• 대한통합의학회지
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• 제10권2호
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• pp.115-123
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• 2022

Purpose : The hamstring is a group of three muscles, biceps femoris, semitendinosus, and semimembranosus, placed behind the thigh. The hamstring is one of the most commonly injured muscles and usually occurs during high-speed, high-intensity exercise. The purpose of this study was to investigate the effect of static stretching and eccentric exercise of hamstrings on flexibility, strength, and functional performance. Methods : This study was conducted on 28 healthy adults. Subjects were divided into a static stretching group (n=15) and an eccentric exercise group (n=13). Subjects measured hamstring flexibility (active knee extension test), hamstring strength (concentric and eccentric peak torque), and functional performance (triple hop for distance and modified 20 m sprint). The intervention was conducted three times a week for six weeks. To compare the difference between values before and after the intervention, paired t-test was used, and an independent t-test was used to compare between groups. Results : In both groups, the active knee extension test, concentric peak torque, triple hop test, and 20 m sprint significantly increased after the intervention compared to before the intervention (p<.05). However, no significant difference was found in eccentric peak torque after intervention in both groups (p>.05). No significant difference was found between the two groups in the effect on the variables (p>.05). Conclusion : Both interventions were found to be effective for flexibility, concentric strength, and functional performance. Eccentric exercise and static stretching are recommended to improve the flexibility and functional performance of the hamstring. This study's results will be considered essential data on the effectiveness of static stretching and eccentric exercise.

• 한국전문물리치료학회지
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• 제31권2호
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• pp.142-150
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• 2024

Background: Scapular dyskinesis (SD) is closely related to imbalance of the rotator cuff (RC) muscles. However, previous studies have only focused on isometric strength. To our knowledge, there has been no study examining potential differences in concentric and eccentric strength and functional strength ratio (FSR) of the RC muscles based on functional parameters related to throwing in with or without SD. Objects: This study aimed to determine whether there was a difference in the RC muscle strength and FSR between the dominant shoulder with SD and the non-dominant shoulder without SD in adolescent baseball players. Methods: Forty adolescent baseball players participated and classified types of SD based on movement patterns using the SD test by two examiners. The isokinetic concentric and eccentric peak torque of the internal rotation (IR) and external rotation (ER) were measured and quantified as peak torque to body weight (PT/BW). Also, the FSR was obtained by calculating the strength ratios of eccentric IR to concentric ER (IRecc/ERcon) and eccentric ER to concentric IR (ERecc/IRcon), respectively. Results: There was a significant decrease in the IR and ER PT/BW in the dominant shoulder with SD compared to the non-dominant shoulder without SD (p < 0.05), regardless of contraction types. However, no significant difference was observed in the FSR in both IRecc/ERcon and ERecc/IRcon ratios. Conclusion: The findings indicate that the isokinetic concentric and eccentric PT/BW of the IR and ER muscles were significantly lower in the dominant shoulder with SD than in the nonthrowing shoulder without SD. Therefore, when establishing a strategy for addressing RC muscle weakness in adolescent baseball players with SD, it is essential to consider an approach that accounts for scapular kinematic recovery.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.145-150
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• 2003

The objective of this study is to investigate the effect of torsional eccentricity on the seismic response of high-rise RC bearing-wall structures with vertical irregularity. For this purpose, two 1:12 scale 17-story RC model structures, the one has concentric shear wall and the other has eccentric shear wall, were constructed and then subjected to a series of earthquake excitations. The test result shows the followings: 1) the layout of shear wall has the negligible effect on the natural period and the base shear coefficient, 2) the eccentric model behaves in the first and second mode while the concentric model has the first mode predominantly, 3) the stiff frame in the eccentric model resists most of overturning moment in the severe earthquake though both frames (the stiff and flexible frames) resist almost equally in the design earthquake.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.585-596
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• 2001

The twenty one individuals with total knee replacement who were admitted to Kang-Dong Hospital for comprehensive physical therapy were studied in order to demonstrate the effectiveness of an isokinetic test program using the Cybex 6000 machine. The subjects were divided into three groups with the isometric exercise group receiving isometric exercise, the isokinetic eccentric exercise group, and isokinetic concentric exercise group receivind isokinetic exercise(eccentric, concentric) to knee flexors and extensors muscles for a six weeks' period using the Cybex 6000. The results are follow: 1. The extensors were increased significantly at all groups after 6 weeks training(p<.05). The flexors were increased significantly at isokinetic eccentric and isokinetic concentric group but no significantly differences at isometric group(p>.05) 2. At the effect of extensors and flexors after 6 weeks training. higher to 30$^{\circ}$ /sec of isokinetic concentric exercise, lower to 120$^{\circ}$ /sec of isometric exercise. 3. The peak torque was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 4. The total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 5. The ratio of peak torque to body weight were more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 6. The average power was more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 7. The average R.O.M in the pre-exercise and post-exercise was not different significantly in all three groups. According to the above results, In the muscle strength recovery for total knee replacement patients, isokinetic concentric exercise group was significantly greater than the isokinetic eccentric and isometric exercise groups after a six weeks training.

• 한국강구조학회 논문집
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• 제14권5호통권60호
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• pp.567-576
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• 2002

중심 및 2축편심압축에 대한 고강도콘크리트충전 각형강관기둥에 대해 실험 및 해석을 수행하며, 실험변수는 기둥의 좌굴길이대 단면폭의 비 $L_k/D$, 편심의 크기 e, 그리고 편심하중의 각 ${\theta}$이다. 실험을 통하여 2축휨을 받는 고강도콘크리트충전 각형강관기둥의 내력 및 거동을 조사한 결과, 2축편심압축력을 받는 CFT기둥의 실험에 의한 최대내력 및 거동은 해석에 의한 값과 비교적 잘 일치하였다.

• 한국공간구조학회논문집
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• 제22권2호
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• pp.29-37
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• 2022

The collapse of reinforced concrete (RC) frame buildings is mainly caused by the failure of columns. To prevent brittle failure of RC column, numerous studies have been conducted on the seismic performance of strengthened RC columns. Concrete jacketing method, which is one of the retrofitting method of RC members, can enhance strength and stiffness of original RC column with enlarged section and provide uniformly distributed lateral load capacity throughout the structure. The experimental studies have been conducted by many researchers to analyze seismic performance of seismic strengthened RC column. However, structures which have plan and vertical irregularities shows torsional behavior, and therefore it causes large deformation on RC column when subjected to seismic load. Thus, test results from concentric cyclic loading can be overestimated comparing to eccentric cyclic test results, In this paper, two kinds of eccentric loading pattern was suggested to analyze structural performance of RC columns, which are strengthened by concrete jacketing method with new details in jacketed section. Based on the results, it is concluded that specimens strengthened with new concrete jacketing method increased 830% of maximum load, 150% of maximum displacement and changed the failure modes of non-strengthened RC columns.

• The Journal of Korean Physical Therapy
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• 제13권1호
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• pp.19-31
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• 2001

The twenty one individuals with total knee replacement who were admitted to Kang-Dong Hospital for comprehensive physical therapy were studied in order to demonstrate the effectiveness of an isokinetic test program using the Cybex 6000 machine. The subjects were divided into three groups with the isometric exercise group receiving isometric exercise. the isokinetic eccentric exercise group, and isokinetic eccentric exorcise group receiving isokinetic exercise(eccentric. concentric) to knee flexors and extensors muscles for a six weeks period using the Cybex 6000. The results were follow :1 . The peak torque was increased significantly in the flexors and extensors of the isokinetic conccentric exorcise among three groups(p<.05). 2. The progress of peak torque was increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<.05). 3. The total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<.05). 4. The progress of total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups(p<;.05). 5. The ratio of endurance was not increased significantly in all three groups. 6. The extensors in the peak torque was likely to recover rapidly than the flexors. 7.The average R.O.M in the pre-exercise and post-exercise was not different significantly in all three groups. According to the above results, In the muscle strength recovery for total knee replacement patients, isokinetic concentric exercise group was significantly greater than the isokinetic eccentric and isometric exercise groups after a six weeks training.

• 한국강구조학회 논문집
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• 제14권6호
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• pp.823-834
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• 2002

Steel-Concrete Column은 H형강의 플랜지 사이에 후프를 용접하고 플랜지 사이의 공간에 콘크리트가 채워진 새로운 합성기둥이다. 본 연구에서는 이 새로운 합성 기둥의 구조성능을 평가하기 위하여 단주압축, 휨, 전단실험을 수행하였다. 각 실험별 실험체들을 순철골 실험체와 철골 콘크리트 실험체로 구성하여 Steel-Concrete Column을 구성하는 철골, 내부 콘크리트, 후프의 내력기여도를 평가할 수 있도록 하였다. 실험결과 Steel-Concrete Column은 $\ulcorner$강구조 한계상태 설계 기준$\lrcorner$ 에 의해 계산된 내력값을 충분히 만족하여 구조부재에 적용 가능하다고 판단된다.

• Steel and Composite Structures
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• 제34권6호
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• pp.909-927
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• 2020

This paper addresses the results of an experimental study involving 10 partially encased composite columns under concentric and eccentric compressive loads. Parameters such as slenderness ratio, ordinary reinforced concrete and fiber reinforced concrete, load eccentricity and bending axis were investigated. The specimens were tested to investigate the effects of replacing the ordinary reinforced concrete by fiber reinforced concrete on the load capacity and behavior of short and slender composite columns. Various characteristics such as load capacity, axial strains behavior, stiffness, strains on steel and concrete and failure mode are discussed. The main conclusions that may be drawn from all the test results is that the behavior and ultimate load are rather sensitive to the slenderness of the columns and to the eccentricity of loading, specially the bending axis. Experimental results also indicate that replacing the ordinary reinforced concrete by steel fiber reinforced concrete has no considerable effects on the load capacity and behavior of the short and slender columns and the proposed replacement presented very good results.

• 대한물리치료과학회지
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• 제10권1호
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• pp.74-82
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• 2003

The purpose of this study is to provide guideline of muscle strengthening exercise for preparing ambulation by presenting suitable ratio of muscle power of agonist & antagonist, and that of concentric & eccentric contraction on behalf of amputee's normal ambulation training and it's strenthening as well. 7 Subjects who have femur amputee for experimental group were able to ambulate naturally without inconvenience and 20 adult subjects of comparison group for comparison were considered to be free from disturbance of ambulation. The method of study was to measure the muscle power of hip pint, was to figure out the ratio of agonist & antagonist, concentric contraction & eccentric contraction, and was to find out mean and standard deviation of each measurement. Every numerical value of comparison was tested by Mann-whitney and comparison group's comparison between left & right value was done with t-test. Results are as followings : 1) Extension force was stronger than flexor force and had no remarkable difference(p<0.05) 2) For normal adults, adduction farce was stronger than abduction force and for amputees, abduction force was stronger while adduction force was the same as the normal without showing remarkable difference(p<0.05) According the result above, I make an assumption that maintaining a proper ratio of muscle power on strengthening exercise for amputee's ambulation training & rehabilitation and finally bring out an improvement of transfer and ambulation.