In this study, theoretical analyses are performed to investigate the characteristics of the static and dynamic stiffness of a nonlinear vibration isolator system. The vibration isolator system is modeled as an equivalent nonlinear oscillator. Based on the model, the static equilibrium and frequency response solutions are obtained with the variations of external static load and/or system parameters. It is shown that the static stiffness of the nonlinear vibration isolator tends to be hardened with the increase of external static load, which prevents the occurrence of excessively large deflection. This static stiffness-hardening effect is more remarkable with a larger spring constant ratio. The dynamic stiffness is also strengthened when the spring constant ratio increases, which enlarges the force transmissibility and reduces the isolation frequency bandwidth. Thus, the static stiffness- hardening improves the robustness of the nonlinear vibration isolator, whereas the dynamic stiffness-hardening rather degrades its performance. Thus, the opposite tendency of the static and dynamic stiffness-hardening effects should be considered in the design process of the nonlinear vibration isolator.

Background: Despite its high prevalence, interventions in plantar fasciitis remain inconclusive. To improve the daily life of plantar fasciitis patients, it is necessary to identify appropriate interventions to improve pain and foot pressure and balance. Improving the interventions for plantar fasciitis is one of the main goals for rehabilitation. Objectives: To investigate the changes in pain and static-dynamic foot pressure and balance through the evaluation of 42 plantar fasciitis patient before and after the foot stretching and joint mobilization interventions. Design: Randomized controlled trial. Methods: The 42 subjects of the study were divided into a stretching group and a joint mobilization group with 21 subjects being assigned to each group. The results before and after the experiment were analyzed by applying stretching and joint movement interventions for a total of 6 weeks. Results: Before and after the intervention, there were significant improvements in the pain index and static-dynamic foot pressure and static balance in both stretching and joint mobilization groups. However, the between-group comparison indicated no significant differences. Conclusion: The stretching and the joint mobilization can improve the pain and static-dynamic foot pressure and static balance in plantar fasciitis patients.

Recently, cultural heritages in South Korea gain many interests of restoration and preservation from the government since many of that have been severely damaged during earthquakes. Many previous studies in both terms of experimental and analytical approaches have been done to examine structural behavior and decide appropriate methods of preservation. Being motivated by such researches, this research aims to investigate a religious stone pagoda dated back to the Goryeo Dynasty in Korea. The structure consists of a granite stone foundation and baked bricks, which resembles the shape of traditional pagodas. In order to examine the structural behavior of the pagoda, an analytical model is implemented using ANSYS, a comprehensive engineering simulation platform. For the time history analysis of the pagoda, several earthquake excitations are chosen and input to simulation modeling. Seismic response of the tower such as time domain, natural frequency, modal shapes and peak acceleration measured at each layer are presented and discussed. In addition, the amplification ratio of the tower is calculated from the accelerations of each layer to determine tower stability in accordance with Korean seismic design guide. The determination and evaluation of status and response of the brick tower by simulation analysis play an important role in the preservation of history as well as valuable architectural heritages in South Korea.

목적 : 서로 다른 디자인의 시표를 사용하여 원거리 자각적 주시시차 교정 전, 후의 정적 및 동적입체시를 비교 및 분석해 보고자 하였다. 방법 : 12명(남자 7명, 여자 5명)의 시각적 불편함을 느끼는 대상자를 선정하였다. MKH 차트, 차트프로젝터 십자시표를 사용하여 원거리 수평 주시시차를 교정하였고, 주시시차 교정 전, 후의 원거리 정적 및 동적 입체시력, 원거리 입체시깊이를 측정하였다. 결과 : MKH 차트, 차트프로젝터 십자시표에서 자각적으로 측정된 원거리 수평 주시시차 교정 값은 각각 0.77±0.53 △, 0.29±0.30 △으로 측정되었고 유의한 차이가 있었다(p=0.011). 주시시차 교정 전 원거리 정적입 체시력은 102.50±73.99″이었고, MKH 차트, 차트프로젝터 십자시표를 사용한 교정 후는 각각 42.50±29.27″ (p=0.003), 50.00±44.52″(p=0.003)로 유의한 감소가 있었다. 주시시차 교정 전 원거리 동적입체시력은 24.46±6.60″이었고, MKH 차트, 차트프로젝터 십자시표를 사용한 교정 후는 각각 15.26±7.61″(p=0.008), 17.56±5.67″(p=0.019)로 유의한 감소가 있었다. 주시시차 교정 전 원거리 입체시깊이는 1,107.08±52.72 mm 이었고, MKH 차트, 중심융합자극점이 있는 차트프로젝터 십자시표를 사용한 교정 후는 각각 1,136.08±62.40 mm(p=0.002), 1,120.00±51.52 mm(p=0.028)로 유의한 증가가 있었다. 결론 : 시표의 디자인에 따른 원거리 자각적 주시시차 교정 값에는 유의한 차이가 있었고, 주시시차 교정 후의 정적 및 동적입체시는 두 시표에서 모두 유의하게 향상되었다. 따라서 원거리 자각적 주시시차 교정은 입체시의 개선에 긍정적인 효과를 줄 수 있는 것으로 생각된다. 본 연구에서는 MKH 차트를 통해 주시시차를 교정한 후 입 체시가 상대적으로 가장 많이 향상되었다.

Background: Foot drop is a common symptom in stroke patients. Tape applications are widely used to manage foot drop symptoms. Previous studies have evaluated the effects of static and dynamic balance and gait on foot drop using kinesiology tape; however, only few studies have used dynamic tape application in stroke patients with foot drop. Objects: The purpose of this study was to investigate the immediate effects of dynamic taping, which facilitates the dorsiflexor muscle, on static and dynamic balance and gait speed in stroke patients with foot drop. Methods: The study included 34 voluntary patients (17 men, 17 women) with stroke. The patients were randomly assigned to the experimental group (n = 17), wherein dynamic taping was used to facilitate the dorsiflexor muscle, or the control group (n = 17), wherein kinesiology taping was used. Before the taping application, velocity average, path-length average, Berg balance scale, and timed up and go test (TUG) were recorded to measure static and dynamic balance, whereas the 10-meter walk test (10MWT) was used to measure gait speed. After the taping application, these parameters were re-evaluated in both groups. Repeated measure analysis of variance was used. Statistical significance levels were set to α = 0.05. Results: Except for the 10MWT scores in the control group, significant differences were noted in all the parameters measured for static and dynamic balance and gait speed between the pre and post-test (p < 0.05). However, the parameters showed significant interaction effects between group and time in the TUG and 10MWT (p < 0.01). Conclusion: These results indicate that compared with kinesiology taping, dynamic taping used in chronic stroke patients with foot drop had a more significant effect on dynamic balance and gait speed.

고령운전자의 인지 및 신체 기능 저하로 인한 교통사고 증가는 점점 심각한 사회적 문제가 되고 있으며, 이 로 인해 면허증을 자진하여 반납하는 제도가 운영되고 있으나 보다 객관적인 평가 방법이 필요하다. 본 연 구에서는 다양한 주행 상황에서 발생하는 정적 및 동적 시각 자극에 대하여 운전자의 시각적 행동을 평가 할 수 있는 운전 시뮬레이션 주행 환경과 시나리오를 구현하는 것이 목표이다. 이를 위해 고령운전자의 주 행 특성 분석에 활용된 운전 시뮬레이션 시나리오를 기존의 연구 문헌들로부터 수집하였고, 정적 및 동적으 로 구분된 표적 자극에 따른 텍스트 네트워크 분석을 통해 주행환경과 시나리오를 재분류하였다. 또한, 유 사한 유형의 시나리오들은 보다 발생 빈도가 높고 표적 자극이 다양한 주행환경으로 병합하였다. 연구 결과 로 신호교차로, 비신호 교차로, 왕복 2차로, 왕복 4차로 주행환경에서의 전체 12종의 시나리오로 구성된 운 전 시뮬레이션 콘텐츠가 구현되었다. 신호등, 정차된 차량, 표지판 등으로 구성된 정적 시각 자극과 주행 중 인 차량, 무단 횡단하는 보행자 등의 동적인 시각 자극이 제시되며, 이에 대한 시선 탐색(Visual Detection), 시지각(Visual Perception), 시각운동기능(Visuomotor Function)의 정량적 측정을 통해 운전자의 시각 행동 평가가 이루어진다. 본 연구에서 제안하는 시나리오 구성 방법은 운전 시뮬레이션 콘텐츠를 구현하기 위한 새로운 접근 방식으로써 시각 자극에 따른 운전 능력 검사 환경 구축에 관한 기초 자료로 활용될 수 있을 것으로 기대된다.

Background: Postural control deficit is a major characteristic in patients with chronic ankle instability (CAI). Elastic ankle tapings are commonly used to facilitate postural control in patients with CAI as well as prevent relapse of a lateral ankle sprain. However, equivocal evidence exists concerning the effect of elastic ankle taping on postural control. Objects: This study aimed to evaluate the effects of elastic ankle tapings using kinesio taping (KT) and dynamic taping (DT) on static and dynamic postural control in patients with CAI. Methods: Fifteen subjects with CAI were participated in this study. The participants performed tests under three conditions (barefoot, KT, and DT). Static postural control was evaluated using the one-leg standing test (OLST) and dynamic postural control using the modified Star Excursion Balance Test (mSEBT). One-way repeated-measures analysis of variance was used to compare center of pressure (CoP) data and normalized mSEBT reach distances among the three conditions (with α = 0.05). Results: The CoP parameters (path length, ellipse area, and mean velocity) of the OLST significantly decreased on applying KT and DT compared with those when barefoot. The normalized reach distances in the anteromedial (AM), medial (M), and posteromedial (PM) directions of the mSEBT significantly increased with DT compared to that in the control condition. Further, the higher reach distances with KT compared with those in the control condition were obtained in the M and PM directions of the mSEBT. No significant differences were identified in any of the OLST and SEBT parameters between the two different taping applications. Conclusion: KT and DT improved static postural control during the OLST compared with the control condition. Moreover, these tapes improved dynamic postural control during the mSEBT compared to the control. Therefore, elastic ankle tapings are useful prophylactic devices for the prevention and treatment of ankle sprain in people with CAI.

Background: The foot is a complex body structure that plays an important role in static and dynamic situations. Previous studies have reported that altered foot posture might affect knee joint strength and postural stability, however their relationship still remains unclear. Objects: The purpose of this study was to identify whether pronated foot posture has an influence on knee isokinetic strength and static and dynamic postural stability. Methods: Forty healthy young males aged 18 to 26 years were included. Foot posture was evaluated using the Foot Posture Index-6 (FPI-6), and the subjects were divided into two groups according to their FPI-6 scores: a neutral foot group (n = 20, FPI-6 score 0 to +5) and a pronated foot group (n = 20, FPI-6 score +6 or more). Biodex Systems 3 isokinetic dynamometer was used to evaluate knee isokinetic strength and hamstring to quadriceps ratio at three angular velocities: 60°/sec, 90°/sec, and 180°/sec. The static and dynamic postural stability in a single-leg stance under the eyes-open and eyes-closed conditions were measured with a Biodex Balance System. Results: There were no significant differences between the groups in knee isokinetic strength and static postural stability (p > 0.05), but there was a significant difference in the medial– lateral stability index (MLSI) for dynamic postural stability under the eyes-closed condition (p = 0.022). The FPI-6 scores correlated significantly only with the dynamic overall stability index (OSI) and the MLSI (OSI: R = 0.344, p = 0.030; MLSI: R = 0.409, p = 0.009) under the eyesclosed condition. Conclusion: Participants with pronated foot had poorer medial–lateral dynamic stability under an eyes-closed condition than those without, and FPI-6 scores were moderately positively correlated with dynamic OSI and dynamic MLSI under the eyes-closed condition. These results suggest that pronated foot posture could induce a change in postural stability, but not in knee isokinetic strength.

이 연구는 65세 이상의 골관절염을 앓고 있는 여성 노인(실험군: 67.2±5.4세; 13명)과 건강한 일반 노인여성(통제군: 66.73±9.7세; 15명)을 대상으로 12주간의 요가 운동 전.후의 평형성(동적평형성 및 정 적평형성)의 변화를 알아보고 골관절염 노인여성의 요가 운동의 효과성을 알아보고자 실시되었다. 이 연구에서 측정된 동적평형성 및 정적평형성은 시각정보(개안, 폐안)의 유무에 따른 2번의 측정이 진행 되었다. 동적평형성 측정은 Spacebalance 3D, (Korea) 기기를 이용하여 측정하였고, 정적평형성 측정 은 주로 사용하는 발의 눈감고 외발서기로 측정하여 결과를 도출하였다. 12주간 요가 운동에 따른 동적평형성(폐안)은 골관절염 실험군(p(.05)에서는 유의한 증가가 나타났으나, 통제군에서는 유의한 변화가 나타나지 않았다. 또한, 동적평형성(개안) 측정에 따른 변화는 실험군(p(.001) 및 통제군(p(.05) 두 그룹 모두에서 유의한 향상 결과가 나타났다. 정적평형성 결과 두 집단(실험군, 통제군) 모두 시기 별로 유의한 향상이 나타났다. 이 연구의 결과로 12주간의 요가 수련은 골관절염을 앓고 있는 여성 노인의 평형성을 증가시키는 유익한 운동임을 알 수 있었다.

Background: Ankle sprain is one of the most common musculoskeletal injuries in the sports population or during usual daily life activities. The sprain can cause functional ankle instability (FAI), and it is very important to treat FAI. However, the optimum intervention method for FAI has yet to be determined. Objects: This study investigated the impact that virtual reality (VR) training program on balance with ankle kinesio taping for FAI. Methods: Twenty-two people were selected for the study and randomly divided into the experimental (n = 11) and the control group (n = 11). The experimental group had attached kinesio taping on the ankle and then implemented a virtual reality exercise program for 30 minutes a day. Nintendo Wii Fit Plus was used for the VR intervention three times a week for four weeks. The control group performed only two measurements without intervention. Results: There were no statistically significant differences in overall, anterior-posterior (AP), medial-lateral (ML) index of the static balance, and significant differences in overall, AP, ML index of the dynamic balance when taping and VR exercise were applied at the same time (p < 0.05). There were no significant differences in overall and ML index of static and dynamic balance compared with before and after assessment between the experimental and the control group, and found differences in AP index of static and dynamic balance (p < 0.05). Conclusion: Kinesio taping may not influence the balance of FAI as great as people expected. VR approach does not affect the static balance of FAI, but it influences dynamic balance in overall, AP, ML index. The authors suggest that VR-based exercises can be used as an additional concept in clinicians for FAI or as part of a home program because the exercises still have limitations.

Background: Anterior cruciate ligament reconstruction (ACLR) causes a reduction in the balance of the lower extremities. Static and dynamic balance were evaluated separately to confirm the decrease in balance in patients underwent ACLR. The commonly used methods include the Biodex Balance System (BBS) for static balance and the Y balance test (YBT) for dynamic balance. No study has evaluated whether the static and dynamic balance of the involved side recovers as much as the uninvolved side one year after ACLR. Objects: The purpose of this study was to investigate the recovery of static and dynamic balance between the involved and the uninvolved sides. Methods: The BBS (overall, anteroposterior index, and mediolateral index) and YBT (anterior, posterolateral, and posteromedial) of 58 patients underwent ACLR were measured one year postoperation. Both sides of the BBS and the YBT were compared using the paired t-test. Results: All the index of the BBS showed no difference between the involved and the uninvolved sides, while all the scores of the YBT showed a significant difference in both sides. The YBT anterior result was 54.64 ± 5.62 cm in the involved side and 56.90 ± 5.41 cm in the uninvolved side (p = 0.001). The YBT posterolateral results were 90.12 ± 10.51 cm and 92.34 ± 9.85 cm (p = 0.013). The YBT posteromedial results were 93.72 ± 8.84 cm and 96.14 ± 9.37 cm (p = 0.002). Conclusion: A year after ACLR, the static balance showed no difference, while the dynamic balance showed a significant difference in the involved and the uninvolved sides. The static balance of the involved side recovered as much as the uninvolved side, but the dynamic balance did not. Therefore, dynamic balance training should be considered in the rehabilitation program for patients underwent ACLR.

Background: Flat-footed persons with collapsed medial longitudinal arch lose flexibility after skeletal maturity, resulting in several deformities and soft tissue injuries. Although arch support taping is usually applied in the clinic to support the collapsed arch, research on the use of different types of tape for more efficient arch support in flat-footed persons is lacking. Objects: The purpose of this study was to examine three conditions (barefoot, kinesio tape, and dynamic tape) and compare their effects on static and dynamic balance in persons with asymptomatic flexible flatfoot. Methods: Twenty-two subjects (9 females and 13 males) with asymptomatic flexible flatfoot participated in this study. The subjects performed the Y-balance test to measure the composite reach score. The subjects also performed a 30-second standing test to measure the center of pressure (COP) path length and a walking test to measure anteroposterior and lateral variability using the Zebris FDM system. One-way repeated-measures analysis of variance compared the three conditions applied to the subjects’ feet for each balance variable. Results: The composite reach score significantly increased following the application of dynamic tape compared with barefoot and that of kinesio tape compared with barefoot. There was no significant difference in the COP path length during standing among the three conditions. Anteroposterior and lateral variability during walking significantly with dynamic tape application compared with barefoot. Conclusion: The results of this study suggest that, in persons with asymptomatic flexible flatfoot, application of kinesio tape and dynamic tape may be effective in increasing the composite reach score in Y-balance test, whereas application of dynamic tape may be effective in reducing anteroposterior and lateral variability during walking.

Background: Lumbar lordosis is a result of muscle shortening and may cause low back pain. Objective: To examine the effects of static and dynamic stretching on lumbar lordosis and low back pain in university students. Stretching is an intervention that can be applied to shortened muscles; however, very few studies have compared the effects of static and dynamic stretching on lumbar lordosis and low back pain. Design: Randomized controlled clinical trial (single-blind) Methods: The 12 selected subjects were randomly assigned static stretching and dynamic stretching groups each containing six students. The subjects in each group performed their respective stretching programs for 17 minutes, 3 times a week for 4 weeks. Lumbar lordotic angle, low back pain, and Oswestry Disability Index (ODI) were measured before and after the intervention. Results: Intragroup comparisons showed significant reductions in lumbar lordotic angle and low back pain in the static stretching group while the dynamic stretching group showed significant decreases in lumbar lordotic angle, low back pain, and ODI. The intergroup comparisons showed significantly greater differences between pre- and post-intervention in lumbar lordotic angle and low back pain in the dynamic stretching group compared to those in the static stretching group while ODI did not show any intergroup difference. Conclusions: The results of this study indicated that, while both static and dynamic stretching helped to reduce the lumbar lordotic angle and low back pain, dynamic stretching was more effective in alleviating lumbar lordotic angle and low back pain compared to static stretching.

In this study, an algorithm applying deep learning to the truss structures was proposed. Deep learning is a method of raising the accuracy of machine learning by creating a neural networks in a computer. Neural networks consist of input layers, hidden layers and output layers. Numerous studies have focused on the introduction of neural networks and performed under limited examples and conditions, but this study focused on two- and three-dimensional truss structures to prove the effectiveness of algorithms. and the training phase was divided into training model based on the dataset size and epochs. At these case, a specific data value was selected and the error rate was shown by comparing the actual data value with the predicted value, and the error rate decreases as the data set and the number of hidden layers increases. In consequence, it showed that it is possible to predict the result quickly and accurately without using a numerical analysis program when applying the deep learning technique to the field of structural analysis.

목적: 동체시력의 특성을 파악하기 위해 동체시력과 정지시력, 순간시력 및 안구움직임의 관계를 분석하였다. 방법: 20-30대 일반인 40명을 대상으로 동체시력, 고대비 및 저대비 정지시력, 순간시력, 주시 및 홱보기 안구움직임을 측정하였다. 동체시력은 상하좌우 방향으로 반전된 Snellen E 시표를 임의로 투사하여 측정하였으며, 시표의 방향을 식별할 수 있는 최고 각속도를 동체시력으로 지정하였다. 정지시력은 4 m 거리 에서 logMAR 시표를 이용하여 측정하였고, 시표의 대비에 따라 고대비(100%) 및 저대비(10%) 시력으로 나 누었다. 순간시력은 다섯 자리 숫자 시표를 이용하여 평가하였고, 시표 노출 시간은 14 ms와 7 ms이었다. 안구움직임은 고정형 안구추적장치를 이용하여 측정하였다. NYSOA King-Devick 검사의 하위 세 가지 시표를 읽는 동안 주시 및 홱보기 안구움직임을 추적하였다. 결과: 동체시력은 고대비 정지시력(r=-0.43, p=0.01), 저대비 정지시력(r=-0.40, p=0.01)과 통계적으 로 유의한 상관관계를 보였다. 순간시력은 동체시력과 상관관계가 없었고(r=-0.29, p=0.07), 시표 식별 시 개입되는 시기억능력(visual memory)의 영향을 축소시켰을 때에도 상관성이 없었다(r=-0.10, p=0.57). 동 체시력과 주시 및 홱보기 안구움직임은 상관관계를 보이지 않았다(fixation counts: r=0.07, p=0.65, fixation duration: r=0.27, p=0.10, saccade counts: r=0.02, p=0.93, saccade duration: r=0.01, p= 0.98, saccade amplitude: r=0.22. p=0.18, saccadic velocity: r=0.23, p=0.15). 다중회귀분석 결과, 동체시력에 영향을 미치는 요인은 고대비 정지시력으로 나타났다(β=-0.43, p=0.01). 결론: 동체시력은 고대비 및 저대비 정지시력에 따른 시각 능력 및 시각의 질과 관련이 있었다. 정지시력, 순간시력 및 안구움직임 중 동체시력에 영향을 미치는 성분은 고대비 정지시력이었으며, 순간시력이나 안구움직임이 동체시력에 미치는 영향은 추가적인 분석이 필요하다고 사료된다.

PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.

The study investigates the effect of different types of visual images, i.e., static images versus dynamic images, on English vocabulary learning. Eighty-four students in the fourth grade of an elementary school participated in this study, and they were divided into two experimental groups and a control group. One of the experimental groups utilized static images, and the other group, videos as dynamic images in vocabulary learning. The control group was provided with the definition or the explanation of each target word in L1. The results of the study manifested that the static image group showed higher scores for the post test than the dynamic image group. The comparison of the pre and post affective tests demonstrated that the static image group showed an improvement in confidence in language learning and the dynamic image group showed positive change in the attitude of all three areas: interest, confidence, and aroused motivation. The analysis of the open-ended questionnaires showed that many participants in the static image group tended to use pictures as retrieval cues to remember vocabulary.

본 논문에서는 구조물에 작용하는 하중의 크기와 진동수에 따른 거동의 비선형성을 확인하고 정확한 예측을 위한 방법을 모색하기 위하여 외팔보의 정적 및 동적해석의 수행에서 선형, 비선형 해석의 결과를 비교하는 연구를 진행하였다. 우선 보의 자유단에 수직방향의 정적 및 동적 하중을 가한 상황을 예측하였다. 선형 해석방법으로 고전 외팔보 이론을 적용하였고, co-rotational dynamic 유한요소해석 기법을 개발하여 비선형 해석방법으로 사용하였다. 먼저 정적해석에서 외력의 크기가 달라질 때 선형 및 비선형 해석 예측이 어떠한 차이를 보이는지 비교하였다. 그리고 동적해석을 통해 가진 진동수의 변화에 따른 보 끝단의 무차원화된 변위의 양상을 연구하였고, 공진진동수 근방에서의 상당한 변위가 발생함을 보였다. 마지막으로 주파수 지연현상을 조사하기 위해 특정 진동수에서의 시간 경과에 따른 보의 변위를 확인하였다.

The aim of this study was to compare the duration of hamstring flexibility improvement after 3 stretching interventions in people with limited hamstring flexibility. Twenty-two subjects (12 men, 10 women) with limited hamstring flexibility of the dominant leg received 3 stretching interventions— modified dynamic stretching (MDS), hold-relax (HR), and static stretching (SS)—in a random order. All the subjects received all 3 interventions at intervals of at least 24 hours to minimize any carry-over effect. Modified dynamic stretching was applied as a closed kinetic chain exercise in the supine position by using the sling suspension system (Redcord Trainer®). The SS and HR interventions were individually performed in the straight leg raising (SLR) position, and all 3 interventions were performed for 3 minutes. Outcome measures included passive knee extension (PKE) measurements. Five post-test measurements were recorded for all subjects at 3, 6, 9, 15, and 30 minutes after the interventions. MDS was associated with a significant increase in knee extension range of motion even at 30 minutes post-treatment. In contrast, the HR and SS stretching methods showed increased hamstring flexibility for only 6 minutes post-treatment. Improvements in the range of motion of knee extension (indicating enhancement in hamstring flexibility) with MDS were maintained longer than those with the HR and SS interventions. Therefore, MDS may be more effective than the other interventions for maintaining hamstring flexibility.

이 연구에서는 선행연구의 녹차-목재섬유 복합보드에 부가하여, 목제품 생산 후 발생하는 부산물인 편백나무 톱밥의 효율적인 이용과 건축내장재로의 응용을 목표로 목재섬유와 편백톱밥 및 녹차를 혼합한 복합보드를 제조하여 동적탄성률에 미치는 톱밥 및 녹차 배합비율의 영향 및 동적탄성률로부터 정적 휨강도성능의 예측가능성을 평가하였다. 목재섬유-톱밥-녹차 복합보드의 동적탄성률은 1.41~1.65 GPa의 범위에 있었고, 목재섬유: 톱밥: 녹차의 배합비율 50 : 40 : 10에서 가장 높은 값을 나타내었다. 이 값은 정적 휨 탄성계수의 1.4~1.6배의 높은 값을 나타내었고, 녹차-목재섬유복합보드보다 2.0~2.9배 낮은 값을 나타내었다. 동적탄성률과 정적 휨 강도성능과의 상관회귀에서는 일부 예외를 제외하고 대부분 매우 높은 상관계수가 확인되어, 양단자유 휨 진동에 의한 동적탄성률로부터 정적 휨강도성능의 예측이 비파괴적으로 가능할 것으로 사료된다.