inter-individual variability, simulated altitude, non-responder, oxygen saturation, repeated sprint training in hypoxia, Sports, GV557-1198.995

This study examined whether inter-individual variability exists in repeated sprint training in hypoxia (RSH) and how peripheral oxygen saturation (SpO2) affects physiological demands and mechanical output, and subsequent training outcomes. Sixteen highly-trained sprint runners completed six sessions of RSH consisting of two sets of 5 × 10-s all-out sprints (fraction of inspired oxygen: 0.15), with pre- and post-tests involving 10 × 10-s all-out sprints in normoxia. Average SpO2, training impulse (TRIMP), and relative total work (relative TW; standardized by pre-test TW) during training sessions were calculated. After the intervention, MPO increased by +3.8% (P = 0.001) and sprint decrement score by +6.0% (P = 0.047). However, inter-individual variability in performance improvement observed and nearly 20% of participants did not obtain performance benefit. Average SpO2 during training sessions correlated significantly with relative TW (r = 0.435, P = 0.008), indicating that participants with higher SpO2 performed more work during training. Relative TW was strongly correlated with performance improvement (r = 0.833, P