Lauren Horsbrough

This project aimed to investigate the effect of a 6-week repeated sprint in hypoxia (RSH) intervention in normobaric hypoxia (NH) on middle-distance performance and performance parameters in middle-distance athletes, and to establish the potential underpinning adaptation to performance enhancement through the use of near-infrared spectroscopy (NIRS). The novelty of this thesis was its aim of producing a protocol which was specific to middle-distance runners, produced with the help of Leeds Beckett Coaches, to replicate a typical track interval session to allow real-world application. 5 trained middle-distance athletes completed a 6-week (12 session) repeated sprint training intervention in hypoxia (3000m in week 1-3; 3750m in week 4-6) or normoxia (sea-level; 0m) (RSN), both completed in a NH chamber to blind the participants. Weekly sessions were comprised of a low-intensity session (6 sets; 6 reps at 90% of 800m pace) and a high intensity session (5 sets: 4 reps at 120% of 800m pace), with intervals of 15-seconds interspersed by 30-seconds passive recovery. Performance outcomes were measured using an 800m time-trial, submaximal and time to exhaustion test (TTE). With underpinning adaptations measured using carbon monoxide (CO) rebreathing to determine haemoglobin mass (Hbmass) and changes in muscle oxygenation measured using NIRS. No overall improvement was found in 800m time-trial performance following RSN (pre: 148.6 ± 16.84 vs. post: 148.6 ± 13.40 seconds), however, participant 6 of the hypoxia group (HYP) showed the greatest overall improvement of 6 seconds. Whereas, following RSN there was an overall reduction in 800m time-trial performance (+1.3 seconds). Aerobic capacity (V̇O2max) and V̇O2 onset kinetics were reduced following RSH and RSN, while mean reaction time (MRT) was improved in HYP (—21.24 seconds; d=2.6, p=0.08). Muscle oxygen saturation (SmO2) was improved following RSH in participant 6 (-2.01 ± 5.25 vs. 6.99 ± 1.35 %). Total haemoglobin (tHb) was increased (19.07 ± 2.67 μM) following the intervention in participant 2 (NOR), and participant 3 increased slightly (1.94 ± 9.88 μM), however, there was no overall trend found for the hypoxic group. Although the findings of this study were inconsistent and showed no overall change, individual improvements suggest that with a greater sample size and greater control on external training to reduce confounding factors, RSH could be a beneficial intervention for improving middle-distance performance through improvements in peripheral adaptations to muscle oxygenation.