• The Journal of Korean Physical Therapy
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• 제16권3호
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• pp.176-191
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• 2004

The purpose of this study was to find the effects of the eccentric exercise induced delayed muscle soreness on proprioception, muscle strength, muscle fatigue, and muscle pain of the elbow flexor muscles. Thirty one healthy male subjects were participated in this study. Before resisted eccentric exercise of the elbow flexors and immediately and at 1, 3, 5, and 7 days post-exercise, pain threshold, proprioception, tension tracking, initial median frequency, and fatigue index were measured. Pain pressure threshold and visual analog scale (VAS) was used to measure muscle pain. Proprioception of the elbow joint was measured by using 3 dimension motion analysis system. Maximum isometric contraction was measured by using digital tensiometer. Electromyography and power spectrum analysis was used to measure initial median frequency (IMF) and fatigue index (FI). Immediately post-exercise, a significant decrease pain threshold was observed that continued to 5 days post-exercise. VAS score was significantly increased at 1 and 3 days post-exercise compared to that of immediately post-exercise. Maximum isometric contraction, IMF, tension tracking ability of the exercised elbow joint were significantly decreased at 1, 3, and 5 days post-exercise compared to that of pre-exercise. FI was significantly increased at 1 and 3 days post-exercise compared that of pre-exercise. Proprioception sense of exercised elbow joint was significantly decreased immediately and at 1, 3, and 5 days post-exercise compared to that of pre-exercise. Proprioception sense of the contralateral elbow joint was significantly decreased immediately post-exercise compared to that of pre-exercise. However, proprioception sense that was measured in close chain kinematic position was not significantly difference between pre-exercise and post-exercise. These results could be useful to determine the resume time for exercising and participating sports activities.

• 콘크리트학회논문집
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• 제15권3호
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• pp.470-481
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• 2003

플랫 플레이트 구조의 외부접합부는 편심전단에 대해 비대칭형의 위험단면을 가지고 있으며, 위험단면의 길이가 내부접합부 보다 작고 중력하중과 횡하중 모두에 의해 편심전단응력이 발생하게 되므로 뚫림전단파괴에 대해 대단히 취약하다. 외부접합부의 거동은 대단히 복잡하며 또한 구조해석에서 사용하고 있는 강도모델이 부적합하기 때문에, 현 설계기준은 실험결과를 정확히 설명하고 있지 못하다. 본 연구에서는 이러한 현 설계기준의 미비점을 보완하기 위하여 슬래브-기둥 외부접합부에 대해 비선형유한요소해석을 수행하였다. 외부접합부에서는 횡하중의 재하방향에 따라 거동 및 최대강도가 상이하며, 해석결과에 근거하여 하중재하방향 별로 외부접합부에 대한 강도모델을 제안하였다. 제안된 강도모델은 실험결과와의 비교를 통해 검증되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.1-4
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• 2008

플랫 플레이트 구조는 다른 구조형식에 비하여 매우 경제적인 구조형식이다. 그러나 횡하중을 받는 플랫 플레이트 구조는 슬래브-기둥 접합부의 뚫림전단파괴에 대해 취약하다. 플랫 플레이트 구조의 외부접합부는 편심전단에 대해 비대칭형의 위험단면을 가지고 있으며, 위험단면의 길이가 내부접합부 보다 작고 중력하중과 횡하중 모두에 의해 편심전다응력이 발생하게 되므로 뚫림전단파괴에 대해 매우 취약하다. 이에 본 논문에서는 플랫 플레이트 외부접합부의 실험결과와 기존 데이터를 바탕으로 ACI 318-05와 CEB-FIP MC 90의 설계기준식을 비교한 결과 편심전단응력, 불균형모멘트에 대해서 CEB-FIP식이 더 정확했고 형상비의 영향은 기둥 형상비가 큰 경우에는 기준식의 적용성에 문제가 있는 것으로 나타났다. 중력전단력비의 영향은 기준식의 제안을 만족하였으나 설계 기준에서는 단순히 중력전단비만 고려하고 있어서 다른 설계조건 변화에 따른 차이를 고려할 필요가 있다.

• 한국전산구조공학회논문집
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• 제26권1호
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• pp.19-28
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• 2013

전단벽-골조 구조시스템의 구조적인 거동은 휨거동하는 전단벽과 전단거동하는 골조의 상호작용에 의하여 결정된다. 이러한 전단벽-골조 구조물의 거동특성을 효과적으로 고려하기 위하여 선행 연구에서는 2차원 T형 강체를 사용한 단순 해석모델을 제안하였다. 본 논문에서는 이를 바탕으로 편심코어를 가진 전단벽-골조 구조물에 대한 효율적인 해석모델을 제안한다. 2차원 등가모델을 3차원으로 확장하여 비틀림 거동을 고려할 수 있도록 하였고, 그 결과 제안하는 등가모델이 편심코어를 가지는 전단벽-골조 구조물에도 적용가능 하도록 하였다.

• Physical Therapy Rehabilitation Science
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• 제9권2호
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• pp.113-119
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• 2020

Objective: The vibration device is one of the most commonly used warm-up devices not only for healthy athletes but also for healthy individuals. Therefore, this study aimed to investigate the immediate effects of local vibration on ankle plantar flexor muscle activation and peak torque in healthy adults. Design: One-group pretest-posttest design. Methods: This was a single-group study comprising a total of 36 (16 males and 20 females) participants. The average age of the 36 participants was 22.3 years. All the participants' concentric and eccentric peak torques of the gastrocnemius lateralis muscle were measured using an isokinetic device. Simultaneously, the participants' muscle activity was measured by surface electromyography. After the pre-experimental data were collected, the participants comfortably sat on the prepared chair with their hips and knees flexed to 90°. While in sitting position, local vibration was applied for 10 minutes using a 1:1 ratio intermittent pulsing mode device based on a previous study. Then, the post-experimental data were collected immediately after the local vibration by performing a similar process performed during the pre-experimental data collection. Results: The results showed a significant difference in muscle activity and eccentric peak torque (p<0.05). On the contrary, concentric peak torque values showed an insignificant difference with pre- and post-value. Conclusions: The results of this study demonstrated that local vibration can be possibly considered as one of the effective ways to increase ankle plantar flexor muscle activity and muscle performance, specifically the eccentric peak torque, in healthy adults.

• 한국전문물리치료학회지
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• 제4권3호
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• pp.70-83
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• 1997

The purpose of this study was to determine the effects of transcutaneous electrical nerve stimulation(TENS) on delayed onset muscle soreness(DOMS). Twenty males performed eccentric exercise of the elbow flexor. Subjects were randomly assigned to one of three groups: 1) a group ($n_1$=7) that received low frequency TENS (7 Hz), 2) a group ($n_2$=7) that received high frequency TENS (500 Hz), 3) a control group ($n_3$=6) that received no treatment. DOMS was induced in a standardised fashion in the non-dominant elbow flexor of all subjects by repeated eccentric exercise. Treatments were applied immediately following exercise and again at 24 hours and at 48 hours after. Subjects attended on three consecutive days for treatment and measurement of elbow flexion, extension and resting angle(universal goniometer), and pain(Visual Analogue Scale; VAS) on a daily basis. Measurements were taken after treatment. Analysis of results using repeated measures analysis of variance(ANOVA) and post hoc tests were as follows: 1) there were between groups differences in pain value at 48 hours after (p<0.05), 2) one-way ANOVA with repeated measurement for pain, resting angle, flexion angle and extension angle revealed significant differences within low frequency TENS group, 3) one-way ANOVA with repeated measurement for flexion angle revealed significant difference within high frequency TENS group.

• 한국운동역학회지
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• 제23권2호
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• pp.159-167
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• 2013

The purpose of this study was to evaluate the gender differences on gait pattern and the kinetics on lower extremities according to the different gait speed. Ten collegiate male students (age : $23.80{\pm}2.94$ yrs, height : $179.40{\pm}5.04$ cm, weight : $66.57{\pm}5.64$ kg) and ten female students (age : $23.40{\pm}2.91$ yrs, height : $166.06{\pm}5.61$ cm, weight : $53.76{\pm}2.75$ kg) participated in this study. To investigate the role, the ratio of the use, and the effectiveness of each joint during gait, we examined the joint work and the contribution to total work. The results of this study were as follows: First, gait pattern was not differ between male and female, hip joint ROM increased with the increase of gait speed both male and female. Second, the eccentric work of the ankle joint decreased with the increase of the gait speed both male and female, on the other hand increased on the knee joint. Third, in the result of the contribution to total eccentric work, male in both the two gait speed was the biggest on the hips joint. However, female in normal gait speed was the greatest on the ankle joint, was the most on the knee joint in the fast gait speed. Forth, the concentric work on the ankle and hip joint increased with the increase of gait speed both male and female. Fifth, in the result of the contribution to total concentric work, there is no difference in the male both the two gait speed, however decreased in the female on the knee joint with the increase of the gait speed, on the other hand increased on the ankle joint.

• 한국강구조학회 논문집
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• 제25권2호
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• pp.209-222
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• 2013

800MPa급 강재와 100MPa급 콘크리트를 적용한 매입형 합성기둥에 대하여 편심압축실험을 수행하였다. 강재단면의 모멘트팔길이와 변형(응력)을 증가시켜 고강도강재의 성능활용을 극대화할 수 있도록, ㄱ형 강재단면을 네 모서리에 집중 배치한 후, 래티스철근, 링크철근, 띠판을 이용하여 일체화하였다. 이 경우 강재단면의 강력한 횡구속효과로 인해 심부콘크리트의 성능도 개선된다. 실험결과 ㄱ형 강재 매입형 기둥은 H형 강재 매입형 기둥에 비하여 최대강도와 유효휨강성이 1.4배 이상 증가하였다.

• Steel and Composite Structures
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• 제33권1호
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• pp.111-122
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• 2019

This paper presents an experimental work on the post-fire behavior of two kinds of innovative composite stub columns under eccentric compression. The partially precast steel reinforced concrete (PPSRC) column is composed of a precast outer-part cast using steel fiber reinforced reactive powder concrete (RPC) and a cast-in-place inner-part cast using conventional concrete. Based on the PPSRC column, the hollow precast steel reinforced concrete (HPSRC) column has a hollow column core. With the aim to investigate the post-fire performance of these composite columns, six stub column specimens, including three HPSRC stub columns and three PPSRC stub columns, were exposed to the ISO834 standard fire. Then, the cooling specimens and a control specimen unexposed to fire were eccentrically loaded to explore the residual capacity. The test parameters include the section shape, concrete strength of inner-part, eccentricity ratio and heating time. The test results indicated that the precast RPC shell could effectively confine the steel shape and longitudinal reinforcements after fire, and the PPSRC stub columns experienced lower core temperature in fire and exhibited higher post-fire residual strength as compared with the HPSRC stub columns due to the insulating effect of core concrete. The residual capacity increased with the increasing of inner concrete strength and with the decreasing of heating time and load eccentricity. Based on the test results, a FEA model was established to simulate the temperature field of test specimens, and the predicted results agreed well with the test results.

• 한국운동역학회지
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• 제31권4호
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• pp.297-307
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• 2021

Objective: The aim of this study was to analyze kinetic variables between thermotherapy and dynamic warm-up during drop-landing. Method: Twenty male healthy subjects (Age: 21.85 ± 1.90 years, Height: 1.81 ± 0.06 cm, Weight: 68.5 ± 7.06 kg) underwent three treatments applied on the thermotherapy of femoral muscles and a dynamic warm-up. The thermotherapy was performed for 15 minutes while sitting in a chair using an electric heating pad equipped with a temperature control device. Dynamic warm-up performed 14 exercise, a non-treatment was sitting in a chair for 15 minutes. Core temperature measurements of all subjects were performed before landing at a height of 50 cm. During drop-landing, core temperature, joint angle, moment, work of the sagittal plane was collected and analyzed. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was Bonferroni. Results: Results indicated that Thermotherapy was increased temperature than other treatments (p = .000). During drop-landing, hip joint of dynamic warm-up was slower for angular velocity (p < .005), and left ankle joint was fastest than other treatments (p = .004). Maximum joint moment of dynamic warm-up was smaller for three joints (hip extension: p = .000; knee flexion/extension: p = .001/.000; ankle plantarflexion: p = .000). Negative work of dynamic warm-up was smaller than other treatments (p = .000). Conclusion: In conclusion, the thermotherapy in the local area doesn't affect the eccentric contraction of the thigh. The dynamic warm-up treatment minimized the joint moment and negative work of the lower joint during an eccentric contraction, it was confirmed that more active movement was performed than other treatment methods.