• 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 Life Science
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• v.20 no.9
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• pp.1394-1401
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• 2010

The purpose of this study was to examine the effect of 12 wk of aerobic exercise on lipid profiles, antioxidant enzyme activities, oxidative products, and autonomic nervous activity (ANA) in children with obesity. We studied 16 children with obesity and 19 age-matched normal weight controls over a period of 12 wk, during which time moderate intense running exercise was performed. Measurements included peak oxygen uptake, body composition, blood lipid profiles, ox-LDL, 8-OHdG, SOD, GPx activities, total mRNA, and ANA. There were no differences in body weight between periods in the OW group, but body weight increased after 12 wk in OR and CO groups. There were no differences in WHR between periods in the OR and CO groups, but the WHR values decreased after 12 weeks in the OW group. In the obese group, the baseline TG was higher than in the controls (p<0.05), while the ANA level was lower. There were differences in antioxidant enzyme gene expressions between periods in all groups. In conclusion, oxidative damage and antioxidant enzyme activities in obese children were found to be similar to those of normal weight children. However, TG was higher and ANA was lower in obese children than in normal weight children. These results indicated that increased TG and decreased ANA levels begins in childhood in obese patients. Also, regular aerobic exercise may modify the antioxidant enzyme gene expression in early life.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.17-27
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• 2020

The purpose of this study is to confirm the effects of a 6-week high-intensity combined training program on canoe athletes' cardiorespiratory function, isokinetic trunk strength, and anaerobic power. For the purpose of this study, the high-intensity combined training program was applied to 9 high-school canoe athletes. The high-intensity combined training program consists of aerobic exercise performed 2 times a week (Tuesday and Thursday), anaerobic exercise performed 3 times a week (Monday, Wednesday, and Friday), and flexibility exercise performed 5 times a week. The core of the high-intensity combined training program was the anaerobic training program performed with 100% weight for repetition; otherwise, the existing training method was divided into the percentage (%) of the 1RM. The aerobic exercise and the gym ball exercise are performed subsidiarily. Results showed that there was a statistically significant difference in height and muscle mass, whereas there was no statistically significant difference in weight, body fat percentage, and BMI followed by the high-intensity combined training program. There were statistically significant differences in maximum oxygen uptake and total exercise time. The angular velocity of 30°/sec showed a statistically significant difference in the peak torque item of flexors only. Also, the angular velocity of 120°/sec showed a statistically significant difference in the total work item of extensors only; however, there was no statistically significant difference in all the items of peak power, average power, and peak drop. In conclusion, it seems that the high-intensity combined training program may be applied as a training program for enhancing canoe athletes' performance. For further studies, more than 6 weeks training program with more participants would show improved results of isokinetic strength and anaerobic power in athlets.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.795-802
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• 1999

Objective : Cardiopulmonary exercise test is a useful tool to evaluate the operative risk and to plan exercise treatment for the patients with chronic obstructive pulmonary disease(COPD). In cardiopulmonary exercise test, most of the measured parameters are recorded at the time of peak exercise, which are hard to attain in COPD patients. So we evaluated the usefulness of the parameter, breathing reserve index(BRI=minute ventilation [$V_E$]/maximal voluntary ventilation[MVV]) at the time of anaerobic threshold($BRI_{AT}$) for the differentiation of COPD patients with normal controls. Methods : Thirty-six COPD patients and forty-two healthy subjects underwent progressive, incremental exercise test with bicycle ergometer upto possible maximal exercise. All the parameters was measured by breath by breath method. Results : The maximal oxygen uptake in COPD patients (mean$\pm$SE) was $1061.2{\pm}65.6ml/min$ which was significantly lower than $2137.6{\pm}91.4ml/min$ of normal subjects(p<0.01). Percent predicted maximal oxygen uptake was 54.3% in COPD patients and 86.0% in normal subjects(p<0.01). Maximal exercise(respiratory quotient; $VCO_2/VO_2{\geq}1.09$) was accomplished in 7 of 36 COPD patients(19.4%) and in 18 of 42 normal subjects(42.9%). The $BRI_{AT}$ of COPD patients was higher($0.50{\pm}0.03$) than that of control subject($028{\pm}0.02$, p<0.01), reflecting early hyperventilation in COPD patient during exercise. The correlation between $BRI_{AT}$ and BRI at maximal exercise in COPD patients was good(r=0.9687, p<0.01). Conclusion : The $BRI_{AT}$ could be a useful parameter for the differentiation of COPD patients with normal controls in the submaximal cardiopulmonary exercise test.