The aim of this study was to evaluate the effects of low-load resistance training with intermittent exposure to hypoxia. Eight male subjects were participated in the low-load (20% 1RM) repetition (25 repetitions per set×6 sets for right and left legs = one session) knee extension training with the training machine under hypoxia (14.0% of oxygen concentration) for 7 weeks (totally 22 sessions). Before and after the training intervention, cross-sectional area (CSA) and muscular strength were measured. The several physiological responses (oxygen consumption, pulse rate, arterial oxygen content and muscle oxygenation level using near-infrared spectroscopy) during the training exercise on the first and last training sessions were also measured. On these two sessions, growth hormone (GH), adrenaline, noradrenarine, testosterone and free-testosterone were measured before and after the training session. CSA and maximal knee extension torque did not change, therefore the training protocol utilized by this study was not sufficient to stimulate the muscle hypertrophy, but muscle endurance capacity was improved. The training with intermittent exposure to hypoxia did not accelerate the secretion of GH, testosterone and free-testosterone which have anabolic effect. The reduction of adrenaline and noradrenaline secretion implied the reduced dependence on glucose metabolism. The improved responses of lowered pulse rate and increased arterial oxygen content during the exercise indicated the adaptation to exercise under hypoxia. The tendency to increase of oxygen consumption on the last session compared to the first session was seemed to be influenced by improved oxygen supply and the shift from the glucose metabolism.

DESCENTE SPORTS SCIENCE Vol.30/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE