• Korean Journal of Applied Biomechanics
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• v.28 no.3
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• pp.159-164
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• 2018

Objective: The aims of this study were to determine the impact peak force and kinematic variables in running speed and investigate the relationship between them. Method: Thirty-nine male heel strike runners ($mean\;age=21.7{\pm}1.6y$, $mean\;mass=72.5{\pm}8.7kg$, $mean\;height=176.6{\pm}6.1cm$) were recruited in this investigation. The impact peak forces during treadmill running were assessed, and the kinematic variables were computed using three-dimensional data collected using eight infrared cameras (Oqus 300, Qualisys, Sweden). One-way analysis of variance ANOVAwas used to investigate the influence of the running speed on the parameters, and Pearson's partial correlation was used to investigate the relationship between the impact peak force and kinematic variables. Results: The running speed affected the impact peak force, stride length, stride frequency, and kinematic variables during the stride phase and the foot angle at heel contact; however, it did not affect the ankle and knee joint angles in the sagittal plane at heel contact. No significant correlation was noted between the impact peak force and kinematic variables in constantrunning speed. Conclusion: Increasing ankle and knee joint angles at heel contact may not be related to the mechanism behind reducing the impact peak force during treadmill running at constant speed.

• Proceedings of the ESK Conference
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• 1993.04a
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• pp.1-9
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• 1993

A human gait study is required for the biomechanical design of running shoes. A tow-dimensional dynamic model was developed in order to analyze lower extremity kinematics and loadings at the right ankle, knee, and hip joints. The dynamic model consists of three segments, the upper leg, the lower leg, and the foot. Each segment was assumed to be a rigid body with one or two frictionless hinge joints. The lower extremity motion was assumed to be planar in the sagittal plane. A young male subject was involved in the gait test and his anthropometric data were measured for the calculation of segement mass and moment of inertia. The experimental data were obtained from three trials of walking at 1.2m/s. The foot-floor reaction data were measured from a Kistler force plate. The kinematic data were acquired using a three-dimensional motion measurement system (Expert Vision) with six markers, five of which were placed on the right lower extremity segments and the rest one was attached to the force plate. Based on the model and experimental data for the stance phase of the right foot, the calculated vertical forces reached up to 492, 540, and 561 N at the hip, knee, ankle joints, respectively. The flexion-extension moments reached up to 155, 119, and 33 Nm in magnitude at the corresponding joints.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.131-138
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• 2014

The purpose of this study was to analyse the effect of the drop height on lower extremity and lower back kinematics and kinetics during drop landing with the use of raised heel insole. Furthermore we investigated the change that occurred in our body. Joint ROM, eccentric work and contribution to total work were calculated in 11 male college students performing drop landing with 8 motion analysis cameras and 1 forceplate. The result were as follows. First, the ROM and eccentric work were increased in all joints with the increase of the drop height. Second, the ankle ROM and eccentric work were decreased with the use of the insole. Third, the use of the lower back was increased as the use of the ankle decreased with the insole. Based on these results, we can infer that putting on the insole may contribute to chronic injury. We recommend not to use the insole during physical activity.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.98-105
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• 2021

Objective: The purpose of this study was to examined the kinematic relationship and differences through the range of motion (ROM), muscle activity, and vertical ground reaction force (VGRF) during forward and backward lunge movements, which are effective in improving muscle strength and balance ability of the lower extremities, and to provide clinical information on more efficient lunge movements. Design: Cross-sectional study Methods: Fifteen adult males who met the selection criteria were tested for their dominant feet.Forward and backward lunges were then performed, and the ROM, muscle activity, and VGRF were measured for kinematic analysis during the lunge movement.The differences betweenthe forward lunge and backward lunge intervention were examined using a paired t-test. Results: A significant increase in the ROM of the knee and ankle was observed during the forward and backward lunges (p<0.05). In addition, in terms of the muscle activity, the peak values of the vastus medialis oblique (VMO) and VGRF also showed a significant increase in the forward lunge compared to the backward lunge (p<0.05). Conclusions: This study showed an increase in VGRF peak value, knee and ankle ROM, and VMO muscle activity during forward lunge. Based on these results, it is considered necessary to apply differently depending on the direction of progress in consideration of the musculoskeletal situation and physical ability during the lunge movement.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.1
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• pp.18-25
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• 1997

Prosthetic replacement is one of the most common methods of reconstruction after resection of malignant tumor around the knee. Gait analysis provides a relative objective data about the gait function of patients with prosthesis. The purpose of this study was to compare the gait pattern of the patients who underwent limb salvage surgery with prosthesis for distal femur and that of patients with prosthesis for proximal tibia. This study included ten patients (4 males, 6 females, mean age 22.7 years, range 14-36) who underwent a wide resection and Kotz hinged modular reconstruction prosthesis replacement and six normal adult(Control). The site of bone tumor was the distal femur (Group 1) in six patients and proximal tibia (Group 2) in 4 patients. The follow-up period ranged from 15 to 82 months (mean : 33 months). The evaluation consisted of clinical assessment, radiographic assessment, gait analysis using VICON 370 Motion Analysis System. The gait analysis included the linear parameters such as, walking velocity, cadence, step length, stride length, stance time, swing time, single support and double support time and the three-dimensional kinematics (joint rotation angle, velocity of joint rotation) of ankle, knee, hip and pelvis in sagittal, coronal and transverse plane. For the kinetic evaluation, the moment of force (unit: Nm/kg) and power (unit: Watt/kg) of ankle, knee and hip joint in sagittal, coronal and transverse plane. In the linear parameters, cadence, velocity, step time and single support were decreased in both group 1 and group 2 compared with control. Double support decreased in group 2 compared with control significantly(p<.05). In contrast to our hypothesis, there was no significant difference between group 1 and group 2. In Kinematics, we observed significant difference (p<.05) of decreased knee flexion in loading response (G2

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.99-116
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• 2003

The purpose of this study was to kinematics factors on during round-off at end of beam-salto backward stretched with step-out to cross on balance beam. Four elite female gymnastics players participated as subject of this study. The methods of this study was analyzed using three dimentional analysis. The results and conclusion of this paper is obtained as follows ; 1. The phase of time was the most short time in board touch down phase and board take-off phase. Also, it was shown a more long time in total time compared to previous study. 2. The horizontal displacement of each phase was shown the most high levels in balance beam landing. The vertical displacement was display a non-linearity increase in board take-of phase, and it was shown the most high levels in vertical displacement during landing of balance beam. 3. The horizontal velocity of each phase was shown the most high levels in board touch down, and it was display a gradually decreased levels because flight during board take-of. The resultant velocity of CG on each phase was shown the most high levels in board touch down and board take-off. 4. The angle of hip joint was shown the most high levels as performed a motion in extension state during board take-off, and the angle of knee joint was display a increased levels because of flight cause body extension in board take-off. Also the angle of ankle joint was shown a increasing levels during board take-off. Considering to this results, it is suggest that the change of kinematics factors in board touch down and board take-off is key role on the effective board control.

• Korean Journal of Applied Biomechanics
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• v.33 no.4
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• pp.147-154
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• 2023

Objective: This study aimed 1) to compare the Landing Error Scoring System (LESS) score and movement patterns during landing of the lesser dorsiflexion range of motion (LDFROM) group to that with the greater dorsiflexion range of motion group, and 2) to identify the correlation between the weight-bearing dorsiflexion range of motion (WBDF ROM), LESS score, and movement patterns during landing. Method: Fifty health adults participated in this study. WBDF ROM was measured using the weight bearing lunge test while movement patterns during landing was assessed using the LESS. The joint angles of the ankle, knee and hip joints during landing were analyzed using the 2D video analysis. After mean value of WBDF ROM was calculated, participants were divided into two groups (GDFROM and LDFROM) based on the mean value. The Mann-Whiteny 𝒰 test was used to identify differences in movement strategies during landing between two groups and the Pearson's correlation analysis was performed to determine relationships between WBDF ROM and movement strategies. Results: The LDFROM group showed the poorer LESS score and stiffer landing kinematics during landing compared to the GDFROM group (p<0.05). In addition, DFROM was significantly related to the LESS score and landing kinematics (p<0.05) except for total hip excursion (p=0.228). Conclusion: Our main findings showed that the LDFROM group had poorer landing quality and stiffer landing movements compared to the GDFROM group. In addition, increase of WBDF ROM significantly improved landing quality and soft-landing movements. To reduce shock during landing such as ground reaction forces, individuals need to better utilize WBDF ROM and lower extremity movements based on our findings. Therefore, intervention programs for safer landings should include exercises that increase WBDF ROM and utilize eccentric contraction.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.315-324
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• 2012

The purpose of current study was to investigate the effects of the heights on the lower extremities, torso and neck segments for energy dissipation during single-leg drop landing from different heights. Twenty eight young healthy male subjects(age: $23.21{\pm}1.66yr$, height: $176.03{\pm}4.22cm$, weight: $68.93{\pm}5.36kg$) were participated in this study. The subjects performed the single-leg drop landing from the various height(30, 45 & 60 cm). Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. The results were as follows. First, the ROM at the ankle, knee, hip and trunk was increased with the increased heights but the ROM at the neck was increased in the 60cm. Second, the angular velocity, moment and eccentric work at the ankle, knee, hip, trunk, and neck was increased with the increased heights. Third, the contribution to total work at the knee joint was not significantly different, while the ankle joint rate was decreased and hip and neck rate was increased in the 60cm, and trunk rate was increased with the increased heights. Lastly, the increase in landing height was able to augment the level of energy dissipation not only at the lower extremities but also at the trunk and neck. The findings showed that drop landing affect trunk and neck with lower extremity joints. Therefore, we need to consider that trunk and neck strengthening including stability should be added to reduce sports injury during prevention training.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.13-23
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• 2010

The purposes of this study was to investigate the biomechanical influence of the walking shoe with a plate spring in the heel and interchangeable heel cushioning elements. Eighteen subjects walked in three conditions: 1) the walking shoes Type A-1 with a soft heel insert, 2) the Type A-2 shoe with a stiff heel insert, 3) a general walking shoe(Type B). Ground reaction forces, leg movements, leg muscle activity and ankle, knee and hip joint loading were measured and calculated during overground walking. During walking, the ankle is a few degrees more dorsiflexed during landing and the knee is slightly more flexed during takeoff with the Type A shoes. As a result of the changes in the walking movement, the ground reaction forces are applied more quickly and the peak magnitudes are higher. Muscle activity of the quadricep, hamstring and calf muscles decrease during the first 25% of the stance phase when walking in the Type A shoes. The resultant joint moments at the ankle, knee and hip joints decrease from 30-40% with the largest reductions occurring during landing.

• Physical Therapy Korea
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• v.20 no.1
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• pp.64-73
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• 2013

The purposes of this study were to develop a new orthosis controlling ankle and knee joint motion during the gait cycle and to identify the effects of the newly designed orthosis on gait kinematics and tempospatial parameters, including coordination of the extremities in stroke patients. Fifteen individuals who had sustained a stroke, onset was 16 months, participated in this study. Before application of the measurement equipment the subjects were accustomed to walking on the ankle-foot orthosis (AFO) or stance control knee with knee flexion assisted-oil damper ankle-foot orthosis (SCKAFO) for 5 minutes. Fifteen patients were investigated for 45 days with a 3-day interval between sessions. Measurements were walking in fifteen stroke with hemiparesis on the 3D motion analysis system. Comparison of AFO and SCKAFO are gait pattern. The difference between the AFO and SCKAFO conditions was significant in the gait velocity, step length of the right affected side, stance time of both legs, step-length asymmetry ratio, single-support-time asymmetry ratio, ${\phi}$-thigh angle and ${\phi}$-shank angle in the mid swing (p<.001). Using a SCKAFO in stroke patients has shown similar to normal walking speeds can be attained for walking efficiency and is therefore desirable. In this study, the support time of the affected leg with the SCKAFO was longer than with the AFO and the asymmetry ratio of single support time decreased by more than with the AFO. This indicates that the SCKAFO was effective for improving gait symmetry, single-support-time symmetry. This may be due to the decrease of gait asymmetry. Thus, the newly designed SCKAFO may be useful for promoting gait performance by improving the coordination of the extremity and decreasing gait asymmetry in chronic stroke patients.