• Physical Therapy Rehabilitation Science
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• 제12권1호
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• pp.26-32
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• 2023

Objective: This study attempted to compare the effects of bridge exercise using a sling according to the angle of the ankle to confirm the effective lower extremity muscle activation posture of patients with patellofemoral pain syndrome(PFPS). Design: Cross-sectional study Methods: Seventeen patients with PFPS were recruited and the muscle activities of the vastus medialis, vastus lateralis, rectus femoris, and gluteus maximus were measured according to the ankle position (dorsiflexion, neutral, plantar flexion). After measuring the maximum number of isometric contractions of vastus medialis, vastus lateralis, rectus femoris, and gluteus maximus, bridging exercise using a sling according to each ankle posture was applied to measure lower extremity muscle activity. The evaluation was performed 3 times for 10 seconds. The three ankle postures were randomly performed and the average values were compared. Results: As a result of this study, the vastus medialis muscle showed high muscle activity in the order of dorsiflexion, plantar flexion, and neutral position bridge exercise (p<0.05). And the vastus lateralis showed high muscle activity in the order of dorsiflexion, neutral, and plantar flexion (p<0.05). However, rectus femoris and gluteus maximus did not show significant muscle activity according to the ankle posture, but muscle activity was highest in the dorsiflexion posture. Conclusions: As a result of this study, muscle activity was high in the order of vastus medialis and vastus lateralis during ankle dorsiflexion. This is thought to be a major factor that can be applied in various ways in clinical practice according to the ankle angle when treating PFPS patients.

• 대한방사선기술학회지:방사선기술과학
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• 제33권1호
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• pp.19-24
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• 2010

본 연구는 원위요골의 회전에 따른 골밀도의 변화를 알아보고 원위요골 골밀도와 요추 골밀도를 비교 분석하였다. 골밀도 측정시 정확한 측정 자세를 알아보고자 자체 제작한 보조기구를 이용하여 수술, 기형이나 외상력이 없는 20, 30대 남성 11명을 대상으로 전완부를 DR(digital diagnostic IR-1100-150 ; Philips)로 촬영하였고 남성 21명을 DXA(QDR 4500W ; HOLOGIC, USA)로 골밀도 측정을 시행하였다. 실험은 두 가지로 수행하였다. 첫째, 보조기구를 이용하여 11명을 대상으로 전완부를 DR로 중립위(0도)를 기준으로 내회전 및 외회전 각각 3, 6, 9도에서 촬영하였고 둘째, 요추 및 전완부(Forearm)의 골밀도를 21명을 대상으로 DXA 장비를 이용해 중립위(0도)를 기준으로 내회전 및 외회전 각각 5, 10도에서 측정하였고 통계프로그램 SPSS 12.0v으로 비교 분석하였다. 그 결과 DR로 촬영한 11명의 원위요골 회전각은 내회전인 경우가 82%(n = 9)로 가장 많았으며, 평균 내회전 각도는 7도였다. 외회전 6도와 중립위(0도)에서도 1명(9%)씩 나타났다. 전체평균 회전각은 내회전 5.1도였다. DXA로 측정한 21명의 원위요골 회전각은 내회전인 경우가 43%(n = 9)로 가장 많았으며, 평균 내회전 각도는 7.2도였다. 외회전은 24%(n = 5)이고 평균 외회전 각은 6도이며 중립위(0도)은 33%(n = 7)로 나타났다. 전체평균 회전각은 내회전 4.1도였다. 요추와 원위요골의 상관 계수는 r = 0.30, p = 0.18로 통계적 유의성은 없었다. 요추의 골밀도가 원위요골의 골밀도를 대변하지 못하기 때문에 원위요골 골밀도의 평가는 원위요골에서 측정해야 한다. 전완부 골밀도 측정시 중립위는 원위요골이 외회전이 대부분이기 때문에 최저 골밀도의 회전각에서 일정하게 골밀도를 측정하기 위해서는 중립위 보다 내회전이 필요하며 내회전 각은 약 5도가 추천된다.

• Structural Engineering and Mechanics
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• 제85권1호
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• pp.105-118
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• 2023

The present work is an attempt to develop a simple and accurate finite element formulation for the assessment of thermal shock/thermally induced vibrations in pretwisted and tapered functionally graded material thin (FGM) blades obtained from Voigt and local representative volume elements (LRVE) homogenization models, based on neutral surface approach. The neutral surface of the FGM blade does not coincide with its mid-surface. A finite element model (FEM) is developed using first-order shear deformation theory (FSDT) and the FGM turbine blade is modelled according to the shallow shell theory. The top and the bottom layers of the FGM blade are made of pure ceramic and pure metal, respectively and temperature-dependent material properties are functionally graded in the thickness direction, the position of the neutral surface also depends on the temperature. The material properties are estimated according to two different homogenization models viz., Voigt or LRVE. The top layer of the FGM blade is subjected to high temperature and the bottom surface is either thermally insulated or kept at room temperature. The solution of the nonlinear profile of the temperature in the thickness direction is obtained from the Fourier law of heat conduction in the unsteady state. The results obtained from the present FEM are compared with the benchmark examples. Next, the effect of angle of twist, intensity of thermal shock, variable chord and span and volume fraction index on the transient response due to thermal shock obtained from the two homogenization models viz., Voigt and LRVE scheme is investigated. It is shown that there can be a significant difference in the transient response calculated by the two homogenization models for a particular set of material and geometric parameters.

• The Journal of Korean Physical Therapy
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• 제15권4호
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• pp.82-89
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• 2003

Although many current low back pain exercise incorporate proprioceptive training, very little research has been performed on proprioception of the low back. To determine wether reposition error is different in male than female. Eighteen young individuals took part in the research, seven male and eleven female. The 3-dimensional position of the lumbar was measured with a CMS70P. Reposition error was calculated as the absolute difference between the neutral position and return position. No significant differences in reposition error were found between male and female. No significant correlations were identified between reposition error and movement direction.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1540-1551
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• 2015

The detection of position and speed in BLDC motors without using position sensors has meant many efforts for the last decades. The aim of this paper is to develop a sensorless technique for detecting the position and speed of BLDC motors, and to overcome the drawbacks of position sensor-based methods by improving the performance of traditional approaches oriented to motor phase voltage sensing. The position and speed information is obtained by computing the derivative of the terminal phase voltages regarding to a virtual neutral point. For starting-up the motor and implementing the algorithms of the detection technique, a FPGA board with a real-time processor is used. Also, a versatile hardware has been developed for driving BLDC motors through pulse width modulation (PWM) signals. Delta and wye winding motors have been considered for evaluating the performance of the designed hardware and software, and tests with and without load are performed. Experimental results for validating the detection technique were attained in the range 5-1500 rpm and 5-150 rpm under no-load and full-load conditions, respectively. Specifically, speed and position square errors lower than 3 rpm and between 10º-30º were obtained without load. In addition, the speed and position errors after full-load tests were around 1 rpm and between 10º-15º, respectively. These results provide the evidence that the developed technique allows to detect the position and speed of BLDC motors with low accuracy errors at starting-up and over a wide speed range, and reduce the influence of noise in position sensing, which suggest that it can be satisfactorily used as a reliable alternative to position sensors in precision applications.

• 전기학회논문지
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• 제67권1호
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• pp.137-141
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• 2018

The voltage drop is important in electric railway for feeding a huge power of train on fixed feeding area. Nowadays it is tried to operate a high speed trains on conventional lines and there is problem on the voltage drop too. It is simulated on the conditions increased the turn ratio of trolley, installed autotransformer neutral line with variable taps. In result, it is compensated the voltage drop between ATs and better on last AT, not on the position of AT. And it is decreased a return current and neutral current of AT because of unbalance between trolley and feeder. It should be studied faster and more controllable the solid state switchs instead of the mechanical one in order to utilize this system.

• 한국전문물리치료학회지
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• 제17권1호
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• pp.1-8
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• 2010

The purpose of this study was to compare EMG activity for pectoralis major muscle during shoulder movement with various abduction angle and rotation position in supine position. Fifteen healthy subjects were recruited for this study. All subjects performed shoulder horizontal adduction holding a 2 kg dumbbell in shoulder abduction $40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$ with shoulder neutral, internal rotation (IR), and external rotation (ER). Surface EMG activity was recorded from pectoralis major clavicle part and pectoralis major sternum part for 5 seconds and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). Dependent variables were examined with 3 (Neutral, IR, ER) ${\times}$ 5 ($40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$) analysis of variance with repeated measures. The EMG activity of pectoralis major muscle was significantly different between shoulder abduction angles and between shoulder rotation positions (p<.05). The highest value of EMG activity of pectoralis major clavicle part among shoulder abduction angles was in $70^{\circ}C$ and, $90^{\circ}C$ in that order. The highest value of EMG activity of pectoralis major sternum part among shoulder abduction angles was in $130^{\circ}C$ and, $90^{\circ}C$ in that order. According to the rotation degree, shoulder ER showed the highest value and IR showed the lowest value in both muscle parts. These results suggest that shoulder abduction $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$ will be effective during manual muscle testing (MMT) and strengthening exercise for pectoralis major muscle. It is also supposed that shoulder ER is the efficient posture for strengthening of pectoralis major muscle.

• The Journal of Korean Physical Therapy
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• 제24권5호
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• pp.334-339
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• 2012

Purpose: This study was conducted in order to compare the ability to control postural sway during perturbation when stroke patients received postural sway induced by head rotation. Methods: This study included 15 stroke patients and 15 healthy adults. Each group was measured by 3D motion analysis for determination of the angle of the neck in static position and by balance performance monitor for estimation of swaying angle in both neutral posture and head rotation position. These results were then analyzed in order to compare the healthy control group and the stroke patients group. Results: In both static posture ($60.7{\pm}4.81$) and dynamic posture ($51.46{\pm}6.87$, $70.8{\pm}6.55$), significant decreases were observed in the angle of head rotation of the patient group, compared to the healthy group (p<0.05), and significant decreases were observed in the sway angle of the patient group when in the neutral position ($3.62{\pm}7$, $24{\pm}0.60$) and head rotation ($3.04{\pm}0.80$, $51.46{\pm}6.87$), compared to the healthy group (p<0.05). Conclusion: According to these findings, patients with stroke tend to restrict the ROM of head rotation and swaying angle in dynamic posture and maintain their posture instability using limitation of head movement relative to the trunk and sway angle of area which is larger than that of affected side in unaffected side.

• 수산해양교육연구
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• 제27권1호
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• pp.63-73
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• 2015

The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, and vastus lateralis during step up exercise according to ankle and knee positions in soccer players with patellofemoral pain syndrome. Methods: Subject(patellofemoral pain syndrome, PFPS: n=8 and without PFPS, non PFPS; NPFPS: n=8) perfomed step up exercise at each knee and ankle position(knee flexion $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$, ankle internal rotation $30^{\circ}$, neutral, and external rotation $30^{\circ}$) while EMG activity was collected. The EMG signals were expressed by the % maximal voluntary isometric Contraction(%MVIC) values. Statistical analysis consisted of two way repeated measures analysis of variance with post hoc analysis. Results: Main results were as follows: 1) EMG of VMO, and VL was tend to be lower in PFPS compared to NPFPS. 2) EMG of VMO and VL with knee flexrion $60^{\circ}$ was significantly higher the results with knee flexion $30^{\circ}$, and $90^{\circ}$. VMO and VL with ankle external rotation $30^{\circ}$ was significantly higher the results with internal rotation $30^{\circ}$ and neutral position. Conclusion: Considering the EMG activity was reduced due to the to the PFPS and that performing step up with knee flexion $60^{\circ}$ with ankle external rotation $30^{\circ}$ position may provide the most effective condition for patients with patellofemoral pain syndrome.

• Journal of Korean Neurosurgical Society
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• 제50권4호
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• pp.377-380
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• 2011

Objective : The purpose of this study was to determine the anatomic relationships between neurovascular structures and the transverse carpal ligament so as to avoid complications during endoscopic carpal tunnel surgery. Methods : Twenty-eight patients (age range, 35-69 years) with carpal tunnel syndrome were entered into the study. We examined through wrist magnetic resonance imaging in three different positions (neutral, radial flexion, and ulnar flexion) and determined several anatomic landmark (distance from the hamate hook to the median nerve, ulnar nerve, and ulnar vessel) based on the lateral margin of the hook of the hamate. The median nerve and ulnar neurovascular structure were studied with the wrist in the neutral, ulnar, and radial flexion positions. Results : The ulnar neurovascular structures usually passed just over or ulnar to the hook of the hamate. However, in 12 hands, a looped ulnar artery coursed 0.6-3.3 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyon's canal (-5.2-1.8 mm radial to the hook of the hamate) with the wrist in radial flexion. During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (-2.5-5.7 mm). Conclusion : It is appropriate to transect the ligament greater than 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the transverse carpal ligament in the ulnar flexed wrist position to protect the ulnar neurovascular structure.