion: In conclusion, performing balance exercises using an unstable surface is a useful method for facilitating trunk-muscle strength and hence trunk stability.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.3
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• pp.81-86
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• 2015

PURPOSE: Bridge exercises are broadly used to develop trunk co-activation patterns that promote spine stability. This study was to analyze the trunk muscle activity during bridge exercise with various shoulder support surface(stable, sling, Swiss ball). METHODS: The subjects were 20 healthy subjects in their twenties. Subjects were performed bridge exercise on 4 different shoulder support surfaces using stable and labile instruments. 1) Bridge exercise on a stable surface. 2) Bridge exercise with their shoulder on a stable bench. 3) Bridge exercise with their shoulder on a sling. 4) Bridge exercise with their shoulder on a Swiss ball. Rectus abdominis, erector spinae, internal oblique, external oblique muscle activities were measured using electromyography. RESULTS: There were significant differences in RA, EO muscles between performing each of the 4 exercises(p<.05). RA and EO was recorded the highest activity during the bridge exercise with their shoulder on a sling. The lowest activity was recorded during conventional supine bridge on a stable surface. There were no differences found for the EO/RA and IO/RA ratio. The EO/RA and IO/RA ratio was the highest in the bridge exercise with their shoulders resting on a stable bench. CONCLUSION: These findings suggest that change of shoulder support surface during bridge exercise may be useful for enhancing the trunk stability.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.89-95
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• 2015

Purpose: The purpose of this study is to determine the effects of visual information on movement time and each angular velocity of trunk and lower extremity joints while healthy adults are in sitting and squat motion. Methods: Participants consisted of 20 healthy male and female adults; movement time and each angular velocity of trunk, pelvis, hip, knee and ankle of sitting and squat motion according to common vision, visual task and visual block were analyzed using a three dimensional motion analysis system. Results: Each angular velocity of the trunk, pelvis, hip, knee and ankle in phase 2 of the sitting showed significant difference according to the types of visual information (p<0.05). Movement time and each angular velocity of pelvis and hip in phase 2 of squat motion showed significant difference according to the types of visual information (p<0.05). According to the common vision, each angular velocity of knee and ankle in phase 1 was significantly fast in sitting (p<0.05). According to the common vision, each angular velocity of trunk, pelvis, hip, knee, and ankle in phase 2 was significantly fast in sitting (p<0.05). Conclusion: Visual information affects the angular velocity of the motion in a simple action such as sitting, and that in more complicated squat motion affects both the angular velocity and the movement time. In addition, according to the common vision, visual task and visual block, as angular velocities of all joints were faster in sitting than squat motion.