• 대한물리치료과학회지
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• 제10권2호
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• pp.53-61
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• 2003

The purposes of this study were to describe and compare pint moments according to 6 types of gait methods during free speed. 15 volunteers(7 male, 8 female: mean age = 23.33 yrs.) participated and performed 6 types of gait methods. From the 3 types of pint moments of lower extremities(hip, knee, ankle and foot), the following results were made: 1. In left hip pint, the flexion-extension moment was not significantly different, but the adduction-abduction moment and rotation moment were showed different curves during stance phase. 2. In left knee pint, the flexion-extension moment was not significantly different, but the varus-valgus moment and rotation moment were showed different curves during stance phase. 3. In left ankle and foot the dorsiflexion-plantarflexion moment was not significantly different but the varus-valgus moment and rotation moment were showed different curves during stance phase. In conclusion, because weight loading gait with 10-20% of body weight were normal gait patterns, It was inferred that all weight loading gaits did not indicate noxious reactions of human body.

• 한국전문물리치료학회지
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• 제15권2호
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• pp.64-72
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• 2008

The purpose of this study was to determine the differences in joint moment in the intact limb of uni-transfemoral amputees and to identify the implications of knee osteoarthritis. As an experimental method, three-dimensional gait analysis was performed on 10 uni-transfemoral amputees and 10 healthy males. Kinematics and kinetics at the hip, knee, and ankle joint were calculated. As a statistical method, independent t-tests were conducted to perform a comparison between the transfemoral amputee group and the control group. The results showed that the external knee adduction moment increased in the transfemoral amputee group (.22 Nm/kg) compared with that of the control group (.13 Nm/kg) at terminal stance (p=.008). External knee flexion moment also increased in the transfemoral amputee group (.24 Nm/kg) but this difference was not statistically significant. External hip flexion moment increased in the transfemoral amputee group (1.35 Nm/kg) compared with that of the control group (.45 Nm/kg) at initial stance, and external hip extension moment decreased in the transfemoral amputee group (-.26 Nm/kg) compared with that of the control group (-.76 Nm/kg) at terminal stance. Although external ankle plantarflexion moment of the transfemoral amputee group increased, it was not found to be statistically significant. The results suggest that the intact limb joint moment of the uni-transfemoral amputees during walking can be different from that of healthy subjects. In conclusion, it was found that there is a link between the increase of external knee adduction moment and the prevalence of knee osteoarthritis in uni-transfemoral amputees. This result is expected to provide some objective data for rehabilitation programs related to knee osteoarthritis in transfemoral amputees.

• 한국운동역학회지
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• 제26권4호
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• pp.369-375
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• 2016

Objective: The purpose of this study was to investigate the possibility of injuries and the types of movement related to damage by body parts, and to prepare for prevention of injuries and development of a training program. Method: For this study, the experiment was conducted according to levels of 60 percentages (ST) and 85 percentages (MA) and 10 subjects from the Korean elite national weightlifting team were included. Furthermore, we analyzed joint moment and muscle activation pattern with three-dimensional video analysis. Ground reaction force and EMG analyses were performed to measure the factors related to injuries and motion. Results: Knee reinjuries such as anterior cruciate ligament damage caused by deterioration of the control ability for the forward movement function of the tibia based on the movement of the biceps femoris when the rectus femoris is activated with the powerful last-pull movement. In particular, athletes with previous or current injuries should perceive a careful contiguity of the ratio of the biceps femoris to the rectus femoris. This shows that athletes can exert five times greater force than the injury threshold in contrast to the inversion moment of the ankle, which is actively performed for a powerful last pull motion and is positively considered in terms of intentional motion. It is activated by excessive adduction and internal rotation moment to avoid excessive abduction and external rotation of the knee at lockout motion. It is an injury risk to muscles and ligaments, causing large adduction moment and internal rotation moment at the knee. Adduction moment in the elbow joint increased to higher than the injury threshold at ST (60% level) in the lockout phase. Hence, all athletes are indicated to be at a high risk of injury of the elbow adductor muscle. Lockout motion is similar to the "high five" posture, and repetitive training in this motion increases the likelihood of injuries because of occurrence of strong internal rotation and adduction of the shoulder. Training volume of lockout motion has to be considered when developing a training program. Conclusion: The important factors related to injury at snatch include B/R rate, muscles to activate the adduction moment and internal rotation moment at the elbow joint in the lockout phase, and muscles to activate the internal rotation moment at the shoulder joint in the lockout phase.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.303-308
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• 2000

The design of column joint is an important part of earthquake resistant design of reinforced concrete moment resisting frames. Beam column joints must provide sufficient stiffness and strength to resist and sustain the loads induced by adjacent beams and columns. This paper investigates the difference of the current design codes which provide a different approach for the design of beam column joint in seismic zone. The model provided by Hitoshi Shiohara(1998) is reviewed in this paper, which provides a good relationship between moment and shear action of interior beam column joint and a role shear reinforcement according to their position.

• Computers and Concrete
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• 제14권2호
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• pp.109-125
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• 2014

The force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges is investigated in this paper using a three-dimensional detailed finite element model. Positive moment reinforcement in the form of hairpin bars as recommended by the National Cooperative Highway Research Program Report No 519 is incorporated in the model. The cold construction joint that develops at the interface between girder ends and continuity diaphragms is also simulated via contact elements. The model is then subjected to the positive moment and corresponding shear forces that would develop over the service life of the bridge. The stress distribution in the continuity diaphragm and the axial force distribution in the hairpin bars are presented. It was found that due to the asymmetric configuration of the hairpin bars, asymmetric stress distribution develops at the continuity diaphragm, which can be exacerbated by other asymmetric factors such as skewed bridge configurations. It was also observed that when the joint is subjected to a positive moment, the tensile force is transferred from the girder end to the continuity diaphragm only through the hairpin bars due to the lack of contact between the both members at the construction joint. As a result, the stress distribution at girder ends was found to be concentrated around the hairpin bars influence area, rather than be resisted by the entire girder composite section. Finally, the results are used to develop an approach for estimating the cracking moment capacity at girder ends based on a proposed effective moment of inertia.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5766-5772
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• 2011

본 연구는 아킬레스 건염 환자들과 정상인들을 대상으로 보행 선형지표와 고관절, 슬관절, 그리고 족관절의 모멘트 변화를 조사하여 아킬레스 건염에 의한 보행의 역학적 변화를 구명하고 아킬레스 건염을 예방하기 위한 예측인자들을 찾고자 실시되었다. 연구의 대상자는 아킬레스 건염 환자 20명과 비슷한 신체조건을 가진 건강한 정상인 20명이며, 대상자가 맨발 상태에서 힘판의 중앙 부분을 밟고 지나가도록 13 m의 거리를 편안한 속도로 5회 왕복하도록 하였다. 또한 대상자가 보행하는 동안 3차원 동작분석 장비를 이용하여 고관절, 슬관절, 그리고 족관절 모멘트를 산출하였다. 수집된 자료들을 SPSS 12.0 소프트웨어를 사용하여 분석하였다. 연구의 결과 아킬레스 건염 환자들의 고관절은 입각기 초기에 신전 모멘트가 감소하였고, 중후반에는 굴곡 모멘트가 감소하였다. 또한 슬관절에서는 입각기 초기부터 지속적인 굴곡 모멘트의 감소가 나타났으며 후기에는 신전 모멘트의 감소를 보였다. 그리고 족관절은 입각기 중반에 저측굴곡 모멘트가 감소하였으며 말기에는 배측 굴곡 모멘트가 감소하였다. 정상인과 비교해 아킬레스 건염 환자들에게서 보행의 역학적인 변화가 두드러지게 나타났으며, 임상에서는 아킬레스 건염 환자의 보행에 대한 변화를 세밀하게 파악하여 치료적 접근을 시도해야 할 것으로 보인다. 그리고 앞으로의 연구에서는 아킬레스 건염 환자에게서 나타나는 역학적인 변화에 대한 조사가 더 이루어져야 할 것이다.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.391-403
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• 2023

In this study, a new type of self-centering beam-column joint with tapered steel plate links is proposed. Firstly, mechanical property of the basic joint (with the prestressed steel strands only, to provide the self-centering ability) and the combined joint (with both the prestressed steel strands and tapered steel plate links, to provide self-centering and energy dissipation simultaneously) is theoretically analyzed. Then, three joints with different dimensions and combinations of tapered plate links are designed and tested through a series of quasi-static cyclic loading tests. Test results show that a nearly bilinear elastic moment-rotation relationship for the basic joint is obtained. With the addition of tapered steel plate links, typical flag-shape hysteretic curves are obtained, which indicates good self-centering and energy dissipating ability of the combined joint. By installing multiple tapered plate links, stiffness and bearing capacity of the beam-column joint can be enhanced. The theoretical moment-rotation relationships agree well with the test results. A simplified macro model of the proposed joint is developed using OpenSees, which simulates reasonably well its hysteretic behavior.

• 한국지진공학회논문집
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• 제19권6호
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• pp.283-292
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• 2015

In the moment frame subjected to earthquake loads, beam-column joint is structurally important for ductile behavior of a system. ACI Committee 352 proposed guidelines for designing beam-column joint details. The guidelines, however, need to be updated because of the lack of data regarding several factors that may improve the performance of joints. The purpose of this study is to investigate the seismic performance of reinforced concrete exterior joints with high-strength materials and unbonded tendons. Three specimens with different joint shear demand-to-strength ratios were constructed and tested, where headed bars were used to anchor the beam bars into the joint. All specimens showed satisfactory seismic behavior including moment strength of 1.3 times the nominal moment, ductile performance (ductility factor = at least 2.4), and sufficiently large dissipated energy.

• 한국지진공학회논문집
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• 제16권6호
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• pp.13-20
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• 2012

In this study, 5-story structures were designed in accordance with KBC2009 for inelastic time history analysis of RC IMRF. Bending moment-curvature relationship for beam and column was identified with fiber model and bending moment-rotation relationship for beam-column joint was calculated with simple and unified joint shear behavior model and moment equilibrium relationship for the joint. The hysteretic behavior was simulated with three-parameter model suggested in IDARC program. The analytical results showed that the inelastic shear behavior of the joint could be neglected in the structural design for seismic design category C but the structure of category D did not satisfy the criteria of FEMA 356 for collapse prevention performance level.

• PNF and Movement
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• 제17권3호
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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.