• 한국전문물리치료학회지
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• 제30권4호
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• pp.275-280
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• 2023

Background: Although warm-ups before exercise are widely accepted, research on sex differences in improving hamstring flexibility is limited. Differences in the physical and physiological characteristics between males and females may result in different responses to warm-ups. Objects: This study aimed to examine sex differences in the effects of specific warm-up on hamstring flexibility. Methods: This study included 24 young adults with hamstring tightness. The participants performed five maximal knee extensions and flexions at 90° flexion of the hip, and the maximal knee extension angle was measured in real-time using a smartphone clinometer application. Results: The groups did not significantly affect the maximal knee extension angle but showed a significant effect for repetition (p = 0.002) and group-repetition interaction (p = 0.002). Males had no significant change in hamstring flexibility; however, females showed a significant increase in flexibility in the 5^th trial compared with the 1^st trial (p = 0.041). These results demonstrated sex-specific differences in flexibility improvement over time. Conclusion: The findings of this study suggest that specific warm-up can successfully improve hamstring flexibility in females. This may be due to various factors, such as muscle stiffness of the lower extremity, estrogen levels, and temperature sensitivity. In clinical settings, specific warm-up might be helpful for females who participate in sports or activities, such as running or jumping, which require a full range of motion in the hip and knee joints.

• 가족자원경영과 정책
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• 제15권2호
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• pp.63-84
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• 2011

This qualitative case study focused on the workers' flexibility needs. We selected eight full-time workers from one 2009 family friendly certified firm for observation and in-depth interview. The workers are categorized into three groups; male employees with housewives, double income family workers depending on extended family, and double income family workers depending on paid babysitter. The spouse's work status and informal extended familial support to child care were crucial factors to influence their work family life styles and flexibility needs. The flex time is the most desirable everyday needs for the dual working child caring parents depending on the paid help. And the female workers' concerned about the stigma effect of the institutionalized flexibility use of the inferior labors.

• 대한기계학회논문집A
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• 제25권7호
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• pp.1125-1130
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• 2001

Dynamic behaviors of an automatic dynamic balancer are analyzed by a theoretical approach. Using the polar coordinates, the non-linear equations of motion for an automatic dynamic balancer equipped in a rotor with the bending flexibility are derived from Lagrange equation. Based on the non-linear equation, the stability analysis is performed by using the perturbation method. The stability results are verified by computing dynamic response. The time responses are computed from the non-linear equations by using a time integration method. We also investigate the effect of the bending flexibility on the dynamics of the automatic dynamic balancer.

• Computers and Concrete
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• 제25권3호
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• pp.273-282
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• 2020

A new seismic design methodology for precast concrete diaphragms has been developed and incorporated into the current American seismic design code. This design methodology recognizes that diaphragm inertial forces during earthquakes are highly influenced by higher dynamic vibration modes and incorporates the higher mode effect into the diaphragm seismic design acceleration determination using a first mode reduced method, which applies the response modification coefficient only to the first mode response but keeps the higher mode response unreduced. However the first mode reduced method does not consider effects of diaphragm flexibility, which plays an important role on the diaphragm seismic response especially for the precast concrete diaphragm. Therefore this paper investigated the effect of diaphragm flexibility on the diaphragm seismic design acceleration for precast concrete shear wall structures through parametric studies. Several design parameters were considered including number of stories, diaphragm geometries and stiffness. It was found that the diaphragm flexibility can change the structural dynamic properties and amplify the diaphragm acceleration during earthquakes. Design equations for mode contribution factors considering the diaphragm flexibility were first established through modal analyses to modify the first mode reduced method in the current code. The modified first mode reduced method has then been verified through nonlinear time history analyses.

• 대한물리치료과학회지
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• 제9권4호
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• pp.35-44
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• 2002

The purpose of this study was to compare the effect of heat therapy, stretching exercise and to verify which method was most effective for lumbar flexibility improvement. Subjects were 20 apparantly healthy person(male10, female10) who did not have any medical problem. They were randomly divided and assigned into 2 groups: heat therapy, stretching exercise. For testing flexibility, trunk flexion, bunk extension, and Schober-test were performed. Pre-test was done prior to the each group's treatment. Test was done at 2nd week, 4th week and 6th week. There were no significant difference in improvement of trunk flexion and trunk extension after 6 weeks treatment among 2 methods. However in all 2 groups, there were statically significant improvement in flexibility as time go on. The rate of improvement was highest at 2nd week, while this was attenuated afterwards. The Schober-test score changed significantly from pre-test to the mid-test and to the post-test, while there were no significant difference among 2 methods of treatment. With the results above, it was concluded that heat therapy, stretching-exercise were all effective for improving flexibility without any significant priorities.

• Structural Engineering and Mechanics
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• 제77권4호
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• pp.463-472
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• 2021

Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.

• 디지털융복합연구
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• 제11권6호
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• pp.91-101
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• 2013

본 연구의 목적은 공급사슬유연성(운영유연성, 물류유연성)과 경쟁우위전략(저원가, 고품질, 납기신속성)간의 관계를 실증적으로 규명하는 것이다. 이를 위해 공급사슬유연성(운영유연성, 물류유연성)과 경쟁우위전략(저원가, 고품질, 납기신속성) 간의 관계에 대한 모형을 구축하였다. 관련된 자료를 수집하기 위해 구미에 위치한 제조 기업에 종사하는 종업원들에게 500부의 설문지를 배포하였다. 수집된 자료들은 SPSS 18.0을 사용하여 기술적 분석, 신뢰성 분석, 요인분석, 상관관계분석, 다중회귀분석 등의 통계적 기법을 활용하였다. 연구결과 운영유연성은 저원가, 고품질전략에 긍정적인 영향을 미치는 것으로 확인되었으며, 물류유연성은 납기신속성 전략에 긍정적인 영향을 미치나, 운영 유연성은 납기신속성에, 물류유연성은 저원가, 고품질 전략에 유의한 영향을 미치지 못하는 것으로 확인되었다. 따라서 기업은 적용하는 공급사슬유연성과 경쟁우위전략과 적절한 조화를 통해 기업전략을 극대화 할 수 있을 것으로 기대된다.

• 국제물리치료학회지
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• 제11권2호
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• pp.2042-2051
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• 2020

Background: Many trials have been conducted the methods and types of intervention of form rollers, but no research has been done yet that mixes the methods and types of intervention. Objectives: To analyze the effects of myofascial release on the improvement of range of motion (ROM), flexibility, pain pressure threshold, and balance. Design: Randomized controlled trial. Methods: All subjects measured ROM, flexibility, pressure pain threshold, and dynamic balance by pre-test. After pre-test, subjects were randomized that static-vibration foam rolling group (n=12), dynamic-vibration foam rolling group (n=12), general foam rolling group (n=12). For the intervention, 3 sets of 90 seconds were applied to each group, and rest time was set to 60 seconds between sets. In the post-test and follow-up test after 10 minutes, all three groups were measured the ROM, flexibility, pressure pain threshold, and dynamic balance. Results: The results of comparing ROM, flexibility, pressure pain thresholds, dynamic balance ability appeared higher significant difference in the pre-post-10 minutes follow up test in comparison between time in the intragroup (P<.001). As a result of comparing the change of pre-post-10 minutes follow up, static vibration foam rolling showed higher significant difference compared to control groups (P<.001). Conclusion: Through this study, when foam rolling is applied within the same intervention time, static foam rolling can be expected to have a better effect than the existing dynamic foam rolling as well as vibration foam roller can expect better effect than general foam rolling.

• Earthquakes and Structures
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• 제7권3호
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• pp.349-365
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• 2014

The dynamic response of structures under extremely short duration dynamic loads is of great concern nowadays. This paper investigates structures' response as well as the associated structural damage to explosive loads considering and ignoring the supporting soil flexibility effect. In the analysis, buildings are modeled by two alternate approaches namely, (1) building with fixed supports, (2) building with supports accounting for soil-flexibility. A lumped parameter model with spring-dashpot elements is incorporated at the base of the building model to simulate the horizontal and rotational movements of supporting soil. The soil flexibility for various shear wave velocities has been considered in the investigation. In addition, the influence of variation of lateral natural periods of building models on the obtained response and peak response time-histories besides damage indices has also been investigated under blast loads with different peak over static pressures. The Dynamic response is obtained by solving the governing equations of motion of the considered building model using a developed Matlab code based on the finite element toolbox CALFEM. The predicted results expressed in time-domain by the building model incorporating SSI effect are compared with the corresponding model results ignoring soil flexibility effect. The results show that the effect of surrounding soil medium leads to significant changes in the obtained dynamic response of the considered systems and hence cannot be simply ignored in damage assessment and response time-histories of structures where it increases response and amplifies damage of structures subjected to blast loads. Moreover, the numerical results provide an understanding of level of damage of structure through the computed damage indices.

• 한국콘텐츠학회논문지
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• 제13권12호
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• pp.966-973
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• 2013

본 연구는 독일의 고용 모델을 바탕으로 고용유연성의 확대가 고용안정성을 침해하지 않고 오히려 근로자와 기업 간 장기적 상생의 목표를 달성할 수 있는 배경과 관련 요인을 탐색하였다. 독일의 고용 및 실업정책의 핵심은 고용유연성의 확대에 있으며, 노사간의 양보와 합의가 주요한 역할을 하는 가운데 정부의 적절한 지원이 이를 성공으로 이끌었다. 특히 효율적인 고용시장정책을 통한 성과 창출과 유지의 이면에는 합리적인 사회적 대화가 자리를 잡고 있다. 독일의 앞선 경험은 우리나라 근로자와 기업의 고용유연성 제고를 위한 모범적인 사례가 될 수 있을 것이다. 제도 활용에 앞서 독일 노사관계의 바탕이 되는 노사간 존중의 관행을 이해하는 것이 필요하며 문화적 배경이 상이한 우리나라에 어떠한 방식으로 적용되는 것이 바람직할 것인지 다각적인 고찰이 선행되어야 한다.