• Title/Summary/Keyword: physical interaction

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Effect of Post-Activation Potentiation according to Sequence of Velocity Using Isokinetic Device on Short-Term Performance of Lower Extremity: Taekwondo Athletes and Healthy Adults

  • Sang-Woo Pyun;Seong-Eun Kim;Jong-Wan Kim;Dongyeop Lee;Ji-Heon Hong;Jae-Ho Yu;Jin-Seop Kim;Hyun Suk Yang;Seong-gil Kim
    • The Journal of Korean Physical Therapy
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    • v.34 no.6
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    • pp.298-303
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    • 2022
  • Purpose: The purpose of this study was to figure out how PAP (Post-Activation Potentiation) phenomenon affects short-term performance efficiently. Methods: This study was conducted with 18 Taekwondo athletes and 16 healthy adults. By using isokinetic dynamometer, two different intervention, TDP (Top-down program) and BUP (Bottom-up program), were performed to measure isokinetic parameter; (peak torque: PT, total work: TW, average power: AP, and average torque: AT) of knee extensor for intragroup, intergroup comparison and two-way ANOVA. Results: The Taekwondo athletes group showed statistically significant differences in all isokinetic parameters PT, TW, AP, and AT after TDP (p<0.05). However, in the healthy adult group, the difference in isokinetic parameters according to the exercise sequence was not statistically significant. (p>0.05). PT and TW at TDP were statistically significant (p<0.05) when the rate of change in TDP and BUP was compared and analyzed considering the difference in physical ability between the Taekwondo athlete group and the healthy adult group. However, AP and AT were not statistically significant. Finally, when examining the interaction between the two groups and two exercise sequence according to isokinetic parameters, only TW (p<0.05) showed a statistically significant interaction, while PT (P=0.099), AP (P=0.103), and AT (P=0.096) did not. This study suggests that short-term performance can be improved through the PAP phenomenon when TDP is applied to the Taekwondo group. Conclusion: According to our result, for Taekwondo athletes, if the goal is to improve short-term performance just before the main game, we suggest a training program through TDP.

Control strategy for the substructuring testing systems to simulate soil-structure interaction

  • Guo, Jun;Tang, Zhenyun;Chen, Shicai;Li, Zhenbao
    • Smart Structures and Systems
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    • v.18 no.6
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    • pp.1169-1188
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    • 2016
  • Real-time substructuring techniques are currently an advanced experimental method for testing large size specimens in the laboratory. In dynamic substructuring, the whole tested system is split into two linked parts, the part of particular interest or nonlinearity, which is tested physically, and the remanding part which is tested numerically. To achieve near-perfect synchronization of the interface response between the physical specimen and the numerical model, a good controller is needed to compensate for transfer system dynamics, nonlinearities, uncertainties and time-varying parameters within the physical substructures. This paper presents the substructuring approach and control performance of the linear and the adaptive controllers for testing the dynamic characteristics of soil-structure-interaction system (SSI). This is difficult to emulate as an entire system in the laboratory because of the size and power supply limitations of the experimental facilities. A modified linear substructuring controller (MLSC) is proposed to replace the linear substructuring controller (LSC).The MLSC doesn't require the accurate mathematical model of the physical structure that is required by the LSC. The effects of parameter identification errors of physical structure and the shaking table on the control performance of the MLSC are analysed. An adaptive controller was designed to compensate for the errors from the simplification of the physical model in the MLSC, and from parameter identification errors. Comparative simulation and experimental tests were then performed to evaluate the performance of the MLSC and the adaptive controller.

The Effects of Balance and Proprioception by Unstable Surfaces Training and Galvanic Vestibular Stimulation (불안정지지면 훈련과 평류전정자극이 균형 및 고유수용성감각에 미치는 영향)

  • Park, Chi-Bok;Cho, Woon-Su;Hwang, Tae-Yeun;Kim, Yong-Nam
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.10 no.1
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    • pp.7-13
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    • 2012
  • Purpose : This study was conducted to examine the effects of unstable surface training and galvanic vestibular stimulation on balance and proprioception. Methods : 4-week training was applied to 40 normal adults in their twenties (unstable surface training group 10, galvanic vestibular stimulation group 10, unstable surface training and galvanic vestibular stimulation group 10, control group 10). Balance and proprioception was measured before the experiment, after two weeks, and after four weeks. Repeated ANOVA was used for balance and proprioception analysis. Results : As a result of repeated ANOVA on balance changes in double support, a significant difference was found in open sight in interaction among groups and periods (p<0.05). As a result of repeated ANOVA on balance changes in double support, there was a significant difference in closed sight and interaction among groups and periods (p<0.05). As a result of repeated ANOVA on balance changes in proprioception, there was no statistically significant difference in interaction among groups and periods. Conclusion : In conclusion, both unstable surface training and galvanic vestibular stimulation had positive effect on balance control and proprioception improvement, and their excellence was not greatly different. Thus, it is possible to use unstable surface training and galvanic vestibular stimulation for physical therapy intervention to improve balance and proprioception. Since the results showed that simultaneous application of two methods had greater effects on difference compared with a single application, it is suggested to use this intervention in the clinical field.

The effects of pulsed ultrasound and continued ultrasound intervention before an exercise on PPT, CK and LDH of EIMD (운동 전 적용된 지속초음파와 맥동초음파가 운동 유발성 근육 손상의 통증과 근피로대사산물에 미치는 효과)

  • Kim, Ha Neul;Jeon, Jae Geun;Shin, Sung Phil
    • Journal of Korean Physical Therapy Science
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    • v.27 no.3
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    • pp.56-66
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    • 2020
  • Background: The purpose of this study was to investigate the effects of pulsed-ultrasound intervention and continued-ultrasound on the PPT (pressure pain threshold), CK (creatine kinase) and LDH (lactate dehydrogenase) recovery of before EIMD (exercise-induced muscle damage). Design: Randomized Controlled Trial. Methods: Thirty subjects who are student in their 20s at a university participated in this study, these subjects were assigned into three groups, a control group (n=10), experiment group I (n=10), and experiment group II (n=10). The subjects in experimental group were intervened by pulsed-ultrasound and continued-ultrasound, while ones on control group weren't by any intervention after induced EIMD. Results: First, In the comparison of the PPT, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the PPT of experimental group II was significantly larger than those of other groups (p<.01). Second, In the comparison of the CK, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the CK of experimental group II was significantly smaller than those of other groups (p<.001). Third, In the comparison of the LDH, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the LDH of experimental group II was significantly smaller than those of other groups (p<.001). Conclusion: The above results revealed that the continued-ultrasound intervention before an exercise had a positive effect of muscle function after EIMD. Therefore we can consider the continued ultrasound as a considerable intervention method to prevent or reduce an exercise injury.

The effect of Whole-body cryotherapy intervention after an eccentric exercise on PPT, CK and LDH of EIMD (원심성 운동 후 극저온 냉각치료 적용이 운동유발성 근육 손상 후 통증, CK 및 LDH에 미치는 효과)

  • Shin, Sung Phil;Kim, Ha Neul;Jeon, Jae Geun
    • Journal of Korean Physical Therapy Science
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    • v.28 no.3
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    • pp.30-41
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    • 2021
  • Background: The purpose of this study was to investigate the effects of WBC on the pressure pain threshold, CK and LDH after exercise-induced muscle injury. Design: A Randomized Controlled Trial. Methods: In this study, these subjects were assigned into three groups, a control group (n=10), experiment group I (n=10) and experiment group II (n=10). The subjects in experimental group I were intervened by WBC (-130℃, 3 minutes) before induced EIMD, experimental group II were intervened by WBC (-130℃, 3 minutes) after induced EIMD and control group weren't by any intervened after induced EIMD. Results: First, In the comparison of the PPT, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the PPT of experimental group II was significantly larger than those of other groups (p<.01). Second, In the comparison of the CK, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the CK of experimental group II was significantly smaller than those of other groups (p<.001). Third, In the comparison of the LDH, there were significant variations with the lapse the time in three groups (p<.01) and there was a significant interaction of time and group (p<.001). In the among group comparison, the LDH of experimental group II was significantly smaller than those of other groups (p<.001). Conclusion: The above results revealed that the WBC intervention after an exercise had a positive effect of muscle function after EIMD.

Study of Effect of Adsorbate-Adsorbent Interaction in Multilylayer Physical Adsorption of Gases on Solids

  • Park, Sung-Ju;Lee, Jo W.;Pak, Hyung-Suk;Chang, Sei-Hun
    • Bulletin of the Korean Chemical Society
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    • v.2 no.2
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    • pp.56-59
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    • 1981
  • In this paper a further generalization of the theory of multilayer physical adsorption previously developed by the authors is attempted so that the effect of vertical interactions between adsorbent and adsorbate can be explicitly taken into account. In this attempt we have to discard the previously adopted assumption that the molecules in the second layer or above are all in the same physical state. In order to estimate the effect of vertical interactions on the adsorption isotherm the interaction energy between an adsorbed molecule and the adsorbent surface is assumd to vary as $r^{-3}$ where r is the distance that the molecule under consideration is separated from the adsorbent surface. Resulting adsorption isotherm is applied to interpret the adsorption data of tetramethylsilane vapor on iron film and good agreements between observed and calculated values are obtained over wide range of pressure.

Topological Analysis on the Dispersion Polymerization of Styrene in Ethanol

  • 손정모;박형석
    • Bulletin of the Korean Chemical Society
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    • v.17 no.3
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    • pp.245-253
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    • 1996
  • A topological theory has been introduced to explain and evaluate the fractional volumes of system materials, the change of the weight and concentration of monomer molecules, molecular weight distribution, and interaction functions of polymer-polymer and polymer-oligomer, etc. for dispersion polymerization. The previous theory of Lu et al. has offered only an incomplete simulation model for dispersion polymer systems, whereas our present one gives a general theoretical model applicable to all the polymerization systems. The theory of Lu et al. considered only the physical property term caused by interaction between matters of low molecular weight (i.e., diluent, monomer, and oligomer) and polymer particles without dealing with physical properties caused by the structure of polymer networks in polymer particles, while our theory deals with all physical effect possible, caused by the displacement of not only entangled points but also junction points in polymer particles. The theoretically predictive values show good agreement with the experimental data for dispersion polymerization systems.