• Title/Summary/Keyword: Joint stability

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Evaluation of the Roadbed Behavior During Tilting-train Operation in Curved Track Using Numerical Analysis (틸팅차량의 곡선부 운행시 수치해석을 이용한 노반거동 평가)

  • Jeon, Sang-Soo;Eum, Gi-Young;Kim, Jae-Min
    • Journal of the Korean Geotechnical Society
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    • v.23 no.6
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    • pp.115-126
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    • 2007
  • The tilting-train is very attractive to the railroad users in the world because it runs with high speed in curved track using pre-existing infrastructure. The tilting-train has a unique allowable speed and mechanism expecially in curved track. Therefore, it should be evaluated in terms of the stability of the train operation and roadbed. In this study, when the tilting-train is being operated with the allowable speed, the behavior of the roadbed is evaluated by examining the settlement and bearing capacity of the roadbed. Additionally, the stability of the roadbed is estimated in the condition of soft roadbed influenced by the weather effects and cyclic train loading. The numerical results show that the roadbed settlements satisfy the allowable settlement when Young's moduli of the upper roadbed and in-situ soil are more than $2,300t/m^2\;and\;3,300t/m^2$, respectively, in the continuous welded rail (CWR) and $3,800t/m^2\;and\;4,600t/m^2$, respectively, in the rail joint.

Comparison of Center of Pressure Displacement during Sit to Stand to Sit and Balance Ability of Subjects with and without Chronic Ankle Instability

  • Hyun-Sung Kim;Seung-Jun Oh
    • Journal of The Korean Society of Integrative Medicine
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    • v.11 no.1
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    • pp.13-20
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    • 2023
  • Purpose : The purpose of this study is to compare the balance ability between subjects with chronic ankle instability and normal people and the center of pressure displacement during the sit to stand and stand to sit. Methods : The subjects of this study were 63 who met the inclusion criteria and were classified into normal group (n=33) and chronic ankle instability group (n=30). The displacement of the center of pressure during sit to stand and stand to sit was measured. And the limit of stability and Y-balance tests were performed to measure the balance ability. Independent t-test was conducted to compare center of pressure displacement and balance ability between groups, and pearson correlation was conducted to analyze the correlation between the center of pressure displacement and balance ability. Results : In the case of the center of pressure displacement, there was a significant difference between the two groups during sit to stand and stand to sit. In the case of balance, both limit of stability and Y-balance test showed significant differences between the two groups. At the time of sit to stand, the center of pressure displacement showed a significant correlation with balance abilities, and at the time of stand to sit, the center of pressure displacement showed a significant correlation with Y-balance test. Conclusion : Chronic ankle instability shows that there is a lot of sway in the body due to compensation to replace the decrease in ankle joint range of motion when performing sit to stand and stand to sit due to sensory input damage such as decrease in ankle range of motion and decrease in ankle proprioception. Chronic ankle instability is expected to have a negative effect on our daily lives in life. The results of this study will serve as the basis for the dynamic approach to objective evaluation, treatment, and prevention of chronic ankle instability.

Peroneal Muscle and Biceps Femoris Muscle Activation During Eversion With and Without Plantarflexion in Sitting and Side-lying Postures

  • Do-eun Lee;Jun-hee Kim;Seung-yoon Han;Oh-yun Kwon
    • Physical Therapy Korea
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    • v.31 no.1
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    • pp.18-28
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    • 2024
  • Background: Lateral instability of the ankle is one of the most common causes of musculoskeletal ankle injuries. The peroneus longus (PL) and peroneus brevis (PB) contribute to ankle stability. In early rehabilitation, isometric exercises have been selected for improvement of ankle stability. To effectively train the peroneal muscles during eversion, it is important to consider ankle and body posture. Objects: This study aimed to compare activation of the PL, PB, and biceps femoris (BF) muscles during eversion in different ankle postures (neutral [N], plantarflexed [PF]) and body postures (sitting and side-lying). Methods: Thirty healthy individuals with no history of lateral ankle sprains within the last 6 months were included in the study. Maximal isometric strength of eversion and muscle activation were measured simultaneously. Muscle activation at submaximal eversion was divided by the highest value obtained from maximal isometric eversion among the four postures (percent maximal voluntary isometric contraction [%MVIC]). To examine the differences in muscle activation depending on posture, a 2 × 2 repeated measures analysis of variance (ANOVA) was conducted. Results: There were significant interaction effects of ankle and body postures on PL muscle activation and evertor strength (p < 0.05). The PL muscle activation showed a significantly greater difference in the side-lying and PF conditions than in the sitting and N conditions (p < 0.05). Evertor strength was greater in the N compared to the PF condition regardless of body posture (p < 0.05). In the case of PB and BF muscle activation, only the main effects of ankle and body posture were observed (p < 0.05). Conclusion: Among the four postures, the side-lying-PF posture produced the highest muscle activation. The side-lying-PF posture may be preferred for effective peroneal muscle exercises, even when considering the BF muscle.

Relationship between Attenuation of Impact Shock at High Frequency and Flexion-Extension of the Lower Extremity Joints during Downhill Running

  • Ryu, Ji-Seon;Yoon, Suk-Hoon;Park, Sang-Kyoon
    • Korean Journal of Applied Biomechanics
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    • v.26 no.2
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    • pp.167-174
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    • 2016
  • Objective: The purpose of this study was to determine the interrelationship between ranges of motion of the knee and ankle joints on the sagittal plane and the attenuation magnitude of impact shock at high frequency (9~20 Hz) in the support phase during downhill running. Method: Fifteen male heel-toe runners with no history of lower extremity injuries were recruited for this study (age, $25.07{\pm}5.35years$; height, $175.4{\pm}4.6cm$; mass, $75.8{\pm}.70kg$). Two uniaxial accelerometers were mounted to the tuberosity of tibia and sacrum, respectively, to measure acceleration signals. The participants were asked to run at their preferred running speed on a treadmill set at $0^{\circ}$, $7^{\circ}$, and $15^{\circ}$ downhill. Six optical cameras were placed around the treadmill to capture the coordinates of the joints of the lower extremities. The power spectrum densities of the two acceleration signals were analyzed and used in the transfer function describing the gain and attenuation of impact shock between the tibia and the sacrum. Angles of the knee and ankle joints on the sagittal plane and their angle ranges were calculated. The Pearson correlation coefficient was used to test the relationship between two variables, the magnitude of impact shock, and the range of joint angle under three downhill conditions. The alpha level was set at .05. Results: Close correlations were observed between the knee joint range of motion and the attenuation magnitude of impact shock regardless of running slopes (p<.05), and positive correlations were found between the ranges of motion of the knee and ankle joints and the attenuation magnitude of impact shock in $15^{\circ}$ downhill running (p<.05). Conclusion: In conclusion, increased knee flexion might be required to attenuate impact shock during downhill and level running through change in stride or cadence while maintaining stability, and strong and flexible ankle joints are also needed in steeper downhill running.

Numerical Analysis of Deformation Behaviour of Underground Opening in a Discontinuous Rock Mass Using a Continuum Joint Model (연속체 절리모델을 이용한 불연속성암반 내 지하공동의 변형거동에 관한 수치해석)

  • Kang Sang Soo;Lee Jong-Kil;Baek Hwanjo
    • The Journal of Engineering Geology
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    • v.15 no.3
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    • pp.257-268
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    • 2005
  • In situ rock mass is generally heterogeneous and discontinuous, with varying degrees of strength along the planes of weakness. The planes of weakness such as joints, faults, cracks and bedding planes, control the strength and deformation characteristics of the rock mass. Subsequently, the stability of underground opening depends upon the spatial distribution of discontinuities and their mechanical properties in relation with geometrical shape of openins as well as the mechanical properties of intact rock materials. Understanding the behaviour of a discontinuous rock mass remains a key issue for improving excavation design in hiかy stressed environments. Although recent advances in rock mechanics have provided guidelines for the design of underground opening in isotropic rock mass, prediction and control of deformation in discontinuous rock masses are still unclear. In this study, parametric study was performed to investigate the plastic zone size, stress distribution and deformation behavior around underground opening in a discontinuous rock mass using a continuum joint model. The solutions were obtained by an elasto-plastic finite difference analysis, employing the Mohr-Coulomb failure criteria. Non-associated flow rule and perfectly plastic material behavior are also assumed.

Measurement of Muscle Strength of Ankle Joint Using Isokinetic Dynamometer in Normal Korean Adults (등속성 운동검사를 이용한 정상 한국인 성인에서의 발목관절 근력 측정)

  • Choi, Seung-Myung;Park, Ji-Kang;Ha, Yoon-Won;Cho, Byung-Ki
    • Journal of Korean Foot and Ankle Society
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    • v.19 no.4
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    • pp.142-150
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    • 2015
  • Purpose: Restoration of ankle stability through the strengthening exercise of peroneus muscles is considered an important factor for achievement of successful outcomes, in the rehabilitation program following ankle ligament injuries. However, there were few definitive data on normal muscle strength, including eversion power by peroneus muscles. This study was conducted to evaluate the muscle strength of ankle joint measured using an isokinetic dynamometer in normal Koreans. Materials and Methods: Sixty adults (120 ankles) were recruited and divided into three groups (20 in their twenties, 20 in thirties, and 20 in forties). Each group consisted of 10 males and 10 females. The selection criteria were no history of ankle injury and no evidence of instability. The peak torque, total work, and deficit ratio were measured using the Biodex$^{TM}$ (Biodex Medical Systems). Differences in muscle strength by age, gender and dominant versus non-dominant side were analyzed. Results: The peak torque of dorsiflexion was average 31.5 Nm at $30^{\circ}/s$ of angular velocity and 18.8 Nm at $90^{\circ}/s$; average 69.3 Nm ($30^{\circ}/s$) and 42.4 Nm ($90^{\circ}/s$) on plantarflexion; average 19.6 Nm ($30^{\circ}/s$) and 10.8 Nm ($90^{\circ}/s$) on inversion; average 12.9 Nm ($30^{\circ}/s$) and 8.0 Nm ($90^{\circ}/s$) on eversion. The deficit ratio of strength in women was average 61.1% of men on dorsiflexion; average 66.2% on plantarflexion; average 48.5% on inversion; average 55.4% on eversion. The deficit ratio in non-dominant foot was average 88.6% of dominant foot on dorsiflexion; average 90.1% on plantarflexion; average 85.1% on inversion; average 85.6% on eversion. Conclusion: The muscle strength of the ankle joint showed a tendency to weaken with age. There were significant differences in muscle strength by gender and dominancy. Further studies for comparison of patients with ankle instability, a comparison between before and after surgery for instability, the correlation between clinical outcomes and the recovery in muscle strength will be needed.

Application of Hinged Transarticular External Skeletal Fixator (HTAESF) for Proximal Tibial Physeal Fracture in a Dog (개의 근위 경골 성장판 골절에서 경첩 관절경유 외고정의 적용)

  • Kim, Kwan;Heo, Su-Young;Lee, Hae-Beom
    • Journal of Veterinary Clinics
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    • v.29 no.6
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    • pp.502-505
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    • 2012
  • An 8-month-old, 3.5 kg intact female Toy Poodle was presented for non-weight-bearing lameness on left hindlimb. In radiological testing, left proximal tibal type II Salter-Harris physeal fracture and fibular fracture were seen. Following open reduction, the fracture was stabilized with cross-pins, tension band wires, and a hinged transarticular external skeletal fixator (HTAESF). The range of the HTAESF was increased to $25^{\circ}$ at 7 days postsurgery and to $70^{\circ}$ at 14 days post-surgery. The HTAESF was removed 3 weeks after surgery. At 6 weeks post-surgery, the fracture was successfully healed with no complications and the patient recovered a normal gait. Seven months post-surgery, the patient had a normal gait and a normal stifle joint range of motion compared to the contralateral normal limb. This is a case in which the combined use of cross-pins, tension band wires, and HTAESF was successful for treatment of a proximal tibial physeal fracture in a dog. It is thought that these methods are beneficial for stability of fracture site and recover of joint's normal range of motion through early joint movement.

Detailed Deterioration Evaluation and Analysis of Conservation Environment for the Seosanmaaesamjonbulsang (Rock-carved Triad Buddha in Seosan), Korea (서산마애삼존불상의 정밀 손상도 평가와 보존환경 분석)

  • Lee, Sun-Myung;Lee, Chan-Hee;Kim, Ji-Young
    • Journal of Conservation Science
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    • v.26 no.3
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    • pp.277-294
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    • 2010
  • The Seosanmaaesamjonbulsang (National Treasure No. 84) consists of light gray and coarse to mediumgrained biotite granite with partly developed pegmatite and quartz vein. The host rock is divided into dozens of rock blocks with various shape along irregular discontinuity plane. The evaluation results of discontinuity systems reveal that the host rock were exposed to instable sloping environments. Results of deterioration diagnosis show that the degree of damage has been made worse by physical weathering and surface discoloration laying stress on part that vertical and horizontal joints are massed. Generally, deterioration rate of the triad Buddha surface cover with 42.7%, however, the rate of physical weathering and surface discoloration are subdivided to 9.6% and 33.1%, respectively. Ultrasonic measurements indicate that the triad Buddha was reached highly weathered grade in general. And the rock material was weaken to show low velocity zone of 1,000m/s along irregular joint systems. Indoor and outdoor mean relative humidity of the shelter was recorded more than 70% during every season, and high frequency appears in high relative humidity range over 95%. Such environments seem to have produced dew condensation on the rock surface with rainfall and supply water, promoted physical, chemical and biological weathering along crack and joint, resulting in high permeation of water and percentage of water content. Therefore, it is judged that for scientific conservation of the triad Buddha it needs environment control through persistent preservation environment monitoring including water problem.

Treatment of Acromioclavicular Joint Injuries Using Clavicle Hook Plates (Clavicle Hook Plate를 이용한 견봉 쇄골 관절 손상의 치료)

  • Kim, Myung-Ho;Seo, Joong-Bae;Moon, Sang-Young
    • Clinics in Shoulder and Elbow
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    • v.13 no.1
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    • pp.92-98
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    • 2010
  • Purpose: To analyze results of treating acromioclavicular injuries using clavicle hook plates. Materials and Methods: Between February 2008 and April 2010, 18 patients with acromioclavicular joint injury treated by clavicle hook plates were reviewed. Using the Rockwood classification, 7 dislocations were classified as type III injuries and 11 as type V injuries. Implant removal was done at least 3 months from initial fixation. Simple X-rays were taken for comparing the state of reduction, and clinical outcomes were evaluated by the Korean Shoulder Scoring System and the American Shoulder Elbow Society score. The average follow-up period was 9 months. Results: On weight bearing X-rays, the average coracoclavicular distance showed a 114% increase compared to the contralateral side at the time of injury. It decreased to 23% by the last follow-up. The mean Korean Shoulder Scoring System and the American Shoulder Elbow Society score were 80 and 74 at the last follow-up. Conclusion: The immediate stability these plates provide allows rapid rehabilitation. Clavicle hook plate fixation for acromioclavicular joint dislocation is considered an effective method for ensuring satisfactory results both radiologically and clinically.

A HISTOLOGIC STUDY OF THE CHANGE OF TEMPOROMANDIBULAR JOINT AFTER UNILATERAL DISTRACTION OF MANDIBLE (편측 하악골 신장술에 의한 악관절의 변화에 관한 조직학적 연구)

  • An, Jung-Mo;Oh, Se-Jong;Cha, Yong-Doo;Kwon, Soon-Yong;Park, Young-Ju;Park, Jun-Woo;Rhee, Gun-Joo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.26 no.6
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    • pp.591-601
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    • 2000
  • The objective of this study was to find out whether the unilateral distraction of mandible has an influence on temporomandibular joint and if it does, how significant the influence is. Four beagle dogs were used in this study. Each dog had two implants placed into the left mandible. The mandible was distracted for 14days with an distraction device as an amount of 0.75mm, twice per day after osteotomy between two implants. Each animals were sacrificed at the second, fourth, sixth and eighth week after the total distraction amount of 10.5mm were gotten. Upon embedding and staining, the specimens were evaluated with a light microscope. The results were as follows. 1. For the second week group, the articular cartilage and osteoid seam of temporal bone and condyle were relatively well maintained. There were not any significant differences between distraction side and non distraction side. 2. For the fourth week group, the periosteal reaction was activated and the articular cartilage and osteoid seam of temporal bone and condyle were severely thickened - especially at posterior portion of distraction side. This findings revealed that the unilateral distraction forces has more influence on distraction side than on non distraction side, and on posterior portion than on anterior portion. 3. For the sixth and eighth week group, the thickness of meniscus in distraction side gradually recovered to the initial level. The thickened articular cartilage and osteoid seam of temporal bone and condyle were decreased in distraction side and showed relatively stable in non distraction side. From this results, we suggest that several considerations are required such as using an occlusal splint, maintaining the stability of bone distraction device and evaluating bone distraction rate to minimize the damages of temporomandibular joint tissues in early stage of distraction side.

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