• 한국전자통신학회논문지
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• 제8권11호
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• pp.1771-1776
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• 2013

본 연구는 대학교 태권도 선수들을 대상으로 정적 스트레칭과 PNF 스트레칭이 선수들의 유연성 향상과 순발력에 미치는 영향을 알아보기 위하여 슬관절의 관절가동범위를 평가하고, 점프수행능력을 평가하여 기능적 수행능력에 미치는 영향을 알아보고자 하였다. 그 결과 정적 스트레칭과 PNF 스트레칭 그룹 모두 관절가동범위와 점프수행능력에 유의한 향상을 보였고, 두 그룹간의 비교에서는 점프수행능력에서만 유의한 차이를 보였다.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.38-45
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• 2017

Background: To improve muscle flexibility, static stretch is the most common type and is considered safe and effective for improving overall flexibility of muscles. During the stretch, the intensity is more likely to be determined by the degree of an athlete's pain and practitioner's skills rather than quantitative measures of stretch. It is necessary to determine the optimal intensity for the stretch. Objects: The purpose of this study is to explore the relationship between hand held dynamometer (HHD) and verbal rating scale (VRS) in comparison of the effects of continuance time on active (walking) and inactive (sitting) movement after static stretch. Methods: A cross-sectional study was conducted with a sample (n=62) recruited from a university. Participants were randomly assigned to 2 different groups (n=31 for each group) based on participants' positions either remaining in sitting or freely walking around for a series of re-assessments. Data was collected at pre-warm up, pre-stretch, post-stretch, and additional assessments at the time of 3, 6, 9, 12, 15, 20 and 30 minutes after the stretch. Results: Relationship between VRS and HHD scores represents very weak correlation (Spearman's p=-.16, p>.05). Pearson's correlation analysis was conducted following the logarithmic transformation of the two scores. Pearson's correlation after the transformation still showed a very low relationship and a poor linear relationship between the two scores (Pearson's r=-.18, p>.05). Conclusion: The optimal intensity for stretch cannot be solely determined by the subjective pain perception. The objective measurement such as HHD could be used in conjunction with the pain perception.

• 대한물리의학회지
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• 제7권2호
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• pp.191-197
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• 2012

Purpose : The purpose of this study was to examine immediate effects of 15 minutes plantarflexor static stretching in quite stance. Methods : Twenty-nine subjects were measured static balance during 1 minute in quite stance with eye closed condition before and after 15 minutes plantarflexor static stretching. Static stretching range was limited from $15^{\circ}$ to $20^{\circ}$ dorsiflexion within comfortable range. Results : The result of this study showed that postural sway significantly increased during 1 minute quiet stance after 15 minutes static stretching(p<.05). Before stretching, postural sway significantly decreased during 41-60 seconds compared to 0-20, 21-40 seconds(p<.05). After stretching, postural sway was decreased significantly over time 0-20, 21-40, and 41-60 seconds(p<.05). Conclusion : The prolong plantarflexor static stretching may require biomechanical, neurological adaptations prior to walking or sport activities for safety.

• The Korean Journal of Physiology
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• 제4권2호
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• pp.19-24
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• 1970

Since the discovery of the muscle spindle by Hassall (1831), an intensive studies of its anatomical and physiological characteristics had been undertaken. Recent morphological studies of Boyd (1962) demonstrated that the muscle spindles have two different intrafusal muscle fibers, nuclear bag and nuclear chain fiber, and these intrafusal fibers are under independent motor innervation by ${\gamma}_1$ and ${\gamma}_2$ motor neurone. Neurophysiological studies of Hunt and Kuffler (1951) showed regulatory effect of ${\gamma}$ motor neurone upon the excitability of the spindle afferents. Harvey and Mathews (1961) observed the dynamic and static characteristics of the two different spindle afferents, the primary and secondary ending. Furthermore, Mathews (1962) postulated the functional existance of two kind of ${\gamma}$ motor neurones, namely, the dynamic and static fusimotor fiber. Recent report of Kim and Partridge(1969) pointed out that the descending vestibular signals had increased the slope of the length-tension relationship in stretch reflex; Kim (1967) demonstrated that the descending vestibular impulses act upon the stretch reflex loop through the ${\gamma}$ motor pathway. These experimental evidences from the morphological and neurophysiological studies on the muscle spindles support the concept that the stretch reflex action of the skeletal muscle operates as a negative feedback control system. The author had discussed the way by which the f system participates in the control of stretch relfex feed back system. that was taken for a prototype of posture and movement.

• PNF and Movement
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• 제13권3호
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• pp.135-143
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• 2015

Purpose: The purpose of this study was to assess the effect of the proprioceptive neuromuscular facilitation (PNF) relaxation technique (hold relax; HR, contract relax; CR) and static stretch (SS) on hamstring flexibility and vertical jump performance in healthy adults over a four-week period. Methods: Twenty-four healthy adults volunteered to participate in PNF and static stretch sessions. The subjects were divided into three groups as follows: 8 subjects in the SS group, 8 subjects in the HR group, and 8 subjects in the CR group. In the HR and CR groups, contractions lasted 15 seconds per trial and consisted of 5 sets of 15 seconds of hamstring contraction immediately followed by 15 seconds of passive static hamstring stretching. For the static group, the participants were asked to stretch by hanging a leg over a table for 30 seconds. Subjects in all groups performed the exercises three days per week for 4 weeks. The active straight leg raising (ASLR) test, active knee extension (AKE) test, and vertical jump test were performed before the intervention and after 1, 2, and 4 weeks. Results: The SS, HR, and CR techniques effected positive improvement in hamstring flexibility and vertical jump performances but neither of the stretching methods had any statistically significant different effects according to group, although there were interactions (between group and time) in the ALSR group from 1 week to 2 week and in the AKE test from pretest to 1 week. Conclusion: Based on the results of the current study, SS, HR, and CR were shown to affect hamstring flexibility and vertical jump performance in healthy adults. In particular, it was determined that within a short period, hamstring flexibility could be attributed more to CR than to SS.

• 패션비즈니스
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• 제1권3호
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• pp.35-44
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• 1997

The purpose of this study is to the processes and quality of local women's apparel production using the stretch fabric and to address the problems related to production in order to provide useful data for producing competitive apparels. The result of the survey can be summarized as follows; 1. Results of surveying the process for raw materials and notions indicated that most of the workers were ignorant of the properties of stretch fabrics. And most factories were stacking the stretch fabrics across improperly, while being aware of the properties of the fabrics through their experiences or in-company test. 2. The major problem involving spreading fabrics was the uneven tension, followed by static electricity, overlap and warp twist. The problems involving the cutting work were melting of the fabric by cutter and difference of size between upper and lower parts. 3. Most of the businesses were not tempering the fabric before and after its linking works due to lack of working space, short delivery time, ignorance and etc. The majority of the sample businesses were operating their cutters at the speed of 3,000 rpm or higher, which suggests a poor technological guidance.

• 소음진동
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• 제9권3호
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• pp.472-476
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• 1999

The effect of static preload on the dynamic properties of rubber materials is rather important, especially when good isolation characteristics are required at high frequencies. However, there are still few papers for dynamic characteristics of compressed rubber components. It was demonstrated in reference (4) that for bonded rubber material of a cylindrical shape, a simplified theory equation between linear dynamic and nonlinear static behavior of rubber material was useful to predict their combined effects. This paper presents the second part of the study. It is confirmed that for the compressed rubber material, the stress can be factored into a function of frequency and a function of strain(stretch). The finite element methodis applied to analyze non-linear large deformation of rubber material and its results are compared with those of a simplified theory equation. The predicted dynamic material properties based on non-linear static finite element analyses have a good agreement of experimental results and those based on simplified theory equation.

• 감성과학
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• 제12권4호
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• pp.519-530
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• 2009

기술적인 발전에 따라 다양한 인터페이스가 등장하고 있다. 2D 일색이었던 인터페이스에 3D가 등장하기 시작했고 정적이던 화면 구성에 움직이는 요소들이 더해지고 있다. 움직임이 있는 자극들이 인터페이스에 쓰이면서 그 적절한 사용에 대해 알아볼 필요가 있다. 본 연구는 이런 움직임에 초점을 맞추고 있다. 특히 움직임의 여러 속성 중에서도 움직임에 스타일을 줄 수 있는 스쿼시 & 스트레치의 적용에 초점을 두고 있다. 본 연구는 움직임에 스쿼시 & 스트레치 기법의 적용이 움직임의 매력도와 감성, 주의에 미치는 영향을 알아보았다. 실험 1에서 참가자들은 스쿼시 & 스트레치 기법이 적용된 구와 적용되지 않은 구 모양 물체의 움직임을 보고 매력도와 움직임 관련 감성어휘를 평정하였다. 그 결과 스쿼시 & 스트레치 기법이 적용된 움직임을 더매력적으로 지각할 뿐만 아니라 해당 움직임을 더 밝고 적극적으로 지각하게 됨을 밝혔다. 실험 2는 스쿼시 & 스트레치가 적용된 구와 그렇지 않은 구를 화면에 동시에 제시하고, 참가자들이 변화를 탐지하는 반응시간을 측정했다. 그 결과 스쿼시 & 스트레치 기법이 적용된 움직임의 변화를 탐지하는 반응시간이 더 빨랐다. 이는 해당 움직임이 더 주의를 끌게 됨을 의미한다.

• 대한기계학회논문집B
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• 제21권2호
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• pp.195-201
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• 1997

Static and non-static flame methods were used to measure the laminar burning velocity of methane, ethane and natural gas. The flame slot angle and velocity of unburned gas mixture were determined by Schlieren method and LDV, respectively, for static flame. The diameter of nozzle was selected as 11 mm. The experimental results containing the stretch effect showed that the maximum burning velocities were 41.5 for natural gas, 40.8 for methane and 43.4 cm/sec for ethane on equivalence ratio of 1.1. Constant volume combustion chamber was also used for non-static flame. The propagation process of flame front was visualized by high speed camera during constant pressure. The maximum burning velocity of natural gas was determined as 42.1 cm/sec on equivalence ratio of 1.15.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1569-1572
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• 2003

Meshfree approximations exhibit significant potential to solve partial differential equations. Meshfree methods have been successfully applied to various problems which the traditional finite element methods have difficulties to handle, including the quasi-static and dynamic fracture. large deformation problems, contact problems, and strain localization problems. A meshfree method based on the reproducing kernel particle approximation(RKPM) is applied to sheet metal forming analysis in this research. Metal forming examples, such as stretch forming and flanging operation, are analyzed to demonstrate the performance of the proposed meshfree method for largely deformed elasto-plastic material.