IntroductionThe use of hypoxic training to improve sports performancethrough enhancing aerobic and anaerobic metabolic path-ways has received much attention in recent years dueto the good results obtained by athletes who born andlive in altitude [1]. However, performance is significantly compromised when high intensity sport is achieved in hypoxia [2]. Although several studies have described thepositive effects of altitude exposure (chronic and inter-mittent) on aerobic [3,4] and anaerobic capacity [5—11]following different hypoxia protocols, other have failedto found these effects [12,13]. By this reason a scientificconsensus on anaerobic training and performance follow-ing the use of hypoxia to improve sea level performanceremain unclear. This can be due at least in part becauseof the large number of studies, which have employeddifferent methodologies or measured different variables