• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.58.1-58.1
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• 2007

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• Exercise Science
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• v.21 no.3
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• pp.373-384
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• 2012

The effects of inspiratory muscle training in conjunction with aerobic exercise on inspiratory muscle strength, pulmonary function, and maximal oxygen uptake(VO₂max) were examined. Twenty four healthy collegiate men were divided into three groups; respiratory muscle training group(RTG; n=8), running exercise group(REG; n=8), and both respiratory muscle training and running group(BTG; n=8). Their pulmonary function, maximal inspiratory pressures(PImax), and VO₂max were assessed before and after intervention. RTG underwent inspiratory muscle training(IMT) with load set to 50 % of PImax, 30 times per session, twice a day, 4 days a week REG ran on a treadmill at 70-75 % of VO₂max for 30 min a day, 4 days a week. BTG participated both IMT and the running exercise. Participant's anthropometric parameters and pulmonary function were not changed. VO₂max increased by 6.1±3.3 %, 5.9±6.6 %, and 10.0±8.3 % in RTG, REG, and BTG, respectively(p< .05), and PImax also increased by 21.7±14.3 %, 19.7±12.0 %, and 27.0±12.1 % in RTG, REG, and BTG, respectively, but no group differences were found. Based on the study, although statistically insignificant, BTG showed the biggest increase of VO₂max and PImax indicating a possible synergic effect of inspiratory muscle training and aerobic exercise on respiratory responses.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.249-260
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• 1990

Maximal cardiac output and oxygen uptake $(VO_{2max})$ were measured during treadmill exercise for seven top-class marathoners and nine non-athletes using impedance cardiograph developed by one of the authors (DW Kim). Results of this study are summarized as belows. 1) New shoes with sponge and silicon rubber attached to the soles were developed to reduce motion artifact during treadmill exercise. Ensemble everaging techneque with the developed shoes was also used to improve the measurement of stroke volume using impedance cardiography. 2) Maximal cardiac output of the athletes, 14.98 L/min, was significantly higher than that of the non-athletes, 13.46 L/min. As maximal heart rate of the marathoners is lower than that of non-athletes, stroke volume of the former is significantly larger than that of the latter. 3) $VO_{2max}$ of the marathoners, 59.38 ml/kg/min, was higher than that of the non-athletes, 40.22 ml/kg/min. At the anaerobic threshold. $VO_{2max}$ of the former was 62.3% of $VO_{2max}$ and this was significantly higher than that of the non-athletes, 57.2%, This results indicates that the marathoners have higher aerobic capacity than the non-athletes. 4) The marathoners showed larger $VO_2$ than the non-athletes at the same cardiac output, indicating that a-v $O_2$ of the former is higher than that of the latter. 5) Maximal systolic pressure of the marathoners was higher than that of the non-athletes, and so was maximal rate-pressure products. These results indicate that heart oxygen consumption rate $(hVO_2)$ of the marathoner is higher than that of the non-athletes is mainly due to higher stroke volume. And higher oxygen consumption of the marathoners is due to higher stroke volume. And higher oxygen consumption of the marathoners is due to their larger a-v $O_2$. The marathoners show both higher threshold and $VO_{2max}$. Especially, measurement of cardiac output during treadmill exercise by improved impedance cardiography is expected to contribute in study of cardiac function of athletes.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.904-913
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• 1995

The purpose of this study is to determine the effects of exercise programs on the treatment of chronic diseases. For this purpose, nine middle-aged women suffering from such chronic diseases as obesity, hypertension and coronary heart disease(CHD) were sampled to perform a 4-month-long exercise program which required the lactate threshold(LT) level corresponding to 70% of maximal oxygen uptake(VO2max). Thereupon, their physiques, physical fitness, blood components and physiological varibles were compared pre and post of exercise program. The results were summarized as follows ; 1) After the 4-month-long exercise program, %fat was significantly decreased, while such variables as grip strength, side step, trunk flexion and leg balance were significantly increased. 2) Blood components such as TG, TC, HDL-C, LDL-C, hemoglobin and hematocrit did not show and change in after exercise program. 3) Physiological varables such as HR, SBP, DBP, HR/LT, SBP/LT, DBP/LT, RPE/LT, VE/LT, VO2/LT and VO2 max showed significant increase after 4-month exercise program. These results suggest that regular aerobic exercise in a long period might help to decrease % fat and to increase aerobic capacity in middle-aged women suffering from chronic diseases.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.976-986
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• 1996

BACKGROUND : Dyspnea is common among patients with cardiopulmonary disease, and "daily disability" is defined as a functional impairment resulting from exercise intolerance. The maximal oxygen uptake(VO2max) during exhausting work is not only the best single physical indicator of the capacity of a man for sustaining hard muscular work, but also the most objective method by which one can determine the physical fitness of an individual as reflected by his cardiovascular system. However, the expense, time and personnel requirements make this procedure prohibitive for testing large group. The walking test is well-known type of exercise and it cost nothing to perform and have good reproducibility. Thus we performed the walking test and investigated correlations with spirometry, ABG and exercise test. METHOD: We observed the walking test and exercise test by cycle ergometer in 37 patients who visited our hospital because of dyspnea. Arterial blood gas analysis and spiromety, dyspnea index were performed, too. RESULT : (1) The VO2max was significantly lower in patients with COPD and cardiovascular disease than asthma and dyspnea on exertion group(p<0.05). The walking test distance was also lower in former. (2) The 12 minute walking test was significantly correlated with VO2max, PaCO2, FVC(%), FEV1(%) in all patients(p<0.05), and the walking test was only conelated with VO2max in patients with COPD(p<0.05). (3) In COPD patients, the VO2max was best correlated with FEV1(%) and FVC(%) and significantly correlated with walking test. But there was no correlation between walking test and FEV1(%) & FVC(%). (4) The 6 minute walking test was well correlated with 12 minute walking test(r=0.92. p<0.01). CONCLUSION : The walking test is the simple method for assessing exercise performance in patient with cardiopulmonary disease and a reliable indicator for VO2max. And the walking test is practical method for assessing on everyday disability rather than maximal exercise capacity. The 6 minute walking test is highly correlated with 12 minute walking test and a less exhausting for the patients and a time-saving for the investigator.

• Journal of Life Science
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• v.20 no.3
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• pp.437-443
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• 2010

This study was designed to examine the aerobic capacity and ventilatory response during an incremental exercise in elite high school cyclists. Twelve boys ($17{\pm}1\;yr$, $175{\pm}5\;cm$, $70{\pm}9\;kg$) participated in anthropometric measurements, incremental exercise testing, and pulmonary function tests. During incremental exercise testing using a cycle ergometer, their maximal oxygen uptake ($VO_2max$), maximal power output, ventilation, ventilatory equivalents for oxygen ($V_E/VO_2$) and carbon dioxide ($V_E/VCO_2$), respiratory rate, and tidal volume were measured. Time variables such as inspiratory time (Ti), expiratory time (Te), breathing time (Tb), and inspiratory duty cycle (Ti/Tb), as well as inspiratory flow rate ($V_T$/Ti) were assessed. Pulmonary function of vital capacity (FVC), forced expiratory volume in one second ($FEV_1$), $FEV_1$/FVC, and peak expiratory flow were evaluated. Their $VO_2max$, maximal heart rate, and Wmax were $57.5{\pm}3.9\;ml{\cdot}kg^{-1}{\cdot}min^{-1}$, $194.1{\pm}8.6\;beat{\cdot}min^{-1}$, and 452 W, respectively. $VO_2max$ was not related to any anthropometric parameters. Most ventilatory variables progressively increased with exercise intensity. As intensity increased, Ti, Tb, Tb decreased while Ti/Tb was maintained. Below an intensity of 250 W, height, weight, body mass index, and body surface were highly correlated with $V_T$/Ti and Ti/Tb (p<0.05). Collectively, $VO_2max$ appeared to be lower than adult cyclists, suggesting a different pattern of ventilatory control as age advances. Morphological characteristics were not related to $VO_2max$ in the population. Time variables of ventilatory response seemed to be related only at an exercise intensity level of less than 250 W. $V_T$/Ti may be related to exercise endurance capacity, but Ti/Tb was similar to adult cyclists.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.174-180
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• 1999

The objective of this study was to investigate the effects of carrying postures and weight of load carried one time on a worker when carrying heavy loads. Six male students participated in this study to perform a manual materials carrying task as subjects. To make comparison of work loads with physical work capacity, maximal oxygen uptake measurement tests were performed with submaximal test. The average oxygen consumption for the tasks of this study was 27.59~31.93% $VO_2$max. The results showed that the weight of load carried one time affects on working heart rate and oxygen consumption($VO_2$). It was found that the workload was significantly lower when handling a 20kg load at a frequency rate of 3times/min than when handling a 40kg load at a frequency rate of 1.5 times/min. There was no difference between carrying postures. It is concluded from the results of this study that the workload can be reduced by controlling conditions of a manual materials handling task.

• Tuberculosis and Respiratory Diseases
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• v.49 no.4
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• pp.495-501
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• 2000

Background : Cardiopulmonary exercise test is a useful test for the evaluation of the cardiovascular and respiratory systems. Obese subjects have an increased resting metabolic rate ($VO_2$) compared to non~obese subjects and the increase is more marked during dynamic exercise, which results in the limitation of maximal exercise in obese subjects. In this study, the influence of the obesity and fat distribution on the maximal exercise capacity were evaluated. Methods : Maximal exercise capacity was represented by maximam maximum oxygen uptake and $VO_2$ max in the cardiopulmonary test. Obesity, total fat content and abdomina1 obesity(waist to hip ratio, WHR) were measured by bioelectrical impedence method. Total of 42 volunteers (male 22, fema1e 20) were evaluated. Results : 1) Weight to height ratio (mean$\pm$SD) was 110$\pm$14.9% in men and 100$\pm$11.1% in women. 2) Fat ratio (mean$\pm$SD) was 23.3$\pm$5.2% in men and 27.55$\pm$3.9% in woman. 3) Waist to hip ratio (mean$\pm$SD) was 0.85$\pm$0.04 in men and 0.8$\pm$0.03 in woman. 4) In men, $VO_2$ max/min/Kg was negatively correlated with obesity, fat ratio, and abdominal fat distribution. 5) In woman, $VO_2$ max/Kg was negatively correlated with obesity and fat ratio, but did not show significant relationship with abdominal fat distribution. Conclusion : Obesity was a limiting factor for maximal exercise in both men and women. Abdominal obesity was a limiting factor for maximal exercise in men but its implication to women needs further evaluation.

• 한국체육학회지인문사회과학편
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• v.51 no.3
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• pp.373-382
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• 2012

The purpose of this study is to predict VO₂max with body index and submaximal metabolic responses. The subjects are consisted of 250 male aging from 18 to 34 and we separated them into two groups randomly; 179 for a sample, 71 for a cross-validation group. They went through maximal exercise testing with Bruce protocol, and we measured the metabolic responses in the end of the first(3 minute) and second stage(6 minute). To predict VO₂max, we applied multiple regression analysis to the sample with stepwise method. Model 1's variables are weight, 6 minute HR and 6 minute VO₂(R=0.64, SEE=4.74, CV=11.7%, p<.01), and the equation is VO₂max(ml/kg/min)= 72.256-0.340(Weight)-0.220(6minHR)+0.013(6minVO₂). Model 2's variables are weight, 6 minute HR, 6 minute VO₂, and 6 minute VCO₂(R=0.67, SEE=4.59, CV=11.3%, p<.01), and the equation is VO₂max(ml/kg/min)= 68.699-0.277(Weight) -0.206(6minHR)+0.020(6minVO₂)-0.009(6minVCO₂). And the result did not show multicolinearity for both models. Model 2 demonstrated more correlation compared to Model 1. However, when we conducted cross-validation of those models with 71 men, measured VO₂max and estimated VO₂ Max had statistical significance with correlation (R=0.53, 0.56, P<.01). Although both models are functional with validity considering their simplicity and utility, Model 2 has more accuracy.

• Exercise Science
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• v.23 no.1
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• pp.1-11
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• 2014

The purpose of this study was to develop and validate regression models to estimate maximal oxygen uptake (VO₂max) from the 20 m Progressive Shuttle Run Test (20 m PSRT) in Korean middle-school girls aged 13-15 years. The 20 m PSRT and VO₂max were assessed in a sample of 194 participants. The sample was randomly split into validation (n=127) and test-retest reliability (n=99, 32 out of 127 participants also performed validity test) groups. 127 participants performed a graded exercise test (GXT, stationary gas analyser) and the 20 m PSRT (portable gas analyser) once to develop a VO₂max prediction model and to analyze the validity of the modified 20 m PSRT protocol (starting at 7.5 km/h and increasing by 0.5 km/h every 1 min). 99 participants performed the 20 m PSRT twice for test-retest reliability purpose. Mean measured VO₂max (39.2±5.1 ml/kg/min) from the potable gas analyzer was significantly increased from that measured during the GXT from stationary gas analyzer (37.7±5.7 ml/kg/min, p=.001) using the modified 20 m PSRT protocol. But it was a narrow range (1.5 ml/kg/min). The measured VO₂max from the potable and stationary gas analyzers correlated at r=.88(p<.001). Test-retest of the 20 m PSRT yielded comparable results (Laps r=.88 & final speed r=.85). New regression equations were developed from present data to predict VO₂max for middle-school girls: y=.231×Laps-.311×weight(in kg)+46.201 (r=.74, SEE=4.29 ml/kg/min). It is concluded that (a) the modified 20 m PSRT protocol is a valid and reliable test and (b) this equation developed in this study provides valid estimates of VO₂max of Korean middle-school girl aged 13-15 years.