Physiological Factors Associated With Declining Repeated Sprint Performance in Hypoxia

This study aimed to investigate the influence of these factors on running performance during hypoxic and normoxic shuttle-run sprinting. Eight male amateur soccer players performed shuttle-run sprints in hypoxia (FiO2 ∼14.8%) and normoxia (random order). Each session comprized 3 sets of 5 × 10 seconds back and forth sprints (4.5 m), with recovery times between repetitions and sets of 20 seconds and 5 minutes, respectively. Sprinting distance, acceleration patterns, heart rate (HR) and breathing frequency were measured during each session (Zephyr-PSM Training System). Redox state and lactate concentration ([La]) were determined before and after each session, whereas rating of perceived exertion (RPE) was assessed after the sprint sessions. Overall distance covered was similar during hypoxia and normoxia sprinting (Δ −8.3 ± 14.3 m, 95% CI −20.2 to 3.6, p> 0.05). During the third set, distance tended to be reduced in hypoxia compared with normoxia (169 ± 6 m, 95% CI 164–174 vs. 175 ± 4 m, 95% CI 171–178, p = 0.070). Differences in breathing frequency during sprinting in hypoxia and normoxia were associated with individual reductions in sprinting distance (r = −0.792, p = 0.019). Despite a somewhat lower running distance during the third set and similar [La], RPE, HR, and redox responses, the preserved overall running distance indicates that the training stimulus might be enhanced in hypoxia compared with normoxia. Alteration of the respiratory patterns during re...
Source: Journal of Strength and Conditioning Research - Category: Sports Medicine Tags: Original Research Source Type: research