• Korean Journal of Applied Biomechanics
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• 제17권2호
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• pp.187-196
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• 2007

The purpose of this study was to find the most effective movement pattern from three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion task, which had the time constraint to complete the performance. 7 healthy subjects participated in left and right side movement task by an external signal, which required the subject to perform the task as fast as possible. Mechanical output and joint kinetics focusing on the lower extremities were analyzed. The results were as follows. In spite of the shortest duration in propulsive phase, the hopping condition showed no difference with other conditions in the work output done and take-off velocity. It resulted from the greatest power output generated during the propulsive phase. A significant difference was found for joint moment and joint power according to the movement conditions. The joint moment and joint power for the countermovement and hopping conditions were larger than those in the squat condition. This was speculated to be due to the extra power that could be generated by the pre-stretch of muscle in preparation for the propulsion. The hopping condition which had substantially more pre-stretch load in the preparatory eccentric phase produced considerably more power than countermovement condition in the propulsive concentric phase. Furthermore during the hopping a large amount of joint moment and joint power could be produced in a shorter time. Therefore it was deemed that the hopping movement is an effective type of preparatory movement which takes much more advantage of the pre-stretch than any other movement.

• Journal of Chest Surgery
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• 제17권2호
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• pp.244-249
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• 1984

Surgical treatment of partial endocardial cushion defect was accomplished in Feb. 1984 in this department. The 5 year old male patient had history of frequent upper respiratory tract infection and since his age of 3 years dyspnea on exertion and palpitation were noted but there were no cyanosis and clubbing. A thrill was palpable on the apex and grade IV/IV harsh systolic ejection murmur and diastolic murmur was audible on it. Liver was palpable about 3 finger breadths and no ascites. Chest X-ray revealed increased pulmonary vascularity, moderate cardiomegaly [C-T ratio; 0.69], and enlarged left atrium. EKG showed first degree heart block, RVH, LVH, and LAD. Echocardiogram showed paradoxical ventricular septal movement and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted left to right shunt [Qp:Qs:2.1:1 ] and moderate pulmonary hypertension [60/40 mmHg]. Left ventriculogram showed mitral regurgitation [Grade III/IV] and filling of left atrium and right atrium nearly same time. Operative findings were: 1.Primum type atrial septal defect [3x2 cm] 2.Cleft on the anterior leaflet of mitral valve. 3.No interventricular communication and cleft of tricuspid valve leaflet. The mitral cleft was repaired with 4 interrupted sutures. The primum type atrial septal defect was closed with Dacron patch intermittently at endocardial cushion and continuously remainder. The post operative course was uneventful and discharged on 22nd postoperative day in good general conditions.

• Korean Journal of Applied Biomechanics
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• 제17권1호
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• pp.41-52
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• 2007

The present study analyzed the two hand backhand stroke motion of six female high school tennis players who won the championship at the National Athletic Meeting in 2006, and drew conclusions as follows. The open angle of the racket at the moment of impact was 90 degree without significant difference among the players, making a wide contact between the ball and the racket. The racket angle was 43 degree at take back and 91 at impact, showing a style of holding the racket rather upright in general. In back swing from the top to the impact, the shoulders and the hips turned by 97 degree and 40 degree, respectively. At the moment of impact, the height of the impact was 54%H, and the position of the impact was 10%H ahead of and 37%H left from the central axis of the body. The right hand made a continental grip and the left hand made a Western or semi Western grip. Through the entire swing motion, the grip angle of the left hand was smaller than that of the right hand, and those who maintained a large grip angle of the right hand at the moment of take back put the racket head slightly farther from the body. In the swing of the racket head from the lowest point to the impact, the vertical length of movement was 11%H and the horizontal length of movement was 60%H, quite long.

• The Journal of Internal Korean Medicine
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• 제33권4호
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• pp.599-608
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• 2012

Objectives : To report three cases of eye movement impairment: internuclear ophthalmoplegia (INO) due to pontine infarction, traumatic abducens nerve palsy, and abducens nerve involvement in Miller-Fisher syndrome. Cases Summary : There were three cases. First, a 64-year-old woman, who was given a diagnosis of INO due to pontine infarction, had left gaze palsy of her right eye while the convergence was intact. Second, a 34-year-old man had abduction impairment of his right eye after a traffic accident. Third, a 66-year-old man, who was diagnosed with Miller-Fisher syndrome, had left gaze palsy of his left eye. Their symptoms improved substantially and their anxieties were relieved after treatment with herbal medicine and acupuncture. Conclusions : There has been no certain cure for eye movement impairment yet. In this report, we present three successful cases of patients with eye movement impairment and show that Korean medical treatment could be a solution for this incurable disease.

• Journal of Korean Tunnelling and Underground Space Association
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• 제17권3호
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• pp.267-281
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• 2015

The ground movement and changes in earth pressure due to the consecutive construction of retaining wall and underground space were studied experimentally. A soil tank having 160 cm in length and 120 cm in height, was manufactured to simulate the vertical excavation like retaining wall by using 10 separated right side walls and underground space excavation like tunnel by using 5 separated bottom walls. The variation of earth pressure and surface settlement were measured according to the excavation stages. The results showed that the decrease of earth pressure due to the wall movement can cause the increase of earth pressure of the neighboring walls proving the arching effect. Experiments simulating continuous construction sequence also identified arching effect, however only 50% of earth pressure was restored on the 10th right side wall due to the movement of 1st bottom side wall unusually.

• The korean journal of orthodontics
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• 제21권3호
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• pp.617-634
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• 1991

The retraction of anterior teeth is one of the fundamental methods in orthodontic treatment and a proper position and angulation of anterior teeth after the retraction are very important for esthetics, stability, and function of teeth. In this research we analyzed, by Finite Element Method, the stress distribution on the periodontal ligament according to the variation of force and moment applied on the crown and predict the pattern of movement of maxillary central incisor. At the same time, the amount of force and moment caused by activation of the loop which was used for retraction of maxillary central incisor was analyzed by Finite Element Method. We observed the following results: 1) We could control the stress distribution on the periodontal ligament by proper moment/force ratio on maxillary right central incisor and predict the pattern of movement of maxillary right central incisor. 2) The amount of stress on the periodontal ligament as well as the moment/force ratio demanded by each pattern of movement increased as the destruction of alveolar bone was worse. 3) The moment/force ratio demanded by each pattern of movement decreased as the angle between the maxillary central incisor and occlusal plane decreased. 4) The force with the open loop was shown to be large compared to that with the closed loop. Also, the force with the helix decreased by 30% compared to that without the helix. 5) Under the same conditions we observed a larger moment/force ratio when the open loop and/or the helix were used.

• Korean Journal of Applied Biomechanics
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• 제32권4호
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• pp.111-120
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• 2022

Objective: This study investigated the effect of pelvic tiltng according to the paralytic side on gait in stroke patients during a 10 m functional movement timed up and go (TUG) test. Method: In this study, gait parameters were measured using a gait analyzer for 20 stroke patients and their gait was analyzed during a 10 m TUG test. For statistical analysis, an independent sample t-test were performed for age, height, and weight among general characteristics of subjects and homogeneity was tested by performing a chi-square test for gender, paralysis side, period of onset, and K-MMSE score. In order to understand the relationship between each variable, Pearson correlation analysis was performed on the variables. Results: First, the right-hand paralyzed group showed correlations in cadence and gait velocity in the up and down tilt of the pelvis, and the left-hand paralyzed group showed correlations in cadence and step length in the anterior and posterior tilt of the pelvis. Second, the tilt of the pelvis was correlated with the Sit to stand, walk forward, walk backwards, turn around at the end point, sit on a chair and the total TUG time in the right hemiplegic group compared to the left hemiplegic group. Conclusion: In this study, a significant correlation was confirmed as a result of gait analysis of right-handed stroke patients divided into a right paraplegic group and a left paraplegic group. In the future, it is suggested that treatment for improving gait of stroke patients should be treated differently for the right and left paralyzed side.

• Journal of the korean academy of Pediatric Dentistry
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• 제1권1호
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• pp.49-55
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• 1974

Electromyographic studies were performed on the action of the masseter muscles. Among the children aged from 6 to 8 years, ten children with normal occlusion and another ten with space maintainer were selected. The children were divided into 3 groups. They were: 1) A group: Children who removed space maintainer 2) B group: Children who inserted space maintainer 3) C group: Children with normal occlusion. The electromyogram was recorded with 4 channel polygraph. (Grass model VII) Electrodes which were cup-typed gold disks, 9 millimeters in the diameter, were located on the superficial layer of masseter muscles. The electromyogram was recorded in the physiologic rest position, molar occlusion, chewing movement, protraction, left lateral movement, and right lateral movement. The conclusions were as follows. 1. In the physiologic rest position, lateral movement, the electrical potentials of the masseter muscles were not changed clearly in each groups. 2. In molar occlusion, chewing movement, The electrical potentials of the masseter muscles of the B group were almost 10% higher than those of A group, and were almost 60-70% in comparision with C group. 3. In protraction, the electrical potentials of the masseter muscles of the B group were almost 40% higher than those of A group, and were almost equal to C group. 4. The electrical activities of the masseter muscles in the mandibular movements were in the following order: (1) Molar occlusion (2) Chewing movement (3) Protraction (4) Lateral movement.

• Korean Journal of Applied Biomechanics
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• 제28권2호
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• pp.109-117
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• 2018

Objective: To compare head and hand movement patterns during squash forehand motions between experts and less-skilled squash players. Method: Four experts and four less-skilled squash players participated in this study. They performed squash forehand swings and a VICON motion analysis system was used to obtain displacement and velocity data of the head and right hand during the movement. Mann-Whitney U-tests were performed to compare head and hand range of motion and peak velocity, and cross-correlation was performed to analyze the head-hand coordination pattern between groups in three movement directions. Results: In terms of head and hand kinematic data, experts had greater head range of motion during down swings than less-skilled squash players. Experts seemed to reach peak hand velocity at impact by reaching peak head velocity followed by hand peak velocity within a given temporal sequence. In terms of head-hand coordination patterns, both groups revealed high positive correlations in the medial-lateral direction, indicating a dominant allocentric coordination pattern. However, experts had uncoupled coordination patterns in the vertical direction and less-skilled squash players had high positive correlations. These results indicate that the head-hand movement pattern likely an important factor squash forehand movement. Conclusion: Analysis of head and hand movement patterns could be a key variable in squash training to reach expert-level performance.

• PNF and Movement
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• 제3권1호
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• pp.27-34
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• 2005

Objective : The purpose of this study was conducted to find correct head and neck patterns, manual contact. verbal commands with proprioceptive neuromuscular facilitation(PNF). Method : This is a literature study with books, seminar note and book for PNF international course. Result : Keep the information of the biomechanics and neural science in head and neck patterns and emphasize that manual contact, verbal commands and visual stimulus. Manual contacting for movement guide and stability of the $C_0/C_1$ verbal command and visual stimulus for correcting of the $C_0/C_1$ movements. Conclusion : In reminder for PNF learning, begin with head and neck and upper trunk patterns. In that time, Knott and Voss(1968) had not enough information about biomechanic movement components and neural science movement components. But Knott and Voss(1968) emphasized that head and neck patterns relate with trunk, upper extremities and lower extremities directly. Alar ligaments are relaxed with the head in neutral and taut in flexion. Axial rotation of the head and neck tightens both alar ligaments. The right upper and left lower portions of the alar ligament limit left lateral flexion of the head and neck. Therefore, head and neck patterns has to be modify. When head moving, eye and vestibular stimulus will be change. During head and neck patterns, must be consider about stimulus of eye system and vestibular system also.