• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.2
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• pp.45-54
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• 2007

The purpose of this study was effect of hamstring length on one leg stance test(OLST) in 108 persons. (men 28, women 80). The active knee extension test(AKE) was applied 3 times on both leg and high score was selected. Then, one leg stance test(OLST) was applied 3 times on both leg and high score was selected. Also, persons divided two group that is normal hamstring length group and shortening group). The result were as follows : 1. The correlation analysis between Lt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.271$, $p_{Rt.}=0.051$). 2. The correlation analysis between Rt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.837$, $p_{Rt.}=0.334$). 3. The independent T -test between Lt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in Lt. leg stance time was no significant difference(p=0.73), but in Rt. leg stance time was statistically significant difference(p=0.04). 4. The independent T-test between Rt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in one leg stance time was no significant difference($p_{Lt.}=0.09$, $p_{Rt.}=0.16$).

• PNF and Movement
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• v.15 no.2
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• pp.177-183
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• 2017

Purpose: This study compared and analyzed the effect of the proprioceptive neuromuscular facilitation (PNF) arm extension pattern and leg flexion pattern on the contralateral lower extremity muscles when the patterns were applied to the same subject. Methods: In the study, 35 healthy men and women who understood the PNF patterns were selected as participants. The participants completed the PNF arm extension-abduction-internal rotation pattern and leg flexion-adduction-external rotation with knee flexion pattern in the supine position. While the patients' completed each pattern, the contralateral leg muscle activity was measured to examine the irradiation effect. The maximum isometric contraction time of the muscles to be measured was kept for 5 seconds, and the mean value was obtained by repeating the pattern three times. Results: When the leg flexion-adduction-external rotation with knee flexion pattern was completed, the muscle activity in the vastus lateralis, vastus medialis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity was significantly greater than that found in the PNF arm extension-abduction-internal rotation pattern. Conclusion: The PNF leg flexion pattern showed greater muscle activity on the contralateral lower extremity than the arm extension pattern. Thus, the PNF leg extension pattern is more effective in the activation of the muscles associated with weight-bearing activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.326-330
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• 2004

This study is object to design and structural analysis of Leg Extension Machine. Design tool is AutoCAD and structural analysis of Leg Extension Machine using result from ANSYS Code. This structural analysis results, many variables such as boundary condition, constraint condition and load condition are considered.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.131-142
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• 2005

This study was investigated the stability of the AK amputee gait through analysing the variability on kinematic variables between the sound leg and the prosthetic limb. The one male, AK amputee who could walk for himself with his prosthetic limb was participated in this study. Six cameras of the MCU 240 and the QTM(Qualisys Track Manager) software were used for data collecting in this study. The relative angle of both segments was the difference between the absolute angle of the distal segment and the absolute angle of the proximal segment. The coupling angles between the prosthetic limb and the sound leg were caculated on the thigh Flexion/Extension in relative to the shank Flexion/Extension and the shank Flexion/Extension n relative to the foot Flexion/Extension. In order to evaluate the variability of segment and joint angle, C.V. was used, and to evaluate the variability for coupling angles, the Relative motion calculated by vector coding method of the continuous methods was used. As stated, the gait pattern of the prosthetic limb was almost similar gait pattern of the sound leg, but the prosthetic limb showed that the gait pattern of the sound leg and the prosthetic limb were not stable against the sound leg.

• PNF and Movement
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• v.17 no.3
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• pp.391-399
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• 2019

Purpose: This study investigated the three-dimensional moment values of the hip joint for subjects with artificial leg length alterations and subjects with unaltered leg lengths. Methods: Forty-two healthy adults (8 men, 34 women) participated in this study. The selected subjects were able to walk normally, had less than a 1 cm leg length discrepancy, and were instructed to wear shoes that fit their feet. The study participants performed 8 dynamic gait trails to measure the hip joint moment using a three-dimensional motion analysis system. Kinetic and dynamic three-dimensional gait analysis data were collected from infrared cameras, and a force plate was used to standardize the weight of each subject. Results: There were significant correlations between the differences in the leg length discrepancy during right extension, right flexion, right internal rotation, and left extension in hip joint moments (p<0.05). There were significant correlations between the differences in shoe conditions during left extension, right flexion, right extension, and right internal rotation in the hip moments (p<0.05). Conclusion: This study suggests that a leg length discrepancy can affect hip joint moment, which may further exacerbate musculoskeletal disorders, such as osteoarthritis in lower extremity joints. Therefore, further studies should be conducted to verify the impact of clinical interventions on differences in hip joint moment values to correct leg length discrepancies and prevent osteoarthritis in lower extremity joints.

• PNF and Movement
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• v.14 no.3
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• pp.195-202
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• 2016

Purpose: This study investigates the influence of applying proprioceptive neuromuscular facilitation (PNF) leg patterns on the activation of three types of mesogluteal fibers at the opposite side. Methods: The target subjects of this study were 19 healthy men who voluntarily agreed to participate in the program. For all subjects, the following four PNF leg patterns were applied while they were in a standing position, and then, the activation of the gluteus medius at the opposite side was measured: (1) flexion abduction internal rotation pattern, (2) flexion adduction external rotation pattern, (3) extension abduction internal rotation pattern, and (4) extension adduction external rotation pattern. In each position, a pattern was executed three times in 5 s, and the average of each measurement was used for the statistics. Results: Among the PNF leg patterns, the activation of the mesogluteal fibers at the opposite side was most significant under the application of the extension abduction internal rotation pattern. The activation of the back muscular fiber was significantly high under the application of the flexion abduction internal rotation pattern. Conclusion: Selective application of PNF leg patterns can improve the functional activity of each mesogluteal fiber.

• Journal of Korean Physical Therapy Science
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• v.30 no.1
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• pp.31-40
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• 2023

Hamstring flexibility is an important factor that affects muscle performance of the lower extremities and is closely associated with sports injuries. Therefore, evaluation of flexibility is important in clinical practice. Results of evaluation are determined by types of tests and cut-off values used; therefore, accurate and detailed understanding of these is necessary before examination. Although the straight leg raise and sit and reach tests are used to evaluate hamstring extensibility, structures including the nerves, fascia, and other muscles can significantly confound the results of these tests. The knee extension test is performed at 90° of hip flexion to minimize the posterior pelvic tilt that occurs during the straight leg test. The knee extension test is most recommended for selective evaluation of hamstring flexibility. The knee extension test is classified into active and passive tests. The cut-off value is usually set at 20° for the active and at 10° for the passive knee extension test. Although a strong association is observed between the two tests, the active knee extension test is preferred in clinical practice because it can be performed by a single examiner, which serves as an advantage. Age, sex, and warm-up exercise tend to affect flexibility; therefore, results should be interpreted with caution. Detailed understanding of each flexibility test is important for reliable evaluation.

• PNF and Movement
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• v.17 no.2
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• pp.263-274
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• 2019

Purpose: This article was conducted to determine the immediate effects of unilateral contract-relax (CR) stretching on contralateral knee extension range and to compare both sides of the knee extension range between experimental and control groups. Methods: This study recruited 16 adult males and females with straight leg raising abilities below $90^{\circ}$. The subjects were randomly divided into an experimental group and a control group comprising 8 subjects each. The experimental group performed direct CR stretching on the right hamstring muscles with straight hip extension adduction, and the control group performed indirect CR stretching on the right hamstring muscles with straight hip flexion abduction. Each group performed CR stretching 4 times with 4 repetitions comprising 10 sec of contraction and a 10 sec break between repetitions. Before and after the CR stretching exercises, the subjects' passive knee extensions were measured at the hip in a $90^{\circ}$ flexed position. The subjects' peak force on the right leg and peak pressure on the left leg during each CR stretching exercise were also measured. Results: After doing CR stretching 4 times, each group showed a significantly increased passive knee extension range on both sides, and there was no difference in the passive knee extension ranges between the groups. The peak force on the right leg was significantly higher in the experimental group than the control group. There was no difference in peak pressure between the groups. Conclusion: After applying unilateral CR stretching, the study subjects experienced a significantly increased passive knee extension range on the contralateral side. For patients who find it difficult to apply stretching techniques to knee joints directly, the use of the proprioceptive neuromuscular facilitation technique of CR stretching may be useful in improving the range of the knee joint on the contralateral side without direct treatment.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.288-300
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• 2015

Since the first jack-up was built, jackups have become the most popular type of mobile offshore drilling unit (MODU) for offshore exploration and development purposes in shallow water. The most pivotal component of the jack-up unit is the leg, which can directly affect the global performance of the unit. In this paper, an investigation into extending the length of the jack up leg is carried out in order to study the enhancement of the rig capability to drill in deeper water approaching the range of the Semisubmersible Drilling Unit (SSDU) (300-1000ft). A study of the performance of a deep-water jack-up unit is performed with different leg lengths. Typical leg scantling dimensions and identical external loads are assigned, and then a detailed Finite Element Analysis (FEA) model is created in order to simulate the jack-up leg unit's structural behavior. A Multi-point Constraint (MPC) element together with the spring element is used to deal with the boundary conditions. Finally, a comparative analysis for five leg lengths is carried out to illustrate their performance, including the ultimate static strength, and weight.

• Physical Therapy Korea
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• v.8 no.1
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• pp.76-88
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• 2001

Back extension exercises have been used for rehabilitation of the injured low back, prevention of injury, and fitness training programs. However, excessive loading on low back can exacerbate existing structural weakness. The purpose of this study was to compare muscle activity of low back muscles during back extension exercises. Twenty healthy male subject s were evaluated. Electromyographic (EMG) activities of low back muscles at L1 and L5 level were recorded during seven different back extension exercises and two reference tasks by surface EMG and saved for data analysis. Reference tasks of lifting 20% and 40% of their body weight were included for comparison. The result were as follows: 1) Single-arm extension and single-leg extension exercises on quadruped position appeared to constitute a low-risk exercise for initial extensor strengthening. 2) When arm extension was combined with contralateral leg extension on quadruped position, EMG activities of low back muscles were increased. 3) EMG activity of low back muscles was highest during the trunk extension exercises on prone position. 4) EMG activities of low back muscles during arm and leg extension exercises on quadruped position were less than those of reference task of lifting 40% of their body weight. These result s have important implications for progressive back extensor muscle strengthening exercises in patients with back pain.