Objective: To explore accuracy and validity of a VO₂max prediction equation of the multistage model using by modified Bruce protocol submaximal exercise test in healthy subjects. Method: Thirty three healthy subjects (age: 44.0±12.9) were recruited. VO₂max was measured during treadmill by direct gas analysis from a maximal incremental test. VO₂max was then predicted from multistage model equation with age, measured oxygen consumption and heart rate during a maximal incremental treadmill test. And the predicted VO₂max values from equation were compared with the measured VO₂max values. Results: The predicted VO₂max values and the measured VO₂max values were highly correlated (r=0.9, p＜0.001). The predicted VO₂max values (2,285.3±536.0 ml/min) were not significantly different from the measured VO₂max values (2,285.5±598.5 ml/min). Conclusion: In healthy subjects, the multistage model equation offers a fairly accurate VO₂max prediction. Therefore the equation can be used in the estimation of VO₂max at modified Bruce protocol in an aerobic exercise program. (J Korean Acad Rehab Med 2008; 32: 549-552)

Objective
To investigate the usefulness of the oxygen uptake efficiency slope (OUES) in the evaluation of cardiorespiratory fitness of the stroke patients. Method: 25 stroke patients who could walk independently were included in this syudy. The symptom-limited graded treadmill test was performed to assess cardiovascular fitness. During the test, minute ventilation (VE), oxygen consumption (VO₂), carbon dioxide production (VCO₂), respiratory exchange ratio (RER) and anaerobic threshold (AT) were measured through respiratory gas analysis. A linear relationship was established between the oxygen consumption and the logarithmic transformation of minute ventilation. From this linear relationship, we obtained a slope that represented the OUES. OUES values were obtained from data corresponding to 75% (OUES₇₅), 90% (OUES₉₀) and 100% (OUES₁₀₀) of the exercise duration. Results: The differences among OUES₇₅, OUES₉₀ and OUES₁₀₀ groups were not statistically significant and these three groups were highly correlated to each other. Maximal oxygen consumption (VO_2max) was positively correlated with OUES₇₅ (r=0.723), OUES₉₀ (r=0.762), OUES₁₀₀ (r=0.809) and AT (r=0.696), respectively (p＜0.01). Conclusion: OUES is considered to be the valuable submaximal index to evaluate the cardiorespiratory fitness of stroke patients who can not reach maximal exercise. (J Korean Acad Rehab Med 2007; 31: 423-426)