Effect of repeated sprint training under hypoxia on normoxic repeated sprint performance

Abstract

Aim: This study aimed to investigate the effect of repetitive sprint training under hypoxia on subsequent normoxic repetitive sprint ability. Methods: Well-trained male rugby players underwent 3 weeks of repetitive sprint training (six sessions of four sets of 5 x 5-s sprints with 25 s of active recovery) in either normobaric hypoxia (Hypoxic; n = 9; F102 = 14.5%) or normobaric normoxia (Normoxic; n = 10; F102 = 20.9%). Pre and post-training performance was evaluated with repetitive sprint (8 x 20 m timed to go every 20 s), and Yo-Yo Intermittent Recovery Level 1 (YYIRl) tests. After each training set, heart rate, oxygen saturation and rating of perceived exertion were recorded. Results: Compared to baseline, both the hypoxic and normoxic groups improved fatigue over the 8 sprints one week after the intervention (Week 1, -1.8 ± 1.6%, -1.5 ± 1.4%, mean± 90% CI in Hypoxic and Normoxic groups respectively). However, from Week 2 onwards, only the hypoxic group maintained the performance improvement compared to baseline (Week 2 -2.1 ± 1.8%, Week 3 -2.3 ± 1.7%, Week 4 -1.9 ± 1.8%, and Week 5 -1.2 ± 1.7%). YYIRl performances improved throughout the recovery period in both groups with unclear differences found between groups. Relative to the normoxic group, the hypoxic group's Sp0₂ was substantially lower, and heart rate substantially higher during training bouts. Conclusions: Repeated sprint training in hypoxia for 6 sessions increases repeated-sprint ability but not YYIRI performance in well-trained rugby players.