PURPOSE: Few recent studies indicate that short-term repeated sprint training in hypoxia (RSH) improves repeated sprint (RS) performance compared with identical training under normoxic conditions (RSN) in endurance-trained subjects. Herein, we sought to determine the effects of RSH against RSN on RS performance under normoxic and moderate hypoxic conditions, using a randomized, double-blind and cross-over experimental design.
METHODS: Fifteen endurance-trained male subjects (age=25±4 years) performed 4 weeks of RS training (3 sessions/week) in normobaric hypoxia (RSH, FiO2=13.8 %) and normoxia (RSN, FiO2=20.9 %) in a cross-over manner. Prior to and after completion of training, RS tests were performed on a cycle ergometer (i) with no prior exercise (RSNE), (ii) after an incremental exercise test (RSIE) and (iii) after a time trial test (RSTT), in normoxia and hypoxia.
RESULTS: Peak power output at the incremental exercise test and time trial performance were unaltered by RSH in normoxia and hypoxia. RS performance was generally enhanced by RSH as well as RSN, but there were no additional effects of RSH over RSN on peak and mean sprint power output and the number of repeated sprints performed in the RSNE, RSIE and RSTT trials under normoxic and hypoxic conditions.
CONCLUSIONS: The present double-blind cross-over study indicates that RSH does not improve RS performance compared with RSN in normoxic and hypoxic conditions in endurance-trained subjects. Therefore, caution should be exercised when proposing RSH as an advantageous method to improve exercise performance.