• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1255-1259
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• 2007

The purpose of this study was to elucidate incidence of $VO_2$ plateau by comparing data derived from different time averaging intervals during incremental cycling exercise to $VO_2max$. Seventeen subjects (age: $23.5{\pm}3.3$ years and $VO_2max$: $3.65{\pm}0.73$ L/min, respectively) completed $VO_2max$ tests on cycle ergometer which breath by breath gas ex-change data were obtained. These data were time-averaged into 11-breath, 15, 30 and 60 s sampling intervals. The incidence of plateau were 100, 35, 24 and 6% for the 11 breath, 15 s, 30 s and 60 s averaging, respectively. No correlation was between ${\Delta}$ $VO-2$ at $VO_2max$ and $VO_2max$ (r=0.008). 53% (maximal HR within 10 b/min) and 100% $(RER{\geq}1.15)$ of subjects met the criteria for attainment of $VO_2max$. This data indicate that shorter sampling intervals (11 breath) is the most suitable for de-tection of the $VO_2$ plateau and RER can be used for the criteria for attainment of $VO_2max$ but not maximal HR. Also, the incidence of a plateau is not related to training status or physical fitness of subjects.

• Physical Therapy Korea
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• v.12 no.3
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• pp.74-83
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• 2005

The purpose of this study was to produce the regression equation from non-exercise $VO_{2max}$ of healthy young adults and to develop a maximal oxygen consumption ($VO_{2max}$) regression model. This model was based on heart rate non-exercise predictor variables (rest heart rate, maximal heart rate/rest heart rate), as an extra addition to the general regression which can reflect an individual's inherent or acquired cardiorespiratory fitness. The subjects were 101 healthy young adults aged 19 to 35 years. Exercise testing was measured by using a Balke protocol for treadmill and indirect calorimetry. The prediction equation was analyzed by using stepwise multiple regression procedures. The mean of $VO_{2max}$ was $39.02{\pm}6.72\;m{\ell}/kg/min$ (mean${\pm}$SD). The greatest variable correlated to $VO_{2max}$ was %fat. The predictor variable used in the non-exercise $VO_{2max}$ included %fat, gender, habitual physical activity and $HR_{max}/HR_{rest}$. The non-exercise $VO_{2max}$ estimation was as follows: $VO_{2max}$($m{\ell}/kg/min$)=55.58-.41(%fat)+.59(physical activity rating)-2.69($HR_{max}/HR_{rest}$)-5.36 (male=0, female=1); (R=.85, SEE=3.64, R2=.72: including heart rate variable); $VO_{2max}$($m{\ell}/kg/min$)=48.47-.41(%fat)+.45(physical activity rating)-5.12 (male=0, female=1); (R=.84, SEE=3.74, R2=.70: with the exception of heart rate variable). As an added heart rate variable, there was only a 2% coefficient of determination improved. Therefore, these results demonstrated that heart rate variable correlation with a non-exercise regression model was very low. In conclusion, for healthy young korean adults, those variables that can affect non-exercise $VO_{2max}$ estimation turned out to be only % fat, gender, and physical activity. We suggest that further research of predictor variables for non-exercise $VO_{2max}$ is necessary for different patient groups who cannot perform maximal exercise or submaximal exercise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2232-2239
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• 2012

This study set out to investigate the effects of the same amount of resting(30 minutes) after $VO_2max$ 20%, 40%, and 60% exercise on the variation of cortisol and catecholamine, serum stress hormones. The research efforts led to the following conclusions: First, there were no significant differences in serum cortisol concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.002 in the $VO_2max$ 60% group. Second, there were no significant differences in serum catecholamine concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.001 in the $VO_2max$ 60% group. Third, no significant differences were found in the changing rates of serum cortisol concentration between right after exercise and during break among different levels of exercise intensity according to measuring time. Fourth, there were significant differences in the changing rates of serum catecholamine concentration in the significance level of p=.000 right after exercise and in the significance level of p=.034 during break In short, there were significant differences only in the $VO_2max$ 60% group according to exercise intensity when the different groups took the same amount of break after exercise. The $VO_2max$ 60% group was also the only group that showed significant differences in the changing rates of cortisol and catecholamine. In conclusion, taking a break after exercise can generate huge effects only when the exercise intensity level is moderate or higher. That is, taking a break will have no significant effects when the exercise intensity level is lower than moderate.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.204-214
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• 1999

Background: Resting pulmonary function tests(PFTs) are routinely used in the evaluation of pulmonary impairment/disability. But the significance of the cardiopulmonary exercise test(CPX) in the evaluation of pulmonary impairment is controvertible. Many experts believe that dyspnea, though a necessary part of the assessment, is not a reliable predictor of impairment. Nevertheless, oxygen requirements of an organism at rest are different from at activity or exercising, and a clear relationship between resting PFTs and exercise tolerance has not been established in patients with chronic pulmonary disease. As well, the relationship between resting PFTs and dyspnea is complex. To investigate the relationship of dyspnea, resting PFTs, and CPX, we evaluated the patients of stabilized chronic pulmonary disease with clinical dyspnea rating(baseline dyspnea index, BDI), resting PFTs, and CPX. Method: The 50 patients were divided into two groups: non-severe and severe group on basis of results of resting PFTs(by criteria of ATS), CPX(by criteria of ATS or Ortega), and dyspnea rating(by focal score of BDI). Groups were compared with respect to pulmonary function, indices of CPX, and dyspnea rating. Results: 1. According to the criteria of pulmonary impairment with resting PFTs, $VO_2$max, and focal score of BDI were significantly low in the severe group(p<0.01). According to the criteria of $VO_2$max(ml/kg/min) and $VO_2$max(%), the parameters of resting PFTs, except $FEV_1$ were not significantly different between non-severe and severe(p>0.05). According to focal score($FEV_1$(%), FVC(%), MW(%), $FEV_1/FVC$, and $VO_2$max were significantly lower in the severe group(p<0.01). However, in the more severe dyspneic group(focal score<5), only $VO_2$max(ml/kg/min) and $VO_2$max(%) were low(p<0.01). $FEV_1$(%) was correlated with $VO_2$max(%)(r=0.52;p<0.01), but not predictive of exercise performance. The focal score had the correlation with max WR(%) (r=0.55;p<0.01). Sensitivity and specificity analysis were utilized to compare the different criteria used to evaluate the severity of pulmonary impairment, revealed that the classification would be different according to the criteria used. And focal score for dyspnea showed similar sensitivity and specificity. Conclusion : According to these result, resting PFTs were not superior to rating of dyspnea in prediction of exercise performance in patients with chronic pulmonary diseases and less correlative with focal score for dyspnea than $VO_2$max and max WR. Therefore, if not contraindicated, CPX would be considered to evaluate the severity of pulmonary impairment in patients with chronic pulmonary diseases, including with severe resting PFTs. Current criteria used to evaluate the severity of impairment were insufficient in considering the degree of dyspnea, so new criteria, including the severity of dyspnea, may be necessary.

• Journal of Nutrition and Health
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• v.32 no.8
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• pp.870-876
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• 1999

The relationship between exercise intensity, oxidative stress and antioxidant status has been studied in sixteen trained male athletes aged 20-25years. Subjects performed 30-40minutes of treadmill running at 65% of VO2 max(high intensity exercise). Blood samples were taken before and immediately after two exercise bouts for measurement of blood antioxidants, indices of lipid peroxidation and susceptibility of crythrocyte to peroxidation. Plasma concentrations of cholesterol(7.3%), vitamin C(7.5%) and uric acid(2.1%) were elevated a little after exercise at 65% of VO2 max(13.7%)were significantly high than before exercise(p<0.05). However, these exercise-induced changes could be partly due to significant decreases in plasma volume which occurred after both exercise bouts(p<0.05). Plasma volume decreased 5.85$\pm$2.06% and 11.25$\pm$2.87% with exercise at 65% and 85% of VO2 max, respectively. The erythrocyte susceptibility to peroxidation after exercise at 65% of VO2 max was unchanged compared with the value before exercise, whereas after exercise at 85% of VO2 max, it was significantly higher than after exercise at 65% and 85% of VO2 max as well as before exercise(p<0.05). A significant increase at 85% of VO2 max, it was significantly high than after exercise at 85% of VO2 max (29.10$\pm$4.76ug/g Hb)when compared with the level before exercise (24.61$\pm$3.45ug/g Hb)(p<0.05). The results suggest that exercise-induced changes in plasma levels of lipid peroxide and antioxidant need to be evaluated, taking the shift in plasma volume into consideration. Also, exercise at high intensity corresponding to 85% of VO2 max alters the erythrocyte antioxidant status in relation to exercise-induced of oxidative stress.

• 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.

• The Korean Journal of Food & Health Convergence
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• v.8 no.1
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• pp.21-30
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• 2022

This study proposed a multiple regression equation for predicting VO2max of elderly men and women using functional performance variables required to conduct daily activities. The subjects of this study were 58 elderly men (72.4±5.9 yrs) and 117 elderly women (73.4±4.5 yrs) aged 65-90 who belong to the senior welfare center. The maximal graded exercise test using a cycle ergometer and functional performance representing muscle strength, endurance, static and dynamic flexibility, mobility, and agility were measured. For statistical processing, multiple regression analysis was performed, and the statistical significance level was α = .05. As a result, the VO2max estimation formula for the elderly was 0.419 (standing up and sitting down a chair) + 0.199 (leg endurance against wall) + 5.383, and R2=0.406. In addition, the VO2max estimation formula for elderly women is - 0.737 (standing up from a supine position) - 0.144 (waking around two cones in a figure 8) - 0.135 (%body fat) + 0.042 (one leg balance with eyes open) + 29.395, R2=0.367 was calculated. The conclusion is that if the maximal graded exercise test is not available, it is considered that VO2max of the elderly can be predicted properly by using the estimation formula calculated based on the functional performance variable.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.107-113
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• 2014

PURPOSE: The purpose of this study was to investigate the correlation between craniovertebral angle (CVA) and cardiorespiratory function ($VO_2max$ and $VCO_2max$) in young adults. METHODS: For this study, the students of D college were questioned and 50 members of D college were participated in our research.. Side-view pictures of each subject were taken in standing positions, in order to assess forward head posture (FHP) by measuring the craniovertebral angle. The craniovertebral angle was measured as the angle between a horizontal line at C7 and a line from the tragus of the ear to the spinous process of C7. And $VO_2max$ and $VCO_2max$ were measured by Quark CPET (cosmed co, USA) while the subjects were performed the treadmill running task of a intensity to set with respiratory mask. Subjucts were Then Pearson's correlation coefficient was calculated to estimate the relationship between craniovertebral and cardiorespiratory function ($VO_2max$ and $VCO_2max$) using SPSS for window. RESULTS: There was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.528, p<0.05). And there was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.566, p<0.05). CONCLUSION: Foreward head posture is related to cardiorespiratory function, and it has a negative correlation with cardiorespiratory function.

• 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.

• 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.