• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.297-308
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• 2011

The purpose of this study was to investigate the relationship among isometric and isokinetic muscle strength, lean body mass(LBM) and bone mineral density(BMD) in the elderly. Eleven males(age, 70.27${\pm}$5.78yr; height, 167.36${\pm}$6.68 cm; weight, 68.34${\pm}$8.23 kg) and thirteen female(age, 69.77${\pm}$4.13yr; height, 152.80${\pm}$4.45 cm; weight, 56.86${\pm}$7.40 kg) participated in this study. In all subjects, LBM and BMD segments was measured by using Dual-energy x-ray absorptiometry(DEXA, Lunar DPS-DM, U.S.A.). Maximum isometric and isokinetic muscle strength of flexion and extension at the knee and elbow, ankle, trunk joints were measured by using an isokinetic dynamometer(CON-TREX(R) Multi Joint Testing Module, Switzerland). The results of this study showed that isometric and isokinetic muscle strength was significantly higher in extension than flexion. In the male and female, hamstring to quadriceps strength ratio(H:Q ratio) was increased as contraction velocity increased. BMD was correlated significantly with trunk extension in the male, but not in the female. LBM was correlated significantly in the male and female with knee extension strength. This study suggests that in the elderly muscle strength training program should put more weight on extensor muscles of the body.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.132-138
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• 2006

With a great requirement of innovation caused by severe competition current companies are encouraged to improve bottleneck areas in production procedure. Specially a chassis line in which assembly processes are mainly carried out manually has the large potential to be automated. The putting of spare tire in trunk in chassis line is still dominated by free dropping method. Through that, parts in trunk such as luggage room lamp, jack and so on were damaged and the complaint of assembler in the next process was occurred due to physical strength. To eliminate these, tile robot system was in this paper developed to place spare tire on the mounting hole in trunk. The movement of robot was synchronized with the velocity of chassis hanger. With this automated system the productivity of the chassis line was increased from the benefits such as simplification of the system using only robot without the mechanically synchronized transport, inserting spare tire into the right position with robot, reduction of damaged parts and production of various type of car.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.1
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• pp.83-89
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• 2018

Purpose : The purpose of this study was to examine the effects of the trunk stabilization exercise in the musical tempo on lumbar lordosis angle, muscle activity and pain. Methods : For the 30 people with lumbar lordosis angle legion and back pain, a random selection was made with MLSE (15) and LSE (15) to measure VAS, lumbar lordosis angle and Muscle Activity. Result : There were significant decreases in intra group comparisons to lumbar lordosis angle were seen in MLSE and LSE groups, and significant decreases in inter group comparisons in MLSE groups. significant decreases in intra group comparisons to VAS were seen in MLSE and LSE groups, and significant decreases in inter group comparisons in MLSE groups. Significant intra-group comparison of muscle activity, MLSE groups increases were rectus obdominis(right/left) and erector spinae muscle(right/left), LSE groups increases were erector spinae muscle(right/left), and significant increases in inter group comparisons rectus obdominis(right) and erector spinae muscle(left) in MLSE groups Conclusion : Based on the above findings, a program to restore the lumbar lordosis angle, and increase muscle strength should be developed at by applying the combine existing trunk stabilization physical therapy technique and musical tempo.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.300-305
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• 2012

Purpose: This study examined the muscle activity of the trunk muscles during weight shifting exercises on a stable and unstable surface. Methods: Ten healthy young subjects (4 males, 6 females) with no medical history of lower-extremity or lumbar spine disease were enrolled in this study. The muscle activity was recorded using surface electromyography (EMG) electrodes from the both sides of the external obliques and erector spinae muscles. Results: The EMG activities of the both rectus abdominalis, both external obliques and erector spinae muscles were significantly higher when the weight shifting exercise was performed on a firm surface than when a balance pad with a balance ball was used. In weight shifting exercises, the EMG activity of the contralateral external obliques and erector spinae muscles was significantly higher than that of the ipsilateral external obliques and erector spinae muscles under all three support surface conditions. Conclusion: Performing weight shifting exercise using an unstable surface is a useful method for facilitating the trunk-muscle strength and trunk stability.

• The Journal of Korean Physical Therapy
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• v.10 no.2
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• pp.57-69
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• 1998

The role of eccentric muscle activities in functional everyday activities and sport is important and equally significant to concentric conditions. Eccentric and concentric exercise and evaluation are, therefore, very important. The purposes of this study were to measure eccentric md concentric peak torgue, percentage of peak torque, average power and percentage of average power of trunk flexors and extensors by using the Cybex NORM isokinetic dynamometer, and to standardize the value obtained. Thirty four young volunteers were tested, 17 females and 17 males, who had no history of back pain or abnormality. Each subjects were tested on three repetitions for isokinetic concentric and eccentric contraction at 5 velocities. The results were as follows; 1) Peak torque percent body weight of eccentric contraction were significantly greater than concentric contraction at each angular velocity and in trunk flexors and extensors(p<0.01). 2) Peak torque percent body weight of concentric contraction were significantly decreased as the angular velocity increased both male and female(p<0.01). 3) Peak torque percent body weight of eccentric contraction were not significantly changed as the angular velocity increased both male and female(p<0.05), 4) Peak torque percent body weight of male were significantly greater than female at each angular velocity and in concentric and eccentric contraction of trunk flexors and extensors(p<0.01)

• Physical Therapy Korea
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• v.5 no.3
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• pp.63-71
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• 1998

Trunk holding test (Sorensen test) appear to have more value than strength test in prediction the occurrence of low back pain. Electromyographic activity of trunk extensor muscles during these test may provide clues to the etiology of neuromuscular-based low back pain. This study investigated the difference in back muscle endurance between healthy adult men and women using surface electromyographic (EMG) power spectral analysis. Thirty hea1thy subjects (15 men and 15 women) performed an unsupported trunk holding test for 60 seconds. Recording surface electrodes were placed over the erector spinae medially and laterally at vertebral levels of $L_1$ and $L_5$. Slope of total frequency was evaluated using the MP100WSW Fast Fourier Transform spectrum analysis program. The slopes of all indices of back muscle fatigue, except right $L_5$, were significantly steeper in men than in women (p<0.05). Our results indicated that the trunk holding test using EMG power spectral analysis of erector spinae muscles is useful for the evaluation of fatigue rate of these muscles. Our results also showed a higher muscle endurance in healthy adult women than in men.

• PNF and Movement
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• v.9 no.3
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• pp.19-24
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• 2011

Purpose : The purpose of this study was to analyze the effect of PNF lower extremity flexion pattern on the eletromyographic (EMG) activity in rectus abdominis, internal oblique abdominal, external oblique abdominal, erector spinae. Methods : Twenty-six healthy adults volunteered to participate in this study. Subjects were required complete following two PNF lower extremity patterns; flexion-adduction-external rotation with knee flexion (D1) and flexion-abduction-internal rotation with knee flexion (D2). A paired t-test was used to determine the influence of the PNF two patterns on muscle activity for each muscle and descriptive statistics was used to determine local/global muscle ratio. Results : The D1 pattern was showed significant rectus abdominis (p<.05) and Median of internal oblique/rectus abdominis ratio was 2.23 and internal oblique/external oblique ratio was 1.53. The D2 pattern showed significant erector spinae (p<.05) and Median of internal oblique/rectus abdominis ratio was 3.06 and internal oblique/external oblique ratio was 1.72. Conclusion : The D1 pattern made rectus abdominis activation increase. The D2 pattern made erector spinae activation increase. As compared D1 and D2 pattern on trunk muscle activation, it's will be useful decision making for the trunk muscle strength and stabilization.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.253-258
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• 2022

Objective: This study aimed to determine the effect of internal abdominis pressure(normal, hollowing and bracing) on trunk muscle activity during one leg bridge exercise. Design: Cross-sectional study. Methods: Thirteen healthy adults (9 men and 4 women) were instructed to perform Internal abdominal pressure(IAP) control(Normal, Hollowing, Bracing) during one leg bridge. Electromyography (EMG) data (% Maximum Voluntary Isometric Contraction, MVIC) were recorded three times on both sides of the participant's Internal Oblique(IO), Effector Spinae(ES), and Multifidus(MF) muscles and the average value was analyzed. Results: As a result, Abdominal bracing one leg bridge (BOLB) group and Abdominal hollowing one leg bridge (HOLB) group showed significantly increased muscle activation of bilateral internal oblique, erector spinae and multifidus activation compared to the Normal one leg bridge (NOLB) group (p<0.05). Abdominal hollowing one leg bridge (HOLB) group had a significant difference in bilateral Internal oblique muscle activation in compared to the NOLB group (p<0.05). Conclusions: Bilateral internal oblique, erector spinae, and multifidus muscles activation in healthy adults at one leg bridge exercise showed greater activation at abdominal bracing. Therefore, in this study, IAP control can be used as an indicator of choice to the dysfunction with trunk muscle weakness and corrective exercise subject's situation when the goal is to activate the trunk muscles by performing one leg bridge.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.353-361
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• 2015

Objective : The aim of this study was to develop the non-powered horse riding device and was to evaluate the elaborate its applicability throughout static structural and transient structural analysis of the outdoor core strength exercise equipment. Method : Fifteen college students (mass: $69.55{\pm}13.38kg$, height: $1.69{\pm}5.61m$, age: $21.42{\pm}1.83yrs$) rode the powered horse riding device and 14 college students (mass: $71.12{\pm}9.74kg$, height: $1.73{\pm}3.31m$, age: $22.50{\pm}1.47yrs$) rode the non-powered horse riding device for the comparison. All motion capture data was collected at 100 Hz using six infrared cameras and the muscular activities were collected using a Delsys Trigno wireless system. The peak forward/backward lean angle, range of motion anter/posterior and vertical COM(Center of mass) movement of trunk and pelvis segment, and muscle activities of six muscles were compared between the two devices by using independent t-test (p<.05). Results : Several kinematic variables (peak forward-backward lean angle and vertical COM movement of trunk and pelvis segment, range of motion of trunk) significantly different between non-powered and powered horse riding device. The muscle activities of Rectus abdominis and External oblique of abdomen on the non-powered horse riding device were significantly greater than those of the powered device. Conclusion : It was concluded that non-power horse riding device could give the effect of core strength exercise as well as the body motion which can simulate the powered horse riding device.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.121-134
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• 2006

The purpose of this study was to analyze the effect of different types of rehabilitation training program on the kinetic and kinematic parameters during sit-to-stand movement(STS) in chronic stroke patients. Two groups of hemiparetic patients, experimental and control, participated in the study. The experimental group participated in a 10-week training program (three sessions/wk, $1{\sim}1.5\;hr/session$) consisting of a warm-up, aerobic exercises, lower extremity strengthening. and a cool-down. The control group participated in an aerobic exercise. Three dimensional kinematic analysis and force platform; were used to analyze the duration of STS, lower extremity angle, and weight bearing ability. The experimental group which had more strength of lower extremity displayed decrease in duration of STS. However, the control group showed increases in duration during sit-to-stand movement. The control group flexed their trunk more than the group did Therefore, it took more time to extend their trunk during STS. The duration in sit-to-stand was affected by the strength of lower extremity and the angle of trunk movement. The angles of ankle and knee joint had an influenced on duration of STS. The post experimental group performed with their feet near the front leg of the chair during sit-to-stand, therefore the duration was decreased. The repetitive sit-to-stand movements as a resistance exercise was effective to hemiparetic patients in learning mechanism of sit-to-stand. The control group showed decreased differences in the vertical ground reaction forces between paretic and non-paretic limbs. Their training program included strengthening exercise that may help improving weight bearing ability. The control group showed increases in the center of pressure in the anteroposterior and mediolateral displacement. This means that the stability of movement was low in the control group. Their training program which combined aerobic and strengthening exercises that are more effective to improve the stability of movement.