We determined aerobic performance ( incremental test to exhaustion and time trial for a set amount of work ) in moderately trained subjects undergoing 6 wk of endurance training ( 3-4 times per week , 60 min per session ) in normoxia ( placebo , n = 8 ) or normobaric hypoxia ( FIO2 = 0.15 , n = 9 ) using a double-blind and randomized design .