Does altitude level of a prior time‐trial modify subsequent exercise performance in hypoxia and associated neuromuscular responses?

We examined the influence of prior time‐trials performed at different altitudes on subsequent exercise in moderate hypoxia and associated cardiometabolic and neuromuscular responses. In normobaric hypoxia (simulated altitude 2000 m; FiO(2): 0.163), 10 healthy males performed (1) an incremental test to exhaustion (VO (2max_2000)) and (2) a test to exhaustion at 80% of the power output associated to VO (2max_2000) for a reference time (947 ± 336 sec). Thereafter, two sessions were conducted in a randomized order: a cycle time‐trial corresponding to the reference time (TT (1)) followed 22 min later (passive rest at 2000 m) by a 6‐min cycle time‐trial (TT (2)). TT (1) was either performed at 2000 or 3500 m (FiO(2): 0.135), while TT (2) was always performed at 2000 m. As expected, during TT (1), the mean power output (247 ± 42 vs. 227 ± 37 W; P < 0.001) was higher at 2000 than 3500 m. During TT (2), the mean power output (256 ± 42 vs. 252 ± 36 W) did not differ between conditions. Before and after TT (1), maximal isometric voluntary contraction torque in knee extensors (pooled conditions: −7.9 ± 8.4%; P < 0.01), voluntary activation (−4.1 ± 3.1%; P < 0.05), and indices of muscle contractility (peak twitch torque: −39.1 ± 11.9%; doublet torques at 100 Hz: −15.4 ± 8.9%; 10/100 Hz ratio: −25.8 ± 7.7%; all P < 0.001) were equally reduced at 2000 m or 3500 m. Irrespective of the altitude of TT (1), neuromuscular function remained similarly depressed after TT (1) both before and after TT (2) at 2000 m. A prior time‐trial performed at different altitude influenced to the same extent performance and associated cardiometabolic and neuromuscular responses during a subsequent exercise in moderate hypoxia.