• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.227-235
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• 2009

The purpose of this study was to analyze differences of 45minutes up-hill walking depending on hiking poles and steady walking time. Seven healthy men volunteered for this experiment. Each of them performed up-hill walking with hiking poles and without hiking poles at speed of 3.5km/h during 45minutes on a treadmill. The treadmill was set 25% up-hill inclination. The lower extremity 4 muscles activity including rectus femoris, tibialis anterior, gastrocnemius, biceps femoris was recorded and assessed by using EMG. And Heart rate(HR) and Rating of perceived exertion(RPE) were recorded and analyzed by 15minutes interval. The statistical analysis was two-way ANOVA with repeated measures to compare effects of hiking poles and steady walking time. The level of statistical significance for all tests was P<.05. The results of this study were following : Integrated EMG about four individual muscles doesn't have statistical significancy. However, the sum of IEMG of the four muscles was decreased some with poles than without poles(p<.0l) and IEMG about four muscles was rut different on steady walking time. Second, HR was increased significantly as time up(P<.01). RPE was decreased some with poles than without poles(P<.05) and RPE was increased significantly as time up(P<.01).

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.63-70
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• 2011

In this paper, we proposed a method for estimating energy expenditure using the unfixed axis of the accelerometer. Most studies adopted waist-placement because of the fact that the waist is close to the center of mass of a whole human body. But we adopted pocket-placement, which is capable of using unfixed axis of sensor, that is more convenient than conventional methods. To evaluate the proposed method, 28 male subjects performed walking and running on a motor driven treadmill. All of subject put on the indirect calorimeter and fixed accelerometer, then data were simultaneously measured during exercise. The regression analysis was performed using the test group(n=20) and the regression equation was applied to the control group(n=8). A strong linear relationship between energy expenditure and unfixed accelerometer signal was found. Futhermore, the coefficient of determination was significantly reliable($R^2$=0.98) and showed zero of p-value. The error of energy expenditure estimation between indirect calorimeter and two types of accelerometer was 15.0%(fixed) and 17.0%(unfixed) respectively. These results show the possibilities that the unfixed accelerometer can be used in estimating the energy expenditure during exercise.

• Journal of Life Science
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• v.22 no.9
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• pp.1180-1186
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• 2012

The purpose of this study was to investigate the effect of exercise preconditioning (EPC) on nerve growth factor (NGF), synapsin I, and choline acetyltransferase (ChAT) in the hippocampus of rats subjected to social isolation (SI). We randomly assigned four groups of male Sprague-Dawley (SD) rats (n=32) to the following treatments: GC: group housing control; IC: isolation control; GE: group housing exercise; IE: isolation exercise (n=8 each group). The rats underwent EPC 5 days a week for 8 weeks, and the speed of the treadmill was gradually increased (grade $0^{\circ}C$). After EPC, they were immediately subjected to SI for 8 weeks. The results showed that the protein levels of NGF, synapsin I, and ChAT in the hippocampus were significantly decreased in the IC group (p<0.05) compared with the GC group. However, these protein levels were significantly higher in the IE group (p<0.05). These results show that EPC may buffer the decline of function in the hippocampus by ameliorating the reduction in NGF, synapsin I, and ChAT induced by SI.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.183-190
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• 2017

Blood flow restriction(BFR) exercise is defined as low and short lengthexercise with pneumatic pressure belts at the top of the limbs. This study was conducted to investigate the effects of walking exercise with BFR on body composition, growth hormone, and muscle damage markers in obese women. Eleven obese women(> BMI 25kg/m2&> body fat 30%) wore pneumatic pressure belts at both femurs and performed walking exercise twice per day, 3days/wk for 4 week (walking 2min; resting 1min). Body weight, BMI and body fat significantly decreased after exercise(p<0.05), while% body fat was slightly decreased after exercise, although this difference was not significant. Growth hormones increased slightly after exercise, although not significantly. Muscle damage markers (CK(p<0.05), LDH(p<0.05) and K+(p<0.01 increased significantly after exercise, but Mb was did not change significantly. These results suggest that 4-weeks ofblood flow restriction exercisecould be used to prevent and treat obesity and related chronic diseases, as well as metabolic syndrome. Moreover, the effects were similar to those observed in response to high intensity resistance programs, despite the short period for which BFR were conducted.

• 한국노년학
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• v.31 no.2
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• pp.355-369
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• 2011

The purpose of this study was to find the effects of long-term combined exercise on regional bone mineral density(BMD) and cardiovascular disease(CVD) risk factors in the elderly with osteoporosis(OP). For the purpose, the subjects of this study were separated by two groups with thirty-one elderly women, who the first group was combined exercise group(CEG, n=16) and second group was non exercise group(CON, n=15). The combined exercise program was made up of warm-up (10min), work-out (aerobic; 30~45min/HRR 40~60%, resistance; 1RM * 50-70%, 8-10 * 2set ~ 10-15 * 1set), and cool-down (10min). Exercise group of the inspection have been trained 5 times a week for 1years. The results : At first, the variables of regional BMD were significantly different to pelvis, spine, trunk and T-score in two groups. At second, the variables of CVD risk factors were significantly different to SBP and DBP as well as TC, TG, LDL-C and HDL-C in two groups. As results of these conclusion, this study have positively effect shown that CEG was superior to CON in regional BMD(pelvis, spine, trunk and T-score), blood pressure(SBP, DBP) and plasma lipids(TC, TG, and LDL-C). Especially, the long-term combined exercise was provides a striking overall health quality of life with improving BMD and reduced CVD risk factors in the elderly with OP. In the future, other researches should deal with specific measures that reduction in mortality due to chronic disease and improvement quality of life for the development of programs in multiple researches of osteoporosis and chronic diseases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4459-4466
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• 2011

The purpose of this study was to compare the lower extremity muscle activities according to the different longitudinal arch and treadmill inclination and to provide basic data on treadmill walking exercise. The selected 17 subjects who had not lower extremity injury and ROM limitation were recruited in this study. The longitudinal arch was divided into normal foot and flat foot. The inclinations of the treadmill were $0^{\circ}$, up hill $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, down hill $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$. The electromyography was used to analyze the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius lateralis and medialis. There were significant differences between the inclination $0^{\circ}$ and down hill $15^{\circ}$. There was no interactive effect of treadmill inclination on the longitudinal arch. The activity difference of lower extremity muscle was not conspicious. There existed the interactive effect between the longitudinal arch and muscle activity. The contrast test within subjects showed positively in the rectus femoris and gastrocnemius medialis, biceps femoris and gastrocnemius medialis. The different longitudinal arch did not influence on the effect(p>.05). There was significant difference between the normal foot and the flat foot. So it is necessary to carry out the long term study.

• Journal of Life Science
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• v.25 no.11
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• pp.1214-1222
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• 2015

The purpose of this study was to determine the effect of Pueraria lobate-root based combination supplementation containing Rehmannia glutinosa and exercise on histone modification in ovariectomized rat hindlimb skeletal muscle. Sixty rats were fed with high fat diet and randomly assigned into the following groups for 8 weeks: 1)HSV; High fat+Sedentary+Vehicle, 2)HSP; High fat+Sedentary+PR, 3)HSH; High fat+Sedentary+Estradiol, 4)HEV; High fat+Ex+Vehicle, 5)HEP; High fat+Ex+PR, 6)HEH; High fat+Ex+Estradiol. Exercise consisted of low intensity treadmill exercise(1-4th wk:15 m/min for 30 min, 5-8th wk: 18 m/min for 40 min, 5 times/week). The result of this study showed that exercise and Pueraria and Rehmannia glutinosa intake suppressed weight gain. Furthermore, exercise and Pueraria and Rehmannia glutinosa intake increased muscle mass. This study observed H3K9 acetylation and demethylation in plantaris muscle in exercised group, but no difference in soleus muscle. To test whether the decrease in HDAC4, HDAC5 and G9a mRNA levels after exercise and Pueraria/Rehmannia glutinosa intake, HDAC4, HDAC5 and G9a mRNA levels were determined by real-time PCR. Only exercise induced HDAC5 and G9a mRNA reduction in plantaris muscle, but not in soleus muscle. In conclusion, these data demonstrates that exercise and Pueraria/Rehmannia glutinosa intake effect on body compositions. These changes are regulated by epigenetic modifications, such as histone acetylation and methylation. Future studies should focus on gene-specific epigenetics and other epigenetic mechanism for Pueraria/Rehmannia glutinosa intake.

• Journal of Life Science
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• v.33 no.3
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• pp.242-251
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• 2023

The purpose of this study was to investigate the effects of 8-week β-hydroxybutyrate (β-HB) administration with and without endurance exercise training on endurance exercise performance and skeletal muscle protein synthesis and degradation using a mouse model. Forty-eight male wild-type ICR mice (8 weeks old) were randomly divided into four groups: sedentary control (Sed+Con), (Sed+Con), sedentary β-HB (Sed+β-HB), exercise control (Exe+Con), and exercise β-HB (Exe+β-HB). β-HB was dissolved in PBS (150 mg/ml) and injected subcutaneously daily (250 mg/kg) for 8 weeks. Mice performed 5 days/week of a 20 min treadmill running exercise for 8 weeks. The running exercise was carried out at a speed of 10 m/min at a 10° incline for 5 min, and then the speed was increased by 1 m/min for every 1 min of the remaining 15 min. Following 8 weeks of treatments, visceral fat mass and skeletal muscle mass, blood parameters, and the markers for autophagy and protein synthesis were analyzed. The data were analyzed with one-way ANOVA (p<0.05) using the SPSS 21 program. Eight weeks of Exe+β-HB treatment significantly lowered blood lactate levels compared with the other three groups (Sed+Con, Sed+β-HB, and Exe+β-HB) Exe+β-HB) (p<0.05). Eight weeks of Exe+β-HB significantly increased maximal running time (time to exhaustion) compared with the Sed+Con and Exe+Con groups (p<0.05). Eight weeks of β-HB administration significantly decreased autophagy flux and autophagy-related proteins in the skeletal muscle of mice (p<0.05). Conversely, the combined treatment of β-HB and endurance exercise training increased protein synthesis (mTOR signaling and translation) (p<0.05). The 8-week β-HB treatment and endurance exercise training had synergistic effects on the increase in endurance performance, increase in protein synthesis, and decrease in protein degradation in the skeletal muscle of mice.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.900-912
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• 1995

Background: Although graded exercise stress tests are widely used for the evaluation of cardiorespiratory performance, normal standards on respiratory gas exchange and ventilatory functions at maximal exercise in Koreans have not been well established. The purpose of this study is to provide reference values on these by sex and age, along with derivation of some of their prediction equations. Method: Symptom-limited maximal exercise test was carried out by Bruce protocol in 1,000 healthy adults consisting of 603 males and 397 females, aged 20~66 years. Among them VC, $FEV_1$ and MVV were also determined in 885 cases. All the subjects were members of a health center, excluding athletes. During the exercise, subjects were allowed to hold on to front hand rail of the treadmill for safety purpose. Results: The $VO_2\;max/m^2$, $VCO_2\;max/m^2$ and $V_E\;max/m^2$ were greater in males than in females and decreased with age. The RR max in men and women was similar but decreased slightly with age. The $V_T$ max was markedly greater in men but showed no significant changes with age in either gender. The mean of $V_T$ max/VC, $V_E$ max/MVV and BR revealed that there were considerable ventilatory reserves at maximal exercise even in older females. The regression equations of the cardinal parameters obtained using exercise time(ET, min), age(A, yr), height(Ht, cm), weight(W, kg), sex(S, 0=male; 1=female), VC(L), $FEV_1$(L) and $V_E$ max(L) as variables are as follows: $VO_2\;max/m^2$(L/min)=1.449+0.073 ET-0.007A+0.010W-0.006Ht-0.209S, $VCO_2\;max/m^2$(L/min)=1.672+0.063ET-0.008A+0.010W-0.005Ht-0.319S, VE max/$m^2$(L/min)=58.161+1.503ET-0.315A-9.871S or VE max/$m^2$(L/min)=47.873+6.548 $FEV_1$-5.715 S, and VT max(L)=1.497+0.223VC-0.493S. Conclusion: Respiratory gas exchange and ventilatory variables at maximal exercise were studied in 1,000 non-athletes by Bruce protocol. During exercise, the subjects were allowed to hold on to hand rail of the treadmill for safety purpose. We feel that our results would provide ideal target values for patients and healthy individuals to be achieved, since our study subjects were members of a health center whose physical fitness levels were presumably higher than ordinary population.

• Journal of Life Science
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• v.28 no.10
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• pp.1186-1192
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• 2018

The purpose of this study was to compare the effects of either aerobic exercise or polyphenols supplementation on mRNA expression of endoplasmic reticulum stress in skeletal muscle of high fat diet-induced obese mice. In the study, mice were divided into five groups: (1) NC (normal diet for 16 weeks as a control, n=10), (2) HC (high fat diet for 16 weeks as a control, n=10), (3) H-Re (high fat diet with resveratrol 25 mg/kg supplementation for 16 weeks, n=10), (4) H-Ch (high fat diet with chrysin 50 mg/kg supplementation for 16 weeks, n=10), and (5) HE (high fat diet with aerobic exercise for 16 weeks, n=10). Aerobic exercise was performed on a treadmill for 40~60 min/day at 10~14 m/min, 0% grade, four days/week for 16 weeks. Endoplasmic reticulum stress related genes were measured by real-time polymerase chain reaction. ATF6, PERK, $IRE1{\alpha}$, and BIP/GRP78 mRNA were significantly decreased in HE compared with those in HC (p<0.05). Also, ATF6, $IRE1{\alpha}$, and BIP/GRP78 mRNA were significantly decreased in H-Re compared with those in HC (p<0.05). ATF6 mRNA was significantly decreased in H-Ch compared with that in HC (p<0.05). These findings suggest that aerobic exercise, resveratrol, and chrysin supplementation changed ER stress markers. However, aerobic exercise was most effective on ameliorating the high fat diet induced ER stress markers. Thus, it seems that aerobic exercise might have a more positive effect on skeletal muscle endoplasmic reticulum stress compared with polyphenol supplementation in high fat diet-induced obese mice.