• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.1
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• pp.15-22
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• 2010

Purpose : This study examines the effects of pre-eccentric exercise and stretch ing to bicepsbrachii to prevent delayed onset muscle soreness and recovery of muscular function depending on the training intensity with 28 normal adults in their twenties. Methods : The subjects were divided into a control group, a group without any previous eccentric exercise, and a stretching group. Pre-eccentric exercise group conducted exercise with the intensity of 25% of maximal voluntary contraction. Pre-eccentric exercise and stretching was applied before to induce delayed onset muscle soreness and after, 24 hour post, 48 hour post, and 72 hour post. Measurements were conducted to examine pain and muscular function changes before, immediately after, and after inducing delayed onset muscle soreness. After inducing delayed onset muscle soreness, measurements were taken at the 24th hour, 48th hour, and 72nd hour. Results : The pre-eccentric exercise group and stretching group showed a significant difference from the control group by isometric contract ion power and mechanical pain threshold as a result of measuring delayed onset muscle soreness. Conclusion : From these results, electrical stimulation using presynaptic inhibition mechanism of transcutaneous electrical stimulation (TES) had positive effects for walking ability on inhibition of muscle tone in lower extremity. The motor level stimulation group experienced a more significant effect than the sensory level stimulation group. Therefore, the transcutaneous electrical stimulation (TES) is considered to be effective on walking ability increasing through inhibition of muscle tone in lower extremity for rehabilitation of post stroke hemiplegic patients.

• The Research Journal of the Costume Culture
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• v.21 no.4
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• pp.606-611
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• 2013

It has been reported that tight sportswear could have complicated influence on physiological function of human body. The purpose of this present study was to investigate the effect of wearing gradient compression tights (GCT) on muscle strength and EMG activity during repeated isokinetic muscle contractions. Four healthy male undergraduate students performed maximal voluntary isokinetic concentric muscle contractions on biomechanical test and training systems with GCT and loose pants as control (Cont) respectively. During each test, the peak torque of extensor and flexor contractions and the surface electromyography (sEMG) of the rectus femoris and medial gastrocnemius was recorded simultaneously, the peak torque was recorded as an indicator of muscle strength, and the average amplitude and mean power frequency of sEMG were calculated as indicators of EMG activity. The results showed that: the peak torque decreased gradually during continuous muscle contractions both when the Cont and GCT were worn, average sEMG and mean power frequency declined along with the repetitions of muscle contractions for both wearing conditions, and the change tendency was consistence with that of peak torque. There was no obvious difference between the peak torque recorded wearing the Cont or wearing GCT, but when GCT were worn, average sEMG was lower and mean power frequency was higher than the Cont condition. In 24 samples obtained from four subjects, 80% of results showed the same trend. So we could make a conclusion that wearing GCT had no obvious effect on the improvement of muscle strength, but it would affect the EMG activity positivly.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.548-554
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• 1985

This research is to find a means of reducing diesel engine combustion noise with none or minimum sacrifice of engine performance by investigating the influence of Cylinder Pressure Level(CPL). For this purpose, modified Wiebe's combustion function, considering the heat release curve as a combustion of both premixed and diffusive combustion portion, was exclusively used to obtain the indicator diagram and computer coeds were developed for the numerical analysis. Following are the results of this research. (1) CPL increases almostly with lag of ignition timing increasing .alpha. and decreasing. theta.$_{d}$, but at the crank angle with the maximal efficiency, CPL is independent of .alpha. and .theta.$_{d}$ with constant value of 200 dB especially at the low frequency. (2) For the constant ignition timing, the effects of .alpha. and .theta.$_{d}$ on CPL were the most significant at the frequency of about 1KHz and 300Hz respectively. (3) For the constant value of .alpha. and .theta.$_{d}$, CPL increases linearly with load but thermal efficiency increase very rapidly with maximum value of load Q$_{T}$=30-40 MJ/Kmol, then starts to decrease slowly. (4) The most effective way of reducing combustion noise without sacrificing thermal efficiency, is to decrease .alpha.. In the case of constant .alpha., there always exists a optimum value of .theta.$_{d}$ with respect to the various compression ratio.o..atio.o..

• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.163-174
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• 2020

PURPOSE: This study examined the effects of Robot Tilt-table Training (RTT) on the lower extremity strength, balance, gait, and satisfaction with rehabilitation, in patients with subacute stroke (less than six months after stroke onset), and requiring intensive rehabilitation. METHODS: A total of 29 subacute stroke patients were divided into an RTT group (n = 14) and a Body Weight Support Treadmill Training (BWSTT) group (n = 15). The mean age of patients was 62 years. RTT and BWSTT were performed for four weeks, three times a week, for 30 minutes. Isometric strength of the lower extremities before and after intervention was compared by measuring the maximal voluntary isometric contraction of the lower extremity muscles. To compare the balance function, the center of pressure (COP) path-length and COP velocity were measured. Timed Up & Go test (TUG) and 10 Meter Walking Test (10 MWT) were evaluated to compare the gait function. A satisfaction with rehabilitation survey was conducted for subjective evaluation of the subject's satisfaction with the rehabilitation training imparted. RESULTS: In the intra-group comparison, both groups showed significant improvement in lower extremity strength, balance, gait, and satisfaction with rehabilitation, by comparing the parameters before and after the intervention (p < .05). Comparison of the amount of change between groups revealed significant improvement for all parameters in the RTT group, except for the 10 MWT (p < .05). CONCLUSION: Both groups are effective for all variables, but the RTT group showed enhanced efficacy for variables such as lower extremity strength, balance, gait, and satisfaction with rehabilitation, as compared to the BWSTT group.

• Journal of Korean Physical Therapy Science
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• v.10 no.1
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• pp.149-157
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• 2003

The purpose of this study was to compare the effects of different exercise types including isokinetic, isometric, and istonic exercise of same exercise intensity on cardiopulmonary function and blood lactate level. The subjects of this study included 17 males college students. Each subjects after pretraining measurement performed isokinetic, isometric and isotonic exercise of 1 week interval using Cybex 6000 System. KBI-C and YSI 1500 were used to measure changes in cardiopulmonary function and blood lactate level respectively. First, comparing changes in RPP relative to exercise type, isokinetic group showed significant difference between before exercise ($7.08{\pm}1.12mg/kg/min$) and post exercise ($18.98{\pm}1.75mg/kg/min$). Isometric group showed that significant difference between before exercise($7.89{\pm}0.98mg/kg/min$) and post exercise($20.22{\pm}2.41mg/kg/min$). Isotonic group showed significant difference between before exercise ($8.14{\pm}0.11mg/kg/min$) and post exercise ($19.84{\pm}2.30\;mg/kg/min$). Second, comparing changes in blood lactate level relative to exercise type, isokineic group showed significant difference between before exercise ($2.99{\pm}0.65mmol$) and post exercise ($6.55{\pm}6.55mmol$). Isometric group showed significant difference between before exercise($1.71{\pm}5.48mmol$) and post exercise ($5.48{\pm}1.97mmol$). Isotonic group showed significant difference between before exercise($1.16{\pm}0.48mmol$) and post exercise($5.21{\pm}1.28mmol$). The results of this study indicate significant differences RPP in isometric exercise and significant differences blood lactate in isotonic exercise.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.49-51
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• 1994

The aims of this study were first to determine the influence of vibration displacement amplitude $(200{\mu}m, 300{\mu}m peak-to-peak)$ at selected frequencies (40-200Hz) on a commonly observed but often undesired motor response elicited bylocal vibratory stimulation, the Tonic Vibration Reflex (TVR). Second, to determine the degree of synchronization of motor unit (MU) activity with vibratory stimuli. Vibration was applied to the distal tendons of the hand flexor muscles. Changes in root- mean-square electromyographic (EMG) activity of the finger and wrist flexor muscles were analyzed both as a function of their initial contraction level (0%, 10%, 20% of the maximal voluntarycontraction: MVC) and as a function of the vibration parameters. The results indicate that the TVR increased with the initial muscle contraction up to 10% MVC: The TVR increased with vibration frequency up to 100-150 Hz and decreases beyond; A significant increase of the TVR with vibration displacement amplitude was observed only for the wrist flexor muscle; MU synchronization at vibration frequency (VF) was found more often in the low frequency range $(f{\leq}100 Hz)$ and tended todecrease beyond; In the high frequency range $(f{\geq}120 Hz)$, MU activity at subharmonic frequency was predominant; The "cut-off" frequency of the synchronization with VF was neither affected by the vibration displacement amplitude nor initial muscle contraction level. The surface EMG turned out to be a useful means to analyze MU synchronization since it is noninvasive, and it can be easily used for analysis of different muscle contraction levels, while single MU technique might have some difficulties at high muscle contraction levels. Furthermore, these results indicate that high frequencyvibration (f>150 Hz) tends to induce less muscle/tendon stress and MU synchronization. Such remarks are of importance for the design of hand-held vibrating tools.ing tools.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.481-489
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• 2018

In this study, the succession and stand dimension attributes related to the disaster prevention function of Pinus thunbergii coastal forests were examined after damage from Diplodia tip blight. In 2015, 101 years after the Taisho eruption, field investigations were performed on the vegetation, soil thickness, and pH of surface soil of P. thunbergii coastal forests in western Sakurajima (Hakamagoshi plot) and Taisho lava flows in southeastern Sakurajima (Seto plot). The Hakamagoshi plot had more woody plant species with larger basal areas than that in the Seto plot. The mean age and height, maximal age and height of plant species, and H/D ratio were all larger in the Hakamagoshi plot than in the Seto plot. These results may be explained by the relatively smaller effect of volcanic ash and gas on forests in the Hakamagoshi plot compared to the Seto plot, resulting in a more suitable environment for many plant species. Although P. thunbergii coastal forests in Sakurajima are currently recovering from damages owing to Diplodia tip blight, there has not yet been a sufficient recovery compared to the results from a 1997 study. Furthermore, the results of assessment based on the H/D ratio and abundance of trees in P. thunbergii forests indicate that both regions are not yet effective in disaster prevention. Thus, it is necessary to establish Pinus trees, which can adjust to harsh environments like coastal areas and are resistant to volcanic ash and gas, to enhance the disaster prevention function of P. thunbergii coastal forests in volcanic regions. It may also be helpful to establish coastal forests with ectotrophic mycorrhizal fungi and organic matter coverage. Additionally, it is necessary to ensure the continuous maintenance of stand density and soil quality, and further develop efforts to prevent Diplodia tip blight and promote forest recovery.

• Journal of Ginseng Research
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• v.45 no.4
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• pp.473-481
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• 2021

Background: Mitochondrial dysfunction is one of the significant reasons for Alzheimer's disease (AD). Ginsenosides, natural molecules extracted from Panax ginseng, have been demonstrated to exert essential neuroprotective functions, which can ascribe to its anti-oxidative effect, enhancing central metabolism and improving mitochondrial function. However, a comprehensive analysis of cellular mitochondrial bioenergetics after ginsenoside treatment under Aβ-oxidative stress is missing. Methods: The antioxidant activities of ginsenoside Rb₁, Rd, Re, Rg₁ were compared by measuring the cell survival and reactive oxygen species (ROS) formation. Next, the protective effects of ginsenosides of mitochondrial bioenergetics were examined by measuring oxygen consumption rate (OCR) in PC12 cells under Aβ-oxidative stress with an extracellular flux analyzer. Meanwhile, mitochondrial membrane potential (MMP) and mitochondrial dynamics were evaluated by confocal laser scanning microscopy. Results: Ginsenoside Rg₁ possessed the strongest anti-oxidative property, and which therefore provided the best protective function to PC12 cells under the Aβ oxidative stress by increasing ATP production to 3 folds, spare capacity to 2 folds, maximal respiration to 2 folds and non-mitochondrial respiration to 1.5 folds, as compared to Aβ cell model. Furthermore, ginsenoside Rg1 enhanced MMP and mitochondrial interconnectivity, and simultaneously reduced mitochondrial circularity. Conclusion: In the present study, these results demonstrated that ginsenoside Rg₁ could be the best natural compound, as compared with other ginsenosides, by modulating the OCR of cultured PC12 cells during oxidative phosphorylation, in regulating MMP and in improving mitochondria dynamics under Aβ-induced oxidative stress.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.540-547
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• 1993

Backgrounds: The measurement of volume of isoflow has been considered as a sensitive test for detecting small airway diseases showing normal pulmonary function in a routine pulmonary function test. To evaluate the functions of small airway among dust exposed workers, the changes of volume of isoflow were measured and its applicability of managing early stage pneumoconiosis patients was studied. Method: The subjects were 67 male, pneumoconiosis with small opacity and FEV1>80%, FEV1/FVC>75% in spirometry and the controls were 20 male, no dust-exposed office workers. The maximal epiratory volume curves after inhalation of indoor air and $He-O_2$ gas mixtures were measured and ${\Delta}V_{max50},\;{\Delta}V_{max75},\;V_{iso}V/VC$ between the dust exposed and control workers were compaired. Results: 1) There were no significant differences between two group in ${\Delta}V_{max50}$ and ${\Delta}V_{max75}$. But the ratio of $V_{iso}V/VC$ of the subjects was siginificantly higher than that of the control (p<0.01). This study confirms that $V_{iso}V/VC$ is a very useful index in early detection of small airway dysfunction. 2) The ratio of $V_{iso}V/VC$ of the subjects was signigicantly different between only smoker group and mixed group(smoker and nonsmoker). It suggestes that smoking is an important cousative factor of small airway dysfunction. 3) As the profusion of the chest X-ray increased, the rartio of $V_{iso}V/VC$ increased, but no significant difference of $V_{iso}V/VC$ was found between categories of pneumoconiosis. The categories of pneumoconiosis and small airway dysfunction may not be related. 4) No significant relationship was established between the duration of work and the ratio of $V_{iso}V/VC$. Conclusions : It is concluded that the measurement of $V_{iso}V/VC$ is useful to detect small airway dysfuction of early stage pnuemoconiosis patents with small opacities but showing normal pulmonary function in a routine pulmonary function test.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.101-135
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• 1968

As physical fitness measured was muscle strength (hand grips, leg extention, back lift, and arm pull and thrust), skinfold thickness (5 different sites), circulatory function (resting heart rate and blood pressure), speed (kinesiological analysis during 100m sprint, record, maximal and final speed), motor function (50 meter dash, ball throwing, standing broad jump, and pull-ups), maximal aerobic power (maximum oxygen intake by field running method), muscle power (leg and arm by inertia ergometer), and general endurance (maximum endurance running time on the treadmill at the speed of 5 MPH and grade of 15.5%) of 1131 Korean children (boys 572, girls 559) aged of 6 to 17 years, who were randomly sampled from 24 primary, middle and high schools at the two districts of Seoul and KyungKi. The results are summarized as follows: 1) The status (height and weight) of the children was almost same as that of the previously reported Korean and Japanese children of same ages. 2) Muscle strength was a gained linearly with geting age in the boys and girls but there was a little improvement in girls aged of 13 years or more. 3) The mean skin fold thickness was increased linearly with geting ages in both sexes, but the girls from 12 to 17 years of age were increased rapidly, and maximum value was 17mm, while boys was 7.0 mm. 4) In the circulatory function, the resting heart rate was decreased, but the blood pressure was increased with ages in both sexes within the normal limits. 5) The maximum and final speed during 100 meter sprint increases with age in boys but girls who are 12 years old or older, were not improved any mere. The patterns of running were same in both sexes, and maximum speed reached at about 30 meters from starting line. 6) The motor function was increased with age in both sexes, but there was no improvement in 12 years of age or older girls. More over records of all functions except standing broad jump was less than those of Japanese in the same age, respectively. 7) The maximum oxygen intake (MOI) was increased considerably with ages and maximum values were 2.93 L/min (boys) and 2.09 L/min (girls) at the age of 17years. This result was almost same as that of the Japanese and Easter Island population, but the value was lower than that of Europe. The average of the maximum oxygen intake per kg body weight per minute from 9 to 17 years of age were around 53 ml in the boys and 42 ml in the girls. 8) Muscle power was increased linearly with ages in boys while there was relatively a little increment in girls. The maximum values of leg muscle in boys and girls at the 17 years of age were 0.168 and 0.088 horse power, respectively. 9) The maximum endurance running time was increased considerably from the age of 9 in boys, while there was no improvement in girls. The maximum values were 6.0 min and 1.8 min, respectively.