The purpose of this study is to predict the physical performance of the high altitude climbers. In the experiment, seven active sportsmen (TG: trained group) and seven sedentary men (UG: untrained group) participated in the experiment. A near-infrared spectroscopy was applied to measure the oxidative dynamic response in skeletal muscle during maximal ramp exercise at sea level (SL: 760 mmHg). In the experiment, six healthy subjects performed the maximal exercise tests to measure the oxidative dynamic response at simulated altitudes of SL, 2,000 m (596 mmHg) and 4,000 m (462 mmHg), respectively. The tissue oxygen saturation (StO₂) during the maximal exercise in the TG was significantly lower than that in the UG, indicating the larger capacity of O₂ extraction in the TG compared to the UG. Significantly higher value of (SaO₂-StO₂) during the exercise at SL was observed in the TG than that in UG. Therefore, it is suggested that O₂ supply to the muscle tissue in the TG is greater than that in the UG. Since a significant decrease in (SaO₂-StO₂) values during exercise at 4,000 m was seen, it is suggested that the O₂ supply to the muscle tissue is limited, especially at higher altitudes.
　These results suggested that the potential high altitude climber should have higher values in the arterial oxygen saturation, O₂ extraction capacity, and the (SaO₂-StO₂) during exercise under acute hypobaric hypoxia.

DESCENTE SPORTS SCIENCE Vol.20/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE