• The Journal of Korean Physical Therapy
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• 제20권3호
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• pp.61-68
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• 2008

Purpose: Protein kinase C (PKC) is a member of a family of serine/threonine kinases that are activated by diacylglycerol (DG) and PKC stimulants. PKC play a key role in signal transduction, including muscle contraction, cell migration, apoptosis, cell proliferation and differentiation. However, the mechanism relating mitogen-activated protein kinases (MAPKs) and PKC, especially in the volume-dependent hypertensive state, remains unclear. Methods: In the present study, I investigated the relationship between PKC and MAPKs for isometric contraction, PKC translocation, and enzymatic activity from normotensive sham-operated rats (NSR) and aldosterone-analogue deoxycorticosterone acetate (DOCA) hypertensive rats (ADHR). Results: Systolic blood pressure was significantly increased in ADHR than in NSR. Physiological salt solution (PSS)-induced resting tension and the intracellular $Ca^{2+}$ concentration ([$Ca^{2+}{_i}$]) were different in the ADHR and NSR. The expression of PKC$\alpha$, PKC$\beta$II, PKC$\delta$, PKC$\varepsilon$ and PKC$\xi$ were different between the cytoplasmic and membranous fractions. However, expression of the PKC isoforms did not differ for the ADHR and NSR. The use of 12-deoxyphorbol 13-isobutyrate (DPB, a PKC stimulant) induced isometric contraction in $Ca^{2+}$-free medium, which was diminished in muscle strips from ADHR as compared to NSR. Increased vasoconstriction and phosphorylation induced by the use of 1 ${\mu}$M DPB were inhibited by treatment with 10 ${\mu}$M PD098059 and 10 ${\mu}$M SB203580, inhibitors of extracellular-regulated protein kinase 1/2 (ERK1/2) and p38 MAPK from ADHR, respectively. Conclusion: These results suggest that the development of aldosterone analogue-induced hypertension is associated with an altered blood pressure, resting tension, [$Ca^{2+}{_i}$], and that the $Ca^{2+}$-independent contraction evoked by PKC stimulants is due to the activation of ERK1/2 and p38 MAPK in volume-dependent hypertension. Therefore, it is suggested that PKC activity affects volume-dependent hypertension and the need to develop cardiovascular disease-specialized physical therapy.

• 한국전문물리치료학회지
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• 제10권1호
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• pp.51-62
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• 2003

The purpose of this study was to compare the relative accuracy of a range of computer-based analysis with respect to EMG onset determined visually by an experienced examiner. Ten healthy students (6 male, 4 female) were recruited and three times randomly selected trials of isometric contraction of wrist flexion and extension were evaluated using four technique. These methods were compared which varied in terms of EMG processing, threshold value and the number of samples for which the mean must exceed the defined threshold, and beyond 7% of maximum amplitude. To identify determination of onset time, ICCs(Intraclass Correlation Coefficients) was used and inter-rater arid intra-rater reliability ranged good in visually derived onset values. The results of this study present that in wrist flexion and extension, the reliability of the inter and intra-examiner muscle contraction onset times through visual analysis showed beyond .971 with ICCs. The reliability of the muscle contraction onset time decision through visual reading, tested with computer analysis, showed a relationship of all the selected analysis methods with ICCs .859 and .871. The objective computer-based analysis comparing with visual reading at the same time is the effective and qualitative data analysis method, considering the specificity of each study method.

• 한국전문물리치료학회지
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• 제14권4호
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• pp.1-6
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• 2007

This study examined the effects of hold-relax with agonist contraction (HR-AC) on the symptoms of delayed onset muscle soreness (DOMS) induced by intensive eccentric exercise of the non-dominant biceps brachii. Ten men (mean age=26.7 yrs, mean height=172.1 cm, mean weight=66.2 kg) and ten women (mean age=27.4 yrs, mean height=165.9 cm, mean weight=60.7 kg) who had not participated in a regular exercise program for the upper extremities in the previous six months were randomly assigned to one of two experimental groups: the HR-AC group, or the control group. We measured joint range of motion (ROM), maximal voluntary isometric contraction (MVIC), and muscle soreness before eccentric exercise, and 24, 48, and 72 hours after eccentric exercise. The subjects in the HR-AC group received the HR-AC technique in the non-dominant biceps brachii. The HR-AC technique was applied 24 and 48 hours after eccentric exercise. There was no significant difference between the HR-AC and the control group. However, the HR-AC group, compared to the control group, had a significant difference between the time points of the various parameters. Increased ROM (p<.05), decreased muscle soreness (p<.05), and reduced MVIC (p<.05) were found in the HR-AC group after 72 hours. Decreased ROM (p<.05) and MVIC (p<.05), and increased muscle soreness (p<.05) were observed in the control group. These findings suggest that the HR-AC technique effectively reduces muscle soreness and increases ROM 72 hours after eccentric exercise.

• 한국운동역학회지
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• 제17권1호
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• pp.121-127
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• 2007

Muscle force produced by muscle fibers is transmitted to bones via tendinous structures(aponeuroses and tendon), resulting in joint(s) movement. As force-transmitting elements, mechanical behavior of aponeuroses and tendon are closely related with the function of muscle-tendon complex. The purpose of this study was to determine strain characteristics of aponeuroses for in-vivo human soleus muscle during submaximal voluntary contractions using an advanced medical imaging technique, velocity-encoded phase-contrast magnetic resonance imaging (VE-PC MRI). VE-PC MRI of the soleus muscle-tendon complex was acquired during submaximal isometric plantarflexion contraction-relaxation cycle (n = 7), using 3.0T Trio MRI scanner(Siemens AG, Malvern, MA). From the VE-PC MRI containing the tissue velocity in superior-inferior direction, twenty regions of interest(20 ROI; 10 on the anterior aponeurosis and 10 on the posterior aponeurosis) were tracked. During the isometric plantarflexion contraction-relaxation cycle, velocity and displacement profiles were different between the anterior and posterior aponeuroses, indicating heterogeneous strain behavior along the length of the leg. The anterior aponeurosis elongated while the posterior aponeurosis shortened during the initial phase of the contraction. Moreover, strain behavior of the posterior aponeurosis was different from that of the Achilles tendon. Possible explanation for the observed variations in strain behavior of aponeuroses was investigated with morphological assessment of the soleus muscle and it was found that the intramuscular tendinous structures significantly vary among subjects. In conclusion, the heterogeneous mechanical behavior of the soleus aponeuroses and the Achilles tendon suggests that the complexity of skeletal muscle-tendon complex should be taken into consideration when modeling the complex for better understanding of its functions.

• 한국운동역학회지
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• 제17권3호
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• pp.61-68
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• 2007

When an active muscle is stretched, its steady-state isometric force following stretch is greater than that of a purely isometric contraction as the corresponding muscle length, referred to as force enhancement (FE). The purpose of this study was to investigate possible effects of muscle architecture on the FE. While subject performed maximal isometric dorsiflexion (REF) and isometric-stretch-isometric dorsiflexion (ECC) contractions, ankle joint angle and dorsiflexion torque using a dynamometer and electromyography of the tibialis anterior and the medical gastrocnemius muscles were measure. Simultaneously, real-time ultrasound images of the tibialis anterior were acquired. Regardless of the speed of stretch of the ECC contractions. the torques produced during the isometric phase following stretch ($37.3{\pm}1.5\;Nm$ ($10{\pm}3%$ FE) and $38.3{\pm}1.5$ ($12{\pm}3%$ FE) for the ECC contractions with $15^{\circ}$/s and $45^{\circ}$/s stretch speeds, respectively) were greater than those of the REF contractions ($34.5{\pm}2.5\;Nm$). Moreover, the amount of FE was found to be stretch speed dependent. Angles of pennation ($\alpha$) during the isometric phase following stretch were the same for the REF ($15{\pm}1^{\circ}$) and the ECC ($14{\pm}1^{\circ}$(LS), $15{\pm}1^{\circ}$(LF)). During the same phase, muscle thicknesses were the same ($14.9{\pm}0.6$, and $14.9{\pm}0.5\;mm$ for the REF and the ECC contractions, respectively). For a large limb muscle, the tibialis anterior muscle, a similar amount of force enhancement was observed as did for other human skeletal muscles. Architectural variables, pennation angle and thickness, were not systematically different between the REF and ECC contractions when FE occurred. Therefore, the results of this study suggest that muscle architecture may have little influence on the production of FE.

• 한국정밀공학회지
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• 제22권11호
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• pp.7-15
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• 2005

• 대한수의학회지
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• 제34권3호
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• pp.471-478
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• 1994

Effects of histamine on the ruminal smooth muscle motility of cattle were investigated in the longitudinal and circular smooth muscle strips. In order to these experiments, specimens were obtained from 35 korean native cattles, 3-4 years old, in Kwang-ju area slaughterhouse. Smooth muscle strips of rumen were made from sample, and then measured the isometric contraction with physiograph in $37{^{\circ}C}$ organ bath. The results were as follows : 1. Histamine caused two different types of response(a contraction or a relaxation) on the smooth muscle of cattle rumen. These responses increased in dose dependant manner. 2. Pyrilamine($H_1$-receptor antagonist) completely blocked contraction in all the preparation and converted the response into relaxation. 3. Cimetidine($H_2$-receptor antagonist) completely blocked relaxation in all the preparation and converted the response into contraction. 4. The contraction induced by histamine($10^{-3}M$) was not Mocked by cholinergic, adrenergic blocker or hexamethonium. 5. The contraction induced by histamine($10^{-3}M$) was markedly inhibited in the $Ca^{2+}$ free(or EDTA 2Na) Kreb's solution and by verapamil.

• The Journal of Korean Physical Therapy
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• 제15권4호
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• pp.442-454
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• 2003

The aim of this study was to demonstrate the effects of silver spike point (SSP) low frequency electrical stimulation on plasma vasoactive intestinal polypeptide (VIP) activities measured by radioimmunoassay from volunteer and the effects of VIP on pain substance-induced contraction investigated by isometric tension methode in animal. The current of 3 Hz continue type, but not 100 Hz continue type, of SSP low frequency electrical stimulation significantly increased in plasma VIP from normal volunteer. The pain substance, such as norepinephrine, serotonin, and prostaglandin $F2{\alpha}$, increased vascular smooth muscle contraction, respectively. These responses were inhibited by VIP applied cumulatively (1 nM - $1\;{\mu}M$), but not serotonin-induced contraction. In addition, serotonin, and prostaglandin $F2{\alpha}$ induced uterine smooth muscle contraction from rat. However, these responses were inhibited by VIP ($1\;{\mu}M$), only serotonin-induced contraction. These results suggest that the VIP regulates pain substance in part and that the SSP low frequency electrical stimulation, specifically current of 3 Hz continue type, significantly increases plasma VIP from volunteer.

• 대한산업공학회지
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• 제25권3호
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• pp.330-335
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• 1999

The goal of the study is to determine the most sensitive parameter to represent the degree of muscle force and fatigue. Various numerical parameters such as the first coefficient of Autoregressive (AR) Model, Root Mean Square (RMS), Zero Crossing Rate (ZCR), Mean Power Frequency (MPF), Median Frequency (MF) were tested in this study. Ten healthy male subjects participated in the experiment. They were asked to extend their trunk by using the right and left erector spinae muscles during a sustained isometric contraction for twenty seconds. The force levels were 15%, 30%, 45%, 60%, and 75% of Maximal Voluntary Contraction (MVC), and the order of trials was randomized. The results showed that RMS was the best parameter to measure the force level of the muscle, and that the first coefficient of AR model was relatively sensitive parameter for the fatigue measurement at less than 60% MVC condition. At the 75% MVC, however, both MPF and the first coefficient of AR Model showed the best performance in quantification of muscle fatigue. Therefore, the sensitivity of measurement can be improved by properly selecting the parameter based upon the level of force during a sustained isometric condition.

• 대한임상전기생리학회지
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• 제10권1호
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• pp.39-44
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• 2012

Purpose : This study purposed to analyze how dynamic stabilization exercise on an unstable surface, and static stabilization exercise on muscle strength and endurance. Methods : For this study we sampled 9 people for the unstable surface dynamic stabilization exercise group, 9 for the stable surface static stabilization exercise group, and 9 for the control group. In order to examine muscle strength and endurance, we measured changes in the maximal voluntary isometric contraction (MVIC) using a dynamometer before, 3 weeks after, and 6 weeks after the experiment. Results : First, with regard to change in muscle strength, flexion strength showed a significant change in interaction by time (p<0.05). Extension strength showed a significant change in interaction by time (p<0.05). Second, with regard to change in endurance, flexion endurance showed a significant change in interaction by time (p<0.05). Extension endurance showed a significant change in interaction by time (p<0.05). Conclusion : In conclusion, this study confirmed significant changes in interaction between the groups and by time with regard to changes in muscle strength and endurance. These results suggest the potential of surface dynamic stabilization exercise as a clinical intervention.