Time trial performance data. (a) Cycle time trial performance at sea level (SL) and hypoxia (HYP) in a group of men exposed to either hypobaric hypoxia (HH) or normobaric hypoxia (NH). Each man exposed to HH demonstrated a greater decrement in TT performance in hypoxia (HYP) than each man exposed to NH at an ambient PO2 equivalent to 4,300 m in each condition. (b) For each matched pair, their sea level (SL) TT performance fell closely on the line of identity, but their performance in HH fell below their matched pair in NH on the line of identity. *P < 0.05 from SL; †
P < 0.05 between groups.